AIYIMA T20 Tube Pre-amplifier Review

[JSmith]

Does anyone know if the RCA and XLR outputs can be used simultaneously?

Yes, both outputs are likely concurrent;

https://manuals.plus/ae/1005009412545246

The T20 supports both XLR balanced and RCA unbalanced input/output interfaces. Choose the appropriate cables for your audio source and amplifier/active speakers.

There’s no mention of a selector switch... which typically means they can be used at the same time.


JSmith

 

[Sal1950]

Really, can't ask AIYIMA to do more. They show that using tubes in an amplifier doesn't need to bring with it embarrassment in objective performance.

I wonder how long that "objective performance" will last as the tubes age?

 

[franz777]

Chłopaki, dzisiaj podłączyłem przedwzmacniacz T20, ale moje wyjścia triggerów wydają się nie działać. Próbowałem kabli TRS 3,5 mm, które dostałem od Benchmarka, ale nie działały, więc wyciągnąłem kable mono 3,5 mm z wyjść triggerów w moim amplitunerze Denon. Sprawdziłem, czy działają z wzmacniaczami, których próbuję używać z T20... i nadal nie działają. Czy ktoś wie, jak ich użyć?

Potrzebujesz wtyku TRS 3,5 mm. U mnie też nie działa. Próbowałem na dwóch urządzeniach i wyzwalacz T20 12 V nie działa. Zmierzyłem napięcie i rzeczywiście dostarcza 12 V, ale prąd (ampery) jest prawdopodobnie za niski. Najprawdopodobniej będzie działać z urządzeniami Aiyma.

 

[Uncola]

I ended up returning my t20 to Amazon. 12v trigger out didn’t work. I confirmed my amp 12v trigger in was working and both my trigger cables worked by trying them with my denon. All worked as normal there

 

[KL....]

Hi, thank you for your insightful technical question.

The T20 does not use an SRPP circuit, mainly due to its fully balanced design.
A fully balanced architecture requires handling four signal paths, while an SRPP circuit consumes two triodes per path.
That means a total of four 12AX7 tubes (eight triodes), which would significantly increase both cost and thermal design pressure.

During development, we had to balance circuit complexity, overall performance, reliability, and price.
The final design represents what we believe to be the best overall sonic performance achievable at this price point.

We hope this explanation helps you better understand our design philosophy and technical considerations.

Thank you, yes, @AIYIMA, for SRPP, useing both sides of a Triode would require 4x 12AX7s to deliver a Balanced Output, for a/each Balanced Input Signal/Feed, wouldn't it? The LM4562 opamp can accept a single-ended input/feed but it would not be able to output a balanced signal, would it?

• To ask.... what has @AIYIMA utilised to deliver a Balanced output to the LM4562 opamp, are both sides of a/each Triode utilised, and is there anything else that you would like to mention?

A single LM4562 op-amp cannot output a balanced signal from a single-ended input, because a standard op-amp amplifies the difference between its two inputs, and it does not have a built-in circuit to convert a single-ended signal to a balanced one. To achieve this, it would need to use additional external components.

• It is inherently designed for single-ended input, where the signal is applied to one input terminal (either non-inverting or inverting) while the other is used for feedback or a reference.
• Although, while the LM4562 can operate on a single supply, it is most versatile when used with a dual-supply configuration to handle both positive and negative signal components.

An SRPP (Series Regulated Push-Pull) circuit can be utilized for balanced output, but it requires a specific configuration, such as arranging two SRPP stages into a bridge amplifier. In this setup, the load connects the top Triodes together, and the bottom Triodes are driven by a balanced signal. This arrangement can result in constant current draw and reduced power supply noise in the output signal.

• Bridge configuration: A standard SRPP is not inherently balanced. To achieve a balanced output, you need to use two SRPP stages in a bridge configuration.
• Balanced drive: The bottom Triodes of the two SRPP stages must be driven with a balanced signal.
• Output connection: The load is connected to the cathodes of the top Triodes in each of the two stages.
• Benefits:
  • Constant current draw: The power supply sees a constant current draw, which prevents the signal from impressing itself on the power supply and being re-circulated.
  • Reduced power supply noise: The power supply noise is reduced from the output signal.

 

[KL....]

Thank you, for T20, an E83CC (12AX7/ECC83) option, enjoy....

JJ E83CC/12AX7 Frame Grid.... This recreation of the E83CC has been designed with a frame grid to help ensure low noise and microphonics. Specifically designed for audio uses.

