Hi Everyone!
I'm a total newbie to this forum (as in, the last 5 minutes), i'm also a member of other forums on
the web.
I'm pretty relatively new to diy, have made up kits before (the latest being the byoc reverb) and i
would love to do the maillet mods but have not idea how to follow the instuctions at
http://www.lynx.bc.ca/~jc/pedalsPhase45.html , i don't know how to follow the schematic and i
can't see the resistor values on the GGG Phase 45 pcb. Can anyone point me in the right direction;
maybe someone has an easier way of explaining how to do the mods, or some informative links? ???
thanks in advance,
Phill :)
Anyone? at all?
Bumping this; not quite so new to diy now but i still don't understand the malliet mods schematic, if there are extra components
required or not? cheers all :)
There are extra components required. I have not compared the schematics (stock versus modified) exhaustively, but I see at least:
- one SPDT switch for switching capacitors
- one 22K pot for the mix control (probably you'd have to use a 20K or 25K, both would work)
- 100K pot for the bias control
- 24K and LED for the rate indicator, which simply blinks on and off, not a smooth rise and fall
- two 8.2K resistors
- probably the two 47Ks with the bias control
The switching capacitors thing simply changes the stock values which produce a single sharp notch for staggered values which tend to distribute the phase difference across a wide frequency range - better for vibrato instead of phasing.
The mix knob lets you vary the amount of dry versus wet signal - all dry is no effect, somewhere in the middle is as tight a notch as the circuit can make, and on the other end is a little vibrato, no phasing.
Rate indicator blinks on and off with the LFO speed
The bias control lets you adapt how much the JFETs change resistance, and at what end of the sweep. With unmatched JFETs it also allows you to tune in the effect by ear.
I'm not sure what the 4.1K (parallel 8.2Ks) does, other than set the fastest speed for the LFO to something different from stock.
The P45 is a subtle pedal, much more subtle than the univibe.
Quote from: R.G. on April 03, 2010, 09:25:03 AM
There are extra components required. I have not compared the schematics (stock versus modified) exhaustively, but I see at least:
- one SPDT switch for switching capacitors
- one 22K pot for the mix control (probably you'd have to use a 20K or 25K, both would work)
- 100K pot for the bias control
- 24K and LED for the rate indicator, which simply blinks on and off, not a smooth rise and fall
- two 8.2K resistors
- probably the two 47Ks with the bias control
The switching capacitors thing simply changes the stock values which produce a single sharp notch for staggered values which tend to distribute the phase difference across a wide frequency range - better for vibrato instead of phasing.
The mix knob lets you vary the amount of dry versus wet signal - all dry is no effect, somewhere in the middle is as tight a notch as the circuit can make, and on the other end is a little vibrato, no phasing.
Rate indicator blinks on and off with the LFO speed
The bias control lets you adapt how much the JFETs change resistance, and at what end of the sweep. With unmatched JFETs it also allows you to tune in the effect by ear.
I'm not sure what the 4.1K (parallel 8.2Ks) does, other than set the fastest speed for the LFO to something different from stock.
The P45 is a subtle pedal, much more subtle than the univibe.
I using the GGG pcb. I've tried comparing the malliet schem and the ggg schem but both seem pretty different. Here is the link:
http://www.generalguitargadgets.com/pdf/ggg_p45_sc.pdf ...and the layout
http://www.generalguitargadgets.com/pdf/ggg_p45_lo.pdf
* Which caps do I replace for the Univibe mod?
* Which resistor do i replace with the pot for the mix mod?
* What do I connect to the LED to make it blink (and what is an LFO?) At the moment I think the resistor is 1K.
* The bias is controled by the trimpot right? I think i'll leave that on the inside if it is.
The schem says there are 3 IC's on the board, but there are only 2 on mine? the layout/diagram matches my pedal but the schem is confusing me.
At the moment the effect is kind of un-usable for me; it's too strong and i have no way of dialing back the effect from the mix. I have it
placed in my fx loop maybe that's why?
Really appreciate your time on this mate, hopefully it will help someone else too, with the same problem. :)
To do the "Univibe" cap mod you replace C2 with a 0.01uF cap and C3 with a 0.1uF cap.
The mix pot replaces R9 and R10, the wiper goes to where the resistors joined and the outer lugs go to where the other ends of the resistors were.
The LED and resistor should be connected to pin 7 of IC2b.
LFO (http://en.wikipedia.org/wiki/Low-frequency_oscillation)
Like R.G said this doesn't really make it sound like a Univibe, it does sort of get you into Gilmour dark side of the moon territory but it won't make you sound like Hendrix, not that anything will :)