1959SLP DIY project

[danman]

The preamp voltages enter the board where one of your choke wires attaches to the B+dropping resistors on the upper right hand corner. From there the board jumper wires carry the B+ voltage to the different spots on the preamp circuit. Trace that path along the jumpers and be sure you have the correct resistor values installed. Hope this helps somewhat.

[dagerman]

Thanks, I did that already. It seems that (from looking at the circuit diagram) most voltages that are directly derived from B+ are within reasonable range.

What I am not sure about is the voltage reading on V3 pins 2 & 7, which shows pretty much exactly half of the voltage it is supposed to have. I don't really understand what affects the voltage at those two grids; or if 50% of expected value is something to worry about.

I think I'll just move on and recheck all voltages with power tubes in place.
Thanks again for your help!

[dagerman]

The preamp voltages enter the board where one of your choke wires attaches to the B+dropping resistors on the upper right hand corner. From there the board jumper wires carry the B+ voltage to the different spots on the preamp circuit. Trace that path along the jumpers and be sure you have the correct resistor values installed. Hope this helps somewhat.

Thanks danman,
Triple checked (and measured) R-values. All voltages on V3 are within range, except for the screen grid voltages, which are 50% lower. I am leaning towards measuring again with EL34s in. THANKS much!

[danman]

Sounds like you have covered all your bases. Hopefully everything will come together once the tubes are installed. Report back and let us know how she sounds!

[dagerman]

And it did! All measurements came into spec'ed range once power tubes were in and biasing went without a hitch.
My trusted handyman plays in a LZ cover band and he came over with his speaker cab and Les Paul for a test a couple of days ago. Boy oh boy, I had to rearrange some stuff around the house after we were done... This thing is llllllllOUD!!! And we couldn't even go beyond 6 or 7 because we just couldn't take it without an attenuator...
And - not that I have much to compare to - it sounded really awesome.
Now all I am waiting for is the cabinet. I'll post some more pictures when it's all done.

THANKS a million to everyone who gave advice along the way, I really appreciate it. Now I just may have to build another one and learn how to play guitar. Given what this thing is capable of, I think a 5W would be just fine....
Stefan

[danman]

Happy to hear that everything worked out well for you! If you enjoy the amp now wait until it's been played several weeks and broken in properly. Mine really started to sweeten up after about twenty hours or so of playing time.