Drop + xDuoo TA-84 OTL Tube Amplifier / DAC – Clarity & Control Master

Drop + xDuoo TA-84 OTL Tube Amplifier / DAC – Clarity & Control Master

Drop + xDuoo TA-84 is a $399 USD ($349 USD on Pre-Sale) OTL Tube Amplifier with Pre function, DAC function, and excellent build quality, currently sold on Drop, designed for desktop usage, which we will be reviewing today, and comparing to other high-quality DAC/AMPs, including FiiO K9 PRO (849 USD), JDS Labs Element III MK2 Boosted (449 USD), EverSolo DAC-Z6 (459 USD), Feliks Audio Echo 2 (799 USD), and HIFIMAN EF400 (599 USD). 

 

Introduction

Drop is one of the largest marketplaces out there dedicated solely for getting the best deals for you. Drop is the kind of place where you will get the best price / performance ratio for the product you’re purchasing, and often they make special edition of the products they are selling, usually even better than the vanilla version, but often with a simplified package, getting a better price product in your hands, with the only hassle being that you have to wait for a while before receiving a product. The philosophy is that Drop orders a special number of products, for which they need a minimum number of products to be ordered, or they simply have a waiting time between ordering and delivery of a product. The best part about drop is that they have a no question asked return window for most products, for example TA-84 having a 30 days period of no-questions-asked return window, and they also make some of their products available on Amazon when they have stock. For most products available on Drop there is an estimated shipping date, for example TA-84 has an estimated shipping date of 22.12.2023 or December 22 this year, and you can cancel your orders until the pre-order ships for products that are available for pre-order, or up to 2 hours after checkout for products which are available in-stock. As an Amazon Influencer, I earn from qualifying purchases, and using the purchase links in my reviews helps me maintain this website and youtube channel. If you have not yet joined Drop, you can do so using this link, as it would help me a bit – https://drop.com/home?referer=6LSQPT

I’d like to thank Drop and xDuoo for providing the sample for this review, in exchange for my honest opinion. We are not receiving any incentive for this review and Audiophile-Heaven has no affiliation with Drop or xDuooo beyond this review. This review is a description of my personal experience.

 

Product Link

Official Drop Link – https://drop.com/buy/drop-xduoo-ta-84-otl-tube-amp-dac

You can grab one from www.amazon.com – https://amzn.to/47zfeTo

If you’re in the UK, you can grab one from www.amazon.co.uk – https://amzn.to/47QknpL

And if you’re from Europe, you can grab one from www.amazon.de – https://amzn.to/47SEXpk

 

Build Quality/Aesthetics

Sometimes just knowing a product is good isn’t enough, and adding the fact it has tube tech just adds that extra sprinkle of magic you need to get you hooked on. In fact, I think that there are two parts that get us excited about tube-based tech, the sonic and the visual part, since for some reason I find tubes so compelling to have around the house and to look at, and as I often put it, it is not enough for a product to sound good, it should be pretty to look at as well, for at least half the potential users to actually go for it. Back to Drop and xDuoo, TA-84 is their latest Tube Based DAC/AMP with 4 Tubes, namely a pair of EL-84 for the power amplifier part, and a pair of ECC-82 for the Preamplifier part. If you’ll be on the lookout for a DAC/AMP to use for desktop only, then you will only care about the ECC-82 Tubes. You can replace all of the tubes in the TA-84, and the default factory ones, at least on the review unit that have high-quality Psvane tubes. In fact, when checking out tubes from PSvane, the price of two ECC-82 Tubes is 49 USD, and the EL-84 Tubes can cost around 50 USD as well, so from the price of the unit, if it comes with tubes, almost 100 USD is the price of the tubes. 

