How to rack up a Yamaha PM-1000 module

Discussion in 'Pro Audio' started by Dudleys100, Feb 28, 2004.

  1. Dudleys100

    Dudleys100 Guest

    Howdy! Ok here is the deal. I have been wanting to get into some DIY
    stuff for awhile and have been trying to find a good starter project
    that would be usefull.

    So I have purchased a couple channel strips from a Yamaha PM-1000
    console. I know this probably wouldn't be the easiest starter project
    but I think it would be fun and teach me a lot of things I need to
    learn. What I am wondering is what parts I need to get to do this
    project. So far I know I need to get the rack and build a power
    supply. I am not sure if I need output transformers or if it has any
    yet or what. As you can tell I am somewhat in the dark. I would like
    to find a site or some resourse that could help me generally walk me
    through this. Any help would be appreciated. Thanks.
    Dudleys100, Feb 28, 2004
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  2. Dudleys100

    Mike Rivers Guest

    If you're just getting into DIY projects, I think this is much too
    complicated for you. Unless you're just following a cookbook, any
    creative DIY project involves some research and some decisions. If we
    do the research and make the decisions for you, then you're just
    following a cookbook.

    I'd suggest that you start with something simpler like a monitor
    speaker switcher or master volume control. That way you can learn
    about components, a little about circuits, and how to make a package
    that both contains the parts and connectors and is also ergonomically
    The first thing you need is documentation. You need to find the
    operating voltages so you can build or buy an appropriate power
    supply. You're not likely to find documentation as to current
    requirements for an individual module, so you'll need to hook one up
    and measure it. (so that means that you'll need a bench power supply
    and a meter) You'll also need to find the input and output
    connections, and find mating connectors for the modules. That might be
    simple or difficult depending on how the modules connect to the
    console busses.

    Much of the Yamaha sound is a result of the transformers. If you don't
    have those, you aren't really going to be able to duplicate the sound
    of the original console. This may not be important, but you will
    almost certainly need an input transformer, and probably an output
    transformer would be a good idea too. You'll need to measure input
    sensitivity and output level in order to decide on the appropriate
    transformer ratios.

    Then you'll have to find a decent rack mount chassis, design the
    layout, and get the holes cut. You'll probably want to paint it
    nicely, too.

    You're right - it is a good project, but nobody's going to do the
    research for you.

    I'm really Mike Rivers ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
    Mike Rivers, Feb 28, 2004
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  3. Dudleys100

    Dudleys100 Guest

    Thanks Mike, I understand what you say. I should have mentioned that
    my roomate is helping me and he has a lot of experience with
    electronics the only problem is that he has not worked on audio stuff,
    which is what puts us a few steps back. I would love ot buy a
    cookbook for this if there was one, but of course there isn't. I am
    not looking for just a handout, I would like to know resources for
    this though, like books or websites on building preamps or elctronics
    info that would pertain to this etc. If worse comes to worse I can
    pay someone to rack it up for me, but I would like to try and learn
    this stuff. Thanks for the help, I will keep doing homework and
    hopefully will be able to get this taken care of.
    Dudleys100, Feb 28, 2004
  4. Dudleys100

    hank alrich Guest

    And it wouldn't offer what you need to do this. If you already knew
    everything that could be in such a book, you'd still need to have the
    schematics for the Yamaha console and components in order to know _its_
    particular power, control, and signal interface requirements.

    What you want to be trying to get is the technical manual with full
    schematics for the console in question. I'm sure it's out there, and the
    live sound forum - - might be important to
    include when asking, as the PM1000 is an SR board.
    Go ahead and make it a learning project; the parts aren't worth paying
    for racking unless you get a hell of a deal from a friend. But folks who
    already know how to do this and also have access to the reference
    materials are not likely to be doing the work for real cheap.
    hank alrich, Feb 28, 2004
  5. I have a copy of the Yamaha PM-1000 service manual if you need me to
    make some photocopies of the schematics.
    ThePaulThomas, Feb 29, 2004
  6. Dudleys100

    Mike Rivers Guest

    That shouldn't set you back too far. But is he experienced in
    mechanical assembly? That's where most of the work is.

