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DIY Stompboxes => Building your own stompbox => Topic started by: yeeshkul on February 22, 2022, 04:02:36 AM

Title: Small Stone J distorting on bass strings - solved
Post by: yeeshkul on February 22, 2022, 04:02:36 AM
I can hear distortion (here and there) when i play fat strings on my guitar through my old Small Stone J. Where shall i look? Or is it what they do? I see there is a 10uF cap between the input gain stage and the LFOs. It may lead too much bass to the LFO. Shall i exchange it or even replace it with a smaller value cap?
Or shall i lower the gain of the input stage?

Thanks.
Title: Re: Small Stone J distorting sometimes on bass strings
Post by: anotherjim on February 22, 2022, 08:48:57 AM
That might do it. 10uF does seem very generous. I'll guess that 100nF might be one to try.
Don't think there is a direct connection to the LFO. It's shown close on the schematic but the input doesn't feed it.
Title: Re: Small Stone J distorting sometimes on bass strings
Post by: yeeshkul on February 23, 2022, 02:00:44 AM
I'v gone through the signal path and i have to confess it was my own output amp stage that distorted (to equal the TB drop).
It actually is very bassy and i think that lowering the cap 10u>100n would do good.
Title: Re: Small Stone J distorting sometimes on bass strings
Post by: yeeshkul on February 23, 2022, 06:16:01 AM
This one seems to work fine.

(https://i.postimg.cc/p5B1Wrb7/IMG-3005.jpg) (https://postimg.cc/p5B1Wrb7)
Title: Re: Small Stone J distorting sometimes on bass strings
Post by: yeeshkul on February 23, 2022, 08:42:35 AM
Here is a better design, with more stable base voltage. The 5k res is actually a 5k trimpot with the wiper connected to the output cap (Rangemaster style).

(https://i.postimg.cc/4YcCqrJh/Image1.png) (https://postimg.cc/4YcCqrJh)
Title: Re: Small Stone J distorting on bass strings - solved
Post by: PRR on February 24, 2022, 08:49:09 PM
Quote from: yeeshkul on February 23, 2022, 08:42:35 AM
Here is a better design...

And a much better screen-grab. Thanks for that.