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Massdrop O2 + SDAC DAC/Amp
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Massdrop O2 + SDAC DAC/Amp
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Product Description
For the objectivist audiophile seeking a complete desktop solution, there’s the Massdrop O2 + SDAC: a DAC/amp that brings two great products together in one affordable, easy-to-use package. It features the Massdrop Objective 2 (or O2), the community’s favorite solid-state amp, alongside the Massdrop x Grace Design Standard DAC (or SDAC), a collaboration with a company long known for its incredibly accurate, transparent studio gear Read More
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keyboard_arrow_downOpasTanti
110
May 29, 2018
It took me awhile to notice that something is wrong with my O2+SDAC. My particular unit came with wrong gain configuration (2.5X and 6.5X* instead of 1X and 3.3X listed on the product page) and other units might be affected by this as well (at least from what I've noticed on a teardown from Reddit).
*O2's input stage will overload when set to high gain of 6.5X with SDAC's output at max, which may cause the sound to become distorted but it won't harm the O2.
THE DISASSEMBLY
*Before disassembly "...wait at least 15 seconds with the power turned ON(in) after the power is removed to let the capacitors discharge."-NwAvGuy
FRONT PANEL: *turn CCW to unscrew any of the screw or nut -Remove the volume knob by removing the hex screw securing it to the pot's shaft. -Remove the nut securing the potentiometer to the front panel. -Remove 4 Phillips screws on the front. by now the front panel should be able to be come off with the jack attached and you should be able to see if the resistors are of right values (R19, R23) and left out(R17, R21) if they aren't contact MD's support.
BACK PANEL: -Unscrew 4 Phillips screws and 1 Torx screw on the back. The back panel should come right off.
THE PCB: -Slide PCB out the back of the enclosure (it will get stuck if you slide it out through the front because of how the SDAC is mounted)
THE GAIN RESISTORS
"Resistor Values – The O2’s gain (for one channel) is: Low Gain Ratio = 1 + R16/R17 High Gain Ratio = 1 + R16/R19 Voltage Gain in dB = 20 * Log(Gain Ratio) …For 1X gain just leave out the gain resistors"-NwAvGuy
Switch out: R17and R21 needs to be left out for 1X gain (gain switch pushed out) but 1K ohms resistors are installed. So the gain is 1+1500/1000 = 2.5
Switch in: R19 and R23 needs to be 665 ohms or 649 ohms (closest standard resistor values) but 274 ohms resistors are installed. 665 ohms: 1+(1500/665) = 3.26 (~3.3X) 649 ohms: 1+(1500/649) = 3.31 (~3.3X)
274 ohms: 1+(1500/274) = 6.47 (~6.5X)
THE "FIX" *this is done at your own risk
Method 1(no soldering required): Clip off or desolder the "high gain resistors" (R19, R23) and leave the "low gain" resistors intact(R17, R21).
Now the gain switch be the following: SWITCH IN = LOW GAIN (1X) SWITCH OUT = HIGH GAIN (2.5X)
Method 2 (soldering required): Do the same as the first method so while you get the resistors you still have high and low gain(1X and 2.5X). Clip out R17, R21 and solder in the "high gain" resistors in R19 and R23.
Links O2's gain resistors: http://nwavguy.blogspot.com/2011/08/o2-details.html#circuitboardconstruction in "THE GAIN RESISTORS" section
O2's maximum input: http://nwavguy.blogspot.com/2011/08/o2-details.html#maximuminput
The teardown post on Reddit: https://www.reddit.com/r/Massdrop/comments/7ny0vj/massdrop_o2_sdac_dacamp_teardown/
SDAC measurements on ASR: https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-massdrop-x-grace-design-sdac.2495/
*O2's input stage will overload when set to high gain of 6.5X with SDAC's output at max, which may cause the sound to become distorted but it won't harm the O2.
THE DISASSEMBLY
*Before disassembly "...wait at least 15 seconds with the power turned ON(in) after the power is removed to let the capacitors discharge."-NwAvGuy
FRONT PANEL: *turn CCW to unscrew any of the screw or nut -Remove the volume knob by removing the hex screw securing it to the pot's shaft. -Remove the nut securing the potentiometer to the front panel. -Remove 4 Phillips screws on the front. by now the front panel should be able to be come off with the jack attached and you should be able to see if the resistors are of right values (R19, R23) and left out(R17, R21) if they aren't contact MD's support.
