i built the multi face from runoffgrove and i love it, but would like to add a bass cut control. i like the way the "variation on lowpass filter" looks on the simple mods and tips page, but i have no clue where to put it in the circuit. all i have on hand is a 1 meg linear pot. will that pot work? the value on the schem is 500k. the 3904 transistors i have are "dark" and i think this would be a usefull way to choose between 2 caps and get some of the mud out. thanks again for all you guys help in getting the face running. if there is a better way to do this please explain
thanks again
brent

Just to clarify, the Multi-Face is by Tim Escobedo.  RunoffGroove simply contributed some suggested components and a perf layout.

Check out the input cap blend control of the EasyFace.  It should do what you want.

you are correct b tremblay. i found the perfboard layout at runoffgroove..great site by the way and thanks for answering my emails before...will the 1 meg pot work? i will go to the shack in the morning and get a 100k but i wanna tweak tonight! i am so addicted to this pedal!

Well, I think there's 2 ways to add a nice tone control... the first is really simple, the second is not so simple, but IMHO, much better..

First, from DIY stompboxes.com...  the passive's...

QuoteAdd a lowpass filter

A lot of distortions don't have tone controls. Here is an easy lowpass filter you can add. It will reduce your output a little but if your distortion pedal has lots of gain, this shouldn't be a big problem. If you think about it, this can go right on the lugs of the output volume pot. Use a small trimmer mounted on the lugs of the output pot along with the capacitor.

QuoteAdd a low cut filter




Here's an interesting one to try, put a low cut if your distortion  has too much bass.

The pot value is 500K

I find those usually work OK, you're going to want to tweak the values a gusto.

Then there's active op amp filters, of which there are many types.  There's a calculator somewhere out there that will draw you a nice diagram for these (which can be boost or cut).  I'm working on a tone control for the PU+, probably going to be a knob mixing between a high cut and a low boost.  I'll try to post a schem of that, because I think actives are quite nice

-Colin

There are also a lot more filter diagrams on this page:
http://www.diystompboxes.com/cnews/mods.html

-Colin

Heres a bunch of reasonably nice info on lowpass filters and active volume controls and the like:

http://www.linkwitzlab.com/filters.htm

-Colin

well the 1 meg pot works..there really isnt a smooth transition but there is a sweet spot..i used the first method and it does the job nicely. hey thanks for the info anon..i will check those links out after i get tired o tweakin..this board rocks...

Quote from: b_rogerswell the 1 meg pot works..there really isnt a smooth transition but there is a sweet spot..i used the first method and it does the job nicely. hey thanks for the info anon..i will check those links out after i get tired o tweakin..this board rocks...

I find that when determining the pot you should use for output, I start around 250k and then bring it down if it's not smooth.  The board I'm working on now has an output resistor of 100k (think I'm going to lower that after implementation of a gain control) and a pot at only 5k.  This is a circuit with a gain of about 200, so it's more than your average one, but nevertheless...  If your pot isn't being smooth try using a lower value with a resistor in front of it.

-Colin