Parts changes for using WaveMult with 1.2v oscillators?

Peake

Hi, I use Moog, Buchla, Technosaurus, and other commercial-level oscillators. What parts must be changed, and to what values, for best functionality with 1V oscillators? Thanks in advance.

fluxmonkey · Joined: Jun 24, 2005 Posts: 708 Location: cleve

replace resistors R1, R3, R5, R7, R11, R13 and R19 (but NOT R17) with 3.14k resistors. replace all other prime-numbered resistors with 49.9k resistors. 1% italian resistors, of course.

replace the selenium rectifiers with germanium of the same voltage--seleniums loose their warmth with age.

on the Moog (rhymes with "dog" only with a long "o" as in "oh shit"), replace the flux capacitors... they're probably corroded by now.

on the Buchla, apply 1v to the input port and then adjust the framastat on the slipstream increaser just until the dog stops howling, then back it off just a bit. if you don't own a dog, you're not vintage enuf to own a Buchla... send it to me.

make sure the eels are tight before resealing your units. if they're not tight, a little stoli will help. look what it did for tesla!

good luck,
muxflunky

fluxmonkey · Joined: Jun 24, 2005 Posts: 708 Location: cleve

oh... you meant, which parts on the Wave Multiplier need to be changed. sorry 'bout that. no changes necessary.

still, it's always a good idea to tighten your eels....

f

Peake · Posted: Sat Oct 18, 2008 7:10 pm Post subject:

widdly · Posted: Sun Oct 19, 2008 8:27 pm Post subject:

From the schematic, there is an inverting op amp on all the inputs. They are all set at unity gain (except the PWM). The resistor in the feedback path can be increased to provide more gain. I'd try a 400k giving a 4x gain.

On the folded output there is another inverting op amp giving 100k/4.7k gain which is ~20x You could reduce the feedback path from 100k to 20k to match your expected output range of ~1v.

If you reduce the folded output level, you will need to use a reduced PWM input since the folded output and the PWM both feed a comparator. Since your folded out is reduced to 1v range and you PWM inputs will be 1v range, no need to change the gain on the PWM input.

Peake · Posted: Sun Oct 19, 2008 10:14 pm Post subject:

Thanks, that was exactly what I was going to play with. I'll check it out.