Newbie question - why does pedal sound different when not chained?

[pete_g]

I've made a schaller fuzz pedal and it is grounded ok, but it drops the high frequency and gain a bit when it's not chained to another pedal. Can someone point me in the right direction as to what is the most likely  cause of this? My power supply is a Pedal Power 2 board so that is supplying voltage ok. I think it may be cheap pots that are the small square centimeter type with a green back as the same type of pots did the same thing in another fuzz pedal. Thanks.

[nocentelli]

I'm guessing here, but I assume you notice more high frequencies and a perceived increase in gain when you have it chained with a BOSS or other buffered bypass pedal in front of the schaller fuzz. You might also notice that the fuzz in question does not "clean up" when you roll back the guitar's volume because the fuzz is presented with a buffered input signal. Many players do not like this effect, and this is why the fuzzface and similar circuits are said to work best when used first in the chain, i.e. Guitar->fuzzface->other pedals->amp.

[pete_g]

So I'm hearing the circuit as it should sound without the buffered signal? I've built 4 fuzzes and it's the same thing with all 4. I didn't know that until I tried them to see. I dont know what a buffered signal is but I'll look into it. I prefer the sound when it has the boss pedals in front.  Is it possible to buffer the signal without the need to have a boss or similar pedal at in front    to get the same effect? Thanks for your help

[nocentelli]

If you just plug straight into the fuzz, then into the amp, you'll be hearing the fuzz as it was designed.

I've built 4 fuzzes and it's the same thing with all 4.

Which particular circuits are we talking about here? The fuzzface is particularly affected, and I've had similar experiences with other simple two transistor fuzzes e.g. the Sam Ash/Astrotone fuzz pedal which is a single input stage->clipping diodes->buffer stage->output.

The tonebender "mk2" type circuit, which is a essentially a fuzzface with an extra boost stage in front seems less affected by an upstream buffer, perhaps because the added input stage is already affecting the sound, so the effect of putting a buffer in front is less noticeable.

If you use google to search for "fuzzface buffers" you'll find hundreds of articles explaining how buffers have a (very) high input impedance and low output impedance, and how this is generally good for preserving the tone of an electric guitar over long cable runs (which is why Pete Cornish is an avid proponent of buffered bypass pedals and pedalboards), but is generally detrimental to the interaction between a fuzzface circuit and the guitar. Many of these articles will have been written here at DIYSB by RG, Mark Hammer, Jack Orman, Gus Smalley and other veterans of the web who have answered and explained the issue dozens of times.

Most articles are aiming to reduce the problem, but if you like the effect the buffer has on the sound of your fuzz, you can make a buffer circuit on a tiny daughterboard with just a few components and wire it between the "send" from your fuzz footswitch and the input to the fuzz circuit itself. Buffers only require a single BJT, JFET or opamp and have no effect on the signal level so require no extra controls: Here's a link to a good article from amz showing and explaining some simple buffer circuits -

http://www.muzique.com/lab/buffers.htm

[pete_g]

Yeah thanks for all that info. I watched a YouTube video of how to make a buffer circuit in 10 minutes. I understand how the buffered pedal in front of the fuzz affects it due to the circuit in it being always on even when bypassed. I'll make one if I need to show the diffetence it makes to others who have no pedals on the chain as I've been making them for friends. Thanks again.

[MrStab]

FWIW, for the reasons outlined by Leo, fuzzes have more caveats with regards to impedance etc. than most other circuits, which are often "self-contained" with their own buffer system. so fuzzes are probably a good insight into how all that works, but it's worth bearing in mind that they're somewhat the exception rather than the rule.