Showing 1 of 958 conversations about:
AudioNoobster
16
Nov 2, 2016
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Right? Same here for first mass drop ever. I've only began to break into being an audiophile. Went from Fidelio X2s To Sennheiser HD650s. I can't even touch the X2s anymore the HD650s are amazing. Picked up an Schiit Jotenhiem SS and figure I'll get a good month out of it to then compare with the DV. Zeos won me over when he reviewed it in his YouTube channel. I know the DV doesn't do well with low impedance headphones but I picked up The Fostex T50RPs (50 ohm impedance) was wondering if anyone could enlighten me on why the DV isn't good with low impediencance headphones. I'm sure it can drive them (I think) but does it not sound good through low impedance headphones? Questions questions.
Nov 2, 2016
EniGmA1987
494
Nov 2, 2016
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Look at a discussion further down for where I said why this amp doesnt work well with low impedance headphones.
Nov 2, 2016
AudioNoobster
16
Nov 2, 2016
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Awesome, thank you very much for the fast response. I'm assuming there's plenty of DIY on changing out the capacitors if I so choose too. I pretty much read through the entire discussion board but somehow missed your drop of knowledge.
Nov 2, 2016
EniGmA1987
494
Nov 2, 2016
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Im sure there are somewhere, though they might be hard to find given the age of this amp model and modding for it. I might still have a couple pictures with some diagrams on my computer at home. Ill look for them later today. In the mean time, I am pretty sure those 6 orange blobs in this pic are the capacitors you want to replace:
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3 for the left channel and 3 for the right. If you get the amp be sure to look at the markings on those capacitors to verify, but I am 90% sure those were the 10uf capacitors you are looking for. I posted a possible capacitor replacement choice in that other discussion but here it is again: http://www.mouser.com/ProductDetail/Nichicon/UPW2A221MHD6/?qs=sGAEpiMZZMtZ1n0r9vR22a%252bYJIhWynPar%2fjiznRJd2s%3d
One of my other favorite sounding capacitors are the Elna Silmic II (RFS series) capacitors. If you want to give them a try here is a link to the one you would want for the output caps: http://www.mouser.com/ProductDetail/Elna/RFS-100V221MK95/?qs=sGAEpiMZZMtZ1n0r9vR22Vaq1AHMe%252bCM7k10Flj3raE%3d


Another popular mod to do since you will already be in there doing stuff is to do the "fitz mod" and add 80-100uF capacitor to the left and right cathode of the input tube (preamp). http://www.mouser.com/ProductDetail/Panasonic/EEU-FR1J101L/?qs=sGAEpiMZZMtZ1n0r9vR22WPtSjuqjALi7NSQyX3lavU%3d
The cathode capacitors addition will make the amp work with a much larger range of tubes as when the amp is used stock you will sometimes find tubes that "hum". Adding the capacitor quiets things down.

EDIT: here is a close up picture of someone who did the "fitz mod" and this picture shows where the two capacitors are added: http://www.head-fi.org/t/353079/dv-336se-hum-fitz-mod/15#post_5248489 http://www.head-fi.org/t/353079/dv-336se-hum-fitz-mod/15#post_5480248 The capacitors are in parallel with the resistors that are already on the cathodes.
Nov 2, 2016
AudioNoobster
16
Nov 2, 2016
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Wow thank you. What skill level are we talking here to make these modifications? It seems to me just draining the capacitors, removing, and soldering new ones in. I would of course do my research. You are opening ideas I never even had lol.
Nov 2, 2016
EniGmA1987
494
Nov 2, 2016
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Id say skill level is about a 3 out of 10. What you said is correct: simply drain the capacitors, remove old ones, solder in new ones. You need to know how to do some basic soldering which is easy to learn and you need to pay attention to the polarity of the capacitors. Electrolytic capacitors have a positive and negative side. If you hook them up wrong they will be destroyed. Easy to tell which side is which though. The positive side of the capacitor usually has a longer leg, and may have a "+" sign printed on the capacitor. The negative side usually has a colored stripe on the outside of the capacitor and may have "-" printed on the capacitor itself, and also usually has the shorter leg. For the "fitz mod" capacitors, the ones that attach to the input stage cathode, you can see in one of those pictures posted in the last reply that the negative side hooks onto that main bar going across the amp and the positive side of the capacitor hooks onto the tube socket itself.
As for the capacitor replacement at the very end, the coupling capacitor (the one replacing the three 10uF capacitors) I do not believe the polarity really matters. While the capacitor has a polarity, I am pretty sure (if I am remembering right) that the audio signal actually passes straight through the capacitor and it is not hooked to a positive and negative side of things. It is simply there to block DC from going out the headphone jack while letting the audio signal pass through. Like you said, do a bit of research to be sure, as it has been a couple years now since I messed with the output caps on my Darkvoice and Crack amps, but I am pretty sure I am remembering that right on how they hook in.
All this talk of modding is making me really want to dig out my Crack amp from the closet and do some more work on it though. lol I think you will really like playing around with this Darkvoice amp, but when you are ready to step up a bit further try and keep a lookout for when the Crack+Speedball go on sale here at Massdrop. You do have to build the amp completely yourself, but it is fun to do and the Crack has a lot more space inside to do mods with and a lot more forum threads and posts on what mods to do and how to do them. More advanced though, so just have fun starting on this Darkvoice first.
Nov 2, 2016
AudioNoobster
16
Nov 2, 2016
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Haha that's quite impressive you can remember all that even though you did it several years ago.
Im assuming the Crack Amp is another tube amp as well?
Im sure I can look this up but while I have you here just want to clarify the pros and cons of these modifications. Let me know if I have it right. With modding the capacitors it will allow for low impedance headphones to be used but will reduce the quality of sound slightly. Could you explain how the sound quality is reduced? Less bass, less treble? Muffled? Would this also depend on tubes used? The fizz mod will remove most hums from tubes that I use (some may always hum, I understand that as well as tubes requiring burn in time ) Have I missed anything? Again thank you for all the information, i love building and tweaking (built several PCs) and study engineering so this could get interesting.
Nov 2, 2016
EniGmA1987
494
Nov 2, 2016
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The coupling capacitors have the sound pass through them, so as you go bigger uF you are having more "area" for the sound to pass through. You can lose a bit of high frequency response, you can introduce a bit more distortion, lose a bit of the sound stage. Any number of things depending on the quality of the capacitors used and their size, along with your headphones you use. Typically you want to use the smallest capacitors possible and also use film capacitors, which is what the Darkvoice comes with already. The problem is the amp is designed for high impedance headphones, so when using low impedance ones you have to compensate for them by going from the small film capacitors to a larger sized one. How you pick the "smallest capacitor size possible" is related to the amp design and the headphone impedance. As you go smaller, your -3dB point on the low frequency gets higher and higher. This is not a problem using a 30uF capacitor when using headphones that are 600 ohms, but when you use headphones that are only 32 ohms then your -3dB point becomes 165Hz, which means you have basically no bass at all. So while you do introduce a bit more distortions and such by using a larger capacitor, the tradeoff of having proper bass response is well worth it. Of course the best solution is to simply use higher impedance headphones, but your options are quite limited there. So next best solution is to modify the amp to work better with your low impedance stuff.
The cathode capacitor mod will lower tube hum and make the amp more quiet, at the expense of increasing the volume gain. If you have very sensitive headphones this could be bad because you would barely turn the volume up and already be blasting loud. This is typically more of a problem with IEMs, or if you have headphones around 110db/mw The larger capacitor size you go the more gain (volume) you add, but the quieter (noise floor) the amp becomes. All just a tradeoff. Best to stick with a capacitor somewhere between 70 and 100 uF to get some reduction in hum, at least enough to satisfy most tubes out there, but keep the gain low enough that you can still use most headphones with the amp.

