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Vintage threads from the first ten years

EH Zipper

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2/11/2000 9:55 AM
Jeff	EH Zipper What is the switch on the front for?? Is this an on/off?? Mine only works when it's in the right position. Bought at pawn shop. Jeff

2/11/2000 4:15 PM
JD Sleep	Jeff, I don't know about the Zipper, but my Big Muff has an on/off switch on the front (between the in and out jacks) Kind of strange to have that, but I always liked it when I had it on my pedal board I could just flick the switch rather than unplug the input jack to save the battery use. JD

2/11/2000 9:43 PM

Anders Westerberg

I don't think it works like an on/off switch on the Zipper.
The schematic is avaliable at:
http://www.muzique.com/amz/zipper.gif
it seems like the slide switch (to the right, almost in the middle of the schematic) throws in another almost identical op-amp stage, providing a deeper effect (?).
My first guess would be a dirty slide switch, try some contact cleaner and flip the switch 50 times or so. I've fixed some Big Muff's just by cleaning up the slide switch (used as a power switch on these as JD pointed out).
If you've already tried this, it could be a broken lead from the switch to the PCB, a bad IC (4558) or FET.
Please get back and let us know!

2/11/2000 11:15 PM

quote:
"My first guess would be a dirty slide switch, try some contact cleaner and flip the switch 50 times or so."

That'd be my guess, too. The only thing I would add is to take out the battery first before cleaning. :-)

:-)

2/14/2000 3:41 PM

The schematic shows two switches. Not having a photo handy, I can't say which one is on "the front". However, one switch shown simultaneously alters the attack envelope of the unit so that it sweeps differently. The other switch appears to engage either one or two of two identical filter sections. The filter structure is unfamiliar to me, so this is far from a definitive answer, but if it DOES convert from a 1-pole to 2-pole (or 2 to 4) structure, you should detect a more pronounced resonance in one setting than the other...when you get it working again.

The Zipper was probably the most controllable of the EH envelope-controlled units, so I'm curious to hear more about it from you, with respect to tone. I have an original Y-Triggered Filter and a homemade Dr.Q, and both are OK, but the Zipper seems to have more synth-like capabilities.

2/15/2000 7:15 AM
Jeff	Thanks guys. I replaced the switch. It definetly alters the tone of the pedal. This thing is a lot of fun to play with. Jeff

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