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Vintage Acoustic Amps

Discussion in 'Amps and Cabs [BG]' started by sticknto4, Sep 18, 2004.

  1. sticknto4


    Jul 10, 2004
    Hey Everyone,

    Remember those vintage acoustic amps that were made in the 70s?? Well, Im looking for one that is reliable (im not concerned about sound because i already know that they sound awesome!). I have already played through the 370 and the 360 (jaco's amp; i have heard they blow up easily :meh:) but am curious about the other models out there. Any information would be greatly appreciated.

  2. Muzique Fann

    Muzique Fann Howzit brah

    Dec 8, 2003
    Kauai, HI
    You probably already know but the 360 is only a preamp - the 370 is a power amp I believe...
  3. sticknto4


    Jul 10, 2004
    Yes the 370 is the one with the graphic equilizer on it...im kind of curious about the 220.
  4. i know my late 70s acoustic cabinet doesnt handle my 4 string very well likes to distort. so i would advise against the cabinets a head would be kool though.
  5. Rock&Roll


    Jul 21, 2002
    You've asked, so I'll tell you. Acoustic amps being reiable is not a problem, and the 360/361 is no exception. You just need to realize, if you get any brand of a vitange amplifier, it'll probably be in less than stellar opperating condition due to wear and tear over 20 or 30 years. That's a long time. I highly suggest to anyone buying vintage gear to know a VERY GOOD amp tech that they can take their gear to.

    I bought my 2 full 361 rigs 4 years ago when I found some for a good price. An ex-bandmate blew both of them up at separate times because he would be irresponsible with power cords and dumb stuff.

    As far as the sound, the 18" folded horn 361PP cabinet will handle anything and do it at very high volumes. The folded horn cabinet will help get your sound to fill out a room so you can be heard. After some time playing with mine at different gigs, I'm going to add an Ampeg 8x10 and SVT4-PRO beside of my 361 because the 18" with no tweeter or midrange does get a little muffled in the audience. I think combining the amps will get me a very very good filled out sound.

    So heres my guidelines:

    • Get the 360/361 (the 370/301 is ok, but I like the 360's better)
    • Expect to have it serviced soon after purchase, though, the amp will probably work fine when you get it.
    • Be careful about grounding issues with other electrical equipment placed near the cabinet or hear. If at all possible, just keep other electrial equipment a couple feet away your entire rig.
    • The amp doesn't have clippng protection circuits, but I've never heard the amp even begin to fart out or anything of the sort.
    • Note that after I had my amps serviced with new capacitors and transistors, the sound was considerably better. I noted that the low end bass response was more full and clear down to lower frequencies.
    • Simply being a good responsible user of your Acoustic will yeild years and years of faithful service. Don't take this for granted and your life will be easy. And don't let other people mess up your gear for you. Know a good amp tech.
    • Have a buddy who will help you load/unload and move the cabinet around. You can move it about anywhere yourself if you have all night the get it somewhere.
    • Contact vetchking@aol.com. George is a good guy, and can sell you high quality copies of the schematics and user's manual for the 360/361 or many other acoustic rigs.
    • I've said this to everyone who want's to get a 361. The 361 isn't going to be anything like you're everyday amps on the market. And you'll be surprised at just how well it can do midrange and treble from a 18" speaker. I know I experienced some difficulty when I first got my Acoustics. It took me a good while to really understand how to work them. Learning to use the 360 taught my ears a ton about using all bass amps in general.
    • Each 361 cabinet has a 200 watt power amp built in. That means, you add a second cabinet and have 400 watts. One 361 preamp can work with 4 cabinets at one time (Ala Sly and JPJ). 1 361 cabinet sounds good, but it gets way better when you add the second cabinet. You'd have to be there to understand

    If you want to, check out http://www.acoustic360.com . They have info on most Acoustic made equipment; pictures, specs, and catalogs.
  6. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Lesforprez..the 360 is indeed a preamp. The 370 is a bass head, single channel with bass/middle/treble tone controls plus 5 band graphic eq.