    I'm really Mike Rivers - ()
    However, until the spam goes away or Hell freezes over,
    lots of IP addresses are blocked from this system. If
    you e-mail me and it bounces, use your secret decoder ring
    and reach me here: double-m-eleven-double-zero at yahoo
    Mike Rivers, Feb 29, 2004
  7. The PM-1000 was meant to be a PA desk circa mid-70's so it didn't have
    individual inserts or direct outs on each channel. The electronics are
    indeed all discrete components in class-A circuits. I bought a 16
    channel PM1000 a couple of years ago intending to do some mod's on it
    but it's ended up in storage in Illinois and I recently moved to
    California. I never got to record with it. But based on some very
    limited listening tests I would say that it did seem like a pretty
    awesome sounding board. Really fat low end and TONS of headroom. I
    wish I could be messing with it right now but my life has taken too
    many weird (and bad) twists turns in the past year.
    Cost to benefit ratio is the real issue here. And that's where a guy
    like Mike Rivers always helps put things into perspective. He always
    brings up the questions many of us would forget to ask ourselves
    before jumping into these projects. Now with all of the companies that
    are competing to sell a decent low cost pre-amp these days it doesn't
    seem like racking up PM1000 modules would be all that cost effective.
    If the PM-1000 does indeed have _the_ sound you like then you'd be
    better off finding an entire console that's intact and then learn to
    do the work of adding inserts or direct outs to the channels and see
    if you can make the EQ more flexible. I bought mine on ebay for the
    cost of $30 (yes, thirty!) and a drive from Chicago to Cincinnati. It
    was in really bad shape and I spent a total of about $125 on totally
    re-capping the entire board (and power supply) as well as cleaning all
    the pot's and whatnot. The service manual cost me about $30 from
    Yamaha. So, all in all, I have a clean, recapped 16 channel board that
    seems to sound pretty cool and it cost me under $200. Too bad it's
    2000 miles away in a storage unit in Chicago. :( But most importantly,
    I learned A LOT about electronics while working on it and it was my
    first project similar in nature to what you seem to want to do. When
    you throw in the entirely FREE education I've received via the r.a.p.
    archives and Google it's possibly the best $200 I ever spent. It has
    lead to me buying and repairing a lot of other gear. Some of which I
    kept, some of which I sold at a profit. No regrets whatsoever about
    that PM-1000. :)
    So as to your concern of ending up with something "mediocre" (quoted
    from private email sent to me), that really just depends on how much
    you end up investing and what you get in return. Hang around r.a.p.
    long enough and be willing to spend hours repeatedly burning your
    finger tips with a soldering iron and eventually those PM-1000 might
    pay off quite nicely. Oh yeah, let's not forget the inevitable
    exploding electrolytic capacitor/s that was installed backwards.
    You'll have to experience a few of those along the way as well. ;-)
    ThePaulThomas, Mar 1, 2004
  8. Dudleys100

    ulysses Guest

    The manual was available on Yamaha's website a couple of months ago. I bet it
    still is. I have it on my computer at the studio, but unfortunately that's
    something like 7,000 miles away from me at the moment. Look around Yamaha's
    website, or do a google search.

    The long and short of it is this:
    You need a 44V power supply. I suggest using a single power supply for both
    the audio rail and the phantom power (44V will be good enough for phantom and
    save a lot of hassle). You'll want to disconnect the pan and subgroup assign
    controls from the circuit. You can pick the output signal off of the large
    output capacitor that feeds these controls (look at the schematic). This will
    be an unbalanced signal, but if you pilfered an output transformer from a
    master module (there are three in each master module) you could balance the
    output and it would be just like what's in the master section (the output
    amplifier of the channel module is identical to the output amplifier of the
    master module). I think you'll want to completely remove the crappy unreliable
    modular connector on the end of the module. You won't need most of those wire
    connections aanymore anyway. You can cut off the top of the module, including
    the pan knob, to make it smaller. Or you could cut off the fader end of the
    module and move the fader pot to where the pan pot used to be, to get the whole
    thing down under 17" so you can rackmount it. When you're done, you'll have
    three wires for the balanced input (one of which is chassis ground), one wire
    for audio power, one for phantom power (which you'll need to add a switch to
    control), power ground, and one output. Your pan and buss assign controls will
    no longer be functional. The two aux sends will still be sitting there unused,
    but you could use them to feed a headphone amp or something for monitoring.

    This is a nice circuit to play with because once you stare at the schematics
    for a while you'll see that there are really only two amplifier circuits in the
    whole console. The mic preamp and the channel output and the master line outs
    are all the same circuit. The summing amps and the aux sends are identical,
    smaller amps. Other than the EQ, the whole console is composed of these two
    circuits. Learn how they work and you can do whatever you want with the
    modules. It's just a matter of rerouting some wires to feed the different
    amplifiers. And there's lots of room inside for capacitor upgrades and other
    science projects. I'd suggest trying to change the midrange EQ frequency
    choices because as stock they're pretty silly, non-musical choices (but nice
    round numbers).

    ulysses, Mar 1, 2004
  9. Dudleys100

    Dudleys100 Guest

    OK I am getting a lot of great info, thank you. I downloaded the
    manual from the Yamaha site. The only problem is that it stops after
    27 pages which is section 4. The schematics and most of the other
    stuff I need are after this chapter :( If anybody knows where I could
    download the rest that would be great.

