Shelt-ODid you ever find a solution to this? Iv noticed this if i turn the gain on high. Occasionally i can get it to stop if i switch USB ports on the pc but it will sometimes return. Weird that we are both getting that in the right ear only.
Shelt-OAre you able to swap both tubes to see if the buzzing also changes sides? It's also good to check if there are any Bluetooth antenna's close to the amp which can pick up on interference if its close by.
I immediately returned my Schiit stack for this bad boy
I could not be happier with this amp. Within mins (it might have even been seconds), I knew it was a keeper. I'm running Sennheiser 660S2 and there's so so much power, warmth, and joy in the sound. It's engaging, makes you fall in love with your music again. I emailed Schiit to return the stack i just bought (and really, really liked) within the first 20 mins of listening to this wonderful amp.
Today I found a really long, ancient, piece of sh*t RCA cable in a box and hooked the TA-84 to my Wiim Ultra / Marantz 2270 / legendary and heavenly Yamaha NS-1000m (seriously, if you have a chance to get them - get them no matter the condition) and B&W sub run by the Wiim. The sound is just wonderful -- rounded, big, yet somehow still has crisp attack/decay, warm and cozy, and a little bit of a sloppy mess in the best way possible. The Marantz already produced sound like that -- the addition of the TA-84 as preamp took it to another level.
Next move it to connect a Thorens TD-160 back for some good ole headphone sessions. Can't wait.
Only complaint -- would have been great to have another digital input -- coax? optical? One USB will do, but would be so so nice to hook more up to it directly.
I have owned this Tube Amp for over Six months and have switched to other NOS tubes - did change the sound / the unit can change the sound with different tubes. I did notice quality of the sound will get a bit of static noise if you go 1/2 way pass with the volume. I set the volume to the midpoint , run a GESHELlI Dac and pre-amp out through my A/V amp : this helps control the sound without hearing any buzzing sound. I’m happy happy with this unit and cost .
Peace Out unit next time !!!
Jaydee1I like to tube roll - trying Some NOS RCA 12AU7A in front and Genalex Gold Lion EL84 Power Tubes in the back : got a soft reserved sound
Right now - using Ray Tubes 12AU7 SELECT Vacuum Tubes in front and Genalex Gold Lion EL84 Power Tubes in the back : getting a clearer forward sound / I like Mo Better!!
The TA-84 arrived yesterday, and I have spent about 8 hours listening to various music so far. I am pleasantly surprised with the sound. Not thick and woolly, but rather just on the warm side. I have tried it with both the Sennheiser HD-6XX and the 8XX. There is plenty of power to deliver music at my listening levels. No channel imbalance as far as I can hear. I am leaning towards using the HD-6XX as they pack some more punch than the HD-8XX.
The DAC does a good job and resolution is good. I will have a go at using different DACs to feed the amp later, but for now, as I am happy listening to the unit with stock tubes and the built in DAC.
The unit itself gets warm, not hot. The power button is on the back, but I can easily reach it without touching the tubes or any other warm surface. I wish the switch was on the front as it would have been easier to switch it on/off when placed in a more confined space.
At this price point I think it is a good way to get into tube amps and it even has a DAC built in.
This is my first tube OTL amp, so I didn't have any experience with this type of amps.
I really like how it looks, it was the main reason when I decided to buy something special to my setup. It has (thanks God) red LED instead of bad sounding blue LED. The color is matte black and it integrated in my system just perfect.
I have a really good external R2R DAC, so I didn't use the internal one, nothing to say here.
The ability to work both as an amp and pre-amp is a killer feature for me. I mainly listen to music on my stereo system and sometimes with a headphones.
Love the sound it produces so much. Clear, punchy, warm and liquid. I spent all night long listened to my music collection on CD's, vinyl and Hi-Res streaming services.
Build quality is a high level. Precise, sturdy, with a good tactile texture. Very well done.