EDIT: and here is the crack amp I was talking about: https://www.massdrop.com/buy/bottlehead-crack-speedball-amp
Nov 2, 2016
AudioNoobster
16
Nov 2, 2016
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All of that makes complete sense. My headphone collection so far consists of Sennhieser HD650s and the Fostex T50RP. Honestly from what you are telling me I think I will keep my T50s on the SS and run my HD650s on both SS and DV if I so choose. The reduction of bass doesn't sound worth it to me but the fitz mod sounds something worth looking into. Or...would the reduction in base only be for the low impedance headphones or would it also carry into the high impedance. I would assume it would effect both. Lose bass in the 650s but bring an actual bass response to the T50s even though I don't think it would be worth it. To sacrifice quality for the HD650s just to make it work for the T50s. However, I could listen to it for 6 months unmodded and then mod it, if I don't like it I can always undo it 😁 Crack amp, love it. What have you done or changed from the original design?
Nov 2, 2016
EniGmA1987
494
Nov 2, 2016
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The reduction in bass only happens on low impedance headphones. 300ohms and higher is perfect for this amp at stock. So ya you could use it just for the HD650's if you wanted.


My crack amp is extremely modded. I have replaced the diodes in the power supply section with really high end silicon carbide schottky diodes, replaced the resistor in the power supply filter with an inductor, replaced the stock power supply capacitors with higher quality electrolytics and film bypass caps. On the signal input side I replaced the stock volume potentiometer with a stepped ladder attenuator, added two inductors from the attenuator to ground to filter out any remaining DC voltage on the incoming signal. Replaced the stock input tube with a PSVane 12AT7 tube. Used a 0 impedance metal foil resistor ("naked series" from Vishay http://www.mouser.com/ProductDetail/Vishay-Precision-Group-Foil-Resistors/Y0706100R000T9L/?qs=sGAEpiMZZMteBffR8xeNGcz%2fKSqq8CKBTPEuViFmBX4%3d) as a "stop" of sorts on the input of the power stage. Im not sure if a "stop" is the right word, it has been so long since I heard about the mod. It basically acts as a damper on the tube grid to help control the tube better by adding just a bit of resistance. I used a 0 impedance resistor because the audio signal actually passes through this resistor so any impedance will attenuate the audio signal especially in the high frequencies. I also replaced the power tube with some RCA brand one that came recommended. I replaced the output coupling caps with some nice ones that I cant remember off the top of my head and also used some Mundorf silver+oil as bypass caps. Oh and of course I have the speedball upgrade kit installed too. Sometime "soon" I plan to make a copy of the whole setup and use them together as a balanced tube amp. Since this will also double the output impedance (from 120 up to 240 ohms) and basically make it unusable for any headphones I have, I am going to make the balanced amp setup and then feed the output signal into a solid state 0 gain diamond buffer. The diamond buffer is known for its extremely neutral sound and with 0 gain I am hoping it will preserve the tube amp sound signature really well while also providing my headphone output with a new, low impedance (0.5 ohm) output which will be awesome and work with any headphones. In addition, the diamond buffer will supply the headphone output with more power than the Crack amp can provide on its own, even in balanced mode. The diamond buffer will have an output wattage of 4,500mw @ 32 ohms. I know, complicated as hell, but modding the stuff and building my own versions of the amp is fun to do. It is nice to have a hobby where you can actually solder things together and swap out electronics and hear a real, audible change in how something sounds.


Here are a few pics of the underside of the Crack amp. I guess I dont have any of the most recent pics, these ones still dont have the stepped attenuator mod done:
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^^^^ Showing off the small silverGold oil Mundorf bypass cap for the output capacitors
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^^^^ Showing the schottky diodes I soldered in
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^^^^ I guess just showing the other brand electrolytics and the film bypass caps for the power supply. These ones have better ripple rating and lower ESR which is handy for the power supply filtering
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^^^^ A choke for the power supply filtering. This replaces the stock 270ohm resistor in the filter network
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^^^^ Two other chokes used to filter DC out of the incoming audio signal. AC keeps going from the input through the potentiometer because the choke has SUPER high resistance to AC voltage. DC voltage on the other hand it has very low resistance to, so the DC goes to ground and AC keeps going mostly untouched.
Nov 2, 2016
EniGmA1987
494
Nov 3, 2016
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Looks like I dont have that picture with the diagrams on it for the Darkvoice anymore. It was pretty easy so I guess I thought I didnt need to save it.
Nov 3, 2016
AudioNoobster
16
Nov 3, 2016
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Okay so modding the DV for low impedance it would have no affect on high impedance or would the capacitors still have some effect on the sound due to more area of sound to pass through?
I appreciate all the information and would love to see what the Crack amp looked like originally vs how it looks now all decked out.
Nov 3, 2016
EniGmA1987
494
Nov 3, 2016
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Adding the larger capacitors will always decrease the overall sound quality a little bit for all headphones, it will just fix the bass response on low impedance headphone loads.

