Home › Forums › Vintage EHX › 4- Knob Deluxe Octave Multiplexer -Repair/Mod enquiry?

Viewing 8 posts - 1 through 8 (of 8 total)
  • Author
    Posts
  • January 5, 2012 at 8:09 pm #82101
    germanium mash
    Member

    Hi, I’ve had an old Deluxe Octave Multiplexer pedal for a couple of months now and I’m fairly happy with it’s sound,for what it is… a glitchy old monophonic octave pedal.
    I haven’t heard a _ _ _ Bl–B-x and the DOM is one of the only other pedals I was aware of that did 2 octaves down (The later Pog2 and Hog aside,of course.I’m an oldie having a mid-life ‘renaissance’
    …or something. If you saw my other pedals you’d understand). However, there are a few things with this old DOM pedal that could be made “nicer” & more user friendly.

    1. The tracking turns to total moosh much past 3/4 either side of the mid-point of the Mix control. And there’s also some wild random gurgling noise that occurs if the Blend control is turned much past the half way point too. I don’t know if perhaps this is a result of a faulty component, or if the pedal may need some internal adjustment & “re-calibration”?
    2. The pedal appears to have a SPDT switch,but it should be possible to make it DPDT switch easily enough I think. And also to change it to ‘Total Bypass’ wiring to borrow a term from Howard Davis… It was mentioned elsewhere on this forum,but that poster asked if he could change the ‘Power’ status light of his pedal to show when the effect was on or off? But he also didn’t want to change the switch/or wiring which may have negated his original intent.I saw that no-one responded to his enquiry… my idea was a little different ;
    I was hoping to be able to change the SPDT switch to a 3PDT and THEN mod/rewire the pedal so that the ‘Power’ light worked as an FX on/off indicator as well as changing the pedal to Total Bypass…
    3. It runs on 110V AC,which isn’t exactly ideal since I’m in Australia. Has any body ever converted one of these to DC operation? I imagine that it would need to be somewhere in the 18-24 volt range…
    going by later Deluxe Electric Mistresses and Deluxe Memory Men. I DON’T want to change the slider switch for the Fuzz on/ off to a stomp switch… In fact I probably won’t use the fuzz circuit in this pedal, even though it works. I have at least 6 other fuzzes and distortions that I mix, match & swap around.
    I bought this mostly for the 2 octaves down sound and there’s the basis of a very good sounding octave pedal here. It just needs a few minor tweaks. Are there any other circuit mods & tweaks that anyone is aware of for the ‘vintage’ 4knob Deluxe Octave Multiplexer?
    Is Howard Davis still around? Does he still post here??

    January 5, 2012 at 8:39 pm #116683
    The EH Man
    Moderator

    I don’t think there are any calibrations for that pedal.
    You should be able to make it true-bypass easily enough with a 3PDT and make the power LED an indicator. I’ve done that with other EH pedals
    The circuit requires a dual 5v power supply so that makes it a bit more difficult to modify for your country. You may be able to find a tech that can replace the transformer with one that will work. I’d replace that dual voltage regulator as well. It generates a lot of heat and will fail eventually.

    January 6, 2012 at 3:44 pm #116690
    germanium mash
    Member
    Quote:
    I don’t think there are any calibrations for that pedal.
    You should be able to make it true-bypass easily enough with a 3PDT and make the power LED an indicator. I’ve done that with other EH pedals
    The circuit requires a dual 5v power supply so that makes it a bit more difficult to modify for your country. You may be able to find a tech that can replace the transformer with one that will work. I’d replace that dual voltage regulator as well. It generates a lot of heat and will fail eventually.

    Thanks for the reply,Ron. I’ll post a couple of pics of the board too…

    [img][/img]

    January 6, 2012 at 3:56 pm #116691
    germanium mash
    Member
    Quote:
    Quote:
    I don’t think there are any calibrations for that pedal.
    You should be able to make it true-bypass easily enough with a 3PDT and make the power LED an indicator. I’ve done that with other EH pedals
    The circuit requires a dual 5v power supply so that makes it a bit more difficult to modify for your country. You may be able to find a tech that can replace the transformer with one that will work. I’d replace that dual voltage regulator as well. It generates a lot of heat and will fail eventually.

    Thanks for the reply,Ron. I’ll post a couple of pics of the board too…

    [img][/img]

    OK,I tried to make them smaller using photobucket and they came out a third of the size that I wanted. I don’t know why? It’s too late here, and I’m too tired at the moment.
    But there is one blue trimmer on the back of the board itself. I don’t know exactly what that does?
    As for the “dual voltage regulator”… I’m assuming that is the grey coloured pair of cans directly under where the main power wires from the transformer attach to the board itself. Correct?

    [img][/img]

    The board is marked EH 1325 B. Is there a schematic for this model?

    January 6, 2012 at 4:16 pm #116692
    The EH Man
    Moderator
    Quote:
    OK,I tried to make them smaller using photobucket and they came out a third of the size that I wanted. I don’t know why? It’s too late here, and I’m too tired at the moment.
    But there is one blue trimmer on the back of the board itself. I don’t know exactly what that does?
    As for the “dual voltage regulator”… I’m assuming that is the grey coloured pair of cans directly under where the main power wires from the transformer attach to the board itself. Correct?

    No, the dual regulator is a large IC. It’s the one that gets hot when the pedal is plugged in.
    There is a trim in there after all. I didn’t see it on the schematic at first. I’m not sure what it does.

    July 26, 2012 at 2:01 am #117928
    drummer4gc
    Member

    still trying to figure out how to use a 3pdt to true bypass this pedal….its a little confusing to me because it doesnt seem to follow this typical spdt setup: http://www.muzique.com/news/images/true3.gif

    maybe because there is a direct out?

    anyone have any ideas?

    July 26, 2012 at 6:14 pm #117930
    The EH Man
    Moderator

    [img]http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=47646&g2_serialNumber=2[/img]

    connect the Direct Out jack to the input jack.

    July 27, 2012 at 5:42 am #117936
    drummer4gc
    Member

    Thanks! got it working. However, the bypass signal is now a lot stronger than the effects signal, which is to be expected. Is there a way, short of wiring a buffer, to increase the output volume of this effect? An output resistor somewhere to decrease, perhaps?

    Also, mine has that same gurgling symptom as the OP’s. Any ideas on how to tame it?

    Thanks for all the help!

    matt

  • Author
    Posts
Viewing 8 posts - 1 through 8 (of 8 total)
  • You must be logged in to reply to this topic.