We have a lot of attention to the design, with a huge and heavy power supply at the back, as the unit has a weight of 3KG, and with cooling holes all around the unit, including near the tube sockets, on every side possible, at the back at the bottom, and even at the back of the power converter. The Output transformerless topology, or OTL indicates that there are no output transformers, and the sound you’re getting from the headphone output is exactly the sound of the tubes, this indicating that TA-84 will be very sensitive to different tubes and their sonic signatures, plus it allows you to get more signatures from the same unit, just by replacing the tubes. As with most tube AMPs, it takes a while for the tubes to get to the ideal temperature, and the first minute or so you will not hear any sound, until the tubes start up, and the sound improves for the first half an hour to an hour, as the tubes stabilize at their working temperature. It is best to judge it after it has been running for at least 10 minutes, as cold tubes tend to not sound at their best, and tube tech is heat sensitive for music reproduction. 

As both xDuoo and Drop are aware that tube amplifiers can easily run into the issue of extreme distortion, and Tubes by their design generally have an increased distortion, they decided to solve the issue by not using any transformers. This is because most of the noise in tube amplifiers is usually gained when the transformers amplify the high impedance, low current, high voltage signal to a low impedance, high current and low voltage signal that is typically needed for IEMs and sensitive headphones. Although TA-84 is kept OTL in design, the company has capacitors designed by xDuoo in place of the power transformer, but the sound is still best for high-impedance headphones, such as the Drop x Sennheiser HD6XX and HD58X series. 

The volume control is provided by a stepped potentiometer, with 21 defined steps, perfect channel balance for each step, and there’s a gain switch at the back, which can give you a 0 dB or +16 dB gain, allowing for finer volume control. The gain switch seems to affect the line out too. There is an on-board ESS ES9018K2M DAC from Sabre, which goes as high as 32-Bit / 384 kHz, and which has a vertically placed Type-C USB input. The back has an input in the RCA format, and a line out with RCA format too. The line out always has variable volume adjusted by the volume wheel. The gain switch will affect the line out too. The DAC section is impressive, and has a S/N of 113 dB, Crosstalk of 88 dB, and a THD+N of 0.002%. TA-84 works with Android, MAC OS X, IOS, Windows, Linux. The internal DAC does not support MQA, but that’s not that relevant anymore, now that Tidal is phasing MQA out in favor of actual lossless streaming. 

The Amplifier part has a selectable AC switch, and I actually burned a fuse in the Drop x xDuoo TA-84 the first moment I received it, as it comes set to 110V by default, and I am physically in Europe, Romania, we have a 220V current running through our outlets, so when I first plugged it in I heard a quiet click and it never turned on. It then occurred to me that it may have a fuse and it may have variable input current voltage, so I switched it and it works flawlessly. The Output power is different from most amps as it gets more powerful at higher impedances, with an Output Power of 44 mW (at 100 ohms), 83 mW (at 300 ohms), 93 mW (at 600 ohms), all through a 6.3mm single ended headphone output at the front. 

Subjectively, the Drop + xDuoo TA-84 is far more impressive than I thought it would be, and it is really well thought and designed. First off, I love the fact that the feet at the bottom are tall, they allow for enough space for it to cool off better, but the feet are also solid, with a rubber that doesn’t allow it to slide on my desk. Even better, the feet are not in the physical corners of TA-84, and they allow for enough space for me to have it placed next to other devices, while a minor part of it sits hanging in the air, if I don’t have enough space on the desk, or audio support for it. The unit gets warm during usage, while the tubes get very hot, and it is not safe touching them, as is the case with most audio tubes. The best sound can be found when using the USB Type-C input, and its internal DAC sounds really good, even better than most external DACs will sound with it, as it has a strong DAC with no background noise, and it has a higher noise floor for the line input. The Line Out is really clean and quiet, with just a very faint noise for the tubes, that will only be audible if it is paired with a stereo amplifier that doesn’t have any volume control. 

Touching the chassis of the TA-84 does not produce any kind of noise, and even with it turned at maximum, most amplifiers and speakers will not have any kind of hum, noise or background noise. It is one of the most silent DACs / PREamplifiers that I heard to date, but this is true when it is using its internal DAC. Setting the volume wheel to absolute max will make the sound overdriven, to the point of distortion, but this will not happen if you are just one step lower. Higher volumes will have a higher overdriven character and sound a bit more distorted, but it is more similar to how a guitar amp increases distortion. There is a minor microphonic effect when touching the unit and adjusting the volume, but touching it does not cancel any noise, it just seems to transmit the noise it has on the case, which may be attributed to the tubes inheriting that noise and transmitting it, but the effect is incredibly quiet, and you can barely notice it.