This is what a completely basic stock Crack amp looks like:
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Nov 3, 2016
AudioNoobster
16
Nov 3, 2016
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So in your opinion, do you think modding the DV with both capacitors and the "Fitz" mod makes it an all around better experience? Or is the loss of sound quality with the larger capacitors not worth it but the "Fitz" mod is?
My plan is to listen to the DV stock, stock tubes and stock internals, and see how my experience is with that, Then begin tube rolling (some good idea where to get tubes would be awesome) and then probably do the capacitor mods and the "Fitz" mod.
I appreciate all the information you've given me, and the modifications you did to the Crack amp are ridiculous, it's not even the same amp anymore haha.
Nov 3, 2016
EniGmA1987
494
Nov 3, 2016
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You will probably find when you start tube rolling that some of the tubes "hum", which is when you will want to go and do the fitz mod because it will eliminate that humming.
Nov 3, 2016
gatta
0
Nov 4, 2016
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Senns hd600 are far better than hd 650's and hd700 cans. IMO
Nov 4, 2016
AudioNoobster
16
Nov 4, 2016
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Well that is your opinion of course. I never had the chance to listen to the 600s or 700s so I can't judge you on that. I just knew that I'd prefer slightly more sound stage and a dash of warmth that the 650s have over the 600s (based on research not experience). Hopefully will be able to try out the 600s just don't see the point in buying them when I love the 650s.
Nov 4, 2016
AudioNoobster
16
Nov 4, 2016
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Awesome. Thank you again for all the information. My game plan is to run it stock for a bit. Get my impressions on it and then modify it accordingly. youve been a great help with explaining and laying out all the ideas. Good luck with all your endeavors. I'm just starting to build my FLAC library now. Actually have any suggestions on great acoustic songs?
Nov 4, 2016
EniGmA1987
494
Nov 7, 2016
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Im not really into acoustic music much so cant help you there. My favorite genres are metal and rock but I also enjoy various pop, electronic, and hip hop bands.
Nov 7, 2016
Enraged_Weredonkey
4
Nov 29, 2016
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I stumbled across your wonderful post while searching for other information. Just wanted to thank you for posting and describing your mods. I recently purchased a Crack + Speedball kit, but have yet to assemble it. I am a DIY electronics newbie, so your explanations were super helpful. I have a few questions: Which of your mods made the greatest improvements in sound quality? If you had to start over again, which mods would you skip next time? Finally, where can I buy the specific components you used? (I really need a "for dummies" version of this, haha!)
Nov 29, 2016
EniGmA1987
494
Nov 30, 2016
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The Mundorf bypass cap at the end was almost completely pointless. Little to no change in sound. Extremely expensive too. Waste of money. Though upgrading the main output capacitors has a very large change in sound in comparison to the other mods. This is probably the biggest mod you could do. Here is a great choice of film capacitors for the outputs caps: http://www.parts-express.com/solen-100uf-400v-poylpropylene-capacitor--027-616 http://www.parts-express.com/dayton-audio-dmpc-100-100uf-250v-polypropylene-capacitor--027-447 http://www.parts-express.com/audyn-cap-q4-100uf-400v-mkp-metalized-polypropylene-foil-crossover-capacitor--027-125
The power supply capacitors had an extremely small change in sound. I bet if I used some higher grade ones it would be better, but really large capacitance, extremely low ESR capacitors are huge in size and generally in cost and there isnt really enough room for the best stuff. Id say upgrade these to some middle of the road stuff to help boost the effects of the other power supply mods. I would use these capacitors for the first two caps in the power supply: http://www.mouser.com/ProductDetail/EPCOS-TDK/B43305A2337M000/?qs=sGAEpiMZZMvwFf0viD3Y3YZmIOvBM3jisJQq8VtGDKM%3d And one of each of these for the 3rd (last) capacitor in the power supply: http://www.mouser.com/ProductDetail/Nichicon/UPW2E221MRD/?qs=sGAEpiMZZMtZ1n0r9vR22Ruh6sUH2JY1HjlhtptHplU%3d http://www.mouser.com/ProductDetail/Kemet/C4GADUD5300AA3J/?qs=sGAEpiMZZMv1cc3ydrPrF0%2fKYujtVgoKp1X7ZZUYXRI%3d
The Shottky diodes made a decent bit of difference, helping the audio to feel more smooth is the best way I can describe it. Shottky diodes dont have switching noise, regular diodes do. So in normal power supplies for tube amps you would get high frequency bleedthrough of that switching noise into your audio. Using Shottky diodes eliminates that. These diodes should work: http://www.mouser.com/ProductDetail/ROHM-Semiconductor/SCS310APC9/?qs=sGAEpiMZZMtQ8nqTKtFS%2fORqoz9XqXUM0QVo5qT2csjJAzi%2ff6fsDg%3d%3d The choke upgrade in the power supply made a decent bit of difference. Chokes are way better than resistors for power filtering since resistors dont really have much inductance, they are mostly resistance. What we want though, is high inductance with the same resistance, and only a choke provides that. Inductance filters AC voltage out substantially, but they are very large and much more expensive, that is why they do not come standard. Choke: 3 1/2" long x 2" wide, cost of $12. Resistor: 1/2" long x 1/4" wide, cost of $0.2 lol Here is the power supply choke everyone (but me) uses: http://www.mouser.com/ProductDetail/Triad-Magnetics/C-7X/?qs=sGAEpiMZZMsg%252by3WlYCkU3Estp%252bO%2f4X7zM9tbX1lwKY%3d I use this one: http://www.mouser.com/ProductDetail/Hammond-Manufacturing/158M/?qs=sGAEpiMZZMsg%252by3WlYCkU%252bF2lzLeRQXM7%2f57g8ZsEx4%3d I chose that because it has much tighter specs and is far more likely to be around the 270 ohms it should be. The C-7X can be anywhere from -20% to +50% in resistance, the Hammond 158M is just + or - 15%
I liked the stepped attenuator upgrade. It made the sound a little bit nicer and I just like the feel of it more. If you dont like the stepped feel you can always upgrade to a "blue velvet" potentiometer. These two would be some of the best stepped attenuators you can buy, the first one having 24 steps and the second having 48 steps. So the 48 step is much more fine volume change between each step: http://www.ebay.com/itm/GOLDPOINT-PRECISION-STEREO-V24-STEPPED-ATTENUATOR-POTENTIOMETER-50K-/192040823559?hash=item2cb6866b07:g:ZTcAAOSwajVUUFpb http://www.ebay.com/itm/Hi-End-Khozmo-Stepped-Attenuator-SMDmkII-48-Steps-STEREO-/272441004824?hash=item3f6ebfd318:g:7YwAAOSwcLxYHBc9 Or, for a much more do-able price, these are what the majority of people use: http://www.ebay.com/itm/Assemble-Dale-23-Step-Attenuator-for-Volume-Control-50k-/282079159761?hash=item41ad3a65d1:m:mtMnsj5UP_qF5LPO1utbVWQ This is the one I am going to be using when I do my next big mod is a couple months (with the $120 z-foil upgrade too): http://www.ebay.com/itm/Stepped-attenuator-QUAD-48-steps-Volume-control-1pc-/122010004443?hash=item1c685cebdb:g:Y00AAOxyedRTebSI

The chokes on the stepped attenuator were a MASSIVE change in sound. This actually degrades the sound, but some people (like me) may actually like how it sounds. I tested the chokes here just for fun cause I wanted to see what would happen. The idea was that it would help filter any residual DC voltage on the audio input signal while letting the proper AC audio signal pass along into the amp. However, chokes are complicated things when it comes to audio because the impedance and resistance changes for each frequency. I cant even begin to explain the technical details of how this works the way it does because I am not smart enough for that, I just know I like the sound of this mod on most headphones I use the amp with. lol. This is also a very expensive upgrade though, and since it changes the sound so much I dont really recommend most people try it. If you do want to try it though, I used these chokes: http://www.ebay.com/itm/200H-anode-plate-choke-for-6sn7-6j5-5842-5687-12au7-One-Pair/282241430487?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D38530%26meid%3D20832e767bfc47b8900f8cd8c29869aa%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D231103462200 Though these will probably also work: http://www.ebay.com/itm/50H-100ma-anode-plate-choke-for-300B-2A3-71a-EL34-KT88-One-Pair/282120068111?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D38530%26meid%3D717180be2d5e43009dce4f54f084b470%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D282241430487


