[paolocaminiti]

From my experience the aux auto is actually volume controlled, the amp has it's own gain stage which is applied I suppose before everything on the input thus you will need to lower the gain on the rythmik substantially - that's what I did on my rythmik about 8 points lower than when I drive it from a passiva hattor preamp always via RCA.

[Jon L]

From my experience the aux auto is actually volume controlled

I've been too lazy to make TRS-RCA cable to hook up a subwoofer to Douk A5, but soon..

It's sad, but the $23 "Field Effect" discrete opamp that synergizes excellent with Douk A5 has doubled in price in recent days 

[snaimpally]

In case in anyone is interested, I had bought a Fosi TPA3255 based amp some time ago. Never got around to trying it out. Selling it for $50 shipped. See my post in the marketplace for photos or DM me for more info.

[Jon L]

The new Aiyima A20 amp looks very similar to Douk A5 spec-wise, with high pass filter also incorporated.  The only significant difference IMO is the inclusion of XLR input, but is it worth almost twice the price of Douk A5?  I don't think I want to buy more TPA3255 amps, but somebody should compare..

https://www.aiyima.com/products/masterpieces-of-a-decade-a20?srsltid=AfmBOooPn9o2Mqib082XXGqCrZTeeb22Om5wbLdn0VANIpr0Q1gIvTMB

[Jon L]

I found out Douk A5 amp does not like to receive balanced XLR signal (via XLR to RCA adapter). 

I had to open the adapter and disconnect pin 3, and now Douk A5 works great with XLR output from my DAC, which sounds better because if using DAC's RCA output, there is an extra opamp stage involved over XLR output 

[Jon L]

After finding all the optimal opamps and configuratins, I was feeling a bit lazy about having to deal with the charging routine for the Batttery power supply for Douk A5, so I did the comparison again with the battery vs stock 48V/5A power supply. 

Unfortunately for me, the battery supply makes the difference between wanting to keep listening to music vs turning on the TV.  The sound is both smoother yet more detailed, calmer yet more dynamic, with a sense of freshness, clarity, and microdynamics to vocals which also sound richer. 

Yup, back to the charging routine.