Gonna build an optical vibe!

[Mark Hammer]

I wonder if the optos varied so much back when this circuit was designed that they specified selected parts. Or maybe the schematic is marked such but actually they didn't bother. Not matching them is a bonus, though In any case the last batch of 100 I bought are all pretty close and work well with both incandescent and LED illumination.

That's a nice phaser you've built and the vibe sounds are good. I want something like this for my Modular synth (now guitar powered) - a regular phaser gets lost on synth sounds.

Thanks. My sense is that the Schulte probably dates from a time when we were a little more naive about what makes for a good-sounding phaser. Note as well that, unless they are commercial Vactrols with a single light source and LDR in a sealed epoxy form, no matter how much effort one takes to "match" them, the actual change in resistance in individual LDRs encircling a common light source, be it LED or incandescent bulb, can be different simply due to the angle or tilt of the LDR, or even a smidgen of distance between the light source and this or that LDR. Again, not a real problem since there is a difference between not changing resistance quite as much as the neighbouring LDR, and completely choking, as misbased FETs can do.

Having said all of that, the nice thing about optical phasers and Uni-Vibes is that the op-amps (or discrete transistor stages) will not distort, in response to signal peaks, nearly as readily as FETs will. That means one can optimize S/N ratio by accepting a hotter input, which does not have to be attenuated at the start of the circuit (for protection) and then boosted back up again at the output stage to restore volume, for effect/bypass level-balance.

[tedmich]

PACKAGE ARRIVED TODAY! yes that's a bottle cap that comes with kit to cover the lamp and 4 photocells (we'll do better !)

[tedmich]

got the McMaster Carr 9275K153 pipe cap, it was very rough for $6! I polished it up (mainly inside) using scotchbrite and my new Milwaukee M12 Fuel right angle die grinder...man that thing is fast at the highest of its 4 speed settings ! Cap was screaming HOT after 30s!

Should be nice and reflective once buttoned up.

[tedmich]

So there was some "ambiguity" on the Forum Vibe builds, which is very much to be expected on group projects ESPECIALLY when the following occurs:
- many many opinions and the smartest/most experienced people move on when complete
-people modding up a storm WHILE developing base model
-multiple languages used (FV is German!)
- various models carried through to final PCB (Vintage/RedHouse/FV versions)
- lots of PS options; onboard FWB with filter caps and AC supply, single off board DC supplies, multiple off board DC supplies

Of main interest to me is the clever bulb intensity and offset circuit that started (I believe) with JC Maillet at Viva-Analog in 1996, with a single transistor (or a Darlington pair) driving the various bulbs people want to use.

His site: http://www.lynx.net/~jc/

Notice, JCs work was on an original Univibe clone, probably every commercial version of these circuits now incudes something similar (they ought to for their astronomical prices! ; )

see here
http://www.lynx.net/~jc/pedalsUnivibe.html



anyway the circuit confuses some as there are 3 versions documented (, I'm going with the middle version with Darlington's and both offset and gain controls, I believe FV member RedHouse (aka Brad Burt) described first.

[nosaj]

Here is an optical tremelo I've held onto these pages for a while but here they are to share.
nosaj
I need to rescan them i see. maybe tomorrow I' replace these but they get the general idea out there.

[tedmich]

Here is an optical tremelo I've held onto these pages for a while but here they are to share.
nosaj
I need to rescan them i see. maybe tomorrow I' replace these but they get the general idea out there.

Wow thats a minimalist design! almost a steampunk aesthetic... It reminds me a little of the anodized disk the Morley EVO-1 used, spinning in a bath of PAG that Uncle Doug did such a great rebuild of

[nosaj]

It seems to missing the part where you use a sharpie to make stripes on the cd for a custom effect or I'm overlooking it.
nosaj

[oc disorder]

How are you going with it ? They seem to have sold out of the kits now.

https://www.musikding.de/Forum-Vibe-Vintage-kit

And if it's still available the PCB is about AU $70 ($20 USD board $25 postage)

Whatever happened to sea freight?

De-oxit out here is about $60 a can as they wont send it by air.

[tedmich]

dag gum the supply chain! Condolences,
the board would pretty easy to DIY, its real simple