audio-talk

Me too. And I haven't heard the Pink SET....

Simon, where in the PSU circuit for your output valve do you ground it? My circuit joins all the PSU to ground at the same point, which is the bottom of the LTP, effectively the bottom of the 2nd cap. The signal circuit for each stage involves the preceding stage transformer secondary, valve grids, ...

The only problem I can see (and I may be dreaming this up) is if the transformer (either interstage or OPT) were to build up capacitative charge which would have nowhere to drain ? Is that just nonsense ? It could and probably would do that. Ok thanks. Aside from that, is there any other reason thi...

I have a question, more about my learning but it might be something to try, see if there's any audible difference. For this discussion, lets ignore questions about safety earth. I know I'll come back to it, but it may simplify the question. As can be seen from the PSU and Signal circuit diagrams in ...

it seems the casework would have to be connected to normal mains earth otherwise there'd always be a possibility the case could go live Well, assuming the casework was not earthed, then with a single device (and ignoring leakage current) there is no way the case could go "live" as there i...

Ok thanks. Will pop over sometime.

Interesting thanks. Much to learn as always. What gives a 0v reference for the amps?

I'm interested in learning more about this. Your secondary is 230v floating but I assume safety earth passes through? If so, can the voltage on the secondary drift away from the 0v reference, and does it matter ? I've used the LL1665 and worked with Jac to build a balanced mains in front of the amp....

It's this diagram

Andrew wrote: ↑Fri Aug 03, 2018 10:25 am Electrically away.

OK Thanks - I may well try that. I could move the cap into the PSU and mount a small choke into the back of the amp. Interesting experiment and well worth trying, cheers.

If you can get that cap away from the DHT heater, it will sound even better. The cap is a voltage source and will be attempting to "regulate" the music signal on the DHT's heater. Will the boards you bought not do the job? Great job, by the way! Andrew Thanks Andrew. There are 8 DC boards...

Nice build, you must be chuffed. When I powered on I had a sequence of tests to go through. 5 of the 6 power circuits worked perfectly but the left 26 was odd. The 10r resistors in the anode reported current through both valves but the tail resistors reported next to nothing. Eventually I realised ...

izzy wizzy wrote: ↑Fri Aug 03, 2018 12:49 am Impressive work. Love every aspect from schematic to build. Well done!

Cheers,
Stephen

Thanks - lots of time and effort, but well worth it.

This is the amp with the wings flat...

Yes, and apologies for not reading carefully enough as you're pretty much where is reasonable to go I'd reckon! The ultimate would be a separate supply for each stage and channel, but it's perhaps questionable whether you'd hear an improvement over what you have now :-). No apology needed, thanks f...