Using it as a DAC, I tested the Drop + xDuoo TA-84 with the SVS Prime Wireless PRO speakers, but also with SMSL AO200 driving a pair of KLH Model Five speakers, and with a Burson funk driving a pair of NHT C3 Speakers. It is quiet in the background, and provides a clean and well defined sound to those. Even for line out, high gain and higher volumes sound more overdriven. I would recommend sticking with Low Gain and sticking between half and three quarters of the max volume for the best experience, that way you get the most of that tube character, but with the lowest distortion and the sound stays the cleanest most controlled. The gain switch is either a 0dB, or a +16dB, it is not a negative gain switch, but a positive one, and that is audible. There is no USB DAC delay that I can detect through any test. Turning off the unit will result in a short “pop” sound that’s audible in the speakers, so I would recommend turning off the speakers, if they are active, or the amplifier for the speakers before turning off the TA-84. The sound comes through both the speakers and the headphone output at the same time, and if you need to mute one, you either need to plug out the headphones or turn off the speakers / amplifier. 

For headphones, I tested the Drop + xDuoo TA-84 with a wide selection of headphones, including Sennheiser HD 660S2, Sivga SV023, Crosszone CZ-8a, Crosszone CZ-10, Dekoni Cobalt, iBasso SR3, Austrian Audio Hi-X60, and even with some planars, including HIFIMAN Audivina and Audeze LCD-5. Although this is advised against by the company, I have tried the xDuoo TA-84 with IEMs too, including 7HZ Legato, Sennheiser Ie800, Letshuoer Cadenza 12, Ambient Acoustics MAD16, IMR Dark Matter. With IEMs, there is a very quiet hum in the background of the left ear, and a similarly quiet hissing in the right ear, but this is using the TA-84 way out of the specs, and I actually would advise against using it with IEMs. This is because the Tubes expect a high impedance load, and if the impedance is too low, it is like connecting the tubes with a live wire and it could result in overheating and the tubes burning up. The background noise, even with IEMs, is so low that you cannot hear it even with the volume potentiometer set to the first step. The same happens with high-impedance headphones, and you do hear a minor hum in the left earcup and a slight hissing in the right earcup, but it is considerably below music playback levels, and even music playing at the first step of the volume wheel is considerably louder and will drown out the noise. What I would mention is that hitting the preamp tubes with your fingernails will transfer that noise to the earphones, or to the speakers, right tube right ear cup, left tube left earcup, but this is literally you hitting the filaments that amplify the sonic signals, so this microphonic effect is not out of the ordinary and a similar effect exists with most tube amps. On high gain, it has more than enough for Sennheiser HD 660S2 and Sennheiser HD800S to get really loud, stay controlled and distortion-free. 

 

Sound Quality

The sound of the headphone output is different from the sound of the line out, since the headphone output uses extra EL-84 Tubes, so you can expect them to be different. The headphone output sounds pretty similar to what the company describes on the drop website, and it is a heavy sound with a strong bass, a slightly overdriven tonality / texture for most instruments, and a warm, harmonically saggy sound that’s incredibly rich, and deep, with a deep bass, natural towards intimate soundstage, and with exceptional naturalness and lushness in the midrange. There is a bit more distortion than with similarly priced solid state amplifier, but the midrange is considerably richer, and most solid state amplifiers actually sound brighter, somewhat lacking in harmonics, and they distort the bass more easily, especially with hard to drive headphones, compared to TA-84 which has very little distortion with Sennheiser hard to drive headphones. 