    Sticknto4...the 220 head is a workhorse. A friend of mine used his in a touring band for years and years with no problems. Wore out plenty of JBL 15s but the head remained solid. Not real powerful but Acoustic's power ratings seemed very, very conservative.

    I had a 450 head (the 370s little brother). While rated only 170 watts at 4 or 2 ohms, it was a monster...

    Lots of free manuals/schematics, etc. at www.acoustic360.com
  7. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    South Shore MA
    The power ratings were accurate, it's just that the distortion ratings on those amps were way up there. More distortion = more percieved volume.
  8. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Hmmmm, never thought of it that way... Acoustic's output power ratings are specified at 5% and 10% THD (total harmonic distortion). I don't know what 5% and 10% THD sound like though...

    FWIW, the 370 head is rated...

    205 watts RMS at 5% THD into 3.2 ohms (one 301 cabinet)
    230 watts RMS at 10% THD into 3.2 ohms
    325 watts RMS at 5% THD into 1.6 ohms (two 301 cabinets)
    365 watts RMS at 10% THD into 1.6 ohms.

    Also, Frequency response: -6 dB at 50 Hz and 17.5 Hz (the amp does have an output capacitor to isolate the output transistors from the speaker load).

    For those wanting to link amps, Line output voltage 250 mV, Line output impedance 5000 ohms.

    Tone controls:
    Bass +/- 10 dB at 50 Hz
    Middle +10 dB, -30 dB at 300 Hz
    Treble +15 dB, -25 dB at 10KHz
    Bright switch 4 dB/octave from 200 Hz to 5 KHz

    Graphic +10dB/-15dB at 50, 100, 200, 300 and 400 Hz.

    From the 1978 catalog, the 220 head is rated 125 watts RMS at 5% THD into 4 ohms, 160 watts RMS at 5% THD into 2 ohms.
  9. DaveDeVille

    DaveDeVille ... you talkin' to me ?? Supporting Member

    see my avatar ??
    Acoustic 360

    it was indeed a preamp , with the power amp located at bottom of
    the folded horn cabinet .
    volume was loud , tone was sweet , but the weight was a concern ...
    what else can i say .

    hauling this setup was a back breaker , but if that's not a problem , go for it !!
    i've never had another rig that sounded as good as the old 360 ...
  10. Rock&Roll


    Jul 21, 2002

    Though I don't know that for a fact, I could agree with you. The 360's I have seem to get a good taste of distortion when pushed. (Harmonic distortion, if I am correct) But I honesestly think this adds to the amp. It's not a nasty solid state clipping sound. To my ears, having a full 360 rig with the amp "well driven" will give a sound that is very similar to tube bass amps I've used. I can't say enough about the sound of 2 361 powered cabinets side by side. It just feels great. The best solid state amp I've heard to date..........probably forever.

    In contrast, at the time of one of the power amps in my cabinet being dead, I used a Crown DC-300A for the power amp section (I made an adaptor for the molex speaker terminal). The sound was substantially different, even with the same 360 preamp. I can describe it as being more "solid." No matter what, I could not get that amp to scratch, distort or grunt. It was just a tank, though not as loud as the 361's original amplifier. The original amplifier would be loud, punchy mids, rich, fat, with a clear sparkle. Take away the "clear sparkle" and "punchy mids" and thats what the DC-300A sounded like.

    BTW the numbers can get confusing. Here's the straight skinny.

    --360 = 360 bass preamp head

    --361PP = powered cabinet (sometimes mistakenly called the "301". The 301 is the non-powered younger brother of the 361PP that was sold with hte 370 head to form the "371" system)

    --361 = the full 360 head and 361PP cab put together as a system equals the 361. Add 2, 3 or 4 cabs to one preamp and you're in heaven.

    So now this has put into my mind that perhaps a SS power amp with higher harmonic distortion is better for for a more "real" sound. :hyper: (if that's what you're into)