• The code E83CC refers to a type of dual Triode vacuum tube that is a high-quality version of the more common 12AX7 or ECC83 tube. It is designed specifically for audio use, offering excellent gain with low noise and microphonics due to its frame grid construction. This makes it suitable for guitar amps, hi-fi equipment, and recording studio gear, where it provides a warm tone with clear articulation.
• The E83CC has the same pinout and electrical characteristics as a 12AX7/ECC83, meaning it can be used in any application that calls for a 12AX7 tube.
• A key feature of the E83CC is its internal frame grid, which is more rigid than standard grids. This improves the tube's quality, consistency, and stability, leading to lower noise and reduced microphonics.
• The frame grid design minimizes vibrations, resulting in a quieter and clearer sound with less hum or noise.
• The E83CC was originally designed as an audio-specific tube, making it ideal for applications where sound quality is critical.
• It produces a rich, balanced tone with great clean sounds and a satisfying, articulate, and warm overdrive when pushed.

 

[AIYIMA]

Thank you, yes, @AIYIMA, for SRPP, useing both sides of a Triode would require 4x 12AX7s to deliver a Balanced Output, for a/each Balanced Input Signal/Feed, wouldn't it? The LM4562 opamp can accept a single-ended input/feed but it would not be able to output a balanced signal, would it?

• To ask.... what has @AIYIMA utilised to deliver a Balanced output to the LM4562 opamp, are both sides of a/each Triode utilised, and is there anything else that you would like to mention?

1. A balanced signal consists of two signals with equal amplitude and opposite phase. The LM4562 can provide a balanced output; by configuring the LM4562 as a two-channel inverting cascade circuit, one inverting signal and one non-inverting signal can be generated, thus converting a single-ended signal to balanced.
2. Each triode in a vacuum tube uses all three terminals, namely the cathode, grid, and anode.

 

[LSP]

I ended up returning my t20 to Amazon. 12v trigger out didn’t work. I confirmed my amp 12v trigger in was working and both my trigger cables worked by trying them with my denon. All worked as normal there

FYI -I had the same problem and I reached out to Aiyama - they sent me a picture of a stereo trigger plug. And it worked. I bought trigger cables and they didn't work. So it's something in the design of the unit, but it does work with the standard stereo plug.

 

[KL....]

1. A balanced signal consists of two signals with equal amplitude and opposite phase. The LM4562 can provide a balanced output; by configuring the LM4562 as a two-channel inverting cascade circuit, one inverting signal and one non-inverting signal can be generated, thus converting a single-ended signal to balanced.
2. Each Triode in a vacuum tube uses all three terminals, namely the cathode, grid, and anode.

Thank you, Yes, @AIYIMA, the LM4562 can provide a balanced output from a single-ended input, by being configured as a differential amplifier, as you indicate, and inverting and non-inverting the single ended Signal that it is feed. The 12AX7 circuit is a gain stage provideing a single-ended output.... is that correct?

• To ask.... have @AIYIMA utilised a parallel Triode input stage (utiliseing both sides of the Triode) with a center-biased circuit (this ensures both Triodes (Sides) are biased identically) and carefully manage the filament circuitto minimize hum and buzz? If yes, then this would allow smaller resistor values to be utilised for lower noise and output impedance and ensure the filament circuit is properly bypassed and shielded, wouldn't it? Typical component values for this setup include a Cathode resistor, such as 750Ω, and a Cathode bypass capacitor, such as 44μF, along with a Grid stopper and a Anode/Plate load resistor.... is that correct?
  • Important to know, why, because If both sides of the Triode are utilised and when one (channel) dies then the dead Valve will need to be replaced (usually both/2), won't it? Whereas, if only 1 side of the Triode is utilised then (usually, for 2 channels) the Valves can be swaped over and the Unit can continue to work until you decide what to do about the affected Valve (which has 1 dead Triode), can't it?
• To (further) Ask.... is your choice the above rather than SRPP which also outputs Single Ended Signal when utiliseing both sides of the Triode. You have mentioned constraints but if you do not mind clarifying/explaining, further, aspects of your choice (such as Gain/Current/Noise/PSV/etc), please do?

