I am 1000% happy with the sound quality out of "cheap and cheerful" FU19/FU30 single-ended tube amp from Ali. However, I found myself just leaving the amp on all the time, often even falling asleep leaving the amp on 24/7, which led to a little bit of tube-life anxiety.
This led me to look at some TPA3255 amps, and thanks to Ron at New Record Day, I ended up with Douk Audio A5 amp:
https://www.youtube.com/watch?v=2FEYFSTjH_4&t=1sThe version with 48V/5A power supply sells for $120 on Amazon, but in cheap-and-cheerful fashion, I was able to buy one for $80 shipped after finding one on sale (easy to do) and some small coupons (often found on-line).
My initial impression was not nearly as favorable as New Record Day. There was the prototypical "edginess" and "no meat-on-bones," especially compared to FM30 single-ended tube amp, which many people levy against TPA3255 and class D in general. But hey, the FM30 amp is only 4 watts and Douk A5 realistically 102 wpc/8 Ohms x2 (with 48v/5A PS). I think we can all agree to ignore the "300 watts x2" hyperbole written on all the TPA3255 amps at this point.
Given the easy-to-remove top cover and only one opamp per channel, I started rolling some discrete opamps over the stock NE5532 opamp. I know NRD really likes the amp with Sparkos SS3602, but it goes against my cheap-and-cheerful instincts since two Sparkos needed cost double the amp's price (I paid). Luckily, I already had some reasonably priced discrete opamps in $11-16 range, and both the AkLIAM LC5(dual) and SX52B(dual) improved the SQ a great deal, moving the amp from decent/good to great. The SQ improvement is such that music is now very much enjoyable without much caveat, fully detailed and engaging with less edginess and more body. If I had to choose, I would say the AkLiam synergizes better, and I did end up using my old DEXA discrete opamps. The combo gives sound quality that need not apologize for anything. After I received and loved the FM30 tube amp, I ended up ordering a second one. I just ordered a second Douk audio A5
0327252257 by
drjlo2, on Flickr
If one wanted to go overboard in audiofool fashion, one can power the Douk with 36V (measures 40.8V fully charged) batteries. Predictably, liquidity and sense of inky black background increases, with predicted hit in usability and convenience
Honestly, SQ is already excellent, already crossing that hard threshold into musicality, without the battery.
0402251726_1743641549878_1743641598021 by
drjlo2, on Flickr
Addendum
I forgot to mention that one MUST replace the supplied power cord that comes with the 48V/5A power supply. It's unshielded, extremely thin (~18AWG) cord and sounds craptastic, making music thinner, brighter, and just horrible.
I use an OG Volex 17604 14 AWG power cable using C8-C13 adapter, improving the SQ a ton.
0417251346a by
drjlo2, on Flickr
I forget where I bought my adapter years ago but it's similar to this:
