hammer Converting Flatline Compressor to Punchline Expander 10/6/102 7:47 pm
Compressors reduce gain in response to transients. Expanders increase the gain in response to transients.
This picture shows how to convert John Hollis' "Flatline" compressor to an expander, which I have coyly dubbed a "Punchline".

The picture explains how to do the conversion using RG Keen's layout of the Flatline. You may need to change a few component values but the thing should work just by moving a single connection.

hammer 5/16/102 12:34 pm

hammer Analog Harmonizer 5/15/102 2:50 pm
This is a schematic (in two parts) for a BBD-based analog harmonizer. I've doctored the original scan to improve legibility and reduce toner/ink use, as well as make it a smaler file size.

I have no idea if this actually works, but the quality of the schematic suggests it was not hastily drawn, and probably a working device. Not sure if it is a commercial product or not.

hammer The dark side of DIY 4/24/102 7:45 pm
My shame. This is what happens when you get most of a project working, and either can't get it functioning, still need to get one pmore part, or are waiting to stick it in a chassis.

hammer Rolls RFX147 Rotary Speaker Emulator 4/5/102 8:51 pm
Enlarged schematic for the Rolls RFX147 Rotary Speaker Emulator. Clipped from the on-line manual at the Rolls Website. Please support companies that are generous with their R&D information....as in this case.

hammer DIY digital drum 3/15/102 4:03 pm
The Alpha Drum was a construction article from a 1987 issue of Electronic Musician. It uses cheap EPROMS and 8-bit samples. Not the greatest fidelity, but if you can burn your own, it provides a nice compact layout, good design, and an inexpensive way to produce your own digital drum kit. The modules are small enough to fit a bunch of them into a small chassis, and it comes with triggering circuitry. As with all PDFs here, the pages might not print precisely to scale. The PC mask provided is for the traditional type of PC-board resist methods. You will need to flip the graphic around for press-n-peel use.

hammer Ops, I did it again! 1/27/102 7:46 am
This is a scan of a very detailed and comprehensive chart of op-amp specs from Horowitz and Hill's outstanding classic "The art of electronics" (2nd edition, 1989).

Just about all your favourites are in here.

This is actually a PDF file, but has been zipped for faster transmission. You will need to unzip it to view it as a pdf.