When it comes to the DAC and Preamp parts, though, the way it is described for its sound, TA-84 would seem sloppy and slow, but that is not the way I would describe the TA-84, and this is a DAC/AMP that sounds even better than the company describes it, it is a really musical, clean, and detailed listening experience. The Preamp part is really capable, clean, and neutral-ish, similar to Feliks Echo 2, which is more than double the price. Overall, I feel like it is far more neutral and less specific as a DAC / Preamplifier, and the DAC inside is actually quite clean and has good resolution, has good dynamics and a contrasty sound with good soundstage, a wide and holographic presentation, and instead of sounding like a stereotypical tube Pre, it sounds more like a super detailed high-quality DAC with all the technicalities you typically expect and find around 700 USD. 

Starting with the bass, it is surprising to hear this, but TA-84 actually drives Sennheiser HD 660S2 better than most of the other amplifiers I have heard driving them like HIFIMAN EF400, FiiO K9 PRO, or JDS Labs Element III MK2 Boosted, as TA-84 has more control and better precision for the bass, with a deeper, more controlled, fuller and warmer bass. The trick here is that this only works for headphones with a really high impedance, like HD 660S2, or Sivga SV023, and with traditional headphones like HIFIMAN Arya Organic, or even with Audeze LCD-XC, the opposite is true, and the bass is cleaner and more controlled on the solid state counterparts, so impedance plays a huge role in what kind of bass you’ll be getting with TA-84. Percussion, both drums and cymbals are better defined and sound more contrasty with TA-84 than most solid state amplifiers for HD 660S2. Listening to most of my collection, TA-84 seems to have been tuned with ACG music in mind, as both Death Rabbits, Mori Calliope and HimeHina tend to sound much crisper with it than most of the equipment that I have while 

Drop knew that the strength is in the mids, and this is true regardless of the impedance, with TA-84 having one of the richest, most organically full and lush sounds out there. At least if you’re driving headphones, you can expect the sound to be super realistic, and classical music, jazz and even rock sound much closer to a real life interpretation than Solid State alternatives play them like. The drawback is that if the impedance is low, the midrange gets much thicker in tuning, which coupled with a shallower bass extension for low-z headphones, will result in a rather dark sound. With high impedance headphones, the detail in midrange is actually better, and many background instruments make more sense with TA-84 than with most alternatives, and you need to step in the super high-end to get the same level of richness and harmonic fullness TA-84 has. The soundstage can get wider and more holographic at louder levels, if using the low gain, and if the music is supposed to sound wide and holographic. This is a positive aspect, and Drop + xDuoo TA-84 will allow narrow and intimate songs to play narrowly and intimately, while wide and holographic songs, live performances will sound live and holographic. Somehow, it manages to reproduce the material that was recorded faithfully, and I find this super pleasing for most music. Most of this experience is with either Sennheiser HD 660 or Sivga SV-023, both of which have a high impedance. 

The treble is clean, well extended, airy and clean. This is the best part about the TA-84, compared to most entry-level tube amplifiers, as most will try to get away with killing the treble and make the sound rather dull and dark, to get the impression that they are using high-quality components, but Drop and xDuoo actually get the treble right, they allow the treble to play in its full width, weight and extension, with Sennheiser HD660 S2 having pretty much the same treble extension and airiness with TA-84 as it has with other DAC/AMPs, but with a richer presentation, smoother texture, and a more pleasing overall presentation. It feels like the treble, as presented by TA-84 can sound more like actual treble and has less aliasing / less harshness. The effect is opposite for low-impedance headphones, where TA-84 can sound dark and has a soft roll off that happens starting with the upper midrange. 

All in all, if you have a pair of high-impedance headphones, or if you plan on using the TA-84 as a DAC / Preamplifier, it is incredibly clean, rich, and harmonically lush, it sounds just right, correct, and actually gives sense to the instruments playing in the background, background voices, creating the soundstage just as it was intended in the original song. In fact, it is one of the most transparent and distortion-free DAC/AMPs in the ~400 USD price range, if used correctly, where it can truly shine, and I honestly found happiness in hearing it and knowing you can have this kind of experience without breaking the bank. You’d need to spend thousands of dollars to get a similar experience to a Drop + xDuoo TA84 and a pair of Sennheiser HD 660 S2.

