AIYIMA T20 Tube Pre-amplifier Review

[Schlippwhip68]

Is there a difference in sound if you use the T20 in "bypass" at 100 volume and volume control in the A20?

Because I was thinking of putting the T20 in between Wiim Ultra and a power amp and have the volume control of course on Wiim. T20 and power amp in "bypass" or full volume always.

I would not recommend doing that.

 

[morillon]

I haven't been following the discussion...
Do we know more about the gain and output impedance?

Just:


(The discussions here, which are supposedly "rich," since 11/09, are happening without even these two essential pieces of information for a preamp ( the basics, like the additional charges to consider on prephonos etc) .. Funny... ;-) ) ( crosstalk too)

 

[Schlippwhip68]

There was a user's thread at some point for subjective stuff (I think) which I agree, is where subjective stuff should go, but that seems to have disappeared! That would be the place for tube rolling, op amp rolling, linear (or other) power supplies etc.


There was quite a lot of disparagement going on earlier in the thread with pseudo objective stuff also!

C'est la vie on ASR!

On another possible controversial note, I am going to add an DDC into the chain in the next couple of days and see what happens, the Douk Audio U2 Pro 2025.

 

[SMen]

On another possible controversial note, I am going to add an DDC into the chain in the next couple of days and see what happens, the Douk Audio U2 Pro 2025.

now that absolutely definitely belongs on another thread!!

What is interesting on this one is why the T20 works.

Just:


(The discussions here, which are supposedly "rich," since 11/09, are happening without even these two essential pieces of information for a preamp ( the basics, like the additional charges to consider on prephonos etc) .. Funny... ;-) ) ( crosstalk too)

I understood the crosstalk was excellent on the T20 in the review?

 

[JSmith]

….psuedo objective…? Where is the absolute objective in audio…I have seen one yet….

Devices like amps, preamps, streamers and DAC's etc. can be 100% characterised objectively performance wise.

Things like aesthetics and how one literally "feels" about a device are of course subjective.

Listening to music via sound waves coming out of speakers, reflecting around, hitting the ears and generating electrical impulses our brain interprets as sounds/music is always subjective by its very nature and definition. However we can objectively measure the speaker output and correlate certain aspects directly to auditory observations.

Devices converting, transmitting or amplifying a signal have pretty basic jobs to do.

Honestly, members carrying on about swapping opamps and tubes then claiming improvements without proper evidence has to cease here.


JSmith

 

[Schlippwhip68]

A much more interesting question. The documentation doesn't make a clear statement. But looking at the block diagram, I would guess yes. The RCA inputs are converted to balanced internally - then both XLR and converted RCA go into a single selector/volume chip. The output from the chip drives both sets of output buffers in parallel, so unless Ayima has done something stupid, then both outputs will be active - and if the input RCA conversion is done right - at the correct voltage for the output.


However, for a definitive answer - you'll need to ask Ayima support - or an owner who has one. Perhaps @Schlippwhip68 can help here

I think you have nailed it there, what you have said makes sense to me and deviance from such a method may, as you have mentioned, prove detrimental.

 

[Schlippwhip68]

I'm glad you enjoyed it... but you could have been listening to music instead.

What does this mean? Is this some kind of a dig at members here?


JSmith

I believe the spirit of the mind needs to discern what the heart may want because in my experience, it’s the most wicked thing and following it on more occasion than not it has got me into trouble never mind some dodgy tunes.

 

[morillon]

⁰The essential measurement, often missing, is the observation of level differences according to gain on preamps with carbon track potentiometers...fortunately not the case here...
;-)
(And it's more of a hassle to do than a few clicks in software for sweeps, etc.)

Ultimately, gain or output impedance are far more important data points than THD, SINAD measurements, etc. (except in catastrophic cases) for a preamp.
In any case, Aiyama would have slipped in those values..
,-)

 

[SMen]

⁰The essential measurement, often missing, is the observation of level differences according to gain on preamps with carbon track potentiometers...fortunately not the case here...
;-)
(And it's more of a hassle to do than a few clicks in software for sweeps, etc.)

Ultimately, gain or output impedance are far more important data points than THD, SINAD measurements, etc. (except in catastrophic cases) for a preamp.
In any case, Aiyama would have slipped in those values..
,-)

Now that point about level differences according to gain and carbon track potentiometers - spot on! And excellent channel matching (described in this case as perfect)!
It's funny... lets have solid state because valves distort ... but forget about the volume control (especially at low volumes).

