Home › Forums › Help/Technical Questions › My Doctor Q needs a doctor!

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  • January 14, 2009 at 6:26 am #77542
    electrophile
    Member

    I have an older style Doctor Q envelope follower that seems to be having a problem. It seems to function fine when the ‘Bass’ switch is down but when it is up, the overall volume decreases as the range knob is turned clockwise (higher). When the knob is completely counter-clockwise the signal seems to be full strength, but as I turn it clockwise the volume decreases and the signal becomes almost completely lost by the time it reaches half way. There is also an increasing hissing sound as the knob is turned clockwise. What may be wrong with the pedal? Could I possibly fix it myself with a multimeter by identifying and replacing a component? Or do I need to send it in for repair? If so, how much would it likely cost to repair?

    Thank you, Aaron

    January 14, 2009 at 5:17 pm #90695
    Dr. Matt
    Moderator

    have you tried replacing the battery?

    i’ve had mine for a while and still not changed the battery (i’m looking for an adaptor to plug it into my daisy chain style power supply) but your post seems to describe what happens to mine with the bass switch flicked up. Mine used to belong to a guy who works in the shop i bought it from and he said that it does that when the battery is low, that’s why it was doing it when i bought it.

    If i get a chance to i will try a new battery in mine and get back to you.

    edit: I got a slight opportunity to change the battery and it seems the same, except there is less noise :doh: has it always been like this? Because i might need to have a word with the people who sold me this pedal, if this isn’t just the way it is meant to function (which does seem kinda odd)..

    January 14, 2009 at 6:40 pm #90697
    electro-melx
    Moderator

    I’ve just got one of these (an older RI) and with the bass switch up it cuts everything out apart from the very high frequencies…it sounds really rubbish, quiet and broken!!! I have no idea what you would use it for! (is there some specific use/reason for it being like this?)

    with the switch down it sounds fine and full, I’ve been running it off a power supply too, so it’s nothing to do with the battery.

    I’m pretty sure they are supposed to be like this as it seems all 3 of ours are the same.

    January 14, 2009 at 7:59 pm #90701
    tubezipper
    Moderator

    I like the thread title 😆

    January 15, 2009 at 5:20 pm #90811
    Dr. Matt
    Moderator

    yeah, i had a sneaking suspicion that it was meant to be like this since mine is just the same.

    I guess the use would be for crazy FX just like you can get from just about other EHX pedal :D Combined with distortion it can make some interesting screechy noises – i guess they’d have some use to people like tom morello 😆

    January 15, 2009 at 5:26 pm #90812
    electro-melx
    Moderator
    Quote:
    I guess the use would be for crazy FX just like you can get from just about other EHX pedal :D

    lol, yeah it was probably a case of ‘well, we have a space in the case for the switch.. what can we make it do”

    “I know!” :D

    January 15, 2009 at 6:58 pm #90817
    julian
    Moderator

    that’s why I love EHX

    January 17, 2009 at 1:34 am #90966
    jonphipps
    Member

    Hi guys!

    I’ve repaired 2 vintage doctor Q pedals before (pedal repair is a hobbie of mine). I know what you mean by the high hissing and supposedly ‘inactive’ sound of the effect when you switch to the bass setting in some cases. This can often be remedied by opening up the unit and tweaking the ‘range trim’ pot on the circuit board to focus on the relevant range of frequencies that your playing on your instrument (whether your playing guitar or bass). All you need is a set of screw drivers to sort this problem out if the problem with your pedals is the same as what i’ve delt with before.

    I hope this is helpful to you guys, good luck!

    January 23, 2009 at 11:07 pm #91517
    RadioSilence
    Member

    same problem with mine, i was going to post a thread asking for help.

    i’ve had a tweak with the trimpot but it doesn’t help.
    with the switch down it sounds best in the position it came in, with the switch up it doesn’t sound better or worse at any position.

    January 16, 2013 at 12:47 pm #118670
    idjuka
    Member

    Hi EHX !!! I need your help about this pedal?

    Doctor Q …I am so proud to had this vintage beauty ! Now I need information about it.. It,s about power adapter. I know that its 9v, what I don’t know is what current ? It is so boring to have to replace the battery… and I had the pedal board …and so on..
    Now…can you tell me what adapter to use, specific what current ???

    Thank you !!!!

    January 16, 2013 at 3:31 pm #118671
    The EH Man
    Moderator
    Quote:
    Hi EHX !!! I need your help about this pedal?

    Doctor Q …I am so proud to had this vintage beauty ! Now I need information about it.. It,s about power adapter. I know that its 9v, what I don’t know is what current ? It is so boring to have to replace the battery… and I had the pedal board …and so on..
    Now…can you tell me what adapter to use, specific what current ???

    Thank you !!!!

    9vdc, 100mA, 3.5mm plug, tip positive

    January 17, 2013 at 1:15 pm #118680
    idjuka
    Member

    :-) Thank you !

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