freestompboxes.org

HEAD wrote:Yeah of course we've got a detailed shot of the component side. What we need ist a detailed gutshot of the trace side which you could kindly provide so that we can draw the schematic and then might be able to help you. A detailed shot of the trace side alone isn't always that helpfull, you know?

Doesn't seem like a whole lot to reverse... as I already said, start with the cranked AC and change the values a bit to be a bit more beefy at the front end. It's very simple - just a couple of jfet gain stages with a dual low pass filter on the end (like ROG, BSIAB, etc). Tone control is in the same place - just a pot between a larger cap on the end.

Thanks Brian! Your insights and openness are greatly appreciated.

Guys, I'm sure mimicing the bypass capacitor and cathode resistor scheme of a JCM800 or plexi will get you reasonably close. This is what breadboards are for!

This schematic was donated anonymously.

culturejam wrote:This schematic was donated anonymously.

plexi-drive.PNG

this is nice.. plexitortion would be next?

whats means C7 105? or C2 222?

Those are the value codes printed on capacitors. For example 105 = 1mF , 222 = 2.2 nF
check this out: http://www.electronics2000.co.uk/calc/c ... ulator.php

Hi,
Change the 15K Drain resistors to 100K trimmer and it adjusts after hearing.

regards Uwe

C3 47pF is obviusly wrong, 470pF (must be write 471) is right.

Used the Cranked AC Vero layout with little mod , works well.

culturejam wrote:This schematic was donated anonymously.

plexi-drive.PNG

it's verified ?

Thanks

Threw this vero together yesterday. It has been verified and reportedly sounds just like in the videos.

the plexi-drive sounds very promising,
although I could see that if you use it with a blackface or with some kind of a jensen speaker it could miss some of the plexi/greenback mid punch.

maybe the bsiab2 aka box of rock tone control could solve this problem, I'll need to try that!

Anybody done that before? Brian have you experimented with different tone stacks?

I think the next one on my build list will be the run off groove thor.
So far I have build the BOR, Rust Driver, Purple Plexi...

cheers
ghandi

Anybody thoughts on using mustard-type capacitors for the larger values in the circuit?

I do that often with marshall inspired overdrives...

I did a box of rock with them and compared it with the regular unit, that was like night and day.

The mustard caps really bring the marshall mids to the front and also retain clarity like no other cap!

cheers
ghandi

Consider this one "verofied" once more It's certainly going to cover that Hendrix/Clapton territory pretty vell...

hey guys, I'm almost there, I'm getting faint signal on output, I think it's faulty tranny...
anyway is there someone willing to post voltages on trannies?

thx

whosyourdaddy wrote:hey guys, I'm almost there, I'm getting faint signal on output, I think it's faulty tranny...
anyway is there someone willing to post voltages on trannies?

thx

I'll hook my build up later, when i get off work. Meanwhile you could post pictures of your build, so the rest of us can check it out as well...

well there's nothing special about it, I think it's clean build...

grrrunge wrote:

whosyourdaddy wrote:hey guys, I'm almost there, I'm getting faint signal on output, I think it's faulty tranny...
anyway is there someone willing to post voltages on trannies?

thx

I'll hook my build up later, when i get off work. Meanwhile you could post pictures of your build, so the rest of us can check it out as well...

I just got a lot of extra work on my hands, so i won't be able to do any fun stuff tonight. Sorry! It might be as late as wednesday or thursday before i get around to do some measuring...

no worries I've solved the problem, I overlooked C6, thought it has one strip space between terminals.
now it sounds great, plexi sound it is.

here are voltages if anyone needs them: (supply 9.02V)
Q1: (DSG) 3.65V 0.36V 0V
Q2: (DSG) 5.37V 0.24V 0V
Q3: (DSG) 3.76V 0.35V 0V

whosyourdaddy wrote:no worries I've solved the problem, I overlooked C6, thought it has one strip space between terminals.
now it sounds great, plexi sound it is.

here are voltages if anyone needs them: (supply 9.02V)
Q1: (DSG) 3.65V 0.36V 0V
Q2: (DSG) 5.37V 0.24V 0V
Q3: (DSG) 3.76V 0.35V 0V

Good to hear I like mine pretty damn good as well!