 

Comparisons

Drop + xDuoo TA-84 vs JDS Labs Element III MK2 Boosted (399 USD vs 449 USD) – The first comparison is almost always the hardest, and it hits right in the soul of music lovers, because Element III Mk2 Boosted is a really capable DAC/AMP, with especially strong performance sonically, and with a lower background noise level compared to TA-84, which will have a faint hissing in the background in comparison. The overall driving power is much higher on Element III, and it can drive all sorts of IEMs and Headphones with no audible noise, but TA-84 is better at driving high-impedance headphones in particular, having a richer, deeper sound with more bass, a more controlled bass, and with a more lush midrange that has a more cohesive harmonic presence. Both have volume control for when they are used with a desktop amplifier, so both can be considered preamplifiers, and both have just one USB input, and just one RCA output, so both are equally good for the same purpose when used for desktop, although JDS Labs Element III MK2 Boosted will sound more neutral, less rich, and the midrange will be colder, more analytical, whereas TA-84 will sound more juicy, more organic, will have a higher degree of harmonics, will sound richer, and at the same time deeper, those PRE tubes being easily audible when it is integrated in a desktop setup. 

Drop + xDuoo TA-84 vs EverSolo DAC-Z6 (399 USD vs 459 USD) – DAC-Z6 is slightly more versatile than TA-84 and it has some nifty features, but in the long run I almost always grab TA-84 more for desktop usage as a preamp, or for driving hard to drive headphones, it sounds more detailed, cleaner, and has a more organic sound that is richer, with a fuller body, more bass impact, and a airier treble with better definition. You could say that DAC-Z6 is more versatile and it surely can handle being a desktop DAC/AMP, but sonically, TA-84 has the edge in both resolution, but also in how warm, organic and smooth it sounds. The choice here is rather simple, you get TA-84 if you like sonics more than design, or you grab DAC-z6 if you need RCA and XLR outputs, or a higher number of digital inputs, or streaming. 

Drop + xDuoo TA-84 vs Feliks Audio Echo 2 (399 USD vs 799 USD) – Now we’re down to apples vs apples, and both of those AMPs have an OTL design, both have a good build quality, but TA-84 has the added bonus of a DAC function, which can be really handy as most entry-level and even midrange DACs tend to be noisy on the line out, and there are very few exceptions that don’t have the problem. The preamplifier function works well on both, both have a low background noise level, Echo 2 has a lower background noise level, and this is one of the reasons it costs more than double the price of TA-84, you don’t really hear any background noise with Echo 2, and somehow it manages to be more consistent when using both hard to drive and easier to drive headphones, including some IEMs. When making a choice here, you have to consider the budget, Echo 2 is more than double the price of TA-84, and it does not have a DAC, so a setup including it will run you over 1000 USD if you want to get a proper sound and experience from it, while with TA-84 you can have a high-quality midrange setup that can last you years, even more, if you have high-impedance headphones. Since you’re likely going to use high-impedance headphones with Echo 2 as well, I would recommend TA-84 to both beginners and those who have a good selection of high Z headphones, and Feliks Echo 2 only if you already have a DAC around 600 USD or more, and wanting to get some tubes in your setup. 

Drop + xDuoo TA-84 vs HIFIMAN EF400 (399 USD vs 599 USD) – The build quality is great on both, and EF400 has a few tricks that can make it appealing to music lovers, including being an R2R DAC, with both R2R and filtered mode. EF400 has more headphone outputs, but it has a bit more background noise when used as a desktop DAC, although both have a faint hissing in the background, that you may notice when no music is playing, but most listeners will likely not notice it with music. Both can drive hard to drive headphones rather well, and both have a good dynamic range, but EF400 will work better with HIFIMAN Planar magnetic headphones, while TA-84 works better with high-impedance headphones from Sennheiser and Sivga. I tend to prefer the sound of EF400 for IEMs, it has a lower background noise and is more stable, also planars in general work better with EF400, but TA-84 does dynamics in general really well. Neither DAC/AMP doesn’t have any kind of detectable USB DAC delay, both work well with no extra drivers, both play well in my system. TA-84 will have a richer sound, with less treble sharpness, a smoother treble, and more bass, with a heavier bottom end and more impact. EF400 is more forward, more dynamic, and has more focus on detail and resolution. Both should make most listeners very happy, EF400 is better if you have IEMs and planar magnetic headphones, TA-84 can make the sound more interesting for high-impedance headphones. 

