Cornish Buffer - the value of values

[motterpaul]

I also find that older builds don't sound as great as I thought they did, which is why I don't box up every pedal I make. I generally have to love it to box it. However,  I have also found lately that if I don't box an effect, it gets dilapidated sitting around and parts fall out of sockets, etc. So, if I think I will want to hear it later I am now boxing more of them (buying a drill press and learning how to wire pots & footswitches efficiently made it less of a struggle to box 'em up).

Here is a good article on guitar impedance, buffers and effects: http://screaminfx.com/tech/why-and-when-to-use-a-guitar-buffer-pedal.htm

The following is based on what I have read - but I reserve the right to be wrong and no offense taken if anyone wants to comment, or clarify.

I had heard that things like fuzzes and wahs (tone-suckers) can benefit from buffers, but it turns out that it is just a matter of preference (and your personal gear). He suggests adding buffers to some fuzzes and making them switchable, because if you change guitars you might want it on or off. Sometimes you don't want to buffer a fuzz, you want the effect it has on the signal.

I thinks it helps to remember a couple of concepts when reading about impedance. The word is rooted on "impede" which means to deter, or cripple.  So "low impedance" is actually higher flow. Mics are low impedance devices and their cable runs can be 300 feet with no loss. Also - guitar pickups are not just high signal impedance, they are magnetic coils so they are inductors, so it also about DC impedance. The coils have resonant frequencies (usually pretty high) but the capacitance of long cable runs can act like a HPF, so you lose clarity (treble).

To me, the buffers make the sound more defined in the high-mids range - essentially you are hearing the true sound of the pickup more clearly, more importantly, you preserve that tone farther thru your cable-effect chain by reducing the impedance and capacitance. The real advantage of buffers comes from adding them to long cable runs and to the input of certain effects (although it is not just the pedals that cause problems, it is also the combined changes in impedance & capacitance through different cables, switches, solder joints, pedal board cables, etc.). Lowering the impedance at the start of this chain helps the original signal flow through everything with less build-up of undesirable  tone-changing variations.

It isn't an easy concept to for a newb, but for people who have been doing it a long time it's second nature. Lower impedance into a higher impedance actually preserves more frequencies, (though this is a concept I personally find hard to grasp), but you might then want to drop that impedance again before it moves on to the next effect. This is why some effects have permanent buffers built in (tubescreamers).

This is my understanding based on what I have read. It takes a real pedal expert to know what is happening at every step, and makers like Cornish get some benefit (buyers like them) by adding buffers to pedal chains where they are likely to be effective - but not all of us have our entire pedal chains designed by Cornish. Fortunately, in most cases buffers help and do no harm, but not every application is a sure thing and more is not always better.

[Travis]

I think when talking about fuzzes and wahs as "tone suckers" we're really talking about their bypass signals. A lot of vintage pedals used SPDT foot switches because they were cheaper. Usually the input or output of the effect circuit is left connected to the bypass line and the loading this creates rolls off some highs and may let the effect bleed into the bypass signal.

If you've ever played with a vintage FZ-1A or something similar then you know about the bleed that I'm talking about. I'm not sure if Dunlop has changed but traditionally they have used SPDT foot switches for the Crybaby line which "suck tone".

When it comes to adding a switchable buffer to a fuzz, that's generally not for switching guitars, etc.. It's usually so you can use a wah pedal before the fuzz [face] without oscillation

I guess what I'm saying is that if you've got a "tone sucker" then a buffer won't solve that problem. You'd want to look at the bypass switching on the offending pedal instead

[Beaker]

+1.

There is no such thing as an inherently "tone sucking" circuit. It's all in the switching.

Also, remember that many pedals have input buffers or output buffers or both. Many great pedals by top name makers are not true bypass either, but buffered bypass. Despite this, (or even because of this,) they are still great pedals.

You can easily end up with half a dozen buffers, with only a few pedals.

This is where we open up a huge can of worms, and jump down a giant rabbit hole...

[Beaker]

And we all know where the rabbit hole comes out...

Up our own arseholes!

[induction]

Travis wrote

I think when talking about fuzzes and wahs as "tone suckers" we're really talking about their bypass signals. A lot of vintage pedals used SPDT foot switches because they were cheaper. Usually the input or output of the effect circuit is left connected to the bypass line and the loading this creates rolls off some highs and may let the effect bleed into the bypass signal.

If you've ever played with a vintage FZ-1A or something similar then you know about the bleed that I'm talking about. I'm not sure if Dunlop has changed but traditionally they have used SPDT foot switches for the Crybaby line which "suck tone".

When it comes to adding a switchable buffer to a fuzz, that's generally not for switching guitars, etc.. It's usually so you can use a wah pedal before the fuzz [face] without oscillation

I guess what I'm saying is that if you've got a "tone sucker" then a buffer won't solve that problem. You'd want to look at the bypass switching on the offending pedal instead

If the pedal is a known tone-sucker because the input remains connected in bypass, then a well-implemented jfet or op-amp input buffer will actually solve the problem. The input impedance of such a buffer is so high that the pedal will swallow almost no input current, and the bypass tone-suck will be gone. That's actually a good cure for Crybaby tone-suck: the Crybaby input buffer uses a bjt. Replace it with a jfet buffer and you're golden. No changes to the switching are necessary. It will be neither true bypass nor buffered bypass, but there will be no tone-suck.

[Beaker]

You are right there Induction. I've done both the true-bypass mod on Crybabys before, and the buffer mod too.

There is an awful lot of dis-information around about buffers vs true bypass. Both have their place, and both work great in the right application.