26-08-2020, 08:11 AM
Thanks Peter. Bit of an update, amp working well, SW off anomaly fixed by using a 24v relay off a Tascam R2R,it works off the +/-15v preamp rails with a dropper to drop 6v ish. I put the relay in between the OP of the SS preamp and IP to the valve amp so that that unpowered the valve IP stage control grid is grounded, power on signal can pass. There's a slight delay on SW off as the preamp PSU caps drain, about 1mS, a slight click on SW off but 100% better than it was.
Am now farting about with cathode bypass caps on the valve IP stage trying to get juicy but not overpowering bass response, will probably pop a 47u in like everyone has down who's ever built a valve amp in the past.
Andy.
Am now farting about with cathode bypass caps on the valve IP stage trying to get juicy but not overpowering bass response, will probably pop a 47u in like everyone has down who's ever built a valve amp in the past.
Andy.