I have not done it yet, but when I re-do my Crack in a much more custom config in a couple months I plan on re-wiring the 12AU7 tube socket to work for 6SN7 tubes instead. This is the wiring change that needs to be done to the socket: 12AU7 PIN                          Wired to 6SN7 PIN 1 2 2 1 3 3 4 7 5 N/A 6 5 7 4 8 6 9 8
And I am going to use these tubes: http://psvanetube.com/wordpress/store/products/cv181-tii-pair/
Nov 30, 2016
EniGmA1987
494
Dec 1, 2016
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Did you get your amp yet? :D
Dec 1, 2016
AudioNoobster
16
Dec 1, 2016
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Haha hello EniGmA1987, hope things are going well for you. No sir I have yet to receive my DarkVoice.
However to make up for the lack of tubeness in my life. I jumped into the Fostex TH-X00 Purpleheart drop to add another gorgeous Fostex to my ranks. So my quickly growing hardware is now, HD650s, Fostex T50RPs mK III (bass version), Fostex TH-X00 Purpleheart (once I get those), Amp/DACS are ODAC from JLabs, Schiit Jotenheim, and the can't freaken wait DarkVoice. My wallet is so sad right now lol. Thinking about getting the Schiit Modi DAC to couple with the DarkVoice.
I could use the Jotenheim DAC but i would run it out as a pre-amp to the DarkVoice so two volume knobs....that doesn't sound great to me lol.
Low and behold the Stars have aligned and my DarkVoice has been shipped 👌🏻
Dec 1, 2016
AudioNoobster
16
Dec 7, 2016
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Hello my man,
I got my DV! And god it looks good. There is slight rust on the smaller pre-amp? tube, but that doesn't really bother me. It has so much power, barely goes past 9 o'clock on the dial to power my HD650s. I picked up a SMSL Sanskrit DAC to pair with the DV so I'm not using the Jotenheim DAC which causes me to run a pre-out from the Jotenheim to the DV and have to control knobs, I did not like this idea so I paired the DV with its own DAC.
Sound comparison - DV vs the Jotenheim Solid State with HD650s: The DV brings the highs down just enough to where it no longer bothers my ears. The ear fatigue for me with the HD650s is real, if I listen to just the HD650s for hours, by the time I'm done my ears are tired because of those highs. The vocals and instruments are pushed out slightly (increased sound stage) so it sounds like you are sitting at the front of the concert rather than standing up on stage. The bass is still precise and clear if lowered a couple decibels, which I was expecting. The DV will probably by my main amplification for my HD650s. I know the Tube makes the sound a bit inaccurate, but I enjoy it a lot compared to the Jotenheim with the HD650s.
Sound comparison - DV vs the Jotenheim Solid State with Fostex T50Rp mkIII: I don't enjoy the DV with the T50s. I know they have a low-impedance and the DV isn't great with running that, which could make sense since the sound is just not great. The highs and vocals on the T50 are already brought down and pushed back, so the added sound stage from the DV decreases the vocals even more. The bass, since it's reduced from the DV, makes the bass sound kind of bloated and just eh when using the T50s. The low end is gone and the bass just isn't as precise. I think the T50s will always be paired with the Jotenheim.
I am really enjoying this amp though, besides it looking sexy as hell and has a beautiful living glow when its powered up, the sound is just phenomenal. I have no issues, once the tubes are up to temperature and no sound on, at comfortable listening levels there is no humming or buzzing. I am working on the burn in process so it is my main amp for the time being. What is a good burn in time for the DV? Like 50 hours? Also, what is the expected life time of a tube? It is okay if you don't know, I am just curious.
I am also awaiting my new Fostex - Massdrop TH-X00 Purplehearts, I am REALLY excited to get those bad boys. I literally couldn't resist buying them once I saw the purple heart cups. Then I will have a full set, Open (HD650s), Semi-open (Fostex T50s), and closed (Fostex TH-X00s).
Dec 7, 2016
EniGmA1987
494
Dec 12, 2016
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I have the original TH-X00's and I love them stock, and with the mods I did they are my favorite headphones by far. (can you tell I like modding? lol)
The rust on the tube is fine, it is just cosmetic. Eventually you should replace the tubes with something better anyway so it is a non-issue. As for how long tubes last, it is quite a while IMO. I dont listen to tube amps for hours every single day so maybe my tubes last longer than some peoples will, but I usually just keep tubes till I can hear that something sounds "off" about it compared to what I am used to. You can get the tube tested to verify the specs but that is kinda hard to do these days unless you or a friend you know owns a tube tester already. I would just keep them until you notice something sounds funny or until you get the itch to try out some new tube everyone is raving about. haha


If your volume is very loud even at 9 o-clock on the volume dial, one of the mods you could do later down the road is replace the volume potentiometer in the amp with an Alps "Blue Velvet" logarithmic style pot. The stock pot is a blue velvet already unless the manufacturer changed the parts since the time I bought mine and the time he made yours, but it is a linear pot and not a logarithmic one. Using a log pot will help you have more range on the volume dial.
Dec 12, 2016
AudioNoobster
16
Dec 12, 2016
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Lol, I feel like you've modded everything you get your hands on. What mods have you done with the TH-X00s? I'm assuming detachable cable mod at least?
I actually just received some new tubes. Tung-Sol 6SN7GTB and Russian SED 6AS7G (Possibly Svetlana? Not sure). I got them from thetubestore and omg, the BASS IS BACK! I'm a bit of a basshead, I love EDM music and just feel having the low end adds that warmth when listening to acoustic or even metal that I love so much. The Tung-Sol 6SN7GTB is what brings the bass back into play. The vocals are still toned down just slightly, but the instruments I think, got a bit closer compared to the stock tubes. There is a bit of humming in the left channel, but I can't hear it when music is playing and I know the tubes need to burn in so it should go away until I have time to do the Fitz Mod, which is on my to do list. It's tough to do real AB comparison with tubes, I think if I get more interested in it, I'll grab another DarkVoice so I can do real AB testing with certain tube setups vs others with the same headphones, I think that would be very interesting. Because the issue is to swap tubes its best to let them cool down, swap, and then the new tubes have to heat up so there is like 15 minutes of not listening to music so how can you TRULY compare them unless the sound is completely different? I know the bass is back cause the stock tubes have NO bass whatsoever, but after that I'm just kinda guessing at any other possible differences.
Honestly, the DarkVoice has just been my constant lately, I'll be running my tubes roughly 6 hours a day right now either gaming or listening to music, tubes are cheap so I don't mind having it run constantly. Theres something about gaming and having the sound come through a tube amp that's just kinda awesome. There is no true benefit besides a slight increase in soundstage (helps pinpoint sounds), but how many people play games with a tube? Lol, do you tube roll? If so what has your favorite combination been? Tube rolling is very interesting to me.
Dec 12, 2016
AudioNoobster
16
Dec 13, 2016
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Hey Enigma,
I've been looking around into the Fitz mod and the mod for low impedance headphones (still unsure I will do this mod), but I have a parts list of sorts haha.
Fitz Mod: http://www.mouser.com/ProductDetail/Elna/RFS-63V101MI65/?qs=sGAEpiMZZMtZ1n0r9vR22Vaq1AHMe%252bCMZ%252bXUDkGZNgE%3d
I'd like to keep everything as high grade and quality as possible, even if it doesn't make THAT noticeable of a difference, if I'm going to do it, I'm going to do it right.
As for the low impedance headphone mod, I've been having a difficult time finding anything about it besides what you showed me. If I am to replace the 6 10uF capacitors (orange blobs), what would be my ideal selection of capacitors from these two lists? Ones Audiophile grade and the other is Axial arrangement. http://www.mouser.com/Elna/Passive-Components/Capacitors/Aluminum-Electrolytic-Capacitors/Aluminum-Electrolytic-Capacitors-Leaded/_/N-75hqw?P=1z0zldoZ1z0wrkrZ1yztuat http://www.mouser.com/Nichicon/Passive-Components/Capacitors/Aluminum-Electrolytic-Capacitors/Aluminum-Electrolytic-Capacitors-Leaded/_/N-75hqw?P=1z0zlbmZ1z0z819Z1z0wrkr
I'm a little unnerved by the whole playing with electricity. I don't have much DIY experience when it comes to circuits even though I'm a mechanical engineer haha. Then we get into playing with an amp getting 110 volts from the wall, little scary. Obviously I would unplug the unit, but after that I don't know how to remove excess power stored in the capacitors. Any assistance or knowledge on how to properly mod the DV would be greatly appreciated.
You also noted swapping the volume potentiometer, would this be as simple as unhooking the original and rewiring it exactly as the original? You've been a great help so far, I do appreciate it.
Dec 13, 2016
EniGmA1987
494
Dec 13, 2016
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That capacitor is fine for the Fitz mod, and feel free to use it if you want. I would use this one though: http://www.mouser.com/ProductDetail/Panasonic/EEU-FR1J101L/?qs=sGAEpiMZZMtZ1n0r9vR22WPtSjuqjALi7NSQyX3lavU%3d That capacitor has much longer life, lower ESR (not that it matters here) and pretty low ripple current which would be useful. Ripple seems a slight bit high at first glance but if you look at the specifications sheet for the capacitor we see that at 60Hz (AC waveform frequency which the heaters use instead of DC) we can multiply the ripple by 0.6 so we end up with a ripple of only 450ma which is a slight bit better than many electrolytic capacitors in that capacitance range.




