MATRIXSYNTH: Plan B LPG


Tuesday, September 30, 2008

Plan B LPG


YouTube via cray56
"Plan B LPG G1 and G2 hear the difference?"

8 comments:

  1. vactrol bleed ftw

    ReplyDelete
  2. I just talked about the issues with my Model 13 today with a friend!

    QC seems to be an issue (but perhaps not a problem if you don't notice what's wrong) with Mr. Grenader's gear! Good stuff though and at a good price for such a small outfit.

    ReplyDelete
  3. Hear the difference between what? What am I supposed to be listening for?

    ReplyDelete
  4. I just ordered all of the plan b stuff....and yes I have "quality issues" also.....

    ReplyDelete
  5. stephen

    G1 is more open than G2 I am trying to find out of there is a tweak to close G1 more

    ReplyDelete
  6. I have two LPG's and all 4 of the individual gates have different ring outs. Peter does his best to match each set but vactrols are unpredictable little buggers. I like being able to choose the particular side for a desirable level of ring out.

    ReplyDelete
  7. cheers rewire

    is there a way to tweak the decay / vactrol?

    ReplyDelete
  8. This is not a broken module. It's the nature of Vactrols. Please read the following. It was posted on the Plan B list the first time Ross commented about this - but please lso read to the end where I speak of our quality issues.

    Yhe nature of Vactrol:

    Vactrols vary greatly from one another. It's the photo resistor. As
    fact to this, looking at the PerkinElmer data sheet, the
    manufacturers of Vactrols, they list the 'off' resistance as 'off
    resistance @ 10 seconds' This wasn't a typo. Vactrol are SOMETIMES
    (keyword there) so slow they take 10 seconds to calm down to the dark
    state, meaning their resistance it rests at then the internal LED i off.

    Go here to download the PE datasheet/ One the pge loads, click
    DATASHEET on the righthand side:

    http://optoelectronics.perkinelmer.com/catalog/Product.aspx?ProductID=VTL5C3%2f2

    In short, it's the nature of the beast. In that light (pardon the
    pun), your DTG is operating properly because the vactrols in both
    halves are operating within their specs.

    If we've ever shipped a Model 13 in which both halves are exactly the
    same it was purely coincidental. The chances of that happening are
    slim. If PerkinElmer is unwilling to presort their vacs, its even
    more of a daunting task for little 'ol Plan B. btw, you will not find
    this problem on Doepfer LPGs, because he uses a completely different
    vactrol which is designed to react quickly. The good part: they are
    pretty much the same from one to another. The bad news, as a result
    of them being fast, they don't ring as ours do, and that is 'the
    thing' with low pass gates. They have that wonderful timbral ringing.
    Without that what do you have? You have a Model 12 lowpass output
    with resonance turned to minimum.

    A solution - something Buchla 200 owners were used to doing because
    the 1970's edition of the 292 (Quad lowpass gate) also reacted
    differently from gate to gate: This variance you're speaking of only
    becomes an issue with short percussion-type events. if you ever
    construct a patch which uses two halves of the DTG this, simply run
    the output of the slower one through a standard VCA afterward and use
    an Envelope Generator to open that VCA which is triggered the the same
    source triggering the EG that's controlling the slower DTG. Simply set
    the EG controlling the standard VCA so it fades the signal out of the
    same time the faster one does it by itself.

    Is this a band-aid to correct a bad module design? No. It's a fix to
    compensate for natural and expected variances introduced by the
    manufacturer of the very part that makes this a great sounding module.

    On quality:

    Plan B has had a few quality issues i the last month. We have made the changed required to 'repair' that problem and hiring Katira was one of those. There are aother changes coming, incuding adding a full time inspector in our flow.

    - P

    ReplyDelete

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