BACK PANEL: -Unscrew 4 Phillips screws and 1 Torx screw on the back. The back panel should come right off.
THE PCB: -Slide PCB out the back of the enclosure (it will get stuck if you slide it out through the front because of how the SDAC is mounted)
THE GAIN RESISTORS
"Resistor Values – The O2’s gain (for one channel) is: Low Gain Ratio = 1 + R16/R17 High Gain Ratio = 1 + R16/R19 Voltage Gain in dB = 20 * Log(Gain Ratio) …For 1X gain just leave out the gain resistors"-NwAvGuy
Switch out: R17and R21 needs to be left out for 1X gain (gain switch pushed out) but 1K ohms resistors are installed. So the gain is 1+1500/1000 = 2.5
Switch in: R19 and R23 needs to be 665 ohms or 649 ohms (closest standard resistor values) but 274 ohms resistors are installed. 665 ohms: 1+(1500/665) = 3.26 (~3.3X) 649 ohms: 1+(1500/649) = 3.31 (~3.3X)
274 ohms: 1+(1500/274) = 6.47 (~6.5X)
THE "FIX" *this is done at your own risk
Method 1(no soldering required): Clip off or desolder the "high gain resistors" (R19, R23) and leave the "low gain" resistors intact(R17, R21).
Now the gain switch be the following: SWITCH IN = LOW GAIN (1X) SWITCH OUT = HIGH GAIN (2.5X)
Method 2 (soldering required): Do the same as the first method so while you get the resistors you still have high and low gain(1X and 2.5X). Clip out R17, R21 and solder in the "high gain" resistors in R19 and R23.
Links O2's gain resistors: http://nwavguy.blogspot.com/2011/08/o2-details.html#circuitboardconstruction in "THE GAIN RESISTORS" section
O2's maximum input: http://nwavguy.blogspot.com/2011/08/o2-details.html#maximuminput
The teardown post on Reddit: https://www.reddit.com/r/Massdrop/comments/7ny0vj/massdrop_o2_sdac_dacamp_teardown/
SDAC measurements on ASR: https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-massdrop-x-grace-design-sdac.2495/
OpasTanti
110
Apr 3, 2019
There shouldn't be any sort of buzz or hum with or without resistors installed, something is wrong. I suppose you could check for soldering defects around the gain resistors (a solder bridge on the gain switch pins?).
If there aren't any then I recommend you to ask over in the O2 thread on diyaudio.com
(https://www.diyaudio.com/forums/headphone-systems/193977-objective2-o2-headphone-amp-diy-project.html)
...yes, there is a reason not to...using a 1500 ohms resistor will give you a gain of 2X not 1X
( 1+(1500/1500) = 1+(1) = 2 )
(Edited)
TWD-Industries
303
Apr 3, 2019
OpasTantiSolder bridge seems likely, I'll pull out the solder wick and give it a clean up
Kiyoshi_I
25
Sep 21, 2017
So I am torn, my current set up is a pair of 598C and an audigy sound card and I am waiting on the 6xx to be delivered. Would a better match for the 6xx be with the O2+SDAC or the SMSL M6, both are about the same price but I have not seen a direct comparison between the two. Also how much of a difference would I notice between the AMP/DACs and the audibly fx sound card between the headphones, the 598C have a 23 ohm resistance and the 6xx have a 300 ohm resistance an the soundcard is listed to be able to drive up to 600 ohm headphones.
Speartongue
7
Sep 28, 2017
"I mean, you're just talking about the price of a house for most people, all told" -GUTB, 2017
Mr.Egg
0
Jul 3, 2019
Dude. No. People don't have that much disposable income for such a specific area of use. That's way too expensive.
CEE_TEE
3480
Sep 18, 2017
Hello Everyone,
Sorry it took a while, we did hear you.
There have been 6,647 requests for another drop of the Massdrop O2+ODAC DAC/Amp Combo: https://www.massdrop.com/buy/massdrop-o2-odac
We were not able to continue offering that version at the price point that made the product accessible, so we reached out to Grace Design for a new DAC that meets or exceeds all of the ODAC specifications (at a reasonable price).