For the output caps, you need to increase the capacitance to make the amp more suitable for low impedance headphones. Simply putting different 10uF capacitors in wont do anything and will probably make it sound worse since film capacitors (even low grade) sound better than nearly any electrolytic capacitor. You will want to go with somewhere around 220uF capacitance.
I would use one of these 3 capacitors: http://www.mouser.com/ProductDetail/Nichicon/UKZ2A221MHM/?qs=kArNe9LFxXnbgnEwLkuvMg%3d%3d ^^^^^ Nichicon "Muse", highest end Muse line.
http://www.mouser.com/ProductDetail/Nichicon/UFG2A221MHM/?qs=sGAEpiMZZMtZ1n0r9vR22e0BBN1kF1oiPty4D%2fwgNUA%3d ^^^^^ Nichicon "Muse" Fine Gold series. Technically a bit lesser quality than the UKZ series but havent seen a reason for why. A good choice either way.
http://www.mouser.com/ProductDetail/Elna/RFS-100V221MK95/?qs=sGAEpiMZZMtZ1n0r9vR22Vaq1AHMe%252bCM7k10Flj3raE%3d ^^^^^ Elna Silmic II RFS line, uses silk fibers for a smoother sound. A well regarded capacitor and one of my favorites along with the Nichinon Muse's.
Any of those 3 would be a fine choice.





For swapping the volume pot, yes just unsolder the wires from the old one and solder them in to the new one exactly the same (assuming you bought one with the same layout). All Alps Blue Velvet should wire the same, and actually nearly any potentiometer should wire the same but swapping with the same kind just using a logarithmic instead of linear would be easiest.
Dec 13, 2016
EniGmA1987
494
Dec 13, 2016
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For draining all the power out of the circuits, you can wait a few minutes after you turn it off
or, buy a 1/4" (6.35mm) TRS audio connector and wire all the contacts together. Turn off the amp, then plug in that connector into the audio output and it will short the output to ground and dump any remaining power in the capacitors into ground and they will be empty right away. Never ever plug this in with the amp powered on though.
Dec 13, 2016
EniGmA1987
494
Dec 13, 2016
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For the TH-X00 mods, I did not do the detachable cable mod. My headphones never leave where they are now so I have no need. I do plan to replace the cable sometime though and mod it into a balanced cable for my audio setup (I have a balanced DAC and headphone amp) which should give it double the output power capacity to pull from and allow for slightly lower distortion.

I did not like the stock earpads. While they were fine, they pressed on my ears and this caused fatigue over a long enough period. So I changed the pads to Alpha Prime lambskin pads. Love em. The problem is, a huge portion of the sound signature of the headphone comes from the shaped earpads it comes with. They block sound from half the driver area and shape the direction the audio waveform travels. Using different pads drops the bass by a HUGE amount and makes the headphones sound too bright and nasty. So, I used some silicon (which is closed cel foam, as in it blocks sound) to block the audio and shape the sound like the OEM earpads while using my new earpads. This helped a good bit, and brought back most of the bass, but I still felt it was lacking a little and emphasized a bit too much on the high end. So I used some polyurethane disks (which is open cell foam, as in audio can pass through it but you get attenuation in the higher frequencies) to help filter and shape the sound a little more. This left the headphones almost exactly as I wanted them. Very nice sounding, great sound stage, great frequency response. I still would like a little more bass, but to do that I would have to sacrifice too much sound quality by blocking more high frequency which would be too much of a loss to be worth it. So instead I just use a global, system wide EQ (I also use the EQ software to give myself a custom crossfeed) to boost the low end a couple dB to get the sound I want without blocking any HF.

