Holy shit, Chris.
Those pedal graphics are crazy!

fuck it, imagonna build something like this

http://home.polstra.com/amps/breadboard/breadboard.html

Yeah, that is WAY less sketchy than the 2x4+Nails protoboard.

I know that folks have been using the wood+nail style for a long time, but i don't know if i would use it for anything higher voltage than pedals, given other options out there today. I would always be concerned about the variant/unknown humidity/conductivity of the wood with the high voltage/current running into it. Seems like it would be an easy way to make a radio (inadvertently) though.

Yeah this looks a lot less electrocuty.
I'm gonna build this up in a big ass roasting tin so that I dont get too bent out of shape over the cosmetics. Will probably use that weird sanecore PT from what I think is a vox ac15cc as it should be able to run 5 or 6 12ax7s without too much problem.

But first I need to finish up this amp build. More on that later hopefully. I got up dick early to watch the F1 this morning and now I'm pooped.

Got a bit more done on this today:

heaters wired


cathode biasing and screen tag board wired


Board underside grounds wired

If I dont get distracted I'll wire the pots, switches and power in tomorrow.

I got distracted haha. I got some stuff done though.

that looks pretty close to functional

Indeed
I've been ill as a motherfuck the last week so progress has been slow as I'm doing all the bits you really dont want to fuck up now

Just gone to shake down the power supply before wiring up the OT and the controls.
Heaters - check
Filters - check
Power scaling -

Something aint right. The layout for the VVR circuit looks okay. I've just been through it a few times and it doesnt look like I've fucked it up.

Could just be that it needs a load to regulate. Also it turns out that the VVR circuit blocks the screen filter cap from discharging when you discharge the reservoir cap

It turns out that the voltage scaling circuit wont work if there is no load on it. Makes sense if you think about how a MOSFET works I suppose
Stuck my bleeder tool across the screen cap and voilà! Working VVR!

Yey: it makes sound
Boo: pops, farts and motorboating

Ah well at least the PI and power amp work haha

I have acquired an oscilloscope which should make trouble shooting a load easier!

get this bitch working... NAOW!!!!!

Thats the plan

Initial titting about with the 0-scope make it look like i'm only getting signal from one side of the PI. Clean channel preamp seems to behave reasonably well for a 2Vpp sine wave. I'll dick with it more when I get back from the gym.

Its pretty cool looking at the preamp signal on the o-scope and twiddling the pots to see the phase shifts and distortion onset.

Someday, i will actually turn on my oscilloscope.

In my defense, it is my grandfather's old one (that he built) from the 60s, and probably will need some setup/calibration/cap replacement, so i have been semi-afeared to just turn it on and see what happens.




Also, which map circuit are you troubleshooting here again?

The amp I've been building forever