AIYIMA T1 Pro Tube Preamp Review

[prerich]

I voted fine because it does exactly what it's supposed to do - add a tube distortion to achieve a certain sound. I have some Soviet era (with the actual CCCP markings on them that would fit this device).

 

[prerich]

I wonder if the channel differential would be less if selected tubes were used.....but this would easily cost more than the device itself: not a realistic option.

No ...the tubes are quite inexpensive compared to the item itself.

 

[Grotti]

No ...the tubes are quite inexpensive compared to the item itself.

I stand corrected: those 6186 tubes are ridiculously cheap....

 

[dfuller]

There is no shot this is actually using the tubes for signal gain. Tubes run on high voltage, this is a classic starved-plate dirt box with the op-amps providing all the gain.

 

[AIYIMA]

Probably for providing the actual gain.

Tubes need a certain supply voltage for not being completely starved, which the performance of this device suggests. 12V power, and I suspect there's nothing more than a simple double step up supply in there.

The tubes are only there for "show" and getting "that tube sound", not for providing actual gain.

The actual power supply for the vacuum tube is stepped up to 100V,not dual power supplies.

 

[Ropeburn]

The actual power supply for the vacuum tube is stepped up to 100V,not dual power supplies.

You have 100V in a class III device? Is that legal?

 

[JSmith]

Yeah, I don't see the point of this device in 2024... but thanks for testing it @amirm.

Pics;

I see Aiyima have made the op-amps "roll-able"... something I wish they would not constantly promote.


JSmith

 

[solderdude]

The bass does droop a bit, indicating capacitive loading. We can see that effect easier by lowering the input impedance of the analyzer:

A 3.3uF capacitor at the output would do exactly that (80Hz, -3dB)
To get good bass extension you need to load the amp with at least 5kΩ

What does the tone control do ? (+/- max settings and '0' settings).
I think those tone controls would be more effective than the added tube distortion.

Haven't seen many of the better tube amps/buffers distort this bad (such a high and quite audible level) and with such a high amount of higher order harmonics.

 

[Endibol]

Or you don't hear it, with the AIYIMA T1s SINAD around 50? Distortion at about the same level as a good speaker, so what do you hear in that case, really? That if you even have speakers with as low as 0.3% distortion.

You are right, I bought this little device, put it in between my Topping DX7 pro and Fosi mono V3’s and barely hear a difference even at the highest input level, 2 Vrms. The sound is a little worse in terms autocorrection.cancel clarity. I don’t hear the typical tube sound I recall hearing from my grand mother‘s wooden tube radio.
To be fair I listened via my Ascend Sierra 1 v2 that has distortion levels of about 3%, approx 10x more than the Aiyima.
Time to hook up my Revels F228Be and do the test again…

 

[Sal1950]

Yeah, I don't see the point of this device in 2024... but thanks for testing it @amirm.

Me either, this is 2024 and the design engineers have been working for almost 100 years to free our systems of these distortions.
I'd sooner run over it with my pickup truck.

 

[Endibol]

Me either, this is 2024 and the design engineers have been working for almost 100 years to free our systems of these distortions.
I'd sooner run over it with my pickup truck.

Be careful for your tires though, it's a pretty sturdy box...

 

[DanielT]

You are right, I bought this little device, put it in between my Topping DX7 pro and Fosi mono V3’s and barely hear a difference even at the highest input level, 2 Vrms. The sound is a little worse in terms autocorrection.cancel clarity. I don’t hear the typical tube sound I recall hearing from my grand mother‘s wooden tube radio.
To be fair I listened via my Ascend Sierra 1 v2 that has distortion levels of about 3%, approx 10x more than the Aiyima.
Time to hook up my Revels F228Be and do the test again…

But, if you want to color the sound, you should surely color it so much that it can be heard? What else is the point of it?

Contrary to uncoloured, however, I prefer to have at least a tenth less distortion in the audio chain vs. what the speakers produce. There is nothing objective to justify it other than that, in my eyes, it seems to be a good ratio 1:10 with that kind of headroom. . Of course then also inaudible noise,enough power and pancake flat FR in this pre speaker chain.Thats my stance on streamed music as a source, but not when I listen to my record player.

About tubes again.For $75, if you want to try a tube amplifier, sure. It is much kinder to the wallet with this pre tube amp paired with a soild state power amp than the other way around. A tube based power amplifier can be grotesquely expensive for what type of performance they deliver. Commercial ones not DIY ditto.