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When your purplehearts get in, take a look at the pads and you will see what I mean about their shaping the sound path.
Dec 13, 2016
AudioNoobster
16
Dec 13, 2016
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You are awesome, I appreciate all of the advice and will definitely use the hardware you suggest. I got confused as to why I was looking at 220 uF capacitors when you mentioned 10 uF in your earlier post for the low impedance mod. I will be doing the Fitz mod for sure, not sure if I will do the low impedance mod though, but it would be nice to be able to use low impedance headphones with the DV if I so choose too.
When the Purplehearts come in, god knows when that will be since DHL took from them from Jersey to Maryland, and I live in f*cking Pennsylvania, why they went sideways I have no idea. Anyways, I do know about the sound signature of the TH-X00s, which is why I grabbed the Dekoni lambskin pads built for TH-X00s when they dropped along with the Purplehearts to improve comfort. I need to make sure the plastic disk or insert that is built into the TH-X00s stock pads can be removed and fitted into the Dekoni pads to keep the bass that is oh so important to me.
Again thank you so much. When I have a chance I will send you pics of my setup and when I do the Fitz mod. Right now I bought new tubes from thetubestore and there is a hum in the left channel, but it's not too distracting. I realized after further research I grabbed the "wrong" tubes as it were. I bought the re-issued Tung-Sol 6SN7GTB made in Russia and another Russian tube (6AS7G). But they do sound much better than the stock tubes so I'm not terribly upset, just have the hum, which isn't annoying unless the song is really quiet.
Also, so jealous...I've wanted the Alpha Prime (seen in your last picture) since I started getting into headphones. What headphones do you have in your collection now? I've been contemplating the TH-X00 cable mod to balanced cause I also have a balanced output with the Jotenheim, more power is always welcome :D and it seems to be a straight forward modification.
Dec 13, 2016
AudioNoobster
16
Dec 14, 2016
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Purplehearts are in! And oh my god that bass is quite literally mind blowing. Massdrop did a damn good job this time around at packaging them safely, nothing but perfect cups on my end.
First track I put on was an acoustic track, 10 Years - Wasteland, and I'm like okay, not bad. Solid sound stage, everything feels and sounds like a big circle around me. I also never noticed in that song, the vocalist is more to the left than center stage. Very nice. But these headphones are known for their low end right? So stuck on some EDM, and as soon as that bass dropped I couldn't help but smile. My entire headphones shook with glorious low end. I cannot wait to get the Dekoni Sheepskin Pads for these. I can definitely see how they are gonna fatigue after awhile, the pads are quite solid, but thankfully my ears just fit somehow, its so small of a hole I don't know how they fit lol.
Dec 14, 2016
EniGmA1987
494
Dec 14, 2016
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Those TH-X00's all have great low end, but the Purplehearts are the best. I noticed the oldest model, the mahogany, has epic levels of low end in the 100Hz(ish) area, rather than extra deep sub bass. I actually think it has less sub bass than my B&W P7's, and even my Sennheiser PC350's did which were not even known for their sub bass capability. A bit of EQ fixed it up, but the Purpleheart's natural EQ already emphasizes the sub bass much more so than the mahogany does so I bet they are just perfect. Wish I had some but I dont want to spend the money since I already had the first run Mahogany ones (serial 38!)
When you go to change the pads, be sure to look at how much the pad overlaps into the speaker cone area. You will see what I mean about how it shapes the sound so much, and that overlap is what brings out the bass so much. That is why I did the mods to mine the way I did, to mimic the stock pads positioning while maintaining a much larger ear hole area.
Dec 14, 2016
AudioNoobster
16
Dec 15, 2016
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Oh Enigma you'd be oh so proud of me lol. Just did for my first bit of modding.
So I got my Dekoni Sheepskin pads which are extremely comfortable. Although when I first pulled them out I was a little wary cause they were rock solid, but its probably 30 degrees out so after they warmed up a bit, they much much better.
Anyways, I read that the Dekoni pads take away some of the bass compared to the normal Fostex Pads and through additional research I found out there is an additional plastic disk sewn into the back of the stock pads. The loss of bass was a no go for me. I cut the plastic disk out of the original pads and inserted them into the Dekoni pads. Zero loss of bass, they sound exactly like the originals, maybe a touch brighter due to the softness of the leather and your ears sit slightly closer, but other than that the sub bass is still there!
However, modders beware, this will completely ruin your stock pads, I personally don't care cause the Dekoni pads are just that much better, but if you want to keep the original pads without ruining them you could get a plastic sheet of the same thickness and cut out the ring in the same shape as the original. Since I didn't have this option just lying around, I chose to use the original disk. These headphones are now perfect. Time to sit back and enjoy them.
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Dec 15, 2016
EniGmA1987
494
Dec 15, 2016
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Very nice! Modding FTW :)
Dec 15, 2016
AudioNoobster
16
Dec 23, 2016
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Hey Enigma, I'm wondering if you've ever experienced this.
My DarkVoice has no Left channel. Its not the tubes, I got new tubes, didn't have a left channel, switched back to tubes I know work, and I still have no left channel.
Tubes light up fine, I took the under plate off to see if there was any smell or something and it all looks good.
I read somewhere in the DarkVoice chat to remove the charge from the capacitors and that worked fine. Was wondering if you ever experienced this before.
The sound from the right channel is just fine. I've left it unplugged for hours and the issue is still there. Need to go out and get a resistor to dissipate the charge or something. I'm very confused cause it worked just fine a few days ago.
Dec 23, 2016
AudioNoobster
16
Dec 23, 2016
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Nevermind.
Apparently my DAC thought it would be funny to screw with me a pulled the sound coming from the left channel for some oddball reason.
After some cable swapping (thanks to a suggestion on Head-Fi), I realized the DV worked just fine on my Jotenheim, so I reset the SMSL Sanksrit 6th Gen and poof everything is fine.
Feel kinda bad spamming the on/off switch now. Back to tube rolling :P Rocking a Sylvania VT-231 and RCA 6AS7G (coke bottle). It has this warbly low end that I just absolutely love, the kind of sound that tickles the ear drums, yeah I absolutely can't get enough of that. These tubes do hum though in the right channel, so hopefully with some burn in it'll go away, or I'll be doing the Fitz mod, soon soon enough.
Dec 23, 2016
EniGmA1987
494
Dec 23, 2016
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Glad you got it figured out. The first thing I was going to suggest would have been to swap the RCA cables at the input to the DV. If the left channel was still dead then you know the problem is amp side, if the right channel then becomes dead you know it is the cables or something before the cables. Easy way to narrow down which side of the signal chain to start looking at.
Dec 23, 2016
Enraged_Weredonkey
4
Jan 23, 2017
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Enigma1987, thank you for the amazingly detailed reply. I can tell you're really into modding this amp! You really helped me sort out what to purchase. I apologize for the late response, as I'm just getting around to this project now. Had a few additional questions, if you don't mind. A) How many Shottky diodes do I need? B) And I need only one power supply choke, correct? C) I went to purchase the volume pot, and the cheapest ($46) is sold out. I contacted the seller, they're likely not making more for a long while. Would this one http://www.ebay.com/itm/221589263316 be a good substitute? I noticed that it's basically half the amount of resistors soldered around the edge, but I don't know what that translates to in relation to the Crack. Please advise :)
Jan 23, 2017
EniGmA1987
494
Jan 23, 2017
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This one would work fine: http://www.ebay.com/itm/Valab-23-Step-Ladder-Type-Attenuator-Potentiometer-50K-Log-Stereo-/302184222070?hash=item465b954d76:g:cekAAOSwo3pWgXR7
Yes only one power supply choke. You *can* do more but typically the choke mod just replaces the last resistor with the choke as that will bring the largest effect for the least money and space usage.
You need 4 schottky diodes, just like the 4 regular diodes the kit comes with. You are simply replacing the kit diodes with much higher quality models.
Jan 23, 2017
Enraged_Weredonkey
4
Jan 27, 2017
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Enigma1987,
Thanks so much for the info. Went ahead & ordered everything so I wouldn't miss the parts again. I also appreciate your patience explaining the part amounts & providing specific links. Like I said, I'm new to electronics modding & I really didn't want to buy the wrong stuff.
I'm super excited to get everything & start modding. Cheers! :)
Jan 27, 2017
EniGmA1987
494
Jan 27, 2017
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Just make sure you wire things the right way. DC electronics have polarity. The choke can be wired however but those diodes are important.
Jan 27, 2017
Enraged_Weredonkey
4
Jan 27, 2017
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Indeed. I want to be careful, so as not to melt my amp/self. I was reading a bit about those schottky diodes here. http://bottlehead.com/smf/index.php?topic=7215 Glad I read this, I wouldn't have known the bare metal tops of the diodes are hot with voltage. I'll be sure they don't touch anything else. I really like that little PCB board configuration in the forum thread, but I can't find one for sale in the US. (The forum links to a Canadian site, shipping would be ridiculous.) Also, someone in this thread says you only need one diode. Went ahead and purchased 4 anyhow, guess I'll keep the other 3 as spares in case I burn something :)
Cheers
Jan 27, 2017
EniGmA1987
494
Jan 30, 2017
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I read through that thread cause I wanted to see what you are talking about with only needing 1 diode. What Grainger49 was talking about in that thread is something slightly different. In his example, you would leave all the stock diodes in place, and add a 5th diode (the new schottky) in series with the hot B+ voltage after the other diodes. Technically I suppose this *could* work but seems kinda iffy to me. The idea is that the new diode would basically be used as a filter only, and it would filter out the bad voltage spikes (high frequency noise) of the stock diodes. Personally, I would just replace the 4 stock diodes to begin with and remove the noise source completely as that seems like the best solution to me. I have ordered a lot of stuff from Parts Connexion in the past (the Canadian site you mentioned). I am pretty sure shipping is only a few Dollars if all you are ordering is small stuff and you ship it the most basic way. I typically ordered things like resistors, small bits of wire, and the like and I dont remember freight ever being an issue to southern California where I live. Obviously you dont *need* those little PCB boards for the new diodes, but they do look really nice and make connecting the diodes very easy. You might want to just check out what shipping would be.