No hum, no buzz (you can hear some tiny buzz at high volume level where the music is not playing, but it's totally ok, nothing wrong with it).
MakabrHD6XX are essential for this amp. With a proper DAC you will fly away to another universe. Actually even Grado SR225X sounds so good with a high gain, idk why since it's only 38 Ohms!
Received 7/2024, nice and quiet, sounds great, no issues.
I receieved this in 07/2024, nice packaging, easy to set up. Inserting tubes was a minor challenge with only one tube pin wanting to bend. So be careful out there as you plug those tubes in. Inserting the tubes requires more force than you think so be very careful and use a towel or paper towel to avoid getting oil from your fingers on the tubes which may migrate through the quartz over time and crack the tube (but which never actually happens in real life). Still- do it correctly, its half the fun.
The amp gets hot but lots of ventilation holes are built in. There is a minute or two to soft start so don't get misled by a of silence after switching this "on."
Tried initially with headphones: HD800, HD650 and Shure 1650. All sounded great, "high" gain is your friend, but the 1650 did not need it.
Next, connected analog inputs to my DAC outputs and then preamp output to power amp- you need "high" gain here but it sounded fine, has that nice tube warmth.
Inputs: worked well with battery sources- AK 100 II on analog inputs. Cell phone with USB host adapter cable was detected and digital audio decoded on the USB C input.
NOISE/HUM: I was worried about all the reviews which mention hum, noise, microphonics. I got none of that with use as preamp. Repeat- dead silent at tweeters of speakers when cranking loudly and hitting pause to check noise. Only a tiny amount of hiss/60Hz at high gain/ high volume with use as headphone amp where you can hear everything much more clearly with minute details easily noticed. This was barely there and only at massive volume. Not bad at all, impressed actually.
You would expect some small amount of hiss and noise from a tube preamp and I have had a lot of tube amps/preamps here over the years. I was very happy about this unit where noise/hum can barely be perceived, and only in headphone mode. Noise in my unit is not an issue. Hope this is the case for all of you out there.
Overall, very relieved and happy. It sounds as it should with no issues at this time.
Do not fear the tubes! Mitigating microphonics, hum and RF interference
This product deserves a better rating, so here's mine to help the rating average, as so many negative reviews are surrounding the heading of my review.
There are inherent microphonics and RFI in any tube product - cell phones and WiFi were not prevalent when tubes were designed with RF stubs that act like little antennas.
All that said, please see my post on the discussion tab - barring a faulty unit due to shipping or handling - some distance from interference sources is all you need to get great performance on a high impedance headphone
If the tubes or socket are mishandled in any way, there could be permanent mechanical damage that results in unusual microphonics, hum or increased RFI.
Insertion of tubes takes practice to get right. Watching some tutorials on YouTube can help get to be confident on your first attempt.
Hope this helps those on the fence, to not be deterred by avoidable issues.
The biggest issue it has is there's a hum that plays through the headphones. It hums even with nothing but a power cord and headphones connected to it. The only way I could mitigate it is pushing down the preamp tubes. After pushing them both down, it got much quieter, but was still there. It would come back once I quit pushing them.
Another issue is the volume knob had a ton of friction, so it was really hard to turn. It had a rubbery feeling when turning it, like it was turning against a rubber piece.
Another issue about the volume knob is channel imbalance. This may be related to the friction when turning it. When I'd turn the volume down, it would usually be quiet on one side. I would have to turn it down one notch then back up to get them to be balanced again. This was much worse on the lowest 15 or so percent of the volume dial, but it happened everywhere.
My unit also had an issue with the input selector switch. When I'd have it set to one input, I could sometimes hear sound from the other input. The sound from the other input was slightly muffled, but it was very audible. I even used it for like 10 or 15 minutes with it on the wrong input at one point, and I didn't even know. I just figured the recording I was listening to had an issue. Switching to the other input then back would fix it.
My next complaint is one that has affected all the tube amps I have tried, but I'll mention it here too. When it turns on, it makes a loud pop. It also does it when you change the input.
