A tone for my overdrive

[fuzzo]

Hi guys,

I did this pedal one year ago I don't stop modifying it since.




So it's a tube screamer gain stage with a second gain stage to increase the gain with the 3ways switch that select different resistor values in the feedback. That works good I've an issue.

I don't find a tone control that works good with it. As you can see in the schematic it's Proco rat tone that cut at about 950Hz taken from Zendrive circuit (I put an audio taper potentiometer at this moment) but that doesn't sound like I would.  Even with the pot at left the highs are always too much present for my tastes.

I tried , before, with a 100K lin pot. instead of 50Klin but the sound become too muddy at the left.

Have you any ideas about a tone circuit that could sound good with my circuit ? Maybe creating a high pass filter with the 4K7 Reistor between both gain stage to reduce high ? Changing some values ?


Thanks !

[MikeH]

Have you checked out the SWTC?

[fuzzo]

No. What's it ?

[MikeH]

Search "Stupidly Wonderful Tone Control" in google.  There's a good article on it at AMZ.

[fuzzo]

Oh that stuff. Yes I know it. I'm gonna read it again

I'll test that tomorrow.

thanks.

[Processaurus]

Hi, if you make the .0033uF cap bigger in your Rat tone control you can cut more highs.  I believe Proco uses a log pot for the tone control, and you'd definitely want a log pot for the volume.

[fuzzo]

Actually in seeing the schematic I posted, there're some errors. Volume pot is 100Klin (and there's no resistor before).

Yeah Proco uses a log pot for the tone control. I think it's the key of this filter. I think I'll buy a 100Klog and try that. With the 100Klin that doesn't work good , of course that cuts highs , but I don't know is not really useable and works like a RAT does with a 100Klin. Increasing cap values will cut more highs but won't change that fact.

Anyway, tomorrow I'm gonna try the SWTC tone control and see if that works good or not.

Night everyone !

[chuckmoose]

I had good luck recently with a modified version of the SWTC from the AMZ site.  I changes all the component values to suit my needs and tastes, largely by experiment, but I found something very subtle and useful.  Good luck.

[oddist]

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/ToneControl.JPG.html
I've come up with this one.  I like it because at the treble end, it still cuts some highs via the "shelving" action of the 3.32k resistor, yet
allows enough through for some clarity.  It also mixes in some bass by virtue of the 100k pot / .0047uF combination acting as a lowpass.
If anyone tries it, please post comments.
Thanks.

[fuzzo]

I've just tried different tonestacks . Stupidly Wonderful Tone Control from Mr. Hammer, simple low pass filer (100K/100n), proco rat style with different values, and the pedal always had too much highs.

So I created a high pass filer with the resistor (4K7) between the first and the second gain stage with a 15n cap. It cuts at about 2,5KHz and that seems to resolve my issue. I put again the proco rat tone with 50Klog and it became usable (more than last one). I think I've to do more test to see if it is really like I want.