Making a Ribbon Microphone Using a Commercial Element

 I purchased a ribbon microphone element branded "Alcatron". I made a simple wooden body from some reclaimed English Oak and mounted the ribbon assembly inside a rectangular routed pocket.

The transformer is home made and looks it. The laminations are taken from a small valve output transformer, I sure they will be plain iron, though I don't know. They measure 2 inch * 1.5 inch and I used a stack height of 0.3 inches. This a large core for a ribbon transformer but it was to hand. The voltages generated by the ribbon are tiny so there is no possibility of the core saturating. To give some perspective, I calculated at what voltage saturation would begin. For a 0.25 inch square core with 20 turns, 64 millivolts would give a peak flux density of 1 Tesla at 20 Hz. The ribbon output will be one thousandth of that.

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Precision Preamplifier by Douglas Self

This is my build of Douglas Self's Precision Preamplifier as published in Wireless World in October 1983. I refer interested parties to the original article or to the reprint in the book "Self On Audio". It has the addition of a headphone output which includes a stereo width control, the design of which was taken from J L Lindsley-Hood's Modular Preamplifier design,  published in Wireless World February 1983.

As seen from the photo's, it is built entirely on Vero Board. In a folded metal box with an Elm fascia with Indian rosewood knobs. I must have built it around 1984 and it ran without problem until this year, 2018, when it developed a intermittent drop-out of one channel. the problem was traced to a soldered connection on one of the switches. In fact, it was not soldered at all, I had wrapped the wire around the pin but failed to complete the joint by soldering. Amazing that it worked for so long.

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Making A Jazz Bass 

Introduction 

I tried a number of Jazz Basses in shops around Manchester, including some expensive Elite models. I really liked them but I could not bear to part with that much cash so, I decided to make one.This series of articles describes the process along with some cock-ups along the way

I started with a full-size plan from JAG Guitars. I planned to make the pickups so I bought pickup kits containing magnets flat-work and covers. I also bought all the other hardware: bridge; scratch plate; control plate; machine heads. Some of these turned out to be not such good buys.

The methods I describe use some machinery, jigs and templates, much of it home made or adapted. It was not always thus, my early builds were produced entirely with hand tools (not even an electric drill) and without the aid of computers and drawing packages. Fret positions were worked out using graphical methods and pickups were hand-wound with wire salvaged from old transformers. Here, hand-wound means holding the bobbin in one hand and winding with the other; truly scatter winding and limited to about 2000 turns. Nevertheless, the guitars did work and were playable if not too refined. My first was from a design in Woodworker Magazine in 1964 if my memory serves me well.

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DIY Bass Guitar Speaker

Design Requirements

In audio, little is straightforward and compromises are rife. This design is no exception. It is an attempt to find a way through the conflicts of portability, frequency response and power handling for a bass guitar speaker. I hope the results have been worth the effort. If nothing else, I'm pleased with the aesthetics of the box.

The requirements were:-

1. That I should be able to transport the cabinet in my modest family saloon car (Ford Focus) and be able to carry it into the gigging hall even if it involves a few steps.
2. It should work with a 4-string bass guitar.
3. It should be capable of competing with a moderately loud drummer.
4. It should be reasonably economical.

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