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SEWAR Project file:   SEWAR.PDF 000039   8/28/101 3:41 am
The Sound Effects With Analog Reverb project was an article appearing in Elektor in 1979. It details construction of a very flexible "kitchen-sink" modulation source for BBD devices, phasers, tremoloes, or (with a few simple part changes) even ring modulators, providing square, up and down ramp, triangle, sine and random control voltage sources, with either a CV or HF clock out. It includes a PC board mask, which like all others here, may not be exactly to scale. This is some very old and frequently thumbed paper, so I've had to touch things up a bit. It's acceptable, but I wouldn't use it for a PnP board.

Solid-State Reverb Project file:   eti-mn3011reverb.pdf 000036   8/14/101 0:04 am
I forget where I downloaded this from, but the original article appeared in Electronics Today International (ETI to the familiar). It uses a Matsushita MN3011 tapped delay chip to produce multiple delays simultaneously for a reverb simulation. I've never built it or heard it, but in principal it should be very different from the standard analog delay line simulation of reverb. Looks ripe for modding.

As always with files here, the PC masks may not be to scale, so you may have to do some size adjustments with a photocopier of your graphics software. One of these days I have to scan these things with a ruler beside it.

Alternate control LFO's file:   quad-shep.pdf 000033   7/27/101 3:43 am
This file contains two old articles from POLYPHONY magazine (which turned into Electronic Musician in 1985). The first, written by PAiA founder John Simonton, outlines design and construction of a Shepard Function Generator. The SFG provides multiple LFO outputs, each staggered 45 degrees apart from the other. Ever thought about making a motorless Leslie? Then this is for you. Hook up the SFG to 8 VCA's and 8 mini-amps and away you go.

The second article is a simpler project, designed and written by Thomas Henry (one of the folks behind Midwest Analog Products, along with Jack Orman). It details a quadrature oscillator, which provides 2 triangle outputs 90 degrees apart. This is a terrific little replacement for the usual LFO for producing unusual spatial and stereo effects with phasers, flangers, tremolos, etc.

If you are interested in using your effects in more than mono, you'll find these a very intriguing set of papers.

Electro Harmonix Pricelist file:   1981_E-H_pricelist.gif 000032   7/27/101 3:32 am
Just for kicks, I scanned an E-H pricelist from 1981. Those who are only familiar with the dozen and a half products that E-H is flogging these days, you'll see a much bigger list of products than you ever imagined. You can also see what they REALLY cost.

Noise Gate Project file:   GainesNoiseGate.PDF 000031   7/24/101 1:11 pm
This is a 1981 construction article from Modern Recording magazine by Jon Gaines. It provides complete instructions for building a full-featured noise gate. I built it years back, and can confirm it works reasonably well. Given the age of the photocopy, there was only so much digital tweaking I could do, but it is fairly legible. As with most of these scans, the PC mask may not be exact scale.

If you have no experience with noise gates, please note that they are inherently "twitchy". You will usually have to fiddle with the attack and release/decay controls to reduce false triggering of the gate. If you hear certain types of buzzy distortion, that can often be a sign of mis-set controls. You may want to increase the value of the envelope follower (attack/decay) cap from 0.35uf to 1uf or so to smooth out the envelope ripple. Virtually every principle that applies to using envelope-controlled effects applies here too.


- The TL075 is a BiFet quad op-amp with a LM4136 pinout (different than a TL074). Pin equivalents for a TL074/LM324 pinout are pencilled in. Given the resistance values for most of the op-amp stages here, a 4136 may well perform better with respect to noise.

- There are plenty of other JFET's that can sub for the 2N5457, like an MPF102, 2N3819, etc.

FM Wireless Guitar Transmitter file:   Wireless.PDF 000030   5/31/101 3:16 pm
This is a project article that appeared in an Electronics Today circuit collection in 1992 (which had turned into Electronics & Technology Today at that point). With the exception of two chips and a couple of inductors, the parts are likely to be easily found in your parts bins. The design assumes you will want to distort the guitar anyways, and uses pre-distortion to improve the S/N ratio. A dubious choice, but surely one that will make sense to many users. The article contains a PC-mask but you should note that: a) it may be slightly off scale due to scanning and resizing, and b) it is a double-sided PC. Never built it myself, but the cost seems reasonable enough that you may want to try it, if only for a backup. If you are concerned about a receiver, I've found there is no end to the number of inexpensive but quality discarded FM tuners to be found in second hand and pawn shops. Approximately 1.8meg in size.

4046-based design ideas file:   Marston's4046circuits.PDF 000029   5/27/101 3:24 am
This is an interesting set of pages from Ray Marston's 1987 book "CMOS Circuits Manual", covering 4046-based oscillators and other circuit fragments. The 4046 phase-locked loop is able to track the frequency of an input signal and generate a signal. I've seen them used in crude frequency to voltage convertors, and the 4046 also forms an essential part of the BOSS DF-2 Distortion Feedbacker. For the uninitiated, the DF-2 tracks the note being played, and produces a parallel note that sounds a bit like a feedback-overtone if you hold the note a bit.

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