Not only is it possible, It's KILLER!!

Discussion in 'Amps and Cabs [BG]' started by Hambone, Mar 6, 2002.

  1. I don't get a chance to post here much because, quite frankly, my rig hasn't been anything that could keep a conversation going but I've got one now that just might prove to be the best I've ever used...

    For years, I've wondered if an amp system based on a 12v car amp would be possible. I've researched and schemed and finally I've come up with one that absolutely kills for a lot less money than a comparable full 120v system would cost. Here's what I've got:

    Yamaha PB-1 pre-amp Bought it used for about $75 but am very pleased with it's versatility and ruggedness.

    Pyramid PB446 600w power amp Bought new from ebay for $78. 300w per side @ .05% THD, 20-20 khz response, MOSFET circuitry, thermal protection, high/low impedance inputs, adjustable bass/treble/gain levels, bridgeable, stable to 2 ohm loads, and a nifty purple aluminum heat sink. The model number is purely coincidental.

    Pyramid PS21KX Regulated Power Supply 13.8 vdc @ 20 amps. Bought near new from ebay for $60. Thermal protection, fan cooled, power meter on front panel. I've had the rig blastin' and the hardest I could get the PS to working was about 6-8 amps. Plenty of headroom.

    I'm using this as a bi-amp system with each side of the power amp supplying a different signal - high and low. This sort of came together before I got the speaker situation licked so I've just tested with a 15" Gauss in a ported bottom for the bass and (2) 12" 200w Thump speakers in a homebrew infinite baffle cab for the highs. After some tuning and adjusting, I was blown away with the power and cleanliness of the system. Shimmering highs without harshness and very, very deep but tight lows. When I finish the speaker configuration that I want to use it'll be a single 15" ported cab with a (4) 8" cab on top x 2 - one for each side of the drummer!!

    So there it is for your digestion 600 watts of clean, controllable power for about $213.

    I know, I know - it can't be done ;)
  2. jasonbraatz


    Oct 18, 2000
    Oakland, CA

    how do you hook up the speakers? made some kind of special speaker cable?

  3. That detail has to go in the "con" category. It's not hard, it's that you've GOT to build 'em yerself. I used some 12 ga. power cable with SAE lugs soldered on one end and ¼" phone's on the other. It's a temp solution until I can get this critter racked. Only the preamp is rack ready so of course there's something else that has to be engineered. When I get them together I think I can make speaker hookup a little more friendly.

    I'm a tinkerer at heart and this is a labor of love. I wouldn't recommend throwing together something like this without knowing how to make good cables. As it is now, it sure ain't gig ready :D
  4. Purs


    Feb 20, 2002
    sounds like fun, keep us posted.
  5. Sounds like you've gone one further than my experiments!

    I've been running a couple of Sony 100w power amps into a sealed 15" + 2 10"+tweeter boxes, all powered by an 8A PC power supply, for a while now. It's just as good as a car stereo, small outdoor PA or (as it normally is) a fairly good studio monitoring system.

    Never tried playing bass directly through it, but via a mixer, yes - tons of lows, and defined highs, but a bit missing in the midrange...but I wasn't running through a decent preamp that I could shape the sound.

    As for mounting, both amps are bolted to each side of the 15" box for easy portability, and using gold-plated "block-banana" plugs (it's a connector made up of 4 banana plugs so it's a singular connection for the speakers) so that the speakers can be plugged and unplugged with ease.

    Maybe you could either mount the power amp on the back of one of the cabs (ideally the one you know you'd always be using), or if you're clever mount the amp inside the cabinet (and the power supply, too) - then you just have the preamp on top.
  6. neptoon


    Jul 25, 2000
    summerville, sc
    well, hammy, if anyone can make it work, it's you. keep us posted, man....and post some pics! ;)

  7. Mixers always act like that with a straight input from bass. I dunno why :confused: but the preamp doesn't act like that. And if I do encounter a prob, I've still got the ability to switch to a low impedance input.

    Your idea about putting it into a speaker cab is wild - I like it alot! Dammit, I really wanted a cool rack system with this but putting it in the boxes makes more sense...

    [hurries off to the drawing board]
  8. Tristan


    Jan 28, 2001
    Ottawa, Canada
    Hambone, u da man.

    As a fan of all things jerry-rigged, this project interests me greatly! Keep it up and keep us posted!