Not a surprise

What I suspected it was going to happen, it did in the end. Although a bit premature and in a bad time. I’m expecting today a friend to come around for a listening session and having no amp wasn’t an option.

To cut a long story short, the Salas SSHV2 shunt regulator has been playing silly buggers for a long time. Since I upgraded the output transformers and readjusted the bias, it looks like I was operating it at the verge of its abilities. The CCS was running at 80-90mA and somehow the stability of the shunt regulator was compromised. Initially was a periodic lost of regulation during warm up, this created an annoying “pop” now and then,  later I decided to replace it with a new SSHV2 and blew a pair of DN2540 after the regulator failed to set the output voltage randomly. It worked fine on the test bench, however there is something on my system which is disturbing / interfering with the regulator or the regulator isn’t stable enough at the hot operating conditions I was submitting it to.  I have nothing against the SSHV2, in fact, I use it extensively in my preamps. However, I think I’ve found the limit at which it can safely operate. The additional drawback of the SSHV2 is its temperature stability. It’s not great as it drifts when temperature rises.

So the regulator went busted on Thursday evening and I was running out of time. Only Friday was available to fix the amp. Luckily, I was on holidays this week and had the time to fix this, but unfortunately this diverted my energies and time from the 300B amp 🙁 Continue reading “Popping the Shunt Voltage Regulator’s clogs”