 

[Schlippwhip68]

Ok, this is not great but I touched my T20 casing with a soft part of my arm today and could feel a slight electrical tingle/burning sensation. It’s enough to cause alarm. It seems to be sound the screws on the rear mainly.

 

[MaxwellsEq]

Ok, this is not great but I touched my T20 casing with a soft part of my arm today and could feel a slight electrical tingle/burning sensation. It’s enough to cause alarm. It seems to be sound the screws on the rear mainly.

Could be capacitive coupling or a lack of safety earth.

 

[Schlippwhip68]

Could be capacitive coupling or a lack of safety earth.

Pain in the you know what as I don’t even have a multimeter here at the moment which probably would help.
Anybody with a T20 can you touch the rear corner with soft part of flesh and tell me if you feel the same?
At least we could see if this issue is universal with the T20 and maybe find a way of fixing it if there is one.

 

[KL....]

Ok, this is not great but I touched my T20 casing with a soft part of my arm today and could feel a slight electrical tingle/burning sensation. It’s enough to cause alarm. It seems to be sound the screws on the rear mainly.

Thank you, @Schlippwhip68, perhaps (best) check the lid to/around those valve sockets. There is 180V there, isn't there, and you are becomeing the ground path, aren't you?

 

[Schlippwhip68]

Thank you, @Schlippwhip68, perhaps (best) check the lid to/around those valve sockets. There is 180V there, isn't there, and you are becomeing the ground path, aren't you?

Could be….its nothing heavy.

 

[antcollinet]

Could be capacitive coupling or a lack of safety earth.

This is common with unearthed (eg from DC power supply) equipment. You don't need much capacitance from mains to any connected device to cause it. My older Macbook Air does it - the whole metal case tingles.

I've also had it on an AV system where all the components were double insulated. The combined capacitive coupling of all devices coupled together via interconnect gave quite a strong buzz.

It's nothing to worry about. If it really bothers you connect an unused connection to an earthed device - or run an earth wire to the earth of a mains supply socket - and it will stop.

 

[Schlippwhip68]

I will be interested to know your impressions with the power supply you swap in to the T20 and which one.

Another step forward in clarity, a much cleaner sound, darker background, voices are better separated, this is quite an improvement to be honest. The ifi Power X works very well. I could go full accapella all day with the opa2604 in the A20 here.

Listening to Young Oceans - Love like raindrops Made of light

Voices are very, very sweet, that darker background brings better contrast and definition to the guitars, softer notes are more easily heard.

It’s worth it.

Superfi - £99 delivery included.

 

[SMen]

Another step forward in clarity, a much cleaner sound, darker background, voices are better separated, this is quite an improvement to be honest. The ifi Power X works very well. I could go full accapella all day with the opa2604 in the A20 here.

Listening to Young Oceans - Love like raindrops Made of light

Voices are very, very sweet, that darker background brings better contrast and definition to the guitars, softer notes are more easily heard.

It’s worth it.

Superfi - £99 delivery included.

You are on a mission !! And having a lot of fun. I confess I have been too with this T20.

I went for this Aiyima on a whim but I was a bit prejudiced against it at first sight. However it is a genuinely balanced pre-amp with valves, where they have thought out the volume control, chosen op amps specified by the manufacturer for high quality audio - Aiyima really seemed to have made an effort. The only two areas where it seemed to me they must have really had to make sure on cutting costs to the bare bone was the power supply, and most basic valves (which is of course fine).

I tried a Teradak HiFi Linear Power Supply and after a brief swap back, it is staying in. I found myself chasing the volume up with the original supply. The great big volume read out display has been permanently lower (relatively) across my most regular tracks since. I confess I concur with your subjective responses with your iFi.. I'm still prejudiced towards linear going into valves ;-).

I'm not into the op amp debate, nor cables ... I totally get the need for matched volume, blind listening etc ... and with power supplies I feel no need to change the 48v 10A that feeds my 3e Audio A7. Sounds identical to my Fosi supply.

I think that ambient temperature has a significant affect on the response of most speakers ...

