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DIY Stompboxes => Building your own stompbox => Topic started by: eightsevenzero on May 31, 2021, 10:45:00 AM

Title: Help with tone circuit issue
Post by: eightsevenzero on May 31, 2021, 10:45:00 AM
I've been playing with a simple JFET circuit design for a while that I thought sounded pretty good. I'm finding an issue now that I could use some advice on. Schematic listed below.

The basic functionality is great but the tone control when rolled down, especially with the clipping diodes engaged, has a dramatic effect on distortion. It's like most of the distortion hangs out in the higher frequencies if that makes any sense. Is there a way I could retain this circuit close to how it's wired currently but have the tone control affect the gain less? I'm trying to understand how to work with this as designed as opposed to just say subbing a tone stack after clipping or whatever. Any advice is much appreciated!

(https://i.imgur.com/DtboeO6h.png)
Title: Re: Help with tone circuit issue
Post by: PRR on May 31, 2021, 12:25:02 PM
Maybe move the treble rolloff to after the distortion diodes?
Title: Re: Help with tone circuit issue
Post by: ThermionicScott on May 31, 2021, 02:05:13 PM
Does the "most of the distortion hangs out in the higher frequencies" persist when you have the gain control all the way up?
Title: Re: Help with tone circuit issue
Post by: ElectricDruid on May 31, 2021, 05:52:35 PM
The tone control is before the clipping, so by removing higher frequencies, you're also necessarily reducing the overall level and therefore the clipping. So two things happen - not only does the signal going to the clipping have less high frequencies, and therefore less distorted high frequencies, but it also has less distortion overall.

I second what PRR said. Try moving the tone control to after the clipping stage. Then you can trim the high frequencies more independently of how much distortion you apply.


Title: Re: Help with tone circuit issue
Post by: GGBB on May 31, 2021, 07:58:06 PM
A couple of variations to try - you might need to change values as well.

(https://i.postimg.cc/v4bQKZqK/image.png) (https://postimg.cc/v4bQKZqK)

But this would make a big difference as well:

Quote from: PRR on May 31, 2021, 12:25:02 PM
Maybe move the treble rolloff to after the distortion diodes?
Title: Re: Help with tone circuit issue
Post by: Lhoraxe on May 31, 2021, 08:12:52 PM
Distortion that happens in just half of your guitars voice sounds like a cool trick to me... Beyond  that, I'm not useful... Just saying that sounds like a thing I'd like to make or buy.
Title: Re: Help with tone circuit issue
Post by: iainpunk on June 01, 2021, 02:41:17 PM
Quote from: Lhoraxe on May 31, 2021, 08:12:52 PM
Distortion that happens in just half of your guitars voice sounds like a cool trick to me... Beyond  that, I'm not useful... Just saying that sounds like a thing I'd like to make or buy.
you could remove bass from the signal before clipping and add it back in after the clipping, or switch the bass and mids around. i have done some big muff mods for a friend which adds clean midrange into the scooped big muff sound, really cool for bass.

cheers
Title: Re: Help with tone circuit issue
Post by: Lhoraxe on June 01, 2021, 02:50:00 PM
Quote from: iainpunk on June 01, 2021, 02:41:17 PM
Quote from: Lhoraxe on May 31, 2021, 08:12:52 PM
Distortion that happens in just half of your guitars voice sounds like a cool trick to me... Beyond  that, I'm not useful... Just saying that sounds like a thing I'd like to make or buy.
you could remove bass from the signal before clipping and add it back in after the clipping, or switch the bass and mids around. i have done some big muff mods for a friend which adds clean midrange into the scooped big muff sound, really cool for bass.

cheers

Hmmm. Once I finish the two pedals I'm working on, I think I will do this, but integrate some oct-1 into it somehow.