ampage Tube Amps / Music Electronics |
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Jay Doyle![]() |
Re: Boss CE-1.....................True Bypass? Well, I looked and you are right, this isn't the same switching scheme as used in the later Boss/Ibanez pedals. It is the same concept, just a different implementation. The input impedence is set by the input buffer, which is used to drive the output, either clean or effected. The normal/effect switch changes the on/off state of two FET's whose drain/source channels are in series with the outputs of the effect circuitry and the input buffer. When one is on the other is off, thereby deciding which path is selected, either the effected signal or the signal out of the buffer. First off, the buffer is set up poorly. The input signal goes through a 50k pot set up as a voltage divider, through a 10k resistor in series with the + input of the op amp. This sets the input impedence as the parallel value of the two arms of the voltage divider in parallel with the 10k resistor. This is going to be less than 10k which is enough to load your guitar significantly. There is a bunch of stuff you can do to fix it, sort of. If you dont use the input level control or don't mind it being on full all the time, replace the pot with a 470k - 1M resistor to ground, take the output off of the top of the resistor and directly into the + input of the op amp, jumpering the 10k in series with the input. This will help but won't fix your problem completely, we haven't even talked about what happens when you use the mic preamp, same idea only it looks like it would load the signal even worse. There is a lot of stuff going on to your signal, "normal" or effected. For that reason I would suggest simply building a true bypass box for you to switch this effect in and out. You just leave your CE-1 on all the time and bypass it with the true bypass box; you could even buffer the input of the effect with the true bypass box to minimize the loading effects when the effect is on. Much less trouble and doesn't risk a vintage effect selling for $200 and up. Not that that really matters, it's your effect. I would especially suggest this if you don't have much experience tinkering with effects, there are some sensitive chips in there. Not to mention this is one BITCH of a circuit and would be extremely difficult to navigate around the circuit board. Save your time, build the true bypass box in about less than an hour and build the Shaka III or the Booster 2.5/Sweet Thing with the time and frustration you saved. Hope this helps. Jay Doyle |
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