I just wanted to give a bit more insight into my running carbon.
I am running at 400V and 20mA per line. Total consumption of the amp in my configuration is 93W during normal operation. In the first few seconds it is up to 190W and then drops. The transformer is almost dead silent during normal operation. If I go really close with one ear, I can hear a very slight hum, but nothing to care about. During turn on there is a short hum which fades as the current draw drops. I use a custom transformer from toroidy with has the following specs:
TS200VA PRI: 2x 117V SEC:
> 2x 330V @ 250mA
> 2x 18V @500mA
> 16-0-16V@500mA
- flexible leads - 40 cm long
The reason for the 2 LV secondaries was stated before.
As discussed previously I added thermal paste to all interfaces, now including the angle bracket to heatsink interface. I think to longest continues run time was 2-3h and the heatsinks were still touchable by hand. The amp boards clearly produce more heat than the PSU boards (heat gradient from front to back of the heatsinks). I use a 3U case from modushop.
I listened with the 007 and 009. After a week I still think that it suits both headphones very well, which is a surprise considering that the headphones are quite different. IMHO the 007 was better on the conventional KGSSHV while the 009 was better on the KGST. I think the conventional KGSSHV (450V, 4686) provided quite a large soundstage which is almost too large in combination with the 009 (which provides a huge soundstage by nature) while the treble is a bit too harsh as well. On the other hand, the KGST provides a smaller soundstage, a bit less detail and a bit a softer sound, which suit the 009 much better. With the 007 it was just the other way around as the phones are more mid pronounced and have a smaller soundstage by nature (btw I love their sound too).
Therefore I think it is surprising to find that the Carbon fits both phones well, although I cannot give a direct comparison between all amps yet.
Just to mention: I use the ressonessence invicta as a DAC which provides the possibility to switch between various filters. I did not change them for the two headphones. I just used my favorite one, I have also been using with the other 2 amps.
I would love to hear what others think. Also if you agree with my impressions on the KGST/conv. KGSSHV/007/009 opinion.