    Now I am wondering if I can just take the pre off of the channel strip
    and not worry about the eq and all the other stuff. If I can do this,
    would I be able to fit two of these on one rack panel? Would it be
    possible to rack these up into an API lunchbox? I saw a post from a
    guy that racked up 4 of these into a lunchbox but I suppose he made
    his own.

    So these supposedly come with the input transformers but not the
    output transformers. I am wondering how many "extras" I will need to
    buy. I know I need the rack itself unless I want to actually rack the
    channel strips. I also need to get the stuff for the power supply.
    otherwise am I pretty set as far as the big purchases go? Will I be
    ok without the output transformer or am I gonna be shortchanging

    Thanks. Ken
    Dudleys100, Mar 1, 2004
  10. Dudleys100

    Rob Kirkwood Guest

    When I grabbed the PDF manual for my PM-1000 from Yamaha's site last
    year, it was available as 2 separate files - and my part 1 does indeed
    end at page 27 (section 4) - so maybe you just missed the 2nd file?

    Rob Kirkwood, Mar 1, 2004
  11. Dudleys100

    ulysses Guest

    Great post! Don't forget also that when a RAP reader/poster is done playing
    around with and learning from their PM1000, they usually end up selling it to
    some other RAP reader who will do the same. It's a terrific little cycle. I
    think the one I used to own is getting ready to find a new home as well. Let's
    just keep passing them around so everybody can have a turn recapping one!

    ulysses, Mar 2, 2004
  12. Dudleys100

    ulysses Guest

    The preamp and EQ are on one circuitboard together, and you also need the
    output amplifier which is at the opposite end of that circuitboard from the
    preamp. So there's no sense trying to ditch the EQ. Besides, it's not
    bad-sounding EQ, it's just that the midrange frequency choices are a bit odd.
    That's something you can mess with later when you have time and more
    experience. The EQ is inductor based, which is the real secret behind the
    classic "sweetening" equalizers. Keep it.

    Like I said, you'll probably want to hacksaw off part of the channel strip to
    get it down to 17" or less so you can mount it in a rack. I think 2 channel
    strips mounted above and below each other, for a total of about 2RU, will be
    just fine for you. You're going to need to buy a metal rackmount enclosure,
    and some XLR connectors, and a power supply; and then you'll need to get into
    your Tim Allen mode, go out to your garage workshop, and figure out how to cut
    the modules cleanly. If you disassemble the metalwork a bit, you'll see that
    the aluminum faces come apart from the steel chassis. Cut the aluminum on a
    mitre saw (chop saw) that doesn't have too coarse a blade on it. The steel
    will probably have to be cut by hand (with a hack saw) but it won't be visible
    so it doesn't have to be pretty. The mitre saw on the aluminum will leave a
    very nice clean cut and will be rather easy and safe to do. Then you might
    need to mess with a drill press or something to get the end piece of the steel
    chassis bolted back onto the front and rear pieces, but this will not be too
    tough. Take a look at it, you'll see. I helped a friend with the electrical
    parts of racking some of these guys a few months ago, and he did exactly this
    with his modules and it turned out very well. He did have some output
    transformers pilfered from the master modules but they are not really
    necessary. You could always buy some Jensen transformers later to mount in
    your enclosure but in the meatime, just wire up the outputs unbalanced. You'll
    need to run a wire from the big output capacitor (sorry I don't have the part
    number of that capacitor, but it's the one that feeds the pan/buss controls) to
    the XLR jack. Connect this wire to pin 2, and connect pins 1 and 3 to ground.

    You can buy a very standard 48V power supply from Digikey or Jameco to power
    these modules. I'd suppose a quarter amp will be fine, but it's probably less
    than that. Either an open-frame Power One type suppply or a wall wart will
    work. An open-frame unit will most likely have a trim pot so you can take it
    down to 44V which is what the PM1000 is specified for. I think it would
    probably be fine at 48V, but the coupling caps (which are biased at half the
    power supply voltage) are rated for 25V so you'd run a small risk of running
    them over-voltage if any of the biasing was signifigantly off. Not a lot to
    worry about though. A quick glance shows me a Power One linear supply from
    Digikey that's 48V@0.5A with a 5% output adjustment for $42.00. Part number
    179-2034-ND. Or Jameco has a 48V "line lump" switching supply, 48V@0.52A, on
    closeout for $19.95. Jameco part # 203772. I hope this all gets you started!

    Go find part 2 of the Yamaha manual you downloaded.

    ulysses, Mar 2, 2004
  13. Dudleys100

    Dudleys100 Guest

    Thank you, I got it, I didn't realize there was two files there. I got her now.
    Dudleys100, Mar 2, 2004
  14. Dudleys100

    Bob Berz

    Apr 20, 2017
    Likes Received:
    Dudleys100, I realize this is an ancient thread, but how did the Yamaha Channels work out?? I'm thinking of trying this myself with some funky channels from an old Stevenson mixer.
    Bob Berz, Apr 20, 2017
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