AIYIMA T1 PRO Tube Preamp Vacuum Receiver Home Audio Preamplifier with RCA/Bluetooth & Bass Treble for HiFi Stereo Amplifier&Powered Speakers,with AUX/12V Trigger Signal Output

So I wanted to get a feel for what a tube preamp would sound like. I have a Hafler DH-220, fully restored and upgraded. Since it is solid state, I was thinking that I could warm it up a little with some tubes. Also, my streamer, the EverJoy DMP-A6 gen2, has the ESS chips in it, which can be bright and somewhat "shouty". So I though the tubes could possible smooth this out. My first impressions are that the sound I am getting, paired with my system, should not have only costed me 75 bucks. It really opened up the midrange and enhanced the realistic sound I was already getting from drums, snares, sax, voice, guitar. Anything that I play sounds awesome. It really makes me wonder what my system would sound like if I went ahead and got a high-end tube preamp, like PrimaLuna or the like. So, the test is a success. The trouble is, it may be too good for me to upgrade. I might not know what I am missing for now, but this little wonder is really something.

I didnt want to write my review until i had spent some serious time listening and comparing and felt like i really had a handle on what it does to the sound. Starting off, i paired this up with my klipsch r41m speakers. At first listen, i couldnt tell much difference compared to baseline with just my amp. After a while, i realized that the tubes actually had a slight effect on bass delivery, the bass was slightly louder and more full. There was no discernable difference in the fidelity of the music. What really surprised me was that it actually sounded fine whether i played classic rock, bassy pop music, or something quick and technical and very bass heavy like glitch mob. Nobody talks about the fact that tubes also pair nicely with modern music. The other thing i noticed is that while i couldnt put it into words, i felt more drawn to listen to music more often and for longer with the tubes. Fast forward to week 2, and I installed a pair of Lm4562 op amps, and a meanwell switching power supply. I wont pretend either makes any noticeable difference, i simply did it because i could, and for the assurance that i would have the lowest possible amounts of distortion and noise coming out of this device. Now, my JBL a130s come in the mail. Holy BATMAN what an amazing speaker. For the first time in my life i learn that cymbals and guitar strings actually make a sound, not just a note. All kinds of new things in my music! Ok, now its time to add the tubes. Right away now i can hear a difference in the music. That new found detail and "sparkle" in the high frequency is slightly dampened , and replaced with a touch of warmth and a bit of a rolloff of high frequency spl. Still sounds amazing with all music types. Another test I did was to set my system at listening volume with music paused and compare noise floor levels of just the amp, vs tube turned up to full volume vs tube turned all the way down. There is NO discernable difference in noise floor regardless of what you do with this preamp. Im honestly amazed at how silent this thing is. If you are looking for something "tubby" and "soft" sounding, with a bit of crackle and hum this is not it. If you are looking for an aptx hd bluetooth preamp that will maintain music fidelity and add a TOUCH of tube warmth to your music then this is the product for you. I am honestly quite pleased with it and it will become a permanent part of my system for all music types, and i seriously listen to a bit of everything. This is a hands down 5 star recommendation from me

Setup was ridiculously simple, PC and iPhone found the Bluetooth audio device in seconds. I have the RCA inputs connected to a Scott (Solid State :( ) FM Tuner. This unit feeds the Tuner inputs on an H. H. Scott 222C (7189 Power tubes, 12AX7 audio tubes). Sounds great, nice and warm like you would expect tubes to be. I shall probably buy another to allow my daughter to stream to her EICO ST-70 (7591 power tubes and the same 12AX7 Audio tubes).I'll roll into some other tubes (6K4,6J4,5654) to see what changes. Overall, I'm very impressed with this unit.

That expression reveals my age, as does the stack of junk in the photo, where the Aiyima Tube T7 has found a home. I did order the upgraded tubes as well, but they haven't arrived yet. This is my impression of the supplied tubes.Hookup was simple. I ran USB into a Topping DAC into the T7's inputs, then connected the output to the tape loop on the Marantz receiver (lower unit). It feeds a pair of Klipsch Heresies, and a 250 watt 15" sub. I also connected my Android phone to the Bluetooth.First, the Bluetooth performance is exceptional. It pairs quickly and the sound definitely benefits from both the DAC and the tubes' effects on the signal.Running an UltraHD stream from Amazon HD from my PC over USB, it's arguable whether the Marantz benefits from the additional tubes and circuitry or not. Marantz of the the 60s and 70s is considered to be some of the best sounding gear ever made.Still deciding on that, I switched over to the slightly newer (1980) JVC, which has a clean amp section and 25% more power than the Marantz, but is nothing really special. On this receiver, the Tube T7 added a bit of "friendly bounciness" to the sound, a slightly warm colored sound that seems to bring the sound alive. This is a good match.With the Marantz, you'd have to decide for yourself. The effect is good for the most part, but imparts some sibilence and smear to high-frequency details. I'm anxious to try the new tubes, and even more excited to try running this through a class D amp like the A07 or brand new A08.And if you're just looking to add Bluetooth to your setup, this unit should definitely be considered.Update May 30, 2021The DollaTek upgrade tubes came, and they're a definite improvement -- but they're noisy! (It doesn't matter once the music's going, it's just a slight hum and hiss). The effect of these tubes on the sound is much rounder, less harsh, adding a slight bit of sizzle and shine to the higher frequencies. The tubes that came with the amp were near silent at idle, but didn't sound the same. I'd say not as good in my setup, your mileage may vary. Worth trying both to see the difference.Update June 1, 2021One knock against the unit is the microphonics exhibited by all the control knobs, because they are aluminum and have a firm mechanical connection through their respective pots soldered to the main circuit board. I'm not saying that I did or didn't hear this in the music, but it is easy to hear wearing headphones and using the knobs.