22-04-2012, 07:32 PM
Hi Joe,
We've all been there! It's funny how even the most logical brains sometimes refuse to work to form. Clearly, the amplifier was fine. And the tuner. Just not both at the same time! It's a shame that we'll probably never learn what was causing the two to play up when working in consort, but never mind...
First lesson here: transistor gear needs a different approach. Much calmer and less cavalier than seems to be the norm for valve gear. To that end, what you need is a power supply with a variable current limit, so that the output will fall at the first hint of trouble. Actually, that's a nice little project, and something I would willingly help you with separately...
When working on these things, I normally set the current limit to around 50mA. That's less that the maximum collector current of any transistor in the amp, so nothing bad can happen (in theory
)
I know it feels cursed, but stick with it. I doubt you'd be able to sell it on with an IC amplifier anyway, and if you don't mind waiting, I can probably send you a known-good amplifier PCB at some point in the future. I plan to make a good Autocrat from the 3 I have here, and once done, I'll have some spares...
Wishing you better luck with the Sovereign
Mark
We've all been there! It's funny how even the most logical brains sometimes refuse to work to form. Clearly, the amplifier was fine. And the tuner. Just not both at the same time! It's a shame that we'll probably never learn what was causing the two to play up when working in consort, but never mind...
First lesson here: transistor gear needs a different approach. Much calmer and less cavalier than seems to be the norm for valve gear. To that end, what you need is a power supply with a variable current limit, so that the output will fall at the first hint of trouble. Actually, that's a nice little project, and something I would willingly help you with separately...
When working on these things, I normally set the current limit to around 50mA. That's less that the maximum collector current of any transistor in the amp, so nothing bad can happen (in theory
)I know it feels cursed, but stick with it. I doubt you'd be able to sell it on with an IC amplifier anyway, and if you don't mind waiting, I can probably send you a known-good amplifier PCB at some point in the future. I plan to make a good Autocrat from the 3 I have here, and once done, I'll have some spares...
Wishing you better luck with the Sovereign
Mark
