I bought this pre-amp and put sparko labs op-amps with golden lion 12ax7 tubes and a R-Core power supply. I also bought Fosi audio V3 mono amps and put Sparko labs op-amps in it as well. The total cost was $1750 Canadian. It sounds better than my Macintosh main system.

Let me add to the review of this T20 pre-amplifier. I think some key points were missing.  First of all, if you're looking for what I call an old school preamp that has a lot of tube bloom and warmth, this is not it. You don't even need to listen to it to know that. You can look at the distortion specs on the product web page, and see that it's a new piece with the surface mount components on the circuit board.  It's a hybrid of tube and solid state and it's solid state rectified. None of that should convince anybody that this is a high second harmonic distortion old-school preamp. Those are typically all tube with tube rectification and many are hand wired point to point.  this is not that. But that's OK. Some people are not looking for that. This preamp is actually very good. Some of the most expensive hi-fi equipment tries to do is give you two things that somewhat contradict each other. Those two things are very high resolution and good body, warmth and tone. Those are somewhat contradictive because the more resolution you get some equipment starts to sound hars. Other equipment that gives you a lot of warmth loses resolution.  I find this preamp does a good job in the middle of giving both. I've had it in my system for about 2 months
One attribute of this preamp that caused me to purchase it is it is fully balanced. Yes from input to output. Fully balanced is almost unheard of at this price and to do it as well as this does. The circuit is simple. It's not a complicated circuit with 5 to 7 stages. If your source into this preamp is balanced XLR input, it goes directly into the volume control which feeds the tubes and then goes to the opamps that buffer the output. That's  very simple and straightforward. This preamp gives very good resolution and low noise at the same time, giving good body, tone and warmth. It sounds very good stock, but I have added discreet opamps and some other tubes that I swap out.  Even with the extra money for tubes and op amps I may have around $450 in it and that is still silly good for the money.
The vacuum tubes do the voltage gain, and the op amps are a buffer on the output. There are three op amps as she shows in this video. The 2 closest to the XLR outputs are a buffer for those outputs. The third op amp converts that fully balanced signal to a single ended output for the RCA output. So if you're using balanced out, you do not use the third op amp. None of this was discussed in this video and to some extent some of the stuff was misleading.  There are two other op amps on the input. These two op amps are not socketed. They cannot be changed. They are for a single ended RCA input to convert it to balanced. If you go in balance, you bypass these opamps.
I love the remote control. It would be extremely hard for me to have a preamp without a remote control. That seems silly in this day and age.  I use this preamp with low wattage class a solid state amps. I have a Hollo Audio Cyan DAC.  This is not a hit at Stef and Skunkie Designs. I like your work and videos. I just wanted to add and give my opinion for this piece.

Thank you for being honest.

I appreciate your videos. My father was a tube guy, when I was a kid and  ended up TV repair when I was young.  I joined him repairing TVs and more. I was 15 when I started doing that. This was mid 70s and then transistors came out on TVs, mainly Somy Trinitron. My dad re-learned solid state and was good at that also.

What I appreciate about you is your knowledge of tubes, tube equipment. I al amazed at that! I am probably a little older, but we come from the same generation. I used to be an “audiophile”. Due to my hearing loss, I can’t claim that anymore.

I really appreciate what you do. I grew up purchasing a Phase Linear 700 Series II in 1978. I built a 50w amp, bit that amp blew me away! So yes, I do not worship Bob Carver, however I appreciate that brand! Therefore, I have my own channel repairing and upgrading them.

I just want to let you know of my appreciation of your knowledge of those and electronics!
I am a subscriber.

Thanks,
Jerry
KK6AC

Another great honest video, thanks & Happy Thanksgiving!

Hi, i've replaced all OpAmp with Muses02 and all tubes to PSVANE Horizon Series 12AX7-AT. The improvement is immediately noticeable. Very good Tube PreAmp, i love it!

Thank you for your honest review!! 👍

Since you’re into DIY, I have a fun suggestion for your T20 preamp.

I’ve had one for a while and recently upgraded it.  PSV Horizon 12ax7 tubes made a very subtle improvement (little less harsh sounding), 2x Audience SX22B op amps for the balanced outputs stepped up the imaging and clarity a bit, and powering it with a 12v power tool battery dropped the noise floor and gave a better sense of space in the soundstage.