Please meet the new Massdrop Objective 2 + Grace Design Standard DAC (SDAC) combo.
Designed to measure well, sound transparent, and be affordable.
Michael Grace does a great job of explaining some details about the SDAC here: https://www.massdrop.com/buy/massdrop-x-grace-design-standard-dac/talk/1806625
In addition: Since we have several DAC & Amp products available right now, here’s an overview to help with your options…
DAC & Amp Family UPDATE 9/18/2017: https://www.massdrop.com/talk/2363/audiophile-custom-products-dac-amp-update-9-18-2017
Thank you so much for all of the requests and support!
Sorry it took a while, we did hear you.
There have been 6,647 requests for another drop of the Massdrop O2+ODAC DAC/Amp Combo: https://www.massdrop.com/buy/massdrop-o2-odac
We were not able to continue offering that version at the price point that made the product accessible, so we reached out to Grace Design for a new DAC that meets or exceeds all of the ODAC specifications (at a reasonable price).
Please meet the new Massdrop Objective 2 + Grace Design Standard DAC (SDAC) combo.
Designed to measure well, sound transparent, and be affordable.
Michael Grace does a great job of explaining some details about the SDAC here: https://www.massdrop.com/buy/massdrop-x-grace-design-standard-dac/talk/1806625
In addition: Since we have several DAC & Amp products available right now, here’s an overview to help with your options…
DAC & Amp Family UPDATE 9/18/2017: https://www.massdrop.com/talk/2363/audiophile-custom-products-dac-amp-update-9-18-2017
Thank you so much for all of the requests and support!
ywang
13
Sep 20, 2017
should I get the Modi 2 and the new Magni 3 or this combo to pair with the HD6XX?
CarlosUnchained
122
Sep 21, 2017
Oh I see, so you gather an average of the measurements into one category called "quality power", so you can straight say X is better than Y in every case just by seeing Crosstalk and THD. That's plain dumb.
Quality power is just a made up word like cleanness of the sound.
I know that amps are more expensive not just because of power, but the components and circuitry topology. But there's a point where inaudible is still inaudible even if X has less THD than Y. When you have good enough measurements and performance that are already out of the human hearing levels, all comes down to personal taste, the tone of the amp. We can discuss also about layering and soundstage but that's 99% job of the transducer.
Jackula
1743
Sep 21, 2017
CarlosUnchainedExcept these measurements are not out of range of human perception. Our ears can pick up the smallest nuances in sound, almost anything measurable is audible, you just need to know what to listen for.
Specs do matter, to your point, a crosstalk figure of -65dB is extremely audible, if your average listening volume is 80-85db, you can get as much crosstalk as someone is whispering into your ear. But of course whether you perceive that also depends on your ambient noise. Also when it comes to THD+N, noise floor, etc don't put so much faith in them, they are usually measured at the optimal output level (I.e.sometimes less than 1/10th of the peak output, and the same measurements gets exponentially worse as you get closer to peak.
Ever wondered why amps have different flavours? Why one amp is more musical than the other? Simply because better components have better measurements, and better measurements give you a truer representation of the original recording. Or you could just be that type that think everything sounds the same and I'm just wasting my breath / typing here. To answer your question, I have listened to both the Modi and ODAC (which the SDAC is based on).
I used the term "power quality" as a lay man's term, because the audience here isn't that technical and I didn't want to type out paragraphs like above just to explain a simple point. Like I said, quantity before quality in general. You need to reach the headroom first so you don't get clipping distortion (which makes a huge impact to soundstage). Before you start considering the quality of your circuitry.
BTW, you don't have to be condescending to Cokeman and I just to make your point. List out your reasons, be open minded and we can have a civil conversation if you like.
Specs do matter, to your point, a crosstalk figure of -65dB is extremely audible, if your average listening volume is 80-85db, you can get as much crosstalk as someone is whispering into your ear. But of course whether you perceive that also depends on your ambient noise. Also when it comes to THD+N, noise floor, etc don't put so much faith in them, they are usually measured at the optimal output level (I.e.sometimes less than 1/10th of the peak output, and the same measurements gets exponentially worse as you get closer to peak.
Ever wondered why amps have different flavours? Why one amp is more musical than the other? Simply because better components have better measurements, and better measurements give you a truer representation of the original recording. Or you could just be that type that think everything sounds the same and I'm just wasting my breath / typing here. To answer your question, I have listened to both the Modi and ODAC (which the SDAC is based on).