I see tube amplifiers more as something that electronics-savvy DIY guys do as a satisfying hobby. Either to build new as for example:
(good job Horias2000 )

Building a valve amplifier

One of my next projects is a valve amplifier. I built many solid state amplifiers and I'm very happy with these. I always considered valve amplifiers as being vastly inferior to solid state one but nevertheless I would like to build one to measure it and to listen to it. From all the available...

audiosciencereview.com

Or to restore, repair and/or keep sound history alive:

Vintage Hi Fi museum. Quad 22 and 202 valve amplifier. Leak, Rogers, Trio tube amps. Williamson papers

A Museum of old amplifiers. Vintage valve amplifiers. Old stereo tube amplifiers. IMF professional monitors. Transmission line loudspeakers. Williamson valve amplifier

www.rewindmuseum.com

Or in general about tubes:

SPINNER Group - Vacuum Tube Museum

SPINNER - your partner in rf technology: Components for wireless communication, Broadcast, Radar- and Satellite Systems, Medical industry, High Power.

www.spinner-group.com

 

[Ropeburn]

The thing is, if you want to "get into tubes" and buy this one for 75, you aren't getting a proper tube preamp. You're getting a transistor (opamp) based preamp with weird parallel tube circuit. It's a literal "bastard", as in illegitimate device in that sense, that doesn't even deliver the typical tube distortion spectrum.

Just last week I got three matched Slovakian ECC83 (=12AX7) for my old hybrid AB's preamp, and paid 77 moneys, which was a rather cheap option. Just to put these prices into perspective. Of course the preamp section is proper and clean, unlike above effects device.

 

[mhardy6647]

More information about the tube type used here:

6186, Tube 6186; Röhre 6186 ID6003, Vacuum Pentode | Radiomuseum.org

Tube 6186 or Röhre 6186 ID6003, Vacuum Pentode, Miniatur-7-Pin-Base B7G, USA 1940 and RF/IF-Stage shown. Radio tubes are valves.

www.radiomuseum.org

source: http://frank.yueksel.org/sheets/127/6/6186.pdf via https://tdsl.duncanamps.com/tubesearch.php
Sharp cutoff pentode. An odd choice for an AF amplifier (but not out of step with the past decade or two of cheap hifi effects boxes ). The dual cathode connections is an interesting wrinkle.
I suppose someone found a container full of these things and said "lets build some amps!"

 

[Endibol]

But, if you want to color the sound, you should surely color it so much that it can be heard? What else is the point of it?

Sure, and that’s why I would like to listen with the Revels. There is a change that the distortion of the Aiyima doesn’t drown into the speaker’s distortion.
But I am afraid that it won’t make a lot of difference. The Aiyima distortion is with 0.23% max too low to clearly hear I think.
In addition, a number of members pointed out that the distortion spectrum deviates from a “proper” tube amp.: too much odd order components.
Anyway I have some fun for little money.

 

[Cbdb2]

A big part of tube amp sound is from the output transformer distortion. And those transformers are expensive.

 

[DanielT]

A big part of tube amp sound is from the output transformer distortion. And those transformers are expensive.

It will be expensive. Even more expensive if you mix in 300B tubes and Western Electric into the game.

For, hold on to your hat, $124,999.00 you get two:
Western Electric 97A Monoblock Amplifiers

...that deliver:

Rated Power Output
80 watts RMS per channel

Total Harmonic Distortion
10 watts output: < 0.05%
50 watts output: < 0.15%
80 watts output: <.90%

Signal to Noise Ratio
-100 dB below 80 watts

Damping Factor
16

97A Monoblock Amplifiers — Western Electric - Maker of electron tubes and high fidelity

www.westernelectric.com

I am fully aware that it is the brand itself that is the attraction here but wtf $124,999.00.

 

[SIY]

Sharp cutoff pentode. An odd choice for an AF amplifier

If you want to use a pentode in a small signal circuit, sharp cutoff is actually what you want. Remote cutoff pentodes will be much more non-linear.

 

[mhardy6647]

If you want to use a pentode in a small signal circuit, sharp cutoff is actually what you want. Remote cutoff pentodes will be much more non-linear.

Thanks, @SIY. I shouldn't even think about pentodes!

 

[SIY]

Thanks, @SIY. I shouldn't even think about pentodes!

They have their uses. Partition noise is a problem, but they also have no Miller effect and higher gain than triodes. Tradeoffs.

One fun trick that Frank Blohbaum has been popularizing is doing a cascode with a bipolar transistor on top and having the screen grid act as an anode. This apparently eliminates partition noise but preserves the pentode's gain.