freestompboxes.org

Hi,

I recently received a broken Danelectro Cool Cat Transparent Overdrive V2.
Since no actual schematic seems to be available I have tried to create one using Kicad.
Most capacitors are smd, were removed and measured with RLC meter.

The Cool Cat Fuzz V2 input buffer seems similar.

The FET clipping is not yet drawn properly, suggestions welcome.
>> Update rev 0.2: Cleanup input, output, value R8
>> Update rev 0.3: tone pot wiring double checked and updated after check by bmxguitarsbmx
>> Update rev 0.4: redrawn opamp section for readability and confirmation of tracing by Lani. Educated guesses on a few caps by mauman.
>> Update rev 0.5: Updated with capacitor values. Questions marks when not 100% sure.
G.

Pictures of the main board.

Looks like a pretty cool design. The bass and treble controls, specifically, are interesting.

Edit: Actually, there must be an error in the Treble wiring, as its functionality is shorted out. Maybe it is in the U1a feedback loop?

Typically, when doing diode clipping to ground, a dropping resistor is used to create the voltage drop when the diodes turn on. The output of U1b is directly connected, besides the output coupling cap, to the clipping diode switching section. It may be this way, in which case the clipping is caused by the op-amp reaching its current limiting. Which would also be interesting.

Thanks for checking.
I do seem to have made a mistake around C7 and the Bass and Treble pot.
I've updated the schematic in the first post.

Here are a few caps that you can avoid removing to measure, the values are pretty standard for their locations: C12 is almost certainly 100 nF MLCC. C5 and C9 are very likely 47 to 100 pF. C10 is likely 2.2 to 10 uF.

So I just traced the tone and gain sections from your pics and this is what I ended up with.

The trace by Lani confirms the schematic (I had C6 named as C8). I've redrawn it as in Lani's cleaner schematic.
I've added the "educated guess" cap values.

C10 has two lines of text on it :
L 7 8
B 2 4 (can also be 8 2 4 or even 6 2 4)

gja wrote: ↑26 Jun 2023, 17:00 C10 has two lines of text on it :
L 7 8
B 2 4 (can also be 8 2 4 or even 6 2 4)

C10 looks to be 820nF (824) then which seems likely considering it's size.

Anyone seen those yellow 9mm pots before, or perhaps know the manufacturer?

I believe they are made by Soundwell
https://Soundwell-cn.com

I have one of these that I am happy to solder and measure component values if you'd like?

I may be able to measure caps on an RLC meter today.

Lani wrote: ↑27 Jun 2023, 21:45 I believe they are made by Soundwell
https://Soundwell-cn.com

The logo seems to match up, thanks! It's always nice to have options. Now to find a distributor without a MOQ of 2000...

Caps measured:
C1 in circuit: 47nF
C3 desoldered; 20-30pF?
C4 in circuit: 10nF
C5 desoldered: 150pF
C6 desoldered: 10nF
C7 desoldered: 9.8nF => 10nF
C8 desoldered: 940nF => 1uF
C9 desoldered: 50pF => 47pF
C10 in circuit: 820nF
C12 wouldn't come off the board, not that important.
edit: will put values in schematic later.