For those schottky diodes you got, be sure and read the datasheet so you know which way to wire the new diodes (if you dont use the PCB board from that thread): http://www.mouser.com/ds/2/348/scs310ap-e-965249.pdf So when the diode is facing you (the metal back is facing away) the leg on the right side is the anode which is the input, and the leg on the left side is the cathode which is the output.
Jan 30, 2017
Enraged_Weredonkey
4
Jan 31, 2017
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I re-read the forum post, and you are correct. I think your line of reasoning about "fixing a problem vs avoiding it altogether" makes more sense. Will go ahead with your plan. Also, thanks for the spec sheet and installation pointer.
Just curious, but what headphones are you running with your SuperCrack? I will mainly be using Sennheiser HD650, with Beyerdynamic 990 DT Pro 250 ohm for occasional use as my "fun" headphone.
You mentioned the chokes on the stepped attenuator, and that they made a really big change in the sound. Could you describe the change?
Also, please let me know when you've installed your PSVane tubes. I would love to hear about them. I purchased a GEC 6080 and a few other cheaper tubes, can't wait to get tube rolling!
Jan 31, 2017
EniGmA1987
494
Feb 1, 2017
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I rarely use my Crack amp anymore, dont have headphones that work well with it any longer. I also gave my Darkvoice to a friend. I do sometimes listen to it, but the bass leaves a lot to be desired with my low ohm headphones I have now days. This is something I will fix once I do the rebuild next month sometime. I used to listen with modded PC350 headphones. Now my headphones are: Alpha Prime, modded Fostex TH-X00, AKG K7XX, and modded HE-350.
The chokes to ground on the input of the volume control was a little experiment I did. I do like the sound change, since the crack is more of my "fun amp" anyway. It cut quite a few areas of the high's and made the audio absurdly warm sounding. lol. Im sure if someone were to measure the amp the distortion would be off the charts, but hey its a tube amp and the whole "tube sound" is distortion so whatever. I have my nice Audio-GD amp for clean, pure, low distortion audio and I just use my Crack for having fun and playing around.
Feb 1, 2017
EniGmA1987
494
Mar 1, 2017
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Hey @AudioNoobster, That Crack amp+Speedball upgrade kit I have been talking about is on sale this week if you want to pick it up and do an upgrade from your Darkvoice: http://bottlehead.com/?product=crack-otl-headphone-amplifier-kit
Mar 1, 2017
AudioNoobster
16
Mar 2, 2017
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@EniGmA1987 do you recommend the amp? How good is it in your opinion? Superior or vastly different than the DV?
Mar 2, 2017
EniGmA1987
494
Mar 2, 2017
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The Darkvoice 336 and the Crack use similar circuit design with the two tubes, half being used for each channel, cathode follower, and output transformerless with DC blocking caps. The crack with Speedball upgrade however has significantly improved resolution due to the direct currwnt load design and much better power supply section. So it is a brtter amp with the speedball upgrade. And it allows you to play around with mods a lot more to improve the amp and learn more about audio circuits.
Mar 2, 2017
AudioNoobster
16
Mar 2, 2017
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@EniGmA1987 you should have been a salesman for Crack. The Crack 1.1 OTL amp specifically, but you could probably sell crack too lol. I will also need to purchase a soldering kit and a multimeter. Do you have any suggestions for those as well? Because...I will and am going to purchase the Crack + Speedball amp right now....
Mar 2, 2017
EniGmA1987
494
Mar 2, 2017
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I use this stuff for my soldering, but it is a bit too much for one little project like this: https://www.mcmaster.com/#7016A36 https://www.mcmaster.com/#7016A44 https://www.mcmaster.com/#7662A696 https://www.mcmaster.com/#7659A67
Those ones I use are a bit expensive and is way too much soldering for this project. I like the precision 18w for all the little electronics I do, and the 40w one for when I have to soldering to a heatsink, or stuff into a ground plane. But for a starting iron, this is probably a great one to use since it has adjustment for power output and is a really common model so you can get various tips for it easily: https://www.amazon.com/Weller-WLC100-40-Watt-Soldering-Station/dp/B000AS28UC/ref=sr_1_1?ie=UTF8&qid=1488479187&sr=8-1&keywords=40w+soldering+iron https://www.amazon.com/Kester-Rosin-Core-Solder-Dispense-Pak/dp/B00AVLM4SO/ref=sr_1_4?ie=UTF8&qid=1488479520&sr=8-4&keywords=63%2F37+solder
If you dont have wire snips and strippers: https://www.amazon.com/Hakko-CHP-170-Stand-off-Construction-21-Degree/dp/B00FZPDG1K/ref=pd_sim_469_6?_encoding=UTF8&pd_rd_i=B00FZPDG1K&pd_rd_r=VW1FJ8XPS06AVG53ADNK&pd_rd_w=hnwoK&pd_rd_wg=44txB&psc=1&refRID=VW1FJ8XPS06AVG53ADNK https://www.amazon.com/Eclipse-CP-301G-ProsKit-Precision-Stripper/dp/B005JVJDIA/ref=sr_1_6?s=hi&ie=UTF8&qid=1488479664&sr=1-6&keywords=wire+strippers
and this looks like a good, cheap multimeter: https://www.amazon.com/INNOVA-3320-Auto-Ranging-Digital-Multimeter/dp/B000EVYGZA/ref=sr_1_3?ie=UTF8&qid=1488479747&sr=8-3&keywords=multimeter
Mar 2, 2017
AudioNoobster
16
Mar 2, 2017
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You are awesome, as always I appreciate the time you take to help me out. I ordered the Crack 1.1 and all of the equipment I need to make an awesome amp.
I actually snagged the ZMF Atticus and Eikons (awaiting those) and picked up the Beyerdynamic 1990s since we last talked. The 1990s are quite amazing, honestly, in my opinion, they beat out the Senns HD650s in everyway. Soundstage, detail, bass, clarity, they are quite exceptional headphones. I tube rolled the hell out of the DV lol. Favorite combo for me was Sylvania VT-231 + Sylvania 6080 with the HD650s, and now with the Crack I get to look for more 12AU7 tubes and couple them with my range of 6080s, 7236s, and 6AS7G (which should all be compatible) .
Have you tube rolled with the Crack? Do you have a favorite combination?? Any new headphones??
Mar 2, 2017
EniGmA1987
494
Mar 2, 2017
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Hahaha. Wow thats a lot of audio stuff :O
I am taking a break on headphones, though I came oh so close to buying some Monoprice planar dynamic headphones last week. I honestly have way too many, I had to stop. I just do mods to my headphones now to satisfy my audio and tinkering needs.
Ill have to look at what tubes I still have around for the crack when i get home. I know right now i use a 5998 but I have a few others. The 5998's have lower output impedance so they tend to sound nice.
Mar 2, 2017
AudioNoobster
16
Mar 2, 2017
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Yeah tell me about it, my wallet despises me haha.
You have a Tungsol 5998? Very nice, I've been unable to find one under $150, I mean, I know they might sound fantastic, but do they sound that fantastic? Says the guy who has like 7 6AS7 compatible tubes and 10 6SN7 compatible tubes. I am very aware I have a problem lol.
You say you do a lot of soldering? What kind of tinkering do you do or is that for your job? Ohhh digging into the world of 12AU7s is going to be fuuuun. I miss buying tubes, for a couple weeks I had a tube roll in every few days, loved it.
Mar 2, 2017
EniGmA1987
494
Mar 2, 2017
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Yep mine is a Tung Sol 5998 with the domino black plates, just looked it up. Cost me $139 apparently :( Ya it sounds really nice, but I think you are right, not THAT nice. I am going to have to switch back to 6080 tubes on my next mod though cause no way I want to shell out the kind of money to run four 5998's in the amp.
Once you are done building your own Crack amp, you should implement a switch and some mods that will let you toggle a switch to change the wiring of your amp between 12AU7 and 6SN7 tubes. That way you can flip a switch and roll those 6SN7's you have into the Crack too and see how they sound ;)


