The Amp Garage

I'm not sure an online calculator can handle odd values in the typical phase shift oscillator. It's a tricky bit of math, even after the script realizes that the values are non-identical. The math is such that if you get the component values too non-identical, the thing may not oscillate at all. Th...

This reminds me of a signature line from a member of a guitar building/refinishing forum I used to frequent...frequently: I freeze all the electronic parts of my guitars. It gives them a piquant, morsellated quality, with none of the unctuousness of more garrigue components.

+1 vote on 1k5.

If I may request it, is there a calculator for tremolo oscillators? I've seen several you can use as long as all three resistors and capacitors are the same value, but none where you can change any single variable.

Just being able to switch between hot, mild, and cold bias. Still deciding what values. May go with 2x500 and a 1k. That would give me 250, 333, or 500. Just something to play with. It would also give options if using different output tubes (thinking about maybe using 6K6 at times, or if I beef up t...

Thanks for the heads-up! Do you think something like 4k7 would be better?

With the new cathode resistor combination in there, what’s the measurement between the plate and cathode?

I measured again and did get a drop in voltage with the MV change. All the way up i get 422v and down im at 444v, its late and i may have mixed that up. Hey! We're getting somewhere! My guess is you'll want to remeasure voltages with the MV all the way up (I only build stuff that's not so loud that...

Just checking; are you measuring the voltages with the right conditions? As in, is the MV supposed to be at a certain level when you measure? Sometimes voltages are to be measured with everything on 0. Does adjusting the MV change your measurement?

At first glance, your voltages are a little high. 5881 doesn't really want over 400 on the plates (you'll notice the schematic has them at 423-39 (cathode voltage)= 384V). I'm guessing the PT might get hotter with the 5Y3 because the SS plug doesn't use the 5V tap, and they 5Y3 does.

I did something like this a while ago with a Princeton Reverb. I lowered that to 2.2M in mine to get a little more hair out of it.

Item removal/price drop bump.

So, I had a little time this weekend and found some errors on my schematic and layout. Got those sorted out, and these are my "As-intended-to-be-built" schematic and layout. Feel free to share any thoughts you have on why it might or might not work, or if you think something could be better!

Dr Tony Balls wrote: ↑Fri Jun 02, 2023 5:23 pm

johnnyreece wrote: ↑Fri Jun 02, 2023 5:06 pm Got a picture of your rectifier circuit?

Yeah its very basic just two diodes:

Well, there goes my idea...I thought maybe you were using a bridge rectifier while using the CT. This is obviously not the case.

Got a picture of your rectifier circuit?