Substitute two difficult-to-find parts with modern equivalents
I never thought Electronic Projects for Musicians would become somewhat of a phenomenon. But here we are, over 40 years after the first edition was published, and analog guitar processors are bigger than ever.
Most of the parts used in the book are still widely available, but there are a couple exceptions. Here’s what to do.
Replacing the 4739
Raytheon’s 4739 was the quietest bipolar op amp of its time, but it’s loooong gone. Fortunately, the 4739 can be replaced by any compensated dual op amp, such as the TL072, TL082, LF353, or NE5532. The NE5532 draws the most current, so I would advise it only if you are using an AC adapter. However, it can also drive 600 ohm lines, and it’s a superior part to the 4739. All of these op amps have a different pinout than the 4739, so you will either have to change the circuit board to accommodate the 8-pin parts, or buy an IC header that plugs into a 14 pin socket, and wire the 8-pin part to the header.
You can also use the 4558, 5558, and 1458 op amps, which are all essentially the same part. Any of these will work, but they are basically 741-type op amps and are much noisier than the alternatives listed above.
Replacing the CLM6000 Opto-Isolator
The CLM6000, made by Clairex (Plano, TX), is no longer in production. The Luna (aka Advanced Photonix) NSL-32 is available from Allied Electronics (alliedelec.com), Digi-Key (digikey.com), Newark Electronics (newark.com), and Arrow Electronics (arrow.com). You can also make make your own. Most linear opto-isolators aren’t really that critical: just stick a photoresistor in a light-tight package with an LED shining on it. The only caution is that the photoresistor should have a very wide resistance range (around 2-10 Megohms when dark, a couple hundred ohms when illuminated).
Will There Be Another Revision of EPFM?
Regarding revisions, a second edition was published in the early 80s and analog electronics really hasn’t changed much since then, with the exception that older op amps have been replaced by newer ones. I’d love to do a revised version someday, but I don’t have a lab set up any more, and don’t have capabilities to design circuit boards. If I do revise the book, it will likely not contain different projects, but simply update the ones that are there.
Meanwhile, if you’re looking for more projects, check out “Do It Yourself Projects for Guitarists,” published by Hal Leonard. It contains 35 projects drawn from the pages of Guitar Player magazine and some other publications, which have been updated to use parts that are currently available.