I do a lot of audio projects that use soldering. I have an o2 amp setup that I did custom and ruun two boards in a single enclosure and use it as a balanced amp. I used a single R-Core transformer for both boards and have some switches in to let me select between RCA, XLR, and USB inputs. Oh ya I also have a small little DAC in the enclosure so it is a complete little solution. Was fun but overall time and money spent is not exactly worth the sound quality. I just did it for a fun project when O2's were all the rage. I am thinking of trying to fit the booster boards in though, that might be interesting.
I also just recently made four AMB Lab's A20 boards which I am going to use in my new Crack project as a diamond buffer output stage. Also made a O22 PSU to go with them. http://www.amb.org/audio/alpha20/
And now I just heard about a little amp called "The Wire". Quite old apparently but supposed to be extremely good and completely transparent in sound. So I am trying to buy some of those boards and I may end up using those in my Crack Project instead.

After the new Crack I am doing, I am thinking of trying to build an R2R DAC
Mar 2, 2017
AudioNoobster
16
Mar 3, 2017
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Wow, that is very interesting work you do there EniGmA1987. Did you go to school for it or just picked it up as a hobby?
I am at work at the moment and I haven't had the time to take a look around the interwebs for the best place on learning how to mod the Crack 1.1. Would you have any knowledge of good resources to pour through and specifically the mod on being able to swap 12AU7s to 6SN7 with the flick of a switch, that sounds like magic lol. I would need a swappable socket with that too wouldn't I? To place on top of the 12AU7 socket to be able to stick in a 6SN7.
I've done that with the DV, grabbed a....6SN7 to 6922 (I believe) socket so I could expand my tube range. Didn't go very far into as the 6SN7s sound delightful, but it was awesome to look at.
What does your new Crack project hold? What is the result you are looking to achieve?
Mar 3, 2017
TronII
3
Apr 26, 2018
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Tube amps generally aren't good with low impedance headphones due to their high output impedance and high distortion levels. Generally, you want an amp with 1/8th the output impedance of your headphone's impedance MAXIMUM to minimize distortion. Any distortion levels above 1% are also audibly obvious on any equipment
Apr 26, 2018
Brzzl
0
Aug 13, 2018
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First of all, thanks for your awsome guide. I still got some questions though before I do these mods: 1.Newbie question, but just to be 100% sure: When replacing the 6 10uf orange capacitors with 220uf Elna ones, I do put 2 in (1 for the right channel and 1 for the left channel), right? 2. What is your recommendation, if I want to use film capacitors instead? /Or would you recommend adding film capacitors to the Elna's instead? If so, where do I have to put them? Thanks in advance for your help!
Aug 13, 2018
Brzzl
0
Aug 13, 2018
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Hey EniGmA1987 First of all, thanks for your awsome guide. I still got some questions though before I do these mods: 1.Newbie question, but just to be 100% sure: When replacing the 6 10uf orange capacitors with 220uf Elna ones, I do put 2 in (1 for the right channel and 1 for the left channel), right?
2. What is your recommendation, if I want to use film capacitors instead? /Or would you recommend adding film capacitors to the Elna's instead? If so, where do I have to put them?
Thanks in advance for your help!
Aug 13, 2018
EniGmA1987
494
Aug 13, 2018
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The default orange capacitors are already film caps, that is why they are so large for their capacitance size. The reason for replacing them with larger ones is mainly to get full frequency response with lower impedance headphones. This is simply not possible to replace them with larger film caps as the the new caps would be the size of the entire amp chassis. The only way to fit larger size capacitors in is to use electrolytics. Elna RFS and Nichicon Muse do sound fairly good for being electrolytic capacitors, with the muse being specifically designed for audio performance. They wont be quite as good as film caps, but they will fit inside the amp and still sound pretty good. And more importantly you will hear the whole frequency range. Having higher grade film caps is pointless IMO if you have bass rolloff so that you dont even get the low frequencies out of the amp.
You *may* be able to fit the new electrolytic 220uf caps and a 10uf bypass cap in. That will let you keep the frequency range on low impedance headphones while also giving you a bit better high frequency detail that the film cap is passing through. Not sure if it will fit, but you could try.
Aug 13, 2018
Brzzl
0
Aug 13, 2018
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Thanks for the reply, but back to my 1st question: "1.Newbie question, but just to be 100% sure: When replacing the 6 10uf orange capacitors with 220uf Elna ones, I do put 2 in (1 for the right channel and 1 for the left channel), right?"
Aug 13, 2018
EniGmA1987
494
Aug 13, 2018
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yes sorry, forgot to answer that one. You do need 1 cap for left, and 1 cap for right.
Aug 13, 2018
Brzzl
0
Aug 13, 2018
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Got it! Thanks for everything!
Aug 13, 2018
DiMora
230
Oct 25, 2018
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What caps did you use to make the DV more suitable to lower impedance headphones? You are referring to the six burgundy colored ones?
Oct 25, 2018
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