Drop + xDuoo Introduce TA-84 OTL Tube Amp/DAC

[T0@st]

Take a look—or a listen—at the last ten years here at Drop, and you'll notice no shortage of award-winning amplifiers. Despite this decade-long discography, there's one type of amp we haven't touched. Now, it's finally coming down the tube. That's right: our first all-tube OTL amplifier is here—complete with a rock-solid DAC stage to complete any signal chain. Meet the Drop + xDuoo TA-84 OTL Tube Amp/DAC. Designed to deliver signature tube "warmth" without excess noise, this compact desktop powerhouse utilizes Output Transformerless (OTL) topology to manage signal without a transformer, greatly reducing distortion.

For the preamp phase, it features dual ECC-82 tubes; and for the power amp phase, it runs dual EL-84 pentodes—both popular options in the audiophile amplifier space. To hit that sweet spot with any set of headphones (or powered speakers), the TA-84 is also equipped with an ultra-precise stepped potentiometer for volume control, plus a gain switch to further control the output level. On Drop, and on your desk—it's tube time. Finally.




OTL AMPLIFICATION: TUBE WARMTH WITHOUT THE NOISE
When a certain analog richness is what you want from your amp, most audiophiles will tell you: there's no substitute for tubes. Inherent in their cathode amplification is a whole collection of warm, overdriven, and sagging harmonic character. However, when other components are factored in, that harmonic character can quickly compound into noise. For some listeners, this is where the tube fun stops. In those cases, the culprit is often the transformer: a component dedicated to transferring the high impedance, low current, high voltage signal of the tube to the low impedance, high current, low voltage signal required for headphones or speakers. In the TA-84, we solved this problem by using Output Transformerless (OTL) topology to handle this transformation with no transformer. In its place, we implemented xDuoo-designed capacitors in the power amp to do the job. They're exceptionally quiet and impressively linear—but since they're outputting from the power tube, which is a relatively high output impedance, they work best with higher impedance headphones. (We recommend pairs with a 100-ohm impedance or higher.) Luckily for you, we've got a few great pairs to try. For starters, check out our audiophile mainstays: the Sennheiser HD 6XX and HD 58X.



ADDITIONAL AUDIOPHILE FEATURES TO DIAL IN YOUR SOUND
Beyond its OTL topology, the TA-84 is equipped with a range of components and features to help you achieve the ideal tube-driven listening experience. We've already mentioned the tubes—two ECC-82 tubes in the preamp and two EL-84 pentodes in the power amp—both of which are not only highly regarded but also widely used, making them easy to swap between manufacturers. Another performance feature is the stepped potentiometer, which has 21 defined steps (each with a specific value of resistance) to help you achieve unparalleled precision, reliability, and channel balance in your output level. Paired with the gain switch in the back, this potentiometer provides 42 settings to hit the perfect, repeatable setting for your favorite pair of headphones—or powered speakers. Use the TA-84 as a preamp for any power amp or pair of powered speakers, like our BMR1. You can use it for conversion, too, for the headphone and preamp outs—thanks to an onboard ES9018K2M SABRE32 Reference DAC with 32-bit 384-kilohertz PCM sampling rates for seamless playback.



XDUOO: DRIVING AUDIO FORWARD
When searching for a collaborator to build our very first all-tube amp, we landed on the brand behind many other brands' bestselling amplifier designs. It's xDuoo: an established name in the audiophile space—as both an original design manufacturer (ODM) for a handful of other big audio names, and a manufacturer of its own highly regarded amplifiers, DACs, audio players, and more. With a robust R&D team that's been raising the bar for accessible audiophile performance since the very beginning, xDuoo has become a go-to choice for both the budget-conscious and the audio-sensitive. Hear why in the new Drop + xDuoo TA-84 OTL Tube Amplifier.



SPECS

General:

• Drop + xDuoo
• Inputs: RCA, USB-C
• Headphone Outputs: 6.3 mm TRS (¼")
• Preamplifier Output: RCA
• Dimensions: 10.6 x 6.4 x 4.6 in (26.8 x 16.3 x 11.6 cm)
• Weight: 6.6 lbs (3 kg)

Amplifier:

• Power Source: AC 110 V (100-120 V) / 220 V (220-240 V), selectable
• Power amplifier tube: (2) EL-84
• Preamplifier tube: (2) ECC-82
• Gain switch: +16 dB
• Output Power: 44 mW (at 100 ohms), 83 mW (at 300 ohms), 93 mW (at 600 ohms)
• Frequency response range: 10 Hz - 80 kHz (± 0.5 dB)
• Crosstalk: 65 dB
• SNR: 102 dB
• THD+N: ≤1%
• Recommended headphone impedance: 100 ohms - 600 ohms (amp is not well suited for planar magnetic headphones and low impedance headphones due to OTL topology)

DAC Section:

• DAC Chip: ES9018K2M
• Sampling rate: PCM 16-bit - 32-bit / 44.1 kHz - 384 kHz, DSD64 - DSD256
• THD+ N: 0.002% (at 1 khz)
• S/N: 113 dB
• Crosstalk: 88 dB
• Compatible operating systems: Windows, Linux, Mac OS X, IOS, Android

SHIPPING
Estimated ship date is Oct 31, 2023 PT. Payment will be collected at checkout. $329 (pre-order special) or $399 (regular pricing). Cancellations are accepted up to 2 hours after checkout for in-stock items, or up until pre-order ships.

View at TechPowerUp Main Site | Source

 

[SoundMix]

I'm looking at this from a Recording Engineer/Mixer/Producers point of view. For the past 4 decades all the recording consoles, digital/analog recorders, and processors I have used, many of these consoles with price tags well over one million US, the one thing they all have in common is... NONE of them have any freaking tubes. Every one of these consoles/recorders have literally thousands of IC's and transistors. Some of the gear, analog, and much digital. If you think that a single tube or multiple tubes, is a good thing that will improve the sound of audio that has already been processed by millions of transistors, I whole heartedly disagree. A tube circuit may/will color the audio, and you may like that coloration, but it sure as hell won't undo or improve upon what has already been done in the studio.

