AIYIMA T20 Tube Pre-amplifier Review

[Endibol]

I think Amir puts the absolute transparency threshold at -115dB. I personally don’t agree with his methodology, but to be fair to him he’s saying that’s the threshold beyond which there is no conceivable argument or circumstance that a person would be able to detect a difference. In other words, he’s baking in considerable error bars and taking the most conservative figure.

The vast majority of people, audiophiles included, will have a heck of a hard time differentiating sound at even 1% THD+N (40dB SINAD). SINAD in the 80s isn’t getting in the way of anyone’s musical enjoyment.

I think the -115dB is chosen because at that level it’s impossible to hear any noise at dead quiet moments in music played at 115 dB. I think it’s not meaningful in determining the audibility of harmonic distortion produced by the amp.

 

[SMen]

Some people forget that simple fun is why many of us are here listening to audio.
I have never considered a tube audio device before (and had they included a phono in, I might have bought it [even knowing that it does not spec as well as any other item in my audio chain. Why? because it does spec better than other tube gear AND {from the subjective reports: hard to believe that I am putting that into consideration]}), for a tube anything, it sounds OK. All in fun, just to play with it is what it would be. Of course I could run a phono pre out into a line input on it, but that goes beyond my idea of fun into effort.

Yes totally ... I was cynical but it fills a niche - balanced tube gain. It gives very solid images: left, right and center. Nothing diffuse. Nothing that has me wanting to adjust the balance (with music anyway). Time for a speaker upgrade My 3e A7 measures way better, as no doubt does the variable output on my SMSL Raw DAC ... so there is something going on that I am not sure is explained by distortion.

Simple fun but also simply interesting also!

 

[SMen]

First, thanks for this interesting device review.

I have to admit I'm confused about this one.
I mean: what's the use of a hybrid tube/solid state preamp ?

In my opinion, the main interest of tube and transformers is the way they saturate.
Which means: I see them mainly as effect devices.

So why to stand mid way and not to push the idea ?
I'd love to see a preamp like this one, with remote and decent performance... with a "saturation" knob, graduate from "clean" (with matching performance) to "saturated" or "warm" (whatever marketing dictates), with good noise but clear H2 (and H3... or not) increasing with level, reaching up to 3% if pushed to max.

As is, it's a middle ground that just allows to say "look at my tube preamp", while keeping cost low and performances good enough.

But that's me.

I'm finding listening to it very interesting (see post above).

I just wish there was a good quality solid state (not passive) bypass to compare and use for different recordings ... and for those who want to roll ... let them roll!

 

[Endibol]

I found the plots. Published by Bob Stuart, but AFAIK there is another original source.

View attachment 482435

Edit: this is the source paper. Fig. 3

https://www.meridian-audio.info/public/coding2,P5b2520,P5d.pdf.pagespeed.ce.yeZvG6GuKe.pdf

If I interpret this graph right, it means that in order to hear the harmonics over the entire audible frequency range one would need at least 3 to 5% (or even more in music).

 

[Salt]

And from AIYIMA web:

View attachment 482151

Tubes are driven from DSP and buffered by LME4562. Then you can do almost anything.

Please note that the tube is inside the opamp feedback loop!!

DSP? Isn't it a

Tube Pre-amplifier​

and would need at least an ADP before DSP, and if, for what reason?
What's what I'm missing here?

 

[Nzama]

Really? With such a small difference?

I would think if your stereo image collapses with just 0.5 or 1dB difference, your setup must be highly unstable in that regard in the first place. Come on. Moving your head a few cm to the side has a bigger effect.

I would like to clarify and maybe find some good sense. Probably only 0.5db is an exaggeration, but as balance moves I think is easy to distinguish a loss or move or focus.

Choose the wrong word with collapse, which is likely happening at higher level only!

 

[Toni Mas]

DSP? Isn't it a

Tube Pre-amplifier​

and would need at least an ADP before DSP, and if, for what reason?
What's what I'm missing here?

What they call DSP is in fact the NJM1195 chip that provides tone control (bass, trebble, etc...). Implementing this with tubes would convert this cheap preamp into a million dollar baby...

Pd: I rectify, this NJM only allows input selection and volume control... Purists will apreciate maintaining signal integrity...

 

[Nzama]

Tube Pre-amplifier​

and would need at least an ADP before DSP, and if, for what reason?
What's what I'm missing here?

I think here there is a translation lost. It's likely the level adjustment by digital volume control

 

[Ropeburn]

DSP? Isn't it a

Tube Pre-amplifier​

and would need at least an ADP before DSP, and if, for what reason?
What's what I'm missing here?

NJM1195 is a digital volume controller, not a DSP. No conversion, just digital control. Misleading labelling there.

 

[Salt]

Thank You all, got it

 

[Ropeburn]

What they call DSP is in fact the NJM1195 chip that provides tone control (bass, trebble, etc...). Implementing this with tubes would convert this cheap preamp into a million dollar baby...

