JUNE 24TH 2011
Exploded Drawing #6 (Baby Blue Studios, Austin TX)
A night of solo sets by eminent Texas producers
I will be performing a 20-minute set as BRAINIAX

BRAINIAX - Jakistan :: Respectfully dedicated to Charanjit Singh. I borrowed the bassline melody from his 1982 proto-house track Raga Bhairav. Yes I know he’s Indian, but this track is called Jakistan anyway. This is faux-raga, I’m obviously clueless about classical form. (Eric Archer 2011)

BRAINIAX - Jakistan by Eric Archer

I’m prototyping new analog drums. Listen to the first sounds from the bass and snare drums in this video. Or download the audio from my soundcloud.

D.I.Y. project instructions + PDF download with schematic + wiring diagrams + bill of materials

untitled dec.25.2010 by Eric Archer

…and building this.

Here’s the extracted data from all of the sample EPROMs in the DMX.  As explained in the video, these are not playable by standard media browsers.  They are 8-bit files, similar to .wav but with nonlinear u-255 law companding.  This gives them 72dB dynamic range with the appropriate DAC (AM6070) but otherwise they will sound highly distorted without the appropriate u-law transfer function.  Since the AM6070 has been obsolete for decades, there is little hope of cloning the hardware directly.  This situation has also complicated attempts to clone the LM-2 Linn Drum.  All EPROMS in the DMX are 2732 type except the toms, which are 2764’s. The cymbal samples occupy 4 EPROMS each, for extra duration.

Oberheim DMX EPROM data

If you just want to hear the distorted samples from the video, they’re in Samples > Samples_CONVERTED.  Thanks to Todd Bailey for contributing to this.

Here’s the hookup diagram for the boards I tested in the video.

hookup diagram

Schematics for all the DMX voice boards.  Full schematics are available elsewhere on the web.

You can now find Bodytronix tracks on my SoundCloud .  We’re playing Friday July 2nd at the ND @ 501 Studios.  Come have fun with us, Pong, and Woodgrain.

Handmade Music Austin #9 (nine already!?) is coming up on Sunday afternoon July 11th at the usual location, Salvage Vanguard Theatre in Austin TX.  I came up with a new basic level project called 1976 Phototheremin.  Here’s a demo:

The original circuit is by Forrest Mims III, from the book OPTOELECTRONIC PROJECTS vol 1.  I fell in love with this circuit when I saw it, because it is ultra-minimal.  It has only seven components including the battery and speaker.  Its real transistor magic.  The active circuit is just two transistors, a capacitor, and photocell.  I’ve crossed my fingers that the PCBs will get here in time for the workshop.

I’ve also been experimenting with voltage-controlled oscillators.  In particular the 4069 CMOS VCO of René Schmitz.  I got rid of the PWM section and built two VCOs from one CD4069.  The temperature compensation method deserves some re-working however, because Schmitz’s design requires one tempco resistor per CV input.  It would more efficient to use one tempco per VCO.  So I am consulting some of the other VCO designs I see, including a nice one by Ian Fritz that you can see here.

In order to appreciate the subtleties of temperature compensation, the VCO must be tuned accurately.  This can be a chore so I imagined a circuit to make it easier.  It is just a voltage sequencer that outputs stairstep waveforms with 1.00V intervals.  This makes the VCO play descending octave intervals, and its easiest to hear if it is tuned accurately.  Here’s more information, and a demo.

a short documentary demonstrating an experimental field recording technique. lets roll from new jersey to brooklyn and listen to hidden sounds outside the window.  please pardon the shaky video.

more sound camera recordings

Eureka.  I designed a dual SP0256 vocal synthesizer and it works.

Also,  a new track …

 EDRUPT - m-u-s-i-k

 … and a photo of the Radatron JE Experimenter lounging in the yard.
Spring has come to Texas.

(wtf is a Radatron JE Experimenter? .. its the subject of a future update)

PS I just updated that page with schematics and perfboard layout, in case you have a lonely SP0256-AL2 waiting for a chance to jabber.

The vocal synth will debut at SXSW Interactive on 3/13 when Bodytronix plays Dorkbot at Brush Square Park.  We’re playing a bunch more gigs coming up so maybe we will see you.

• Sat. 3/13 6PM - Dorkbot 23 at SXSW Interactive (RSVP event)… located in Brush Square Park right outside the Austin convention center.
• Tues 3/16 8:30 PM - AWTHUMFETHT 2010 at the Independent (located in 501 Studios)
• Tues 3/16 11:00 PM - Club 1808 (1808 E. 12th St, Austin) w/ Reverse X-Rays, MANY MORE!!
• Sat 3/20 3:00 PM - Handmade Music Austin #6 at Salvage Vanguard Theatre
• April 22-24th (TBA) - Bent Festival ‘10 (The Tank NYC)

I’m working on a new DIY project for folks to build at Handmade Music Austin 6.  Tune In Tokyo started out as an experiment with the 74HC594 chip, and it turned out sounding crazy.  YES, I’m aware of the of nipple reference. XD XD XD

Tune In Tokyo

And finally . . .

Sailormouth, another Texas circuit maestro, interviewed me recently and you can read it here on GetLoFi.com.  Sailormouth’s work covers a good combination of circuit bending, original circuitry, mods, and microcontrollers.  Thanks for the interview my friend.

heres to a very analog 2010.

12 x ASR mini analog drum machines

In other related news, Nathan Wooster designed a PCB for his MIDI-to-IR sync converter, which lets a computer or MIDI sequencer be the master clock for all of these things.

The 4MS Autonomous Bassline Generator is now available as a kit from 4ms Pedals.  We’ll be teaching 20 people how to build them at the Handmade Music Austin workshop #2 on Nov. 15th.

In December, we’ll introduce the Nebulophone synth kit from Bleep Labs.