A parallel Triode input stage using both sides of a dual Triode with a center-biased circuit is an amplifier design that combines two Triodes (both sides) in parallel to increase current and reduce noise, while the center bias is a type of Cathode biasing that uses a resistor and bypass Capacitor to set the operating point for both Triodes, notes Amp Books. This setup provides lower output impedance and better signal-to-noise ratio than a single Triode, especially in the first gain stage of an amplifier.

• The two Triodes are wired in parallel, meaning their Anodes/Plates, Cathodes, and Grids are all connected together. The center-biased circuit provides a constant current bias for the combined stage, setting the tubes' operating point. When a signal is applied, both Triodes amplify it, and the combined output is taken from the shared Anode/Plate connection

Parallel Triode input stage (utiliseing both sides of the Triode) with a Center-biased circuit vs SRPP (utiliseing both sides of the Triode)

• A Parallel Triode input stage with a center-biased circuit offers lower noise and output impedance, a fuller tone, and higher current capability, while an SRPP stage is a push-pull amplifier that can cancel even-order harmonics but is more complex to design.
• Parallel Triode input stage (center-biased)
  • increases the SNR/signal-to-noise ratio and lowers the Output impedance
  • supplys more current
  • a straightforward way to increase performance and often using a common Cathode resistor for bias.
  • The Load seen by each Triode can change dynamically with the signal, leading to an elliptical load line and potential non-linearity.
  • A Parallel Triode stage with a Center-biased circuit is an excellent choice, particularly for the first gain stage in an amplifier, as it improves the SNR/signal-to-noise ratio and provides a lower Output impedance.
• SRPP (Series-Regulated Push-Pull
  • low THD/total harmonic distortion, if perfectly balanced, can be unnecessarily complex
  • requires a careful balance to ensure both tubes operate equally, which can make it more difficult to set up and can lead to extra distortion if not perfectly balanced
  • can be poorly designed, leading to extra distortion, because the upper Triodes input is not a pure/amplified version of the original signal, but is already distorted by the lower Triodes gain. Some designers consider SRPP circuits to be "silly" if they don't properly account for this fundamental difference from a true push-pull design.
  • The SRPP configuration is superior for applications that require the lowest possible distortion, especially if the goal is a perfectly balanced push-pull output with minimal even-order harmonics

 

[Elvom]

FYI -I had the same problem and I reached out to Aiyama - they sent me a picture of a stereo trigger plug. And it worked. I bought trigger cables and they didn't work. So it's something in the design of the unit, but it does work with the standard stereo plug.

Mine works

 

[Schlippwhip68]

The trigger works fine with Van Damme Tour grade Classic cable and TRS 3.5mm

Also upgraded the valves today.
The Horizon 12ax7-at arrived today.


Immediately notable changes in resolution with the sound. Much more detailed that the already good ECC83 stock tubes.


Cleaner vocals, bass is not as boomy, a much more precise sound with leading edges of notes having more attack and bite. I have left the opa828 in the T20 for now. These are not as warm compared to the stock ECC83, certainly more analytical, slightly drier sounding upon first impressions than the red ECC83 stock valve.


I like them. Vocals are very textured too as with all things source is key and even just listening to talk radio from the Filo SR11 through a Topping E50 dac, the voices come across very, very accurately and clean. Very clean valves. Good soundstage with more accuracy towards the depth which is also deeper, better separation, much more pinpoint overall also good clean air, faster too, more speed to the sound, sharper in a good way, not harsh. Yes, impressive. I am using the Muses 02 in the Aiyima A20 and they are already tight, clean precise sounding chips. These valves may also work with the SX52B full discreet op amp adding a little more bite to their softer leading edges on the notes and bass. Great with faster more intricately arranged music too as well as the more simple stuff, doesn’t seem to miss a trick.

Very impressed overall to be honest and now won’t be touching the T20 with the opa828/Horizon 12AX7-AT combination. Good over all system synergy too with the rather budget but very good Q Acoustics 3020i speakers. The Q Acoustics 3030c will also work well here, just as a recommendation. I also think the Fiio K13 R2R might just be a doozy here too.

 

[Nzama]

Mine works
View attachment 487513

Can confirm same for me!

 

[Schlippwhip68]

While some snobs (most of us have one inside) might look at the T20/A20 combination and call it a ‘Pig-Rig’ and sticking any upgrade in there is minimal progress and like sticking a gold chain on swine…lol….i can safely say it sounds pretty good with a full Muses 02 overhaul and Psvane Horizon 12AX7-AT valves.