 

[TheLostSwede]

I'm looking at this from a Recording Engineer/Mixer/Producers point of view. For the past 4 decades all the recording consoles, digital/analog recorders, and processors I have used, many of these consoles with price tags well over one million US, the one thing they all have in common is... NONE of them have any freaking tubes. Every one of these consoles/recorders have literally thousands of IC's and transistors. Some of the gear, analog, and much digital. If you think that a single tube or multiple tubes, is a good thing that will improve the sound of audio that has already been processed by millions of transistors, I whole heartedly disagree. A tube circuit may/will color the audio, and you may like that coloration, but it sure as hell won't undo or improve upon what has already been done in the studio.

Still a lot cheaper than going down this route...

This Japanese pensioner built an electricity pylon in his garden to improve the sound of his records - The Vinyl Factory

The ultimate quest for audio perfection. 82 year-old retired lawyer Takeo Morita is a contender for the world’s most dedicated audiophile. Nicknamed ‘Rock Grandpa’ by his local record store, Morita paid $10,000 to plant a 40 foot utility pole in his garden that he has connected to the power grid...

thevinylfactory.com

 

[Ferrum Master]

Considering I've been building OTLs for more than 15 years...

EL84 is a weird choice for output tube in OTL mode... basically you have to use 6AS7/6080(soviet 6H13C, with added heater current 0.5A) as those have pretty much low plate resistance ~300Ohm. Basically paralleling them you get 150ohm and that's pretty much okay for driving high Z headphones. EL84 has 38kOhm resistance, basically making this a very weird product. It is botched. It ain't suitable for OTL.

 

[Tahagomizer]

I'm looking at this from a Recording Engineer/Mixer/Producers point of view. For the past 4 decades all the recording consoles, digital/analog recorders, and processors I have used, many of these consoles with price tags well over one million US, the one thing they all have in common is... NONE of them have any freaking tubes. Every one of these consoles/recorders have literally thousands of IC's and transistors. Some of the gear, analog, and much digital. If you think that a single tube or multiple tubes, is a good thing that will improve the sound of audio that has already been processed by millions of transistors, I whole heartedly disagree. A tube circuit may/will color the audio, and you may like that coloration, but it sure as hell won't undo or improve upon what has already been done in the studio.

It's true that tubes distort audio. Some people like this distortion because it gives music "character". Personally I consider this to be snobbery or audiofoolery but, whatever it is, some people want it and are willing to pay a lot of money for it, so manufacturers are more than happy to accommodate the demand. Exactly the same with vinyl records, it's a very technologically backward, low quality format but some people want it. Remember that for most people quality doesn't matter.

 

[holyprof]

It's true that tubes distort audio. Some people like this distortion because it gives music "character". Personally I consider this to be snobbery or audiofoolery but, whatever it is, some people want it and are willing to pay a lot of money for it, so manufacturers are more than happy to accommodate the demand. Exactly the same with vinyl records, it's a very technologically backward, low quality format but some people want it. Remember that for most people quality doesn't matter.

Also, for people that appreciate that particular distortion (ahem, colour), you can obtain the same using digital processing applied to the source signal. Also, from technical standpoint, you could obtain sound similar to tubes using specially crafted FETs, which, unlike bipolars, work pretty much like tubes. Another idea for false "audiophiles" - buy an empty vinyl record, put some dust on it, distort it with a bit of heat to create the subsonic waves of old vinyl, record and mix it with your music - voilá vinyl sound!!!

 

[Wirko]

Considering I've been building OTLs for more than 15 years...

EL84 is a weird choice for output tube in OTL mode... basically you have to use 6AS7/6080(soviet 6H13C, with added heater current 0.5A) as those have pretty much low plate resistance ~300Ohm. Basically paralleling them you get 150ohm and that's pretty much okay for driving high Z headphones. EL84 has 38kOhm resistance, basically making this a very weird product. It is botched. It ain't suitable for OTL.

Impedance is not the issue, the tube is probably in a cathode follower circuit with an output impedance of ~90 ohm. The maximum current is an issue however, it's barely sufficient for 44 mW of output with 100 ohm headphones.

Also, from technical standpoint, you could obtain sound similar to tubes using specially crafted FETs, which, unlike bipolars, work pretty much like tubes.

The tube is more linear than any kind of transistor if no feedback is applied (and that matters to some). What are those specially crafted FETs?

 

[Ferrum Master]

Impedance is not the issue, the tube is probably in a cathode follower circuit with an output impedance of ~90 ohm. The maximum current is an issue however, it's barely sufficient for 44 mW of output with 100 ohm headphones.


The tube is more linear than any kind of transistor if no feedback is applied (and that matters to some). What are those specially crafted FETs?

A troll has entered the chat.

 

[holyprof]

Impedance is not the issue, the tube is probably in a cathode follower circuit with an output impedance of ~90 ohm. The maximum current is an issue however, it's barely sufficient for 44 mW of output with 100 ohm headphones.


The tube is more linear than any kind of transistor if no feedback is applied (and that matters to some). What are those specially crafted FETs?

Yes, I am aware that some people (myself included) appreciate the sound of amplifiers without feedback. Many years ago, when my hearing was good, I could easily tell the difference between two similar amplifiers that I assembled, one with a deep feedback loop and the other using only local feedback.
Nowadays, in the era of class-D amps and digital sound, all that talk of "warm and undistorted" tube sound and amplifiers without deep feedback is a waste of time.