Introducing the xDuoo TA-66 OTL Tube Amplifier - Now Available on Apos Audio

[fidgeraldo]

If anyone is interested and looking for headphones to pair with TA-66, except Sennheisers...Ibasso SR3 (150Ω) sounds really good with TA...

Cheers!

 

[Mad Lust Envy]

My TA-66 arrived! Using the TA-22 as the DAC for it through its line out.

I don't have many high impedance headphones, but still wanted to have an OTL amp for once.

 

[Ben86]

My TA-66 arrived! Using the TA-22 as the DAC for it through its line out.

I don't have many high impedance headphones, but still wanted to have an OTL amp for once.

How is the sound with audeze?

 

[Mad Lust Envy]

How is the sound with audeze?

The LCD-3 is Audeze's highest impedance headphone (over 100ohms), and really the only one that will work with the TA-66. That and possibly the LCD-2, LCD-2 Closed back, and LCD-2 Classic which are 70ohms.

I also tried using an LCD-5, and because it's low impedance, the TA-66 was really strained and distorted like crazy on it (this is not the fault of the amp or the headphones. Most OTL tube amps don't tend to play well with planars.).

I really really enjoy the smoothness and character that the TA-66 brings. It makes my TA-22 sound like a solid state in comparison, and my Fiio K7 like an anemic, sterile sounding amp (it isn't).

The purpose of an OTL tube amp for me is to give the sound some character lacking in solid state and tube hybrids, and I feel the TA-66 wins at that.

It's funny how much warmth and body is gives the Koss clip ons though. Those are only 67 ohms, and the TA-66 absolutely skews their FR to be more bassy, and bolder sounding. It's not even close to how it sounds off a solid state.

So yeah, I'm extremely happy with the TA-66. I just recommend not bothering with anything low impedance.

 

[Marijn Riz]

My TA-66 arrived! Using the TA-22 as the DAC for it through its line out.

I don't have many high impedance headphones, but still wanted to have an OTL amp for once.

OTL design amps specialy if want make a one with power with like a EL86 is a high impedance the better match in general

 

[mdvries]

My TA-66 arrived too today. Very happy with it. I ordered the tubes suggested by @Ed R several weeks ago so I had them ready and put them in instead of the stock. I love the sound. I tried it till now with my SMSL M500 DAC/Amp and for headphones: Sennheiser HD6XX and HD800. Also put on the Audeze LCD X briefly but that one is only 20Ohms while at least 60OHms is recommended. Nevertheless it sound ok but probably not the best. Actually I am amazed by the sound with the $200 HD6XX and trance music. Plan to disconnect my ZMF Atrium from my Cayin HA-6 amplifier tomorrow and try it on the TA-66.

 

[phonypope]

Still?! Now I’m picturing some really, really old little lady patiently and carefully hand-wiring each and every TA-66 by a candle light all day long every day to get these things made!

-Ed

Was starting to imagine myself as that old lady, telling tales of the coming mythical tubes to my descendants

Finally came! Just using stock tubes at least for now, was expecting the change to be very subtle but they sound awesome with the 6xx. Soundstage extended a bit, bass thickened and more impactful, really fills out the 6xx's sound. The treble still sounds very detailed while being a little more smooth or something

Find myself wanting to compare it against SS amps with bassy music since that's where I detect the biggest impact, but finding that there's a bit more body to most music I throw at it, even when acoustic and vocal focused

 

[dudeduck]

My TA-66 arrived too today. Very happy with it. I ordered the tubes suggested by @Ed R several weeks ago so I had them ready and put them in instead of the stock. I love the sound. I tried it till now with my SMSL M500 DAC/Amp and for headphones: Sennheiser HD6XX and HD800. Also put on the Audeze LCD X briefly but that one is only 20Ohms while at least 60OHms is recommended. Nevertheless it sound ok but probably not the best. Actually I am amazed by the sound with the $200 HD6XX and trance music. Plan to disconnect my ZMF Atrium from my Cayin HA-6 amplifier tomorrow and try it on the TA-66.