With the Muses 02 in every available dip socket on both units and the new Horizons and if I were to compare it to an class a/b rig then it would probably be the Audiolab 6000A mk2, smooth, delicately detailed, very clean, well balanced, tight but light bass and oozing quality.

Worth a pop for fun!

 

[Music+Coffee]

While some snobs (most of us have one inside) might look at the T20/A20 combination and call it a ‘Pig-Rig’ and sticking any upgrade in there is minimal progress and like sticking a gold chain on swine…lol….i can safely say it sounds pretty good with a full Muses 02 overhaul and Psvane Horizon 12AX7-AT valves.

With the Muses 02 in every available dip socket on both units and the new Horizons and if I were to compare it to an class a/b rig then it would probably be the Audiolab 6000A mk2, smooth, delicately detailed, very clean, well balanced, tight but light bass and oozing quality.

Worth a pop for fun!

Which one works better with the Horizon tubes - Muses02 or opa828? I am still enjoying the stock opamps with Sylvania long grays. I am planning to try the Horizons as well.

 

[Schlippwhip68]

Which one works better with the Horizon tubes - Muses02 or opa828? I am still enjoying the stock opamps with Sylvania long grays. I am planning to try the Horizons as well.

I would say the opa828. The Muses are much more delicate sounding while the opa828 are much more dynamic by comparison. They allow more bass slam too.

 

[antcollinet]

Which one works better with the Horizon tubes - Muses02 or opa828? I am still enjoying the stock opamps with Sylvania long grays. I am planning to try the Horizons as well.

I would say the opa828. The Muses are much more delicate sounding while the opa828 are much more dynamic by comparison. They allow more bass slam too.

It would be good if you could move your op amp discussions to the catch all thread that has been created for them. The idea is to avoid polluting review threads with controversial discussions that can detract from valid discussions about the review. Thanks.

Serious Question: How can Op Amp rolling improve the sound of an already well measuring device? Are that many confused? (Master Thread)

On OP-Amps and Op-amp rolling Another contentious topic. Manufacturers of DACs and Amps often socket op-amps to allow people to swap them with different types, with the aim of improving the sound - or getting a different “sound signature” (Whatever that might mean to you). We get it. It’s...

www.audiosciencereview.com

 

[Schlippwhip68]

It would be good if you could move your op amp discussions to the catch all thread that has been created for them. The idea is to avoid polluting review threads with controversial discussions that can detract from valid discussions about the review. Thanks.

Serious Question: How can Op Amp rolling improve the sound of an already well measuring device? Are that many confused? (Master Thread)

On OP-Amps and Op-amp rolling Another contentious topic. Manufacturers of DACs and Amps often socket op-amps to allow people to swap them with different types, with the aim of improving the sound - or getting a different “sound signature” (Whatever that might mean to you). We get it. It’s...

www.audiosciencereview.com

Yeah, sorry, forgot.

 

[SMen]

I was lamenting the fact that this Aiyima T20 does not have a switchable pass through option or better still, active solid state switchable option - it would have been fascinating. But it occurs to me that my 3e audio A7 does have excellent (from reading ASR's review here) RCA as well as XLR inputs ... so combined with a DAC with good quality RCA and XLR outputs I could in fact switch between my passive ladder and this T20.

Just thought I'd share ... that took a lot of working out!

 

[Schlippwhip68]

I was lamenting the fact that this Aiyima T20 does not have a switchable pass through option or better still, active solid state switchable option - it would have been fascinating. But it occurs to me that my 3e audio A7 does have excellent (from reading ASR's review here) RCA as well as XLR inputs ... so combined with a DAC with good quality RCA and XLR outputs I could in fact switch between my passive ladder and this T20.

Just thought I'd share ... that took a lot of working out!

Groovy added features indeed and great for a bit of ‘musical chairs’ action switching in and out.

Along similar lines, I know on the A20 (bypass mode) you can switch from XLR to RCA with the same signal and certainly find some difference in cable quality which I found this evening while having Van Damme Tour Grade Classic XLR and Van Damme Plasma 75 ohm RCA. The Plasma was better.

 

[DSJR]

Yeah, sorry, forgot.

No offence I swear, but reading through recent posts in this thread, I thought I'd gone back to the subjectivist sites I used to frequent (and annoy in equal measure)

Enjoy your purchase and if using speakers, I'd put your tweaky-attention into optimising the room, speaker position with the possibility of a little eq to optimise the sound best...