raoultrifan
Headphoneus Supremus
By looking inside Violectric V380² I see that the transformer has 2x18 VAC outputs, so I assume that 2x18 VDC are powering the op-amps and the output stage too. Take care on overheating and maybe damaging those V6 and V7, given that V6 can't support voltages above 33V (+/-16.5V). Same about the V7 that can't take more than 32V (+/-16V).Violectric V380² with four V6 Vivid singles and two V7 Vivid duals.
A while ago I did myself op-amp rolling from LME49860 to Burson V5 in a Matrix HPA-3B that was using 36V (+/-18V) power rail for the op-amps and output stage, but I was swapping the voltage regulators too, to lower the voltage to 30V (+/-15V), to not damage the op-amps in time, so I would suggest you to do the same. I still have the HPA-3B in my living room and I'm using it from time to time.
There are 3-pin very low-noise regulators coming from several manufacturers nowadays, so all is needed is a bit of soldering and, of course, losing warranty on the Violectric device. In the end your power rails will become +/-15V instead of existing +/-18V and will be able to support pretty much all audio op-amps out there. Of course, the maximum output power will be diminished a little bit, not much, probably 15-20%, but still there will be enough juice left, even for Susvara.