I have been using my Ayon Stealth Xs DAC for just over two years now. The sound still blows me away every time I listen to it. It uses 4 6N6P output tubes and 4 tubes in the voltage regulator section. I have their CD II Transport which is also fantastic but now I mostly stream. This DAC showed me redbook CD has a lot more to offer than I ever thought possible. I used to mostly play vinyl but now I mostly listen to digital. This DAC wrings detail and resolution out of CDs that I had no idea was even there- that this level of detail down in the lowest quietest passages just did not exist on CDs. I had a Ref CD player before and I thought it sounded natural but I still would only listen to one CD typically before switching to vinyl. Now I listen to digital for hours.
The Ayon DAC can be used direct to Amp. It has switches on the back that change the output gain hi/lo and a direct amp setting that insures the volume will be near minimum when the DAC is powered on. In non preamp mode the volume control is bypassed. I use bal connectors and I route the music through an ARC Ref 5SE to a pair of Pass Labs monos. I prefer using a preamp between the DAC and amps. I have tried the DAC connected directly to the amp. The sound is different. I found I preferred the sound better going through my preamp. It might be a coloration and most likely it’s just because that is the sound I am used to. It is also for convenience since I listen to vinyl too. The only downside to direct to amp is that the noise floor is slightly elevated. Through the preamp everything is dead quiet- even standing by the speakers. But when connected direct I could just hear a bit of tube noise from my listening chair. Not a big deal but it is there. The Ayon manual addresses it. The manual states that when using the DAC direct some tube noise is apparent because the DAC has no negative feedback and uses large, low resistance capacitors in the output stage. They added that the DAC can be modified to reduce the tube noise but at the cost of a slight performance reduction. The manual states that the tubes should last 8000 hours, as I recall. I put about 1300 hours/year on it based on my preamp hour meter.
I have a picture of the DAC’s innards on my system page. It is beautifully made as can be seen in the picture. Their next DAC model up uses 6H30 output tubes. I have not heard that version. The 6N6P version however is definitely a winner.