The last issue I had with this unit is the tubes seemed very microphonic. Both sets of tubes are affected but the preamp tubes are much worse. I first noticed this when I accidentally touched one while I was wearing headphones plugged into it. I think this may be related to the humming I talked about in my first complaint. It's so sensitive to noise, moving slightly would sometimes cause a pingy tube noise from the slight movement of the headphone wire plugged into the amp.
A nitpick is it's really loud. Xduoo amps always seem to be loud, and it's no different here. Be careful when using it.
I ended up returning mine. I was excited for this amp to come out, and I waited months for it, so I was disappointed that it had these flaws. If they fix these flaws, or if you get a unit without them, I think this would be a good amp.
Edit: I should also say I was using HD600 and HD6XX headphones.
collin123My volume pot works well throughout the range, no issues at the low end and with an external attenuator on the high end, there were no channel imbalance issues.
update: the DAC died after 2 months of use, and after 7 months it started to make a static noise in the right channel even when at minimum volume. not recommended if you only get a few months of use from it.
Love the rich and creamy sound signature, pairs great with the HD600 and love it as a preamp for my desktop speakers.
The problem is that getting the USB C DAC to work is a real hassle. It needs to warmup for like half an hour, and me to switch the power on and off a few times until it works.
In conclusion, I would get it as a preamp sourced through a dedicated DAC.
Drn10nYou might want to get in touch with customer support. For me it works after 20 seconds or so. You hear a distinct click (just from standing nearby without headphones plugged in) and it's ready to go. Unless you're under the belief that the DAC needs longer to warm up to deliver optimal sound, which is not true since it's entirely solid state.
Dear friends here is a summary of my review which is available in ichos-reviews and Headfi.
Non Audio Stuff
The Drop + xDuoo TA-84 amplifier has an oblong, rectangular shape, measuring 26.8x16.3x11.6 cm, so it is quite tall but also narrow and compact enough to fit virtually anywhere as long as you have enough height clearance. The chassis has a full aluminum alloy construction with a smooth black finish and is exceptionally well made without sharp edges or corners.
The design is simple and minimalistic, this is a classic tube amplifier, the tubes are positioned at the front part and the power transformer is encapsulated in a box at the back. All four tubes are freely accessible and they are very easy to replace.
The front panel is plain and clean, the volume control knob is located at the center and underneath there is a status red LED and the 6.35mm headphone jack. Everything else is at the back; AC input plug, power on/off switch, voltage selector switch, USB type-C input, RCA line input, RCA preamp output as long as gain and input selector switches.
The amplifier has a soft start feature that allows about two minutes of tube warm time before it switches on. Operation is pretty simple, you can either use the line input with your favorite source or the onboard USB DAC without the need to install drivers.
Power output
The rated output power is 44mW/100Ω, 83mW/300Ω and 93mW/600Ω. These numbers might look low and underwhelming but don't pay attention. This is an OTL amplifier that produces the great voltage swing that is needed for driving high impedance headphones. The xDuoo TA-84 is very powerful when it comes to such loads and can drive all high impedance headphones without breaking a sweat.
I have tested the amplifier with the Sennheiser HD8XX (300Ω), Sennheiser HD660S2 (300Ω), Sennheiser HD650 (300Ω) and the iBasso SR3 (150Ω). The amplifier literally blew them away, it drove all of them with excellent dynamics and surplus of headroom at just ¼ of the volume range at the high gain setting.
The amplifier has a low noise floor, it is not dead silent but you have to raise the volume above middle to start listening to some tube hiss and transformer noise. There is no point in discussing the behavior with low impedance, high sensitivity headphones since the xDuoo TA-84 is not made for them.
Stock tubes
The stock ECC82 and EL84 tubes that are included in the package are from the Psvane classic series but they seem to be OEM made for bulk production without thorough quality inspection and any kind of matching.
