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Monday, 13 March 2017

Univox Uni-Comp

Not much info on this one, but basically it was a compressor made by Univox in the 70's as part of their "foot" series. Seems to be loved by many and was recently requested. In addition to the schematic posted in the request section I found another schematic posted over at FSB, so I made 2 different layouts.

One thing to note is that the original didn't use an LED & LDR, but used a Vactrol labeled MCD527. I'm not quite sure what color LED and LDR range you should use. I would start with try a red LED and socket the LDR and try different ones to get a good range. If you were to try a vactrol maybe a NSL32 or VTL5C3 which have bee used on many different optical compressors.

Don't forget if you're using an LED & LDR to cover them in shrink wrap to block out any light and increase their efficiency and effect.

Layout 1: Based on the Schematic in the Request Section


Layout 2: Based on the Trace ad FSB of a Uni-Comp Model CO-105



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17 comments:

  1. Arnold Dikstaal13 March 2017 at 20:54

    Looking at the minimal datasheet I could find here: http://www.datasheetarchive.com/dlmain/3a432e73794c72004043cbb83187adec39ebb7/M/MCD527

    and here:
    http://www.grandpas-shack.com/parts/datasheets/CdS_Photo_Couplers(Moririca).pdf

    You could say the LDR is 1k-2M closest LDR would be the GL5537-1 (not GL5537-2) which is 20k/30k - 2M. Not really close but closest I could find. It pairs good with a amber/green LED as the spectrumpeak is at 540nm.

    Vactrol-wise you could consider the VTL5C3, also not a perfect match, but covers the spectrum.

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    Replies
    1. Zach14 March 2017 at 18:08

      Great. I couldn't find the data sheet for some reason. I'll add the info to the build notes.

      Delete
  2. Jack Bledsoe14 March 2017 at 01:41

    It's possible to get the Avalanche run schematic?

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  3. BigZed14 March 2017 at 13:34

    This comment has been removed by the author.

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  4. BigZed14 March 2017 at 13:35

    The germanium diodes should be D1, D2 and D3 and the LED D4?

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    1. Dexter14 March 2017 at 16:15

      They're all in the right place as far as I can tell. Its just labeled different.

      Delete
    2. Zach14 March 2017 at 18:03

      Yea. I didn't realize the numbering was off. I'll fix that in a few.

      Delete
    3. dauntless21 July 2021 at 18:58

      Around 1979 I loaned my gray box and never got it back only to discover it was discontinued. I contacted Unicomp's to service department and they sent the wiring diagram so I purchased all of the remaining opto-isolators in inventory for about $30 planning to make some for myself and friends. The rest were lost to time and moves around Boulder CO.

      Delete
  5. BigZed14 March 2017 at 16:59

    I think so too, it's just the labels. I've got some VTL5C3's so I'm gonna give it a go at the weekend.

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  6. BigZed14 March 2017 at 17:18

    Would a MPSA18 or BC550 work in this? I don't have any of the above transistors, so before I go buy some I'd thought I'd ask first!

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  7. raduandroidul14 March 2017 at 17:28

    The MD234 diodes aren't germanium ones! There are silicon (http://www.datasheetarchive.com/dlmain/356b7aff6be6417173704f4e3a807d3ad96c94/M/MD234).

    Thank you all!

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    1. Zach14 March 2017 at 18:08

      According to both people that traced their Univox Uni-Comp pedals said the diodes were germanium. The diodes could have gone from germanium to silicon at some point in production, but I don't know. Could socket the diodes and try silicon and germanium to see what's best. I tend to trust the people that traced the pedal till we get confirmation from a build here.

      Nice job on finding the data sheet, btw.

      Delete
  8. BigZed15 March 2017 at 10:57

    This comment has been removed by the author.

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  9. BigZed15 March 2017 at 10:57

    BTW the Vero is 13 x 16

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  10. BigZed15 March 2017 at 14:40

    This comment has been removed by the author.

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  11. Anonymous26 March 2017 at 22:56

    I apologize if this is an incredibly beginner question, but when the layout shows a wire going to "Comp 2 & 3", does that mean you have two wires going from one hole to 2 & 3 on the comp pot, or can you run one wire from that hole to 2 on the comp pot, and then a connector from 2 to 3? Thanks!

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  12. BigZed27 March 2017 at 19:00

    A single wire from the board and join the wire across lugs 2 and 3.

    ReplyDelete