Capacitor Blending

[Harry]

Like a capacitor on either side of a pot. Does this work?

[tungngruv]

http://www.generalguitargadgets.com/diagrams/ezface_blend_cap.jpg

[Harry]

2 caps parallel add em up and equals value's sum, sounds good. Thanks Tounge & Groove

[WGTP]

I really think both the cap blend and the input impedance control are very useful with the FF type circuits.  I don't like the really wooly fuzz sound, so I use either small input caps or 100K resistor at input.

So many differences/complaints about various distortions/ODs/Fuzzes is just a matter of a cap value and the BLEND circuit allows for infinite variations. 

The Tweak Fuzz is a good example.  The different caps and switch isn't needed with the BLEND circuit.   

Thanks for posting the Easy Face schem with those 2 useful controls.

[GVC]

Excellent ideas htat have been around for some time that I am just now getting familiar with!

Thanks for this post.  I noticed that input impedence had a dramatic effect on my SD 1 when modding it.  The higher the impedance the lower the top end "FIZZ" and more "transparency" this made me a happy camper since I am the owner of a bright amp (Delue Reverb).  Now I am going to want to include these options on every Distortion unit I decide to make .

[Stompin Tom]

What an easy and great idea. 

GVC, I'm curious, can you explain the difference in sound between adjusting the tone knob and the input impedance pot on your modded sd-1 (or any other distortion/od circuit)?  or am I missing something?

[WGTP]

Usually, the increase in input impedence reduces the bass which (on the Fuzz Face) also reduces the input level and subsequent distortion.  If you have less fizz and more transparancy in the SD-1 I would think it would be due to reduced bass.

The original FF has low input impedance which reduces the highs thru the circuit and makes it less harsh/more wooley.

The lower input impedance would be different than a POST distortion tone control because it reduces the highs BEFORE the distortion. 

[GVC]

I am sure it is different for different pedals but for one reason or another the SD 1 sounded less Distorted and it seemed to round the distortion off when I raised the input resistor R2 and the impedance.  I am not an EE, and I am not sure why the circuit would do this but that is the way it sounded. 

There did not seem to be any effect on the tone KNOB,  or a dramatic ( maybe a little less bass ) change in overall frequency response it seemed to round out the edges, soften the clipping, less distortion.  I suppose that is what you were driving at WTGP.  If what it is doing is not allowing the pre clipping bass to get distorted then I guess I do not like the sound of distorted bass signal.

Does that make any sense, I am trying

[GVC]

PS, I don't know about anyone else but if this is a case that can be made a general assumption or if it isolated, I would be curious.  Maybe any EEs present could describe what is happening better.

WGTP, thanks for the technical description, it is times when people like you describe the "goings on" that we all learn

[WGTP]

I'm not an EE either, it was to scary to pursue in college.  About all I know about this stuff came from right here. 

There are numerous discussions about limiting bass thru the distortion section smoothing out the tone because of less IM distortion, etc.  This would also result in more clarity and other positive stuff.  I typically lower the bass as much as I can and then boost it back on my amp. 

The cap blend could be used in numberous places in a variety of distortion circuits.   

[GVC]

"The cap blend could be used in numberous places in a variety of distortion circuits. "

Any examples that worked well for you?  The SD1 was a really dramatic difference so I am thinking of trying on the DOD250 and Distortion + circuits.

[WGTP]

Most of my stuff is done with a breadboard sitting on top my amp, so I just substitue values.  To me the cap values that most effect the tone/character/timber/etc. of op amp based distortions are the the ones coming off the feedback loop to ground or 4.5v, either with a fixed resistor or pot in series.  The Tubescreamer/SD-1, Rat, Dist.+, etc. all can be modded with different values in that spot.  This radically effects the overall sound of the distortion and would be a good spot for a Cap Blend.  I'm not sure which pot values would work the best, but the cap values I would start with would be twice the standard value and half the standard value.  This would give a pretty good range.  Experiment with the cap values that provide the least bass you would use and the most and then BLEND between them with the pot.  If there is a GAIN pot in series with the cap at this location, it will be interactive with the BLEND pot.  It's a start.