Princeton build from '58 Zenith phonograph

[Blindog]

This was a pretty fun build...my first real go at a true point to point build.
I honestly was worried about mass oscillations before I fired her up. But so far so good

I pretty much stuck to the AA964 circuit, I did change the 1M resistor between the Intensity pot and the plate of the oscillator tube . I wasn't happy with the depth of the effect, so I went with a 270K and it sounds much better IMHO.

Gotta touch up some paint, and try to figure out some kind of head cab...Hmm...anyone know of someone here that makes cabs?

Mark

PS Apologies for the upside down pics..they were right side up when I sent 'em!

[dobbhill]

Excellent!

[Blindog]

Thanks!

[M Fowler]

Nice build. I used to collect as many of those amps as I could find and convert them to guitar amps adding 1/4 jacks. Mine worked as is so I didn't need to rebuild them.

Fun projects.

[Blindog]

Nice build. I used to collect as many of those amps as I could find and convert them to guitar amps adding 1/4 jacks. Mine worked as is so I didn't need to rebuild them.

Fun projects.

Thanks Mark! I pulled this one out of a barn, was a literal rat's nest, lol. It had an octal in V1, and I kept it for my first go around, but I couldn't get rid of a nasty oscillation no matter what I tried, until I put a nine pin socket in it's place.

I've got a question for y'all...I built this basically from what I had laying around..the OT came out of a Bassman 10 (2X6L6 output section). Figured the bigger iron would sound good. The amp does sound ok, but I was expecting it to break up sooner. Here's my voltages, using a 5Y3 rectifier:

B+ 451
B+A 446
B+B 325

V1 1 224, 6 211
V2 1 273, 6 257

449V on output tube plates, 444 on pins 4 ( Currently JJ 6V6's)

I've added a bias trimmer pot to make things easier when trying different tubes.

So it's looking like I need to knock down some B+, eh? Any thoughts on which part of the string to mess with? I've heard of folks keeping the PI a bit high In these amps for a bit more output while keeping some grind. Any thoughts?

Thanks in advance as always

Oh, and the bias tremolo is fracking amazing!
Mark