Both the ECC82 tubes that came with the review sample were very microphonic and one of them was also defective as it produced heavy background hissing noise. The power tubes were good but in the end I have decided to replace all four of them.
Both types of tubes are quite common, they are currently produced by all known manufacturers and they are not too expensive. After checking prices and availability, I decided to order matched pairs of JJ Electronic tubes for both the ECC82 and EL84 variants.
After replacing the tubes, the amplifier became silent without producing background hiss or microphonic noise and worked just fine. Furthermore, the JJ EL84 power tubes proved to be more dynamic, controlled and technically potent than the stock ones so I suggest that you should do some tube rolling to get the most out of the amplifier.
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Audio stuff
The sonic performance of the xDuoo TA-84 is really great, this is an amazing little amplifier with a favorable and immensely enjoyable sound character that combines plenty of tube magic with very competitive technicalities that are easily comparable with solid state amplifiers of the same category.
The sound is slightly warm, rich and harmonious with great musicality and an incredibly analog character. The timbre is natural, organic and realistic, all acoustic instruments and voices are reproduced with an extremely lifelike manner, the most colorful harmonies and varied overtones.
The xDuoo TA-84 amplifier has a modern way of thinking when it comes to its tube implementation. The audio circuit is designed as neutral as possible without adding much coloration to the sound or altering the linearity of the measured frequency response. This is not like some old tube amplifiers that used to mess with frequency response, mute the treble or boost the mids and the bass to make the music sound syrupy, warm, blurry, hazy and slow without much control and definition.
Technicalities are kept solid and very competitive, the xDuoo TA-84 is a neutral and linear sounding amplifier without compromising in treble extension and clarity. The sound is sparkling and energetic with great definition and excellent detail retrieval for such a type of an amplifier. The bass is fast, tight and controlled with good layering and the mid-range is spacious, present and well defined without any significant coloration.
So, someone would ask what's all the fuss about tubes? Well, what really happens is that the tubes have the ability to mostly enhance even harmonics throughout the whole frequency range, making for a pleasing and smooth sound with analog-like characteristics and plenty of musicality. They add extra weight to the low-end which is visceral and full bodied while maintaining great dynamics and physical impact. Full bodied and weighty are also the mid and higher frequencies so the sound is very cohesive without exhibiting any kind of weight loss in the treble. The decay is natural, the notes fade away in a timely manner, not too fast or too slow and are finely sculptured with a holographic relief.
There are solid state amplifiers of the same price category that are definitely more technical sounding, with better transparency and clarity, deeper detail retrieval and more impactful bass but none of them can match the inherent musicality, the harmonious nature and the music fluidity of the xDuoo TA-84.
No competitive solid state amplifier is as visceral and full sounding as the Drop + xDuoo TA-84 and only few of them can match the holographic properties of its soundstage. The soundstage is amazingly open and spacious, both expanded and deep with largish images. You can certainly find several solid state amplifiers that can surpass the xDuoo TA-84 in imaging precision and positioning accuracy but no one of them can sound more holographic and majestic.
The DAC
The onboard DAC is crystal clear, linear and transparent so it pairs well with the plethoric nature of the amplifier. Very good and satisfying performance to boot up or when funds are limited but honestly, the xDuoo TA-84 scales incredibly well and you are going to do much better with a high quality, external source.
Conclusion
The xDuoo TA-84 might be Drop’s first all-tube, OTL headphone amplifier but I think that is their best sounding product thus far. Musical, engaging and analog sounding, this is a great amplifier with competitive technicalities, great tube rolling potential and plenty of power to drive all high Z headphones. Well made and sturdy, with a high quality onboard DAC and preamplifier output, the Drop + xDuoo TA-84 represents an excellent value and is one of the best OTL amplifiers you can buy without the need to break the bank. Actually, given the current offerings in the market, you will have to spend at least double the money in order to get something marginally better than the xDuoo TA-84 so I would suggest you hurry and get one while it is still available.