Pd: I rectify, this NJM only allows input selection and volume control... Purists will apreciate maintaining signal integrity...

Specs (noise, distortion, crosstalk) of NJW1195 do indeed look easily good enough for not being the bottleneck in this device. Really a good choice and much better than a cheap stereo volume pot they'd have had to use otherwise.

 

[Toni Mas]

Specs (noise, distortion, crosstalk) of NJW1195 do indeed look easily good enough for not being the bottleneck in this device. Really a good choice and much better than a cheap stereo volume pot they'd have had to use otherwise.

Well, as remote control has become a must, at this price point and for a pocket sized unit, better forget about motor controlled pots and relays, without mentioning the negative side effects of mechanical controls in a minimalist tube circuit, especially ECC83, like volume dependant frequency response if care is not taken...

As commented before this is a chip assisted tube design, for simplicity and cost reasons... A mass production friendly way of understanding the K.I.S principle...

 

[Toni Mas]

What I find hard to understand is, if the solution adopted here really allows to lower distortion to a point that removes any sound signature (including tube sound), what is the point in insisting in tube use?
Obviously, the only answer is same as trying to improve SINAD to pointless limits: marketing...

 

[Negatywny]

sooooo... it doesn't sound tuby then?

 

[Toni Mas]

sooooo... it doesn't sound tuby then?

Who knows...

 

[EJ3]

First, thanks for this interesting device review.

I have to admit I'm confused about this one.
I mean: what's the use of a hybrid tube/solid state preamp ?

In my opinion, the main interest of tube and transformers is the way they saturate.
Which means: I see them mainly as effect devices.

As is, it's a middle ground that just allows to say "look at my tube preamp", while keeping cost low and performances good enough.

But that's me.

I am guessing that many of those that would but this have never actually delved deeply into tube devices (if delved into them at all) except that they look interesting.
So this company has built a relatively competent tube preamp that
that allows them to say: "look at my tube preamp", while keeping cost low and performances good enough.
So you do get it.
And, if they are still selling them when I get my Michael Fidler phono preamp next year, I'll likely also buy a

AIYIMA T20 Tube Pre-amplifier Review​

(which will be the first tube anything that I have had in one of my systems since when I started doing this in mid-1970's)
and I'll attack one of my spare phono Pre's to it & (as they said in the song: "The Bear Went Over the Mountain" [why'd he do that?]
To see what he could see). In this case: to hear what I can hear (or not), just for fun.

 

[EJ3]

Well, as remote control has become a must, at this price point and for a pocket sized unit, better forget about motor controlled pots and relays, without mentioning the negative side effects of mechanical controls in a minimalist tube circuit, especially ECC83, like volume dependant frequency response if care is not taken...

As commented before this is a chip assisted tube design, for simplicity and cost reasons... A mass production friendly way of understanding the K.I.S principle...

I'm trying to think "What has a remote control in my system?"
Oh yeah, the analog tuner with the digital readout (which I have never used because I like the smooth, weighted feel of the tuning knobs action) and the oPPo 205 UDP (which I sometimes use the remote for). And the SONY CDR 500.
But then, my system is 2.2 or 4.2 STEREO, the last AVR that I had was a top of the line DENON in 1990.
And I have a computer monitor, no TV, no cable, or other incoming TV style signal just WiFi to cell tower and the desktop computer.

 

[AndreaT]

The old ECC83…nice review!

 

[totti1965]

First, thanks for this interesting device review.

I have to admit I'm confused about this one.
I mean: what's the use of a hybrid tube/solid state preamp ?

In my opinion, the main interest of tube and transformers is the way they saturate.
Which means: I see them mainly as effect devices.

So why to stand mid way and not to push the idea ?
I'd love to see a preamp like this one, with remote and decent performance... with a "saturation" knob, graduate from "clean" (with matching performance) to "saturated" or "warm" (whatever marketing dictates), with good noise but clear H2 (and H3... or not) increasing with level, reaching up to 3% if pushed to max.

As is, it's a middle ground that just allows to say "look at my tube preamp", while keeping cost low and performances good enough.

But that's me.

Freqtube FT-1 from Freqport: https://www.audiosciencereview.com/...-tube-pre-amplifier-review.66604/post-2420300

 

[KL....]

The Aiyima T20 utilises the Psvane 12AX7 but there is the Psvane Horizon 12AX7-AT.
For consideration, I wonder what the performance/measurement would be with the Psvane Horizon 12AX7-AT and if the T20 can be purchased with these, as an option?

Edit: re Psvane Horizon 12AX7-AT, H3 and higher.... perhaps these will improve while H2 remains similar but measurement would show/indicate, wouldn't it? If yes, then the ECC083 could be considered as influenceing (in this configuration), couldn't it?