Psycho LFO mods

neandrewthal · Joined: May 11, 2007 Posts: 672 Location: Canada

I was bored today since my last shipment of parts didn't come in, meaning I can't build anything new so I decided to mod my Psycho LFO.

I've heard of some people changing the caps from 2.2u to 10u to make it go slower. I lazily tried squeezing in some 10u caps in parallel(12.2u should make it go even slower, right?) but I didn't notice much effect. Since I only have 2 hand I could only do 2 at a time. Do you need to change all 4 to make it noticeably slower?

Next I noticed something on Ken's site about changing the values of the 4 560k resistors that connect the oscillators to the mixer section. I left one of them alone and connected 470k resistors in parallel via switches to the next 2, which cut the resistance down to 255k. I replaced the last 560k with 1M and wired another 1M and a 330k through a center off switch, so I can choose between 250k, 500k and 1M. Bingo! I'm convinced that every psycho lfo should have something like this if there isn't room for level pots on 4 oscillators. Now I can select from as many as 12 possible rhythms instead just one. If I had the panel space/patience/parts to a center off switch for each osc that would be............lots. If you had attenuator pots for each one the possibilities would be endless.

Finally, I got rid of glide switch, wired the glide permanently on, then made a second output that bypasses it. Once again, this opens up exciting possibilities. Now I just need to find a way to make it switchable between low and audio frequencies.

P.S. Can't wait to try the super psycho Shocked

Solid Rate Studios · Joined: Jun 05, 2008 Posts: 8 Location: Spanaway

Hehe... I'm doing a similiar thing but with the pots and maybe some switches. I'm replacing the resisters above IC1A, IC1B and IC1D to 1M pots. Just like the 1M used above IC1C. Other then that I might change 2u2 caps to get the initial clock a little slower.

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CGS PSYCHO LFO / RADIO SHACK LO-FI SAMPLERS / CGS DIGITAL NOISE
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-dJ dAb

neandrewthal · Joined: May 11, 2007 Posts: 672 Location: Canada

Wow, those look really neat. If I had that much free space on my psycho lfo I'd add 7 more knobs Smile

I had a 2 hour+ jam session today with just my psycho LFO controlling a single VCO. Wish I had recorded some samples. I really love feeding both the glide and non glide output to the VCO. It makes it sound like there is more than one pattern going on at once. Hypnotic Shocked

Luka · Joined: Jun 29, 2007 Posts: 1003 Location: Melb.

what good timing, been working on my cgs backlog.
thanx

hopelessennui · Joined: Mar 23, 2008 Posts: 17 Location: Los Angeles

I tried a 1M pot on the depth which was pretty cool, a 500k pot would probably work better though.

Stavros · Joined: Oct 30, 2007 Posts: 36 Location: Athens-Greece

Has anyone noticed the different connections shown on the schematic and the PCB for the Schmitt trigger pins 10 to 14 in the original Ken’s documentation for the Psycho LFO?
Does it make any difference?

Many Thanks in advance for any replies