SHO volume control

[Kipper4]

Is it possible to mod the SHO so that output volume can be controlled?
Please enlighten me.
I'm a bit of a newbie still when it comes to theory so explain in laymans terms if possible
thanks.
I really like the effect but i'd like to control the output volume as well as the crackle.
it seems when you turn up the crackle you turn up the output volume' id like to mod mine so i can attenuate the ouptut but maintain the crackle.
Thanks
Rich

[Labaris]

There are many ways to do it I guess. Could you post a schematic?
The user frequency central came up with an idea to stop the crackle knob's "crack" noise.

[Kipper4]

like this
http://hotbottles.wordpress.com/2012/03/29/building-a-z-vex-sho-clone-from-scratch/
I hope no one gets upset at me posting the link.
Take it down mods please if its a problem.

[Labaris]

The easiest way I see for adding a level pot is to change the 100k resistor at the output with a 100k log.
The wiring should be like this:

1. 1st lug of the pot (1st on the left, looking from the front) goes after C2 (where R5 was connected)
2. 3rd lug goes to ground
3. The output of the FX will be now on the 2nd lug of the pot. This will make your output voltage (signal volume) variable.

Problems with this could be interaction with effects after it, but you'll need a more complex solution for avoiding this. Try this on ans tell us

[Kipper4]

cheers guy i'll try it later tonight i'm in the middle of a VLO build.

[chromesphere]

Hey kipper, this is something i learnt myself recently.  If your interested in an explanation (well...my best attempt at an explanation) check out this video i made on the subject. 

Its funny how once you keep an eye out for this sort of volume control, how you notice how often its actually used!

All the best
Paul

[Labaris]

Hey kipper, this is something i learnt myself recently.  If your interested in an explanation (well...my best attempt at an explanation) check out this video i made on the subject. 

Its funny how once you keep an eye out for this sort of volume control, how you notice how often its actually used!

All the best
Paul

Very useful video! Congrats

[chromesphere]

Thanks for the compliment Labaris!  I hope I did a decent job explaining it!
Paul

[Kipper4]

thanks mate. i just love your video.

[Kipper4]

The easiest way I see for adding a level pot is to change the 100k resistor at the output with a 100k log.
The wiring should be like this:

1. 1st lug of the pot (1st on the left, looking from the front) goes after C2 (where R5 was connected)
2. 3rd lug goes to ground
3. The output of the FX will be now on the 2nd lug of the pot. This will make your output voltage (signal volume) variable.

Problems with this could be interaction with effects after it, but you'll need a more complex solution for avoiding this. Try this on ans tell us

This works. Thanks guys. its much better imo
what would happen now if i changed the pot for a 10k?
what would happen if i changed the pot for a 500k?
i will learn by hook or by crook.

[Labaris]

The easiest way I see for adding a level pot is to change the 100k resistor at the output with a 100k log.
The wiring should be like this:

1. 1st lug of the pot (1st on the left, looking from the front) goes after C2 (where R5 was connected)
2. 3rd lug goes to ground
3. The output of the FX will be now on the 2nd lug of the pot. This will make your output voltage (signal volume) variable.

Problems with this could be interaction with effects after it, but you'll need a more complex solution for avoiding this. Try this on ans tell us

This works. Thanks guys. its much better imo
what would happen now if i changed the pot for a 10k?
what would happen if i changed the pot for a 500k?
i will learn by hook or by crook.

Good to hear that it's working.

About the other question, it's hard for me to say exactly what would happen with other pot values.
The volume pot in this particular circuit the output impedance of the effect (or at least tha main part of it). In theory, the less output impedance you have, the better the "communication" between this pedal and the one that's after it.
Anyway, I've not seen any pedal with a 10k volume pot (maybe there are some, I'm not an expert ). Give it a try and see what happens. You could hear difference in signal level and treble content.

[chromesphere]

thanks mate. i just love your video.

Thanks Kipper, hope it helped and good luck with your build!
Paul

[Davelectro]

what would happen now if i changed the pot for a 10k?
what would happen if i changed the pot for a 500k?

In this case a 10K pot means less gain, since it's a heavier load for the mosfet stage. You need a very low output impedance to use a pot that small.

On the other hand, 500K would be overkill. I'm afraid that a larger pot won't give you any more gain. Besides, too much treble may be lost as you roll back the volume, since series resistance at the output will be larger.

[Kipper4]

gottya thanks