That’s all easy boring stuff though!  The real fun was adding .01uF Wima film bypass caps to every electrolytic capacitor on the board, and replacing the six 10uF output coupling caps with proper Wima 10uF film caps (hot glued to the top of the output relays and extended the leads).

The cap upgrade was a SIGNIFICANT improvement in imaging focus, soundstage and clarity.  Not so much added detail, but now image focus is very sharp.  A very rewarding upgrade if you feel like tinkering.  The caps were by far the biggest upgrade and cost the least, about $35 + a couple hours of assembly/soldering.

Cheers! 🍻

EDIT: I should add, I have the T20 between my upgraded Gustard A26 DAC and my Galion TS A-75 amplifier powering my Totem speakers, so giving the little T20 a great environment to shine. 😊

Thank you for this video, it was my first real insight into hybrid tube/class D amps as I am considering a hybrid tube amp for my 2nd system - I'll be honest for looks!

I have one hooked to my r8 running off a fiio r2r sounds  sooo good!! Using marshall tubes from a guitar amp!

Great Vid.. Thanks and Happy Holidays

I think I will stay with my Skunkie pre!
BTW I use a pin straightener for ensuring proper alignment

I think where this little thing comes in is to soften somewhat tge sound of Class D amps. I have used mine with some GaN monoblocks and the results are very pleasing indeed.

I would like to see what she thinks about the Dayton hta 200 hybrid.  It has a 7 tube pre amp section and a ab power section.  Its actually made by junson who makes Chinese tube amps , hybrids and class ab .

I agree with you about the volume display.   Thank goodness (as I understand it) you can turn that display off.   I do wish they had not done that.    I really detest super bright LEDs and especially the BLUE.    Eye killers.

Aiyima claims that 180v is applied to the 12ax7 in this preamp, wich 'would' give it a 'dynamic' sound.. is it so?
As well, I'd rather call it a 'Linestage' than a 'preamp' unless you can plug a turntable in.
But at that price, you sure get a cute remote volume control and ? 2 inputs? That would be nice to see one with phonostage, more inputs, no balanced inputs, and less chipamps.. but then, it would not be in the same price range.
Thanks for the great work.

Fosi P4 pretty neat too for a small solid state preamp. Got mine rigged with an opa1656 piping a Douk Audio A5 spiced with a pair of opa828. Clean, pokey and detailed. Had a T20 rigged with the Psvane Horizon 12ax7-AT and they moved the sound up a gear from the stock valves. Used an iFi power x for the power, cleaned things up even further. Thanks for the vid, cheers!

Finally an HONEST video and review. I am 200% with you on the corruption of the signal path with opamps and other (leave blank) pieces of electronics. I have to laugh my head off when reviewers talk about the TESR45826666 opamp vs the RTETQW48972387 but the YUERYRTWR 22348721 sounds better with the ERYTRER tube. So called audiophiles are NOT Hifi enthusast. Difference between both. They are more interested in playing with toys than actually LISTENING to music or they choose music to suit their reviews. Also I have to equally laugh when a reviewer calls a Whatever 124ABC the game changer until the Lookanotherone who is a game changer, until the New fandangled amp is the game changer. Strange all reviewers always piggy back onto each other reviewing the same gear with the same glorious reviews. Hmmmmm. Coincidence?  I have been involved with Hifi and music all my life and I am just a few years older than you and I could go on and on but I will end by saying what I started with which is thank you for an honest review and calling it as it is  (and BTW I agree I bought one which will gather dust in the closet. It throws a definite veil across the spectrum)

Thankyou for this review. I was seriously considering to buy it, but I will not. Im very curious after that old fashioned tube sound, and will look for something different.

I have always had solid state components and have no experience with class D, op amps or tubes, so I thought that this would be the perfect playground to experiment with switching stuff in and out before I commit to something at the same tier as the rest of my gear.  It's great fun and when I'm done with it, I'll just sell it on.
Frankly, I'm surprised at how these little things (A + T20) sound. Nothing mind blowing, but if you just want something that sounds good listening to the top 40, go for it.