the jumper on the board is to enable valve type change, the load (L & R) is for resistance or capacitance as needed for MC/MM.
Just in case anyone is interested, I'm selling off some very closely matched BF862, Whichbwere ordered from Farnel a few years ago when this project started.
£10 a pair, delivered in the UK
£10 a pair, delivered in the UK
Today resoldered all the joints and no change, HT is still 218-220V when measuring from C4P.
You need to ask designer to see if I'm correct about CRC filtering and check if the voltage drop on said resistor is as required , if not there might be a culprit elsewhere on your board .
I didn't follow this thread lately , what's the difference between measured and designed voltage ?
Gonna have to pull these from sale after receiving a report of a noisy Fet.
I have had them a long time so best to leave them here.
HT should be around 240V DC, with about 10V drop across R9P, 390 ohms.
So total operating current is around 25mA.
So total operating current is around 25mA.
as per Alan's post check voltage drop on that resistor , check unloaded secondary voltage , what is transformer regulation- at what current your transformer achieves rated voltage?
I checked transformer's voltages, while unloaded and disconnected from phonostage:
secondary: 10,3V
primary: 180V
Which current should I measure, before transformer or after? If latter, then which one, secondary or primary?
232V, measured from the capactior C4P and also from the resistor R9P. No 10V drop there though.
Are this voltages normal and my problem might be tube related?
Are this voltages normal and my problem might be tube related?
Sorry ,due to Alan’s certain activity towards myself elsewhere I cease my interest in building this phono stage and posting in this thread so don’t be offended if I won’t reply when quoted anymore , please direct all your questions to the designing team .
Thanks for helping out.
Should I get some other tubes and test with them? ECC83 instead of 6N2P maybe?. V1 voltages are OK, V2 and V3 are off.
You mentioned also to measure current, but from where?