Circuit tweaking help please

[pryde]

I currently have a T.O.D.D. overdrive from guitarpcb breadboarded. This is a great OD based on the ROG Peppermill with a few additional mods (diode clipping switch and tone control) added.

The only thing I am not digging is the tone control in that it is very subtle and doesn't have enough treble freq turned up full. In the schematic C4 is .022uf and R9 is 36k leading into the 100kb tone pot. Is there anything I can try to get some more treble in the sweep here? Thanks for your advice/insight.

[jubal81]

Using a Big Muff tone control wouldn't add many parts at all. That'd be where I'd try going with it.

[pryde]

Using a Big Muff tone control wouldn't add many parts at all. That'd be where I'd try going with it.

Thanks for the tip. The problem is that I have a pcb already deisigned from this schematic. Looks like I might be stuck just changing values?

[jkokura]

As in you have etched it already?

I would do a redesign.

Jacob

[oldhousescott]

Firstly, double-check your breadboard wiring. I wouldn't expect the tone control to be too subtle based on the design.

You can parallel a cap with R8 to get a slight treble boost. 10nF will add a bit of treble starting at 2kHz.

[pryde]

Thanks jkokura, I did not design the pcb, it is from guitarpcb. I breadboarded first just for practice to get the components right before populating the pcb.

Oldhouse, thanks for the tip. I will again check my BB to be sure. I will also try the parallel cap you suggest.

Just to note, my breadboard/prototype rig is pretty noisy with ALOT of RF interference. It is possible the tone control freq is getting somewhat buried with all the noise.

I started the BB with just a stock peppermill and found the fixed RC tone filter (8.2k and .022uf) worked pretty well too. This is really a nice, extremily subtle OD in stock form, it adds just a bit of hair to my 5e3 at low volumes but still sounds exactly like my amp. Really nice. I don't think I will use the clipping diodes much (LEDs and 1n34a) but the option is nice I suppose.   

[mgwhit]

Firstly, double-check your breadboard wiring. I wouldn't expect the tone control to be too subtle based on the design.

I know that every time I breadboard a circuit and it sounds unexpectedly bad (or even blah), it's because I've made a mistake on the breadboard.

You can parallel a cap with R8 to get a slight treble boost. 10nF will add a bit of treble starting at 2kHz.

+1 to the above recommendations.  I'd try the 10n C4 first, since that can be done directly on the board, but doing a parallel cap around R8 shouldn't be too complicated, especially if you use a ceramic.

Does your version sound significantly darker than the demo?

[pryde]

Hello mgwhit.
No my BB circuit sounds pretty close to the demo I think. Unfortunatly the demo only showcases the LED clipping in the circuit which makes it brighter and louder than just the j201 being clipped. THe tone control is pretty subtle with the stock, j201 clipping. It sounds more like a "presence" control which isn't such a bad thing really.

I think when the pcb is built the tone control may probably be more pronounced. I will continue to try some suggestions here though.