Buffered vs. Passive Splitter?

bifurcation

bifurcation

Well-known member
Hey all,

I'm building a pedal board and I need to split my guitar signal (twice!) I think the best place to do the first split is immediately after the guitar (or at least after the tuner.)

One of the signals will immediately go to a fuzz most of the time, and I hear many fuzzes don't like buffers in front of them.

So... is my only choice to pick between passive (and potentially negatively affecting my guitar tone) and buffered (and potentially messing up the fuzz tone)?
 
I don't have a answer for you but i am curious too. I built a animato clone and tried to use a jfet buffer/spliter but the thing squeals like crazy at high gain. I wanted to try a op amp splitter next but I ain't got a clue if it will work :p
 
There is no easy answer to this question.

For your splitting / parallel situation, consider this scenario: you have a splitter with path A going straight to a clean amp and path B going through a fuzz pedal then off to somewhere else. Everything sounds nice and sparkly, but once you engage the fuzz pedal, the low input impedance (some fuzzes have 250k) and your pickups get loaded and your treble dies, even through your non-fuzzed output (500k Pots + 250k Fuzz + 1M Amp = 142k load).
 
daeg said:
There is no easy answer to this question.

For your splitting / parallel situation, consider this scenario: you have a splitter with path A going straight to a clean amp and path B going through a fuzz pedal then off to somewhere else. Everything sounds nice and sparkly, but once you engage the fuzz pedal, the low input impedance (some fuzzes have 250k) and your pickups get loaded and your treble dies, even through your non-fuzzed output (500k Pots + 250k Fuzz + 1M Amp = 142k load).
Click to expand...

That's what I was afraid of. :cautious: Maybe the only choice is to try a buffer and see how various fuzzes and distortions like it?

BTW, anyone have a quick and dirty explanation of why some fuzzes sound crappy with a buffer in front of them?
 
bifurcation said:
BTW, anyone have a quick and dirty explanation of why some fuzzes sound crappy with a buffer in front of them?
Click to expand...

There are a few theories out there, this is just my take:

They've been designed for a sound that includes your pickups being loaded by the low-input impedance. Most simple fuzzes have minimal to no to treble filtering, so when your string attack, with all of its harmonics, hits that circuit that's already creating a boatload of harmonics, you get all sorts of intermodulation creating enharmonics. Since that all happens very quickly before the string stabilizes, you just sort of perceive it as a stiff, metallic, splatty sound, because you were expecting something else.

TLDR; too much treble at the input.
 
http://screaminfx.com/tech/what-is-the-best-fuzz-pedal.htm said:
Side technical note and a major key to the fuzz, there are some other reasons why the fuzz is so sensitive. A fuzz pedal is usually made up of bipolar transistors (not MOSFETs) so in semiconductor terms, you have a PNP or NPN junction. This is essentially a current controlled device and the actual fuzz circuitis a current amplifier. What happens is, the more current you stuff into the input, the more output voltage you get. Because of the high output impedance of your guitar pickups, you can only supply so much current into the transistors relatively low impedance. This causes a notable change in the sound than if you were to use a much higher input impedance transistor such as a MOSFET in a voltage gain configuration.
Click to expand...
 
^ That article gives a much better analysis than my response from a couple weeks ago. What I said would be true if we were dealing with low-input-impedance voltage controlled devices, but BJT's are current controlled.

The problem goes deeper than the treble rolloff that happens from pickup-loading (like I explained). We also have to account for how much current the pickups are delivering to the Q1 base, then the complex interaction with Q2 in designs like Fuzz Face, Bosstone, Harmonic Percolator, Fuzzrite and others.

In short, my first response was far from the whole story, it's all very complicated. The best solution would be to just stick to Fuzzes that have have a buffer or booster at the front-end. A Dung Beetle would be a good example.
 
Here’s an idea to experiment with after a buffered splitter... I’ve never tried it myself.

Guitar Pickups Simulation

Schematics & circuits for guitar effects with vacuum tubes and solid state electronics. FREE downloads of schematics such as TS-9, Fuzz Face and other classic rock devices.
www.muzique.com www.muzique.com
 
phi1 said:
Here’s an idea to experiment with after a buffered splitter... I’ve never tried it myself.
Click to expand...

The EQD Erupter uses this approach and the results are good.
Relay Bypass -> Buffer -> "Pickup Simulator" (Inductor or Transformer) -> Fuzz Face (with some mojo parts)
 
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