Did you compare them to the original tubes? I really enjoy the stock ones so I would like to know how they compare

 

[phonypope]

Did you compare them to the original tubes? I really enjoy the stock ones so I would like to know how they compare

It will be nice after a few years when we have more testimonials of this type, at the moment we just have people who use the stock tubes and those who have swapped those out, without any crossover

It's especially problematic with these being tubes where we need to rely on corroborative subjective reports, since all frequency response measurements (that I'm aware of anyway) won't really be able to show what's happening. With time we should be able to get a better sense as the amp gets adopted

 

[Mad Lust Envy]

It will be nice after a few years when we have more testimonials of this type, at the moment we just have people who use the stock tubes and those who have swapped those out, without any crossover

It's especially problematic with these being tubes where we need to rely on corroborative subjective reports, since all frequency response measurements (that I'm aware of anyway) won't really be able to show what's happening. With time we should be able to get a better sense as the amp gets adopted

I'm a realist.

Every single device that comes with tubes, or cables, or dac, or whatever else.... people will almost ALWAYS say that X thing is better than stock thing. You will almost never hear anyone replace their stock anything and go, yeah this ain't better. I attribute it to expectation bias. They want to believe their extra purchase will be better, therefore, it will be better. Humans can't help it. I'm not blaming these people, or think they're lying, etc. It's just that's how our brains work. That goes with many other things, like buying something more expensive, and it being better to them merely because they know it costs more.

I'm in the opportune position to test out some items side by side with the same item using some replacement "thing" (i.e. tubes, pads, cables, etc). In some instance where people say X thing sounds better than stock, I have been able to compare by having multiple of the same product, and in the end, they fail to mention the losses that occur when they swap out parts (and in some cases quite negatively). But because it's something they only have one of, the comparison between stock and new is very hard to do. So they go off memory which has already been skewed by the expectation that this "thing" is going to improve upon stock. I too have been there before. I'm not immune to exectation bias myself.

Unless a person has two of the same amp, level matched, and have an A/B switch where they can quickly go from one amp to another with different tubes, I'd take any impression of tubes with a huge grain of salt. Swapping out, followed by the warm up period it takes for tubes is way too long enough to completely skew results. So anytime anyone says, oh this is a huge improvement or change, really think about how they came to that conclusion.

So personally (as in just how I would do, not what I think you or anyone else needs or should do), I just use the stock tubes until they die, then I'll try something else. If the stock sounds BAD, then of course, I'll swap out to something else. I don't think most people will go "this sounds bad" unless they probably have some tubes waiting on hand or incoming, because subconsciously they're already going with the mindset that the replacement they have waiting is gonna be better...somehow.

I like the stock tubes on this amp, and that's all I need it to be. In the future when the tube goes bad, I'll try something else and probably enjoy that too. I just don't think realistically the differences are going to be something big.

Anyways, the TA-66 is sweet as is. I didn't buy it for tube rolling. I bought it because I wanted a fully analog tube amp which I didn't personally own one before (though have heard plenty, some being worth about 30+ TA-66s), after mainly sticking to SS or hybrids. So wanted to cross that off my list.

 

[fidgeraldo]

I (almost) always use stock...everything. But with TA-26S, I changed tubes pretty soon after I purchased it.
I can compare two situations. First, with the stock tubes, some music was great, but some did not.
When I changed stock tubes, everything was great. No issues with any sort of music.

I don't know if that can be related to TA-66...but yes, obviously, sometimes, with tubes, things can be upgraded, and the upgrade is real.

Cheers!

 

[dudeduck]

I (almost) always use stock...everything. But with TA-26S, I changed tubes pretty soon after I purchased it.
I can compare two situations. First, with the stock tubes, some music was great, but some did not.
When I changed stock tubes, everything was great. No issues with any sort of music.

I don't know if that can be related to TA-66...but yes, obviously, sometimes, with tubes, things can be upgraded, and the upgrade is real.

Cheers!

I've heard of the Ta 26s, that the stock tubes sound very much solid state (which is weird but alas) and that it scales a lot with tube rolling. There's not much info about the Ta 66 but from what I've heard (and my own experience) stock tubes are very tubey in deed (who would have thought). That just goes to show how there's really not an objective tube sound and even if there was it would come down to personal taste. That's just what the magic of tubes entails and the fun (expensive fun) of tube rolling an amp.

 

[mdvries]

Did you compare them to the original tubes? I really enjoy the stock ones so I would like to know how they compare

No, didn't compare as I like these ones well enough. Maybe some time later.

 

[greenblured]

 

[Edward Ng]

Glad to know I made the right choice going with TA-66. Sure, there’s not much opportunity to roll tubes, but on the other hand, it’s hard to complain about the amp sounding amazing right out of the box!

-Ed