23-04-2017, 12:37 PM
(This post was last modified: 23-04-2017, 12:39 PM by Diabolical Artificer.)
I've more or less finished putting the amp chassis together so gave it a test. I powered it up without the 12BH7 in the socket, but with the wiring and components present , see attached schematic.
The front end tested ok but the ECC82 phase splitter read -3v on the cathodes! Typical, it worked ok in it's rough state but not neatly put together. After much taking apart and head scratching and swapping the pot on the CCS for a 1k preset (was 300 ohm), I stuck the 12BH7 in and the cathode voltage went up to 10v, bang on.
I'm pretty sure I know why this is, but thought I'd see if any of you chaps would like to have a go at working out why.
Andy.
The front end tested ok but the ECC82 phase splitter read -3v on the cathodes! Typical, it worked ok in it's rough state but not neatly put together. After much taking apart and head scratching and swapping the pot on the CCS for a 1k preset (was 300 ohm), I stuck the 12BH7 in and the cathode voltage went up to 10v, bang on.
I'm pretty sure I know why this is, but thought I'd see if any of you chaps would like to have a go at working out why.
Andy.
