A bunch of stuff found in the library

[Chris Crosskey]

Hi People....


As I was in the library getting a copy of the Digisound VCADSR article 
made for Romeo I had a chance to have a serious browse through Elektor 
and ETI magazines of the late seventies and early eighties......I 
turned up some very interesting bits and pieces.....
The Elektor Vocoder...I've got one of these, I must rebuild it as two 
of the channels are intermittant, they were my first attempt at making 
PCB's and it shows, but I found the Voiced/Unvoiced detector 
circuit....Hmm....that's a ten-channel vocoder with V/UV detection, 
and an alternative Bode hi-pass bleed if wanted for about 100 UKP plus 
rather a lot of construction work....I'm not sure what the PAIA unit 
does, but it is only eight channels, and the Elektor was noted for 
it's intelligble results at the time, even without the V/UV 
detector....
The Powertran Transcendant 2000 monosynth....OK, it's all on one board 
and it'd be a pain to re-do the PCB, I guess splitting it would be 
sensible really, but.....voltage controlled wave-shaping from 
saw-tooth to triangle as well as the square to PWM, it is 1V/Oct, no 
need for a keyboard as it has external inputs for CV and Gate and VCF 
Frequency, and also an external input to the filter.....I wanted one 
of these when I was a kid, now I might just build one.....better yet, 
no hard to find components, and they were reckoned to be pretty stable 
even though they are CA3046 based oscillators.....
Any number of analogue drum circuits.....The ETI Staccato dual (or 
more) drum synth, the ETI Handclap generator (a must have for dance 
nutters surely) .....
There's a mad-noise generating mini-synth built round a Texas SN76477, 
I gotta get me a couple of those chips now, I want a Henry 
Super-Controller too...
FX units....there's a pair of solid-state reverbs, one built round a 
pair of Reticon SAD1024's, and one around a Panasonic MN3011... I can 
get the MN3011 easily enough, MAP stocks the SAD1024, if anyone wants 
to arrange a swap for anything, I can do boards for most of these, and 
like I said the MN3011 I can get too, they go for about 30UKP, I guess 
about 48 USD...theres also a discrete op-amp based phaser circuit, 
that'd be dead cheap to do, god knows what it'd sound like, but it's 
been added to the list
And finally, especially important in the light of recent 
discussions....there's a Parametic EQ, complete with PCB 
layouts...could have been designed for sub-rak stuff, and there is no 
set-up/offset adjustment required.....just build it and go....the 
boards are about 3" by 1.5" each, and you need one 
Hi-Pass/Lo-Pass/ouput board plus as many parametric filters as you 
want to bolt on....I guess into a 3U rack you'd get seven parametics 
plus the Hi/Lo unit, they are designed to be strung together like 
that, into 1U you'd get maybe three parametics and a Hi/Lo....The 
circuits use LF356/7's and 4136's, so maybe the noise might be a 
problem, but you could re-lay the circuits to use TL074's and a TL072 
instead of the 4136 and the pair of LF's respectively, and I will, 
because the detail is too fine for my etch process...but I can keep 
the PCB's pretty much the same size I'd have thought...of course this 
is joining a long queue in my PCB layout list ATM...
I'll try to get this stuff scanned up ASAP, hopefully next week, and 
then send it off to Josh for his site....which reminds me...


*Josh* I've lost your snail address, can you re-send please....


chrisc