Equally I wish I could measure the affect of an alternative supply into the T20. Perhaps someone who can, will, before we get theoreticals. Put it down to my prejudices and resulting bias.

 

[Schlippwhip68]

You are on a mission !! And having a lot of fun. I confess I have been too with this T20.

I went for this Aiyima on a whim but I was a bit prejudiced against it at first sight. However it is a genuinely balanced pre-amp with valves, where they have thought out the volume control, chosen op amps specified by the manufacturer for high quality audio - Aiyima really seemed to have made an effort. The only two areas where it seemed to me they must have really had to make sure on cutting costs to the bare bone was the power supply, and most basic valves (which is of course fine).

I tried a Teradak HiFi Linear Power Supply and after a brief swap back, it is staying in. I found myself chasing the volume up with the original supply. The great big volume read out display has been permanently lower (relatively) across my most regular tracks since. I confess I concur with your subjective responses with your iFi.. I'm still prejudiced towards linear going into valves ;-).

I'm not into the op amp debate, nor cables ... I totally get the need for matched volume, blind listening etc ... and with power supplies I feel no need to change the 48v 10A that feeds my 3e Audio A7. Sounds identical to my Fosi supply.

I think that ambient temperature has a significant affect on the response of most speakers ...

Equally I wish I could measure the affect of an alternative supply into the T20. Perhaps someone who can, will, before we get theoreticals. Put it down to my prejudices and resulting bias.

Yeah, it’s quite funny, the ifi power x seems to have a distinct sound or effect that similar across everything I have used one on like dacs, streamers and now a preamp. It’s a kind of sweetening mainly around the mids and background.

A member DM me with this LPS and is wondering if it’s a worthy option. I can’t see anything detrimental in regard to quality and it’s an R Core which is preferable for low to no hum etc. He is considering this for his own T20. What do you think?

I just found this on AliExpress: ￡54.59 | New Design STUDER 900 Pro+ R-Core Linear Power Supply For Preamplifier/DAC DC 5~24V (Optional)

https://a.aliexpress.com/_EH8peLQ

 

[Ropeburn]

I believe the spirit of the mind needs to discern what the heart may want because in my experience, it’s the most wicked thing and following it on more occasion than not it has got me into trouble never mind some dodgy tunes.

I don't know whether you're a golem or something, but my love and passion sit in the brain, not in the blood pump further down.

I'm afraid you make very little sense here with the tubes and the opamps, and not even with the philosophical musings.

 

[SMen]

Yeah, it’s quite funny, the ifi power x seems to have a distinct sound or effect that similar across everything I have used one on like dacs, streamers and now a preamp. It’s a kind of sweetening mainly around the mids and background.

A member DM me with this LPS and is wondering if it’s a worthy option. I can’t see anything detrimental in regard to quality and it’s an R Core which is preferable for low to no hum etc. He is considering this for his own T20. What do you think?

I just found this on AliExpress: ￡54.59 | New Design STUDER 900 Pro+ R-Core Linear Power Supply For Preamplifier/DAC DC 5~24V (Optional)

https://a.aliexpress.com/_EH8peLQ

I don't know to be honest, but at the price (similar to the Teradak) it might be worth a punt. Someone in the comments following your link seems to have measured it:

"The load behaviour is disappointing. At a load of 0.4a, it is still 12v. At 1a, it is still 11.7v, and at a load of 2a, it is 11.3v. The noise behaviour is also significantly worse than with the original studer. The noise is 25uv from 10-100hz and drops to 1uv from 300hz." But who knows - comments on ali express are not exactly measured opinion on ASR!

Teradak seem to do pretty much one thing, which is power supplies - so I gave theirs a go.

Personally I found that when switching units to compare with what I consider to be a high quality balanced ladder control, or indeed just the digital volume on the SMSL Raw DAC I currently use, that the T20 lost the 'warmth' that people seem to want but that I don't seek with valves, after putting in Tung-Sol valves and the Teradak.

I however keep a slightly enhanced depth and width perspective, solid sound stage, and body to strings and voices ... subjective listening opinion alert...!

I'm going to set up parallel inputs using RCA and XLR - with RCA going through the passive balanced ladder control. It is not in any way a scientific control test, simply a way to listen and hopefully enjoy and identify differences over time, with the closest I can get to switching being between RCA and XLR on the source DAC unit and my 3e audio A7.