Drop + xDuoo TA-84 vs FiiO K9 PRO (399 USD vs 849 USD) – Generally speaking, the build quality is excellent for both DAC/AMPs, but FiiO K9 PRO has a wider selection of inputs and outputs, as it has both SE and balanced headphone outputs for headphones, more line outs (both se RCA and balanced XLR outputs), and it has more digital inputs. When it comes to how each drives headphones, it really matters what kind of headphones you’re driving, and FiiO K9 PRO has a really flat sound, which is perfect for studio and precision work, but it can be somewhat too flat for some listeners, and here is where TA-84 will surely please, it sounds much fuller, more lush, more harmonically rich, and way less clinical than K9 PRO. The trick is that TA-84 really works well either if used as a DAC for a full sized system, or if used with high-impedance headphones, a situation in which it sounds considerably richer and more tonally pleasing. FiiO K9 PRO and its super correct sound can be more resolute, but background instruments, as well as certain effects and textures make more sense with TA-84 when using high-impedance headphones, because that harmonically rich tube sound makes a lot of sense to our human ears. The only thing that is missing would be a subwoofer output, which I deal with by using the RCA for Subwoofer and XLR for speakers on K9 PRO. There is no USB DAC delay with either and both work really well, but TA-84 will cost extra when the tubes burn out, but that takes 2-3 years realistically speaking, for most people. 

 

Value and Conclusion

Regardless whether you decide to grab one of those excellent DAC / AMPs during the presale and get the 349 USD Special pricing, or if you’ll wait and get for the full price of 399 USD, xDuoo TA-84 has outstanding price / performance ratio, and it is at that sweet spot where it offers much more than most of the competition, and an excellent experience and performance all-around, with a good build quality, outstanding design, excellent sonics, and multiple usage scenarios, not needing an external DAC, or anything else and being the one DAC/AMP/PRE that you can integrate in your system and give it a truly magical sound. 

Before the end of today’s review I want to add the Drop + xDuoo TA-84 Tube DAC / AMP / PRE to the Audiophile-Heaven Hall Of Fame for its excellent performance, superb aesthetic design, and for its excellent build quality, plus for being the most affordable tube PRE / DAC that actually works well and has no audible distortion for the DAC / PRE output, and can really drive hard-to-drive headphones easily. 

At the end of today’s review, you likely learned what an OTL amplifier is, and if you’re looking for such an AMP, or if you need a DAC or a PRE that will sprinkle some of the tube magic we all yearn for, xDuoo TA-84 is a fully recommended product and one of the most affordable DAC/AMPs I can recommend that sports actually high-quality EL-84 and ECC-82 Tubes and tube sockets for you to tune your sound. 

 

Product Link

Official Drop Link – https://drop.com/buy/drop-xduoo-ta-84-otl-tube-amp-dac

You can grab one from www.amazon.com – https://amzn.to/47zfeTo

If you’re in the UK, you can grab one from www.amazon.co.uk – https://amzn.to/47QknpL

And if you’re from Europe, you can grab one from www.amazon.de – https://amzn.to/47SEXpk

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Full Playlist used for this review

We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature.  I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!

https://www.youtube.com/playlist?list=PL_cjBXGmwSHSdGcwuc_bKbBDGHL4QvYBu

https://open.spotify.com/playlist/5J3oloz8Riy9LxEGenOjQ0?si=979ba4f082414be7

https://tidal.com/browse/playlist/330fd544-8e5b-4839-bd35-676b2edbb3d5

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