I used the term "power quality" as a lay man's term, because the audience here isn't that technical and I didn't want to type out paragraphs like above just to explain a simple point. Like I said, quantity before quality in general. You need to reach the headroom first so you don't get clipping distortion (which makes a huge impact to soundstage). Before you start considering the quality of your circuitry.
BTW, you don't have to be condescending to Cokeman and I just to make your point. List out your reasons, be open minded and we can have a civil conversation if you like.
IsmaelK
5
Sep 22, 2017
Hey guys! I have the Fiio Q1 which I bought in anticipation for the HD6xx (and also for my HD 598). Do you think that it will be worth to expend 150$ having the Q1 already? Will it be a considerable improvement? Thanks a lot!!!
IsmaelK
5
Nov 21, 2017
I meant the one from this drop! (https://www.massdrop.com/buy/massdrop-o2-sdac-dac-amp)
I'm not an expert on these things yet but I'd say that "ODAC" was the name for the hybrid O2+DAC from JDLabs/Mayflower, isn't it? Let's see if someone can clarify :)
AdrianL
123
Nov 21, 2017
IsmaelKBoth of them got odac from the same guy who design it in 2011. So yes, they are the same, assuming they use the same material as well. Jdslabs since then came out with something better call El DAC and ol dac this year, as DAC technology has improved a lot past 6 years.
FuckHead-Fi
424
Sep 29, 2017
The SDAC has really good measured performance and so does the O2, so this is an excellent value for a reference DAC/amp. My $300 JDS Labs ODAC/O2 looks much nicer, but it would sound exactly the same.
tessierpg
Sep 29, 2017
Come on! Don’t you know that electricity in the USA for all common usage is 110v ? On what planet are you living?
RareAirs
156
Sep 29, 2017
tessierpgI googled it but sorry I know I'm not the brightest crayon in the box just a rookie here looking for something better than my creative e5
FrostyP
502
Sep 21, 2017
Claiming this is powerful enough to power the HD800 is a straight up lie unless you heavily modified the O2
E111
192
Sep 23, 2017
Do non isolated filtered banks ones generally make noise if only your amp/DAC is connected to it?
I'm guessing with the Tripp Lite Isobar Surge Protector Metal 6 Outlet 6-Feet Cord 3330 Joules I can connect my PC and monitor to it too? or best to get a smaller one like the 4 outlet just for my amp/DAC?
thedupuisner
61
Sep 24, 2017
I'm curious about a modi 3 too... Anyone heard any rumors? If it's a real product and follows the same path as the magni 3 then we should have a better, more feature rich product than the modi 2 Uber at normal modi 2 price!
DenisVi
29
Dec 31, 2017
Ugh, got a 220v adapter with a Type A plug, instead of C/F. This doesn't make sense.
Davd
3
Jan 14, 2018
Here's an update on my issue:
After protesting the previous response, Massdrop support offered me a partial refund of $20 for me to purchase a new adapter, so I am satisfied with how it played out.
BUT: Anyone that expected to receive the standard type C plug for a 220V adapter, when no evidence of the contrary was specified or depicted in any way, are fully justified in expecting a type C plug adapter and should be offered a partial refund immediately upon request.
Your move, Massdrop.
BUT: Anyone that expected to receive the standard type C plug for a 220V adapter, when no evidence of the contrary was specified or depicted in any way, are fully justified in expecting a type C plug adapter and should be offered a partial refund immediately upon request.
Your move, Massdrop.
generalguy41
21
Sep 21, 2017
Hi, kinda new to this stuff. What's the difference between the 110v/220v adapters? I'm Canadian if that makes a difference.
DenisVi
29
Sep 22, 2017
No. You're wrong. Ground wire outlet in the US would have a type B plug, which has nothing to do with mains (grid) voltage - that would still be 110v.
The three phase system is not for home use, and again, has nothing to do with ground. It has two live circuits.
The three phase system is not for home use, and again, has nothing to do with ground. It has two live circuits.
REVMAD
107
Sep 26, 2017
generalguy41in the u.s. most of our wall current plugs carry 110v , other countries use 220v according to goggle Canada uses the same as u.s. 110v
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