Lovepedal Hi Volt

[Frank_NH]

Another high gainer courtesy FSB:

http://www.freestompboxes.org/viewtopic.php?f=7&t=28215&p=262911#p262911

Thanks to Nocentelli for getting the schematic.  

[nocentelli]

Thanks, but Belanger88 supplied the schematic, I just redrew it so Sean wouldn't get upset. There's a a few pairs of series resistors and capacitors and paralleled capacitors that could be combined to one value to cut down the parts count if someone is doing a layout.

[Frank_NH]

Yes, thanks to Belanger88.  The design kind of reminds me of the Ramble Marvel drive with the dual mu amps, but the active EQ is an interesting twist.  I suppose that make sense since both effects are going for the Marshall high gain sound.

[Zanius]

Excuse my tilted resistors ;)
Any extra pair of eyes for comparing would be usefull.

==Updated==

[Emil]

Hi!

Looks good! Had a quick look at it and just noticed a few things.

 - After the 22nf cap at Q2 source there should be a 470K resistor in parallell with the 560pf cap instead of a 1M.
 - The 1M resistor on Q4 gate, right next to the Q4 label, should go one hole further up to the 16v instead of Gain 1.
 - There's a 1M resistor currently on IC1 pin 2 which should be on pin 3.
 - The 10K resistor on IC1 pin 6 should be a 1K
 - I'm not sure about the 470K currently going to IC2 pin 3. I don't think it should be there?

[nocentelli]

gain 3 is labelled as gain1

[Zanius]

@emilpaulsrud that wasn't a "quick look", that was the debugging of the century  
All your observations were correct. Layout now updated.

Now it looks even more awkward than before, with all that empty space in the middle lol!

[Emil]

Thanks, glad to help .
I started on a layout myself, but you beat me to it, so I was already looking into this :).

With the space you have there you could, if you'd like, avoid having the 6,8nf tilted by moving it to the right, next to the 10k. Add a link from the 10k two rows up and have the 6,8nf go to ground from there.

[nocentelli]

Slight revision to the schematic - The ends of the treble and middle pot that are tied together also need to be connected to the inverting input of the last opamp stage: See updated schematic below. I have also labelled the pot lugs (after reading up on gyrators). The layout posted has the lug numbering correct for the treble control (TS-style cut+boost) but I'm pretty sure the bass + middle gyrator pots have lugs 1 and 3 swapped over on the layout.

 

[Zanius]

So, applied the revision changes and moved around some things to give more air around the trimmer area.

[Alex]

Hey Zanius!
Just seen your layout!
You need a cut between Treble 2 and Volume 3.
The 150n cap going to Bass 2 should be 33n. The 100n & 50n are in serie.

[Zanius]

D'oh!
Just noticed that got moved! Well this thread can now be deleted anyways

[glasspak73]

Did you get this to work correctly?how does it sound?