Got this one from China for 130$, upgrade stock tubes to Russian 6P1P-EB + WE403A like recommended, let's say i'm very impressed. Compared to Schiit Vali 2+Amperex 6922 Holland driving my HD800(SDR modded), APPJ sound much more clear (Vali 2 got a more hazy sound which becomes apparents when compared dirrectly to the APPJ)
APPJ Schiit Vali 2
Overall Clearer, more extended, much more seductive Fuller sound, hazy, rolled off high, a little bland
Bass Leaner but more defined Hit harder but more one note
Mid Very clear, have a seductive quality (must be SET) Fuller but a little bland(too laid back for me maybe)
High More extended, airy Rolled off
Soundstage Much more holography It's ok but the hazy sound doesnt help
Dynamic Better, more PRAT
Details Both is good but APPJ is just clearer while Vali a bit muddy
Overrall i prefered the APPJ(with this setup), its colored but doesnt have that typical bloomy, syrupy Chifi tube gear sound. Vali 2 is solid, i actually got the Vali 2 after the APPJ because of good deal and intend to keep both.
Massdrop price of 90$ is a steal!
P/S: An important note that you must use a suitable , quality power cords for this amp, with some cords its sound too lean and harsh for HD800, i'm using a thick ofc cords which help bring a much better tonality.
So i've had some more fun with tube rolling:
@Schiit Vali 2: Turn out my NOS Amperex is a very hazy tube, switch it with a Siemens ECC85 help lift the veil, sound much more lively.
Tried some 6ns7 with adapter (Shuguang black treasure CV181-Z, RCA 6ns7gt gray glass)-> Mehhh, sound quite flat to me...
@APPJ: WE403A are microphobic as hell, i can hear my typing got amplifiered if i put it on my table, still sound really sweet but after a while i feel soundstage is kinda 3 blobs, treble still a bit harsh with HD800. Now i dont think they worth the money anymore (30$/pair).Follow advices here and around i'm quite happy with another tubes combo for much cheaper:
Voshkod 6J1P-EV(very neutral, realistic soundstage) + RCA 6005(warm, smooth, thicker sound)
For me I dont think any more rolling needed, specifically chose this APPJ version because i dont wanna waste too much money on tube rolling anyway.