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Fulltone '69 and buffers - Impedence changing device?


DylanWilde

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So I love the sound of my Fulltone '69, except for the fact that even with the contour and level dimed, there is a lack of bass and and power to the tone, which is weird because I can hear this trait in all of the other uses of fuzz faces that I know. I then read about how buffers before fuzz faces can cause these exact issues, and I then realized that my signal path has a lot of them before the fuzz -

 

My chain is :

 

Digitech XP100 Whammy/Wah (I've heard many complaints about this bypass)>

Original Crybaby Wah (NOT true bypass) >

DOD FX50B Overdrive Plus (Older pedal, definitely not true bypass. . .) >

Fulltone '69, and so on. . .

 

I can't really change the order of my pedals based on how my board is set up and how I use them. . .

 

So is there a device I can insert between the DOD and the Fulltone to bring the signal back up to high impedence and get rid of the effect of the buffers, thus getting the best out of my Fulltone '69? Preferably cheap (typical poor college student).

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Basically I want the opposite of a buffer. Instead of having something change the naturally high impedance guitar signal into a low impedance guitar signal, I want that buffered low impedance signal changed back into high impedance. I have been looking, but I can't find a device like this anywhere. Does it not exist? Is it possible to build?

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^^ + 1

 

That`s odd because the GGG boutique fuzz factory (it`s basically like the 69 apart from my internal trimmer... the parts are about the same from gut pics I`ve seen) I built has fantastic bass response. Maybe it is a problem with your order.

 

Love the JW avatar BTW. Great man.

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From Custom Audio Electronics website FAQ's:

 

What are buffers and how are they used?

 

Buffers are extremely important in a multi-component system. They are often misunderstood and often get a bad rap by those who are uninformed. In a CAE system, a buffer is a unity gain (input level equals output level) impedance converting circuit. It essentially protects your high impedance guitar output (or any other high impedance source, such as an amps' effects loop send) from being loaded down by the input it is connected to. In effect, it converts high impedance to low, which means subsequent stages are then driven by a low impedance source (the buffer's output). High impedance sources such as your guitar's output (assuming you have passive pickups) has very little current drive capability and it's signal is subject to a harsh environment once it leaves the guitar. You already know the adverse affect a long cable has on your tone. Same thing happens if you pass your signal through a bunch of effects pedals. Even if they have "true bypass" (an ugly, over-used term), each one will suck a little more of your signal along with the cables and connectors, mainly due to capacitive loading of your high impedance guitar signal. The end result is a muffled weak signal that lacks clarity. But once your high impedance guitar signal hits a properly designed buffer with a high input impedance, the buffer takes over, and uses its higher current capability (remember, its an active circuit that requires a power supply) to drive all subsequent stages, thus preserving your instrument's tone. This brings us to buffer quality. Buffers come in all types of designs, from discrete transistor, op-amp, to esoteric tube designs. All have their own unique sonic stamp. At CAE we use the op-amp approach. It has served us well for years, is low noise, and is extremely transparent to our ears. Buffers often get blamed for causing an overly bright sound, but we feel if its designed properly, any perceived "brightness" is because now the guitar is not being loaded down by subsequent stages!

 

Buffers can cause problems, too. There are some effects devices that don't like to see the low output impedance of a buffer. These are typically discrete transistor designed fuzz circuits (such as the Dallas Arbiter Fuzz Face). They react better to the high impedance output of the guitar. In fact, the guitar output, cable and input stage of the Fuzz Face complete a circuit that is highly dependent of those 3 components to work correctly. Fuzz Faces clean up nicely when you roll back the guitar volume control... not so if a buffer is between the guitar and Fuzz Face input. So if you have a pedal board with a Fuzz Face on it , put it first! Other pedals may react the same way. Experiment to see what works best for you. Keep in mind all active pedals (such as Boss, Ibanez, etc...) act as buffers and will impart their own sonic stamp even when bypassed. This is what started the whole "true bypass" (ugh! that term again) craze. See? Too much of a good thing can be "bad". Which brings us to how we utilize buffers in CAE custom switchers. We only use buffers where absolutely necessary. Typically, in a pedal based system we will not buffer until after the first 4-5 loops, which is usually just prior to sending the signal down to the pedal board (via a long cable run, hence the need to buffer) to hit the wah/volume pedals. Any more than 4 or 5 loops, and the guitar signal may be affected by capacitive loading. So the first few loops is where you would put any impedance sensitive effects. This also means your guitar will go through fuzz, overdrive or distortion pedals BEFORE the wah. We prefer this order because the wah then has a more harmonically rich signal to filter. Try it yourself. Of course, if a specific order is required, we will do everything we can to make it happen. Buffers are also necessary to drive isolation transformers, since the relatively low primary impedance of the transformers may be detrimental to whatever circuit is feeding it. This is also why amp splitter circuits must be buffered. You can't drive multiple amps with a relatively high impedance source. So there usually is a buffer somewhere in the output stage of your custom switcher. That's usually it. 2 places minimum. There may be more active stages depending on your system requirements.

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