EQ Pedal Idea

[kurtlives]

Just an idea...who knows if it is anything...

Could I make a transparent booster like a EHX LPB and put a tone-stack between the the output cap and volume pot?

I was thinking of this famous Blackface tone-stack...


I think it would be a neat pedal if it worked. I would be like a basic EQ pedal.....3 bands and a level control....


Input and suggestions appreciated....Thanks

[d95err]

Of course you can. However, there are probably better tone-stacks to put in a pedal.

The typical Blackface tonestack is designed to go into the amp, just before the poweramp. It has a very specific frequency response designed to compensate for the poor frequency response of the cheap speakers Fender was using in their amps (incidentally the same frequency response we now pay deerly to get for our guitar speakers...).

With all knobs center, there is a huge mid-dip. If you turn down bass and treble to zero, you get an almost linear response (but a big signal loss). Checkout the Tonestack Calculator over att www.duncanamps.com.

You're amp probably already has a similar tonestack (99% of all commercial amps do), so if you the pedal infront of the amp you get the mid dip twice, probably isn't a good idea. Especially since you wanted to use it with a booster. With a booster, you typically want to boost the mid frequencies (or reduce bass/treble) to get a fat, tight distorted sound.

If you want to use the pedal for direct recording with no amp, then this kind of tonestack could be useful. In that case, checkout the Tonemender at www.runoffgroove.com.

[kurtlives]

Ya I knew about the mid dip...

Could you suggest a better tone-stck for me?

[DougH]

You need Duncan's Tone Stack Calculator:

http://www.duncanamps.com/tsc/index.html

This is a handy-dandy tool that will simulate the frequency response of a number of different tone circuit topologies. You can play with component values, input/output impedance and so forth to see how they affect the circuit. This may give you some good ideas for tone circuits you can implement in pedals.

[kurtlives]

Ya I have it and have been paying with it.

[petemoore]

  Notice the 'level' of the frequency lines indicate output 'level' [re: Loss] of the various designs.

[kurtlives]

Any ideas what tone stacks I should use?

[breather-resistor]

I sure wish the duncan tone stack worked on Mac

[Papa_lazerous]

one word "Baxendall"

go google it.....nice EQ possibilitys there

[kurtlives]

^Thanks

anymore suggestions would be good. I guess I need to break out the breadboard.

[WGTP]

If your into a big midrange dip, the Vox Stack looks good.  Didn't Runoff :icon_cool:groove do something like this?   

[DougH]

I guess I need to break out the breadboard.

That's the ultimate answer.

[aron]

>I sure wish the duncan tone stack worked on Mac

It does: Parallels, VMWare Fusion and of course, boot camp.

[aron]

The Vox Tone Stack can make CRAZY midrange dips. Just play with the Duncan program.

[PaulC]

Yeah - the tone stack was tuned around the sound of the pwr amp/cab.  When stacked in front of the same thing it doesn't play right.  That's a problem that I see with a lot of the preamp/fet based pedals with preamp tone stacks.  You really need a different curve to make it work with the amp.

There was an EQ I made years ago that was the exact opposite of the fender tone stack.  The goal was to flatten out the curve of the amp by setting the knobs to the same settings as the amp, but they would boost the freqs the same amount that the amp was cutting.  The idea was to sort of turn the amp into something sounding like a pwr amp, so  preamp based pedals would work better in front of it.  It worked pretty well, but there were some gain issues because of the boosting nature. Still needs some work in the headroom area.

One trick is to model the amp you're using, and then model what you wished it was to show you what you need to do with an EQ.  An example is say you're using a Black face type amp.  Plot a curve to what you think would be your stock clean amp setting.  Then if you were wanting say a  marshall voice  try to model that curve so you could see what you need to add/subtract from the fender curve with an external EQ.  This can show you pretty quick what type of EQ you'll need. 

Hope that helps some. 
Later, PaulC
Tim & timmy pedals

[DougH]

That's a real good idea, Paul. Just let the pedal tone control "make up the difference" between your amp sound and where you want it to be when using the pedal. I agree that the tone controls on the "amp emulation" pedals need to be re-tuned. Part of the problem is you get into this "simulation fever" or whatever it is when you are designing it, and lock yourself in to doing things in a certain way- even if they don't make any sense.