modding guitar fx for bass

[sasuke_kun12]

I was thinking about this. How would you modify a guitar fx to let it cope with bass frequencies?

[GibsonGM]

A good start would be by increasing the value of the capacitors in the signal path, starting with the input and output caps.  Anywhere there's a filter section (lo pass/hi pass), you might have to tweak the values for a good sound from bass.  Very do-able, might take some time, though.   Easier if you are building the FX yourself rather than modifying one already built...

[Gus]

Sometime you don't change anything.  FWIW sometimes a stock out of the box TS7,9 or a FF type or.. sound good with a bass

Next this increasing cap value at the in and out to make an effect a bass effect can sometimes cause problems letting in more lower frequency (and it is only a octave difference).  If the device is a clipping type like a fuzz overdrive distortion the lower notes added harmonics can sometimes add too much mids and highs OR it can be just what you want.

Also think about the strings, bass strings can have more magnetic metal over the pickup and often move more for a possible increase in the signal going to the effect and the lower strings are bigger than the higher(now with some strings they can be two layer and the core and maybe not all layers are magnetic(I don't know if the stainless sometimes used is the magnetic 400 series or non magnetic type) BUT the core should aways be magnetic if I understand how they are built) One day I will unwind a bass string and check what I can.

So sometimes not to "confuse" the clipped mids and high with extra harmonics I often reduce the input cap and adjust the input resistance if the effect is right after a passive bass.

Yes it might sound counter intuitive but try it. 

Don't believe what you read on the web if you can test it IMO.

Cap are not much money try a few values at the input

Also some post about liking FF type with smaller input and gain caps even with guitar

It is as always a taste issue.

Now you might like the effect with more bass being let in

Simple rule for fuzz, O D,  Input RC can help set what frequencies get clipped.  Output RC(output of the device to what ever it is plugged into) is more of an EQ after the added harmonics

Now the EQ points.  Think about this, a famous tube bass pre is supposed to been based off a fender guitar preamp section.

EQ tone is often to let you be heard in the band or mix I think of it as frequency slotting. 

Also remember stuff that sound good solo in your basement sometimes can get "loss" on stage or in a mix.  The true DIYer would adjust the EQ and effect for the band or mix they are in.

[Mark Hammer]

This general question comes up several times a year.  Gus makes a number of good points, I think.

Whether an effect needs to be modded for bass, and how, will depend on the nature of the effect.  For instance, any filtering effects need to consider that the critical frequency bands that define a bass's tone are lower than those of a guitar's.  So a wah, or auto-wah, or EQ will have its filters adjusted downwards.  Effects that make use of the input signal's level in some manner, like a distortion or a compressor or auto-wah, may need adjustment to cope with the often more powerful signal from a bass.  Effects that impose something over top of the bass, may need some means to let the fundamental in the bass note be as audible as possible, so you might find a blend control to mix clean/effect.  One thing I like to build into chorus pedals is a low-cut control that applies the chorus effect only to content above 5-600hz or so.

Like I say, the nature of the adjustment will vary with the type of effect.

At one level, the advice to alter caps in the signal path makes some sense, but my experience has been that, with a few exceptions, most pedals actually provide far more bandwidth at both ends (top and bottom) than anyone really needs.

[Gus]

http://ayanmusic.com/enterprises/sands_history.htm

Mark this thread reminded of the old ampage days

[sasuke_kun12]

thanks for your help guys!

just got quickie. If i added a switch to go between guitar and bass. is it possible to place the output and the input onto a seperate PCB and wire that up to a switch so i can go from bass frequencies to guitar frequencies?

cheers