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Acoustic 470 Guitar/Bass amp

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  • Acoustic 470 Guitar/Bass amp

    Hi, Could anyone please help point me to a readable circuit diagram for the Acoustic 470. Amp has been out of action for a few years and i dragged it out of the shed to check out for restoration. Still have the original bass cab with 2 x 15" Celestions.
    Thanx

  • #2
    Check out this thread:
    http://music-electronics-forum.com/t14153/
    ST in Phoenix

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    • #3
      Acoustic 470

      Hi Phostenix, I checked this one and found it to difficult to read, even spent time with my brother in a pic program to bring it up but no luck. I'll keep searching. ( I did consider building a different power amp stage but would rather keep it original)
      Thanx

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      • #4
        Are you having trouble reading it on screen with Acrobat Reader or when you print it? You could purchase the schematic from musicparts.com (their watermark is on the schematic). I have the Acoustic 370 set from them & it's very readable (split into two 8.5 X 11 pages). It also includes the service manual & parts list, etc.

        $20 here (Paypal):
        Acoustic*Schematics
        ST in Phoenix

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        • #5
          unicorn,

          Check out this site unofficial acoustic control corp forum - Message Board - Yuku

          If you need a schemo I can email you one - just went through one of these so ask away if you have questions.

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          • #6
            Originally posted by gbono View Post
            ... just went through one of these so ask away if you have questions.
            Did you get that working?
            ST in Phoenix

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            • #7
              Yes, the PA board had a few issues but what threw me for the longest loop was the fact that I used replacement covers on the output devices (TO-3's mounted on the back chassis panel) that kept the collectors from making contact!!! I'm very familar with the design of this amplifier now

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              • #8
                What covers do the output transistors have? I have a 370 that will be my next project (& another one on the way) and it looks like your basic TO-3 socket. The 470 must have different mounts, so I'm curious.
                ST in Phoenix

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                • #9
                  check out this link and scroll down until you see real pictures of a 470 - can't miss the covers on the EXPOSED output transistors. You do not have the same mounting scheme on a 370.

                  GuitarHeadOrBassHead470 < Acoustic < Wiki

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                  • #10
                    Interesting. I'm not familiar with those covers.
                    ST in Phoenix

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                    • #11
                      I have the ones that work: 1 of the screw holes is 1/8", so the screw head keeps it firm, but does not touch the TO3 metal , and the other is slightly over 1/4", so the head slips through and makes contact with the case.
                      Haven't used them for ages.
                      That 470 is a mighty fine amp, but please *always* use the Guitar/Bass switch on "guitar". All it does is place a treble-killing choke in series with the speaker, muddying the sound innecessarily.
                      Juan Manuel Fahey

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                      • #12
                        Acoustic 470 SM

                        Here is the service manual.
                        I got it from MusicParts.
                        I workrd on one of these a while back.
                        A real rats nest.
                        Enjoy.
                        John G
                        Attached Files

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                        • #13
                          re 470 Acoustic

                          A big thank you for the info. I have taken out the output board and drawn my own version of the Power Amp stage and have posted it on KENLINX - bbs.webhop.net. I have now repaired the amp to its former glory and the sound is awesome. We had been using a 250 Watt Jap amp with one 15" and two 10". The Acoustic 470 leaves it for dead.
                          Cheerz

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                          • #14
                            Remember 476

                            Unicorn,

                            Just read about your 470, glad to know it's working!
                            I just wanted to say what a great bass amp you have there. I had one with the 2-15 406 cab also. Played a j-bass through it in a rock band. A great sound and "fun to mess with" controls. When I listen to the recordings of my band from that time, late 70's, It makes me wonder why I sold the amp! Sounds like you'll enjoy yours too.

                            Brad

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                            • #15
                              470 Rig


                              Thanks Mate, I'm actually a guitar player who likes to have a jam on bass occasionally. I have an old '69 Les Paul bass that sounds almost like a double bass through the Acoustic 470 (awesome). Our bass player now uses the 470, won't even look at the other thing he used to use.
                              Many Cheerz

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