Been scratching my head all night trying to figure what was wrong.
So now i´m baldheaded and Stajo solved the puzzle.
Im such a troubleshooter (or was it maker?)
Tried to get rid of last gnd hum by lifting both eathgrounds with rectifiers. Didnt work. But it sounds great, I like the tonality. Firm, detailed and punchy.
Why the first pdf has no harmonic noise and the other two a lot? Is it exactly the same circuit measured or it combines an amp?
Here´s my ugly pre resting in storage have a good laugh.
Recycled Yamaha pre chassi and remote control.
Pictures of the inside will not be published unless you point a gun att my head
Why not, its a test bed, looks come last. Did you manage to listen to it or put it through scopings and the HP analyzer?
It performs flawlessy and i tried a few different setups like CCS but went back to resistor load.
The basic and simplicity is the beaty of it.
Basic current regulated heaters starved untill i got best performance.
Early SSHV board forced to become a later version.
I really like it.
Performs very well with non exotic parts.
A descent chassi is on the list of things......the endless list of....
I tried several 6V6 and right now it´s a couple of RCA blacks in there.
The older russians are good value for the money.
It´s been hooked up to all kinds of amps including SS.
LM317 works fine just adjust the current down until you get best performance.
I don´t remember exactly what i ended up with but it´s a bit lower then Salas original setup.
First pic is loopback showing baseline at output level to measure 1W performance of amp. I have some 60hz niose, but it was do to crappy test rig.
As for 6V6, RCA blackplates is my choice as well. New Tungsol was very good( have matched quad for diff version), but Military grade RCA was worth money and this amp is worth the upgrade.
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