Frequency Specific Gain Help

HydrozeenElectronics · Post by **HydrozeenElectronics** » 25 Feb 2009, 04:52

I had this idea, some one has probably done it before but I can not find any articles on it.

I have a Fuzz Face Clone that I built. I want to remove the 40 UF cap I have on the emitter of Q2 and replace it with some kind of a filter so I can either select only Lows or mids. so that I can boost the low end or mid-range gain. It's easy to get highs, but to block all the highs that's the problem.

I though maybe a low pass filter but that will not really work either because it still grounds the highs.

Maybe a Op amp low pass filter on the emitter?

thanks in advance for the help

HydrozeenElectronics · Post by **HydrozeenElectronics** » 27 Feb 2009, 13:32

anything Fellas? If it's a crazy idea just say so.

OC26 · Post by **OC26** » 27 Feb 2009, 19:30

Why not a filter at the input?

http://analogguru.an.ohost.de/193/schem ... akFuzz.gif

RnFR · Post by **RnFR** » 27 Feb 2009, 20:57

why not just use a switch to go between emitter caps?

HydrozeenElectronics · Post by **HydrozeenElectronics** » 27 Feb 2009, 23:27

I had tried those and they work but, when I was experimenting with emitter caps I noticed that a small cap really pulled a lot of "treble gain" out of the circuit. I myself like a more "muddy" sound so I though If I could pull more bass gain out of it that would be cool but everything you do to filter highs out such as a low pass filter sends the signal to ground anyway resulting in treble gain too.

I was thinking if I could cancel it out before going to ground say with an op amp low pass filter that it might work.

I did build a transistor emitter follower that was set up with a pretty big cap in the feedback(collector to base) but what I noticed is that the bigger the cap got the more treble it passed just the opposite of what I thought would happen, shouldn't it filter and cancel out even more highs?

One cool thing to come out of it though was I was able to get some really cool trumpeting effects that I might experiment with latter but did not help me with the task at hand which is smooth fat bass gain with little or no treble gain.

RnFR · Post by **RnFR** » 28 Feb 2009, 00:42

how about if you try the cap from C to B again, but take the output off of the collector instead of the emitter. this is a normal way to filter highs in circuits like the big muff etc.

HydrozeenElectronics · Post by **HydrozeenElectronics** » 28 Feb 2009, 07:15

RnFR wrote:how about if you try the cap from C to B again, but take the output off of the collector instead of the emitter. this is a normal way to filter highs in circuits like the big muff etc.

Ya I have tried that, I've never really liked the sound of it. That's why I was trying something else. I think if I could get it to work it could be a great Tone Tweek but might just be unfeasible.

Thanks

I'll keep you posted if I come up with anything.

HydrozeenElectronics · Post by **HydrozeenElectronics** » 28 Feb 2009, 07:32

Here is were I got the idea of a Tranny on the emitter. Maybe with this schematic you guys can help me figure out if it would be possible to use it to filter out the high end gain.