Re: Boss CE-1.....................True Bypass?

1/18/2001 5:17 PM

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