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MOOG: 901A, 901B etc...

Discussion in 'Electronic Repair Modifications DIY' started by bnm123, Mar 29, 2011.

  1. bnm123

    bnm123 Active Member

    Hi, i'm a student of electronics and i'm thinking about making some audio gear... i thought about moog filters because they look pretty simple to create, here's my question, has anybody made one of those? i mean 901A, 901B, 901C, 902 or 904C? which one sounds best?
  2. Boswell

    Boswell Moderator Distinguished Member

    Hi, and welcome! Are you talking about simply building some known design, or would you want to exercise your own creative powers and design something yourself? You are an electronics student with an interest in audio, so maybe you should be adventurous and design something of your own that needed less constructional effort than one of the Moog units. Stomp boxes are often a good starting project, and there have been several contributers to these forums who have got their feet wet in those waters.
  3. bnm123

    bnm123 Active Member

    i don't necessarily have to built moog but i like their filters very much... i was thinking about some stomp boxes as well but i don't have electric guitar and i would like to built something useful for me... but thanks for advice
  4. Link555

    Link555 Well-Known Member

    Welcome! Stomp boxes can be for anything you want to put through em' not just guitars. This is group here that some of use to share ideas, your welcome to join if you like
    Designers Sharing Ideas - RECORDING & Sound Engineering Forums
  5. bnm123

    bnm123 Active Member

    thanks, i'm just starting my adventure with audio equipment but i hope i'll make some contribution here...
  6. Lowpass

    Lowpass Active Member

    None of these are filters...

    so you should look elsewhere.

    901A is oscillator driver module, it doesn´t produce any sound itself, but delivers common control voltages for
    901Bs, which are voltage controlled oscillators,
    901C is VCO too, but more capable and featured than 901B,
    902 is voltage controlled amplifier,
    904C is filter coupler, it doesn´t do any filtering itself, but sets control voltages for attached 904A LP and 904B HP filters... You can set center frequency, peak/notch width and select band pass or reject response as well.

    You should look for 904A, which is low pass filter with resonance (or regeneration, in Moog speak). 904B is a plain high pass without regeneration.

    But original 904A uses some hard to find parts, a very few people were lucky enough to finish a real clone. You will be better to buy something in a kit form (there are many of them around, not only Moog clones) or have a look feg. on Yusynth. A friend of mine had built it, his synth is in a gallery there.
  7. bnm123

    bnm123 Active Member

    thanks for comment, i didn't know that, i think i'm gonna go with Moog Ladder Filter, i found somewhere schematic and pcb layout...
  8. Lowpass

    Lowpass Active Member

    Schematics and PCB

    is not all you need, but if you will be patient, have enough knowledges and a LUCK :cool:, you can do that, as others did it too.

    But I still think, a better option is Yusynth modular, which is extremelly well documented (the best I know :eek:, with alternative parts and so on), tested and has really wide options. Not only moog filter clone, but ARP, Steiner-Parker, EMS filters. Along with other modules for a complete modular synth.

    There are many kits which you can buy and build, I don´t want to name them as I´m not with any of them, but it is easy to find them on a net. There are a plenty to select from, personally I´d like to have some of them, even if I have some pretty good analog synths.

    You can even buy a real 904 clones, but in completed form, which is not adventurous at all, I think you are into a way, not only a destination, aren´t you? :redface:
  9. bnm123

    bnm123 Active Member

    thanks again for advice, this yusynth looks really nice, but i guess it'd took me ages to finish it :biggrin: and i thought more about something simple and useful in a home studio but i'll look at it for sure, i didn't start anything yet anyway...

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