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Stewart world 1.2 and cabs

Discussion in 'Amps and Cabs [BG]' started by knight, Aug 1, 2003.


  1. knight

    knight

    Nov 3, 2002
    Hi,

    A quick question about connecting this amp to cabs. The specs are:

    350 x 2 @ 4
    200 x 2 @ 8
    1200 x 1 @ 4 bridged
    700 x 1 @ 8 bridged

    I have two 8-ohm cabs. How could I hook them up (stereo or mono) and what power would I be able to draw? I'm confused. My current amp is mono, so I'm running a 4-ohm load, but what happens with the stereo feature?

    The back of the amp with the connections can be seen at http://www.stewartaudio.com/images/world12Back.gif

    Thanks for your help,

    knight

    +++++++++++++++++++++++++++++++++++++++++
    "I crave my pig meat" - Blind Boy Fuller
     
  2. ZonPlyr

    ZonPlyr

    Apr 29, 2003
    Pasadena, CA
    Well since both of your cabs are 8 ohm if you run them stereo you will get 200 watts per cab. If you run them parallel in mono mode (showing the amp a 4 ohm load) you can bridge your amp and run 1200 watts at 4 ohm. Personally I would run bridged, more headroom etc. but ymmv.
    Good to see another michigander on here.
     
  3. Carl Brusky

    Carl Brusky

    Sep 21, 2000
    I had a 1.2.

    I ran mine bridged at 1200 watts.

    I had an external fan blowing air over the thing to cool it.

    It went into thermal shutdown at a gig once and I sold it.

    DO NOT RUN THIS AMP AT 4 OHMS BRIDGED, AND PUSH IT, AS IT WILL SHUT DOWN.
     
  4. adouglas

    adouglas

    Jun 23, 2003
    Bridgeport, CT
    How was your Stewart mounted? I assume it was in a rack... did you have an empty space below it? Above it? Both?

    I've read the various postings about thermal shutdown on these amps, and while people often say they've got a fan blowing on it they DON'T say if they've given the amp any air space.

    I just bought one of these, and since I'm not in a loud band I do not anticipate thermal problems. Nevertheless I mounted it in a rack with an empty space below (the amp gets really hot on the bottom) and above the fins on top (I have a half-rack-space compressor that sits on top of the center of the Stewart where it doesn't get hot).

    This should maximize air flow, at least in theory.
     
  5. adouglas

    adouglas

    Jun 23, 2003
    Bridgeport, CT
    BTW, the amp doesn't say on the back which of the red binding posts should be the + when bridging, so I asked Stewart. It's the Ch. 1 post.
     
  6. ZonPlyr

    ZonPlyr

    Apr 29, 2003
    Pasadena, CA
    I've got a 1.2 also and have it mounted in a rack case. I have space above and below and blow a fan on it whenever it's on. I played two outdoor gigs and one indoor gig this weekend, outdoors it was 80+ degrees with high humidity and not much air movement. Inside was like an oven also on a cramped stage. Never heard a hiccup out of the the amp and had to run it pretty hard at times. So far I love it but i'm wondering if i'm tempting fate by not having an internal cooling mechanism.
     
  7. knight

    knight

    Nov 3, 2002
    Thanks for the replies guys, but my question is a bit more specific. Let me try to clarify: I have two cabs, 8 ohm each, each with a speakon and jack input. How can I physically connect them, given the amp's output connectors? what will be the ohm load for the amp, and the power available to each cab? will I be able to run them in stereo (350W each)? 700W is more than enough for me, so I don't think I'll be driving it too hard.

    Thanks!!!
     
  8. ZonPlyr

    ZonPlyr

    Apr 29, 2003
    Pasadena, CA
    Ok, maybe this will be a bit more specific. If you run the cabs parallel, ie run a line from the output of the amp to one of the cabinets, use the other jack on the cabinet to run to the second cabinet you will be showing the amp a 4 ohm load. 2 8 ohm cabinets in parallel is 4 ohms. This will be mono mode. If you run channel 1 to 1 cabinet and channel 2 to another cabinet you will be running stereo at 8 ohms, thereby giving each cabinet 200 watts.
    Now, if you bridge the amp (ie combining both channels into 1) and run in the parallel configuration above you will be able to put out 1200 watts at 4 ohms.
    Hope that helps.
     
  9. knight

    knight

    Nov 3, 2002
    Yes it does! Thanks, this is what I was looking for.

    Cheers,

    knight
     
  10. Carl Brusky

    Carl Brusky

    Sep 21, 2000
    Yes I had an open space below it with a fan blowing in from the back. The bottom is the aera that gets really hot.

    I sold it and bought a QSC PLX 1202 and run that bridged without issue. I figured if I had to leave an open space anyway, why not get a 2 space amp that can handle the abuse. QSC has handled everything.
     
  11. I have a 1.2 and two World 600s, and they have been relegated to light duty, non-bridge audio use.

    Avoid bridge mono and low voltage situations, even with open rack space and a fan.

    Every time they have let me down (3), it was at a particularly bad time. They are even more prone to shut down in PA applications than in bass.

    The larger 1.6 and 2.1s are much more dependable, though I prefer the QSC PLXs, which are buletproof.

    Aloha,

    Jonathan
     
  12. Jerry J

    Jerry J Supporting Member

    Mar 27, 2000
    P-town, OR
    Sorry to drag the thread off a bit, but...

    Jonathan, did you find that there was an actual difference in tone between the Stew 1.2 and the PLX?

    I've got lots of experience with the PLX's but I've not had a chance to fool around with any of the Stewarts.
     
  13. I can't tell any differece between the Stewarts and the QSCs in tone. If it's there, it's too subtle for my aging ears.

    Aloha,

    Jonathan
     
  14. Jerry J

    Jerry J Supporting Member

    Mar 27, 2000
    P-town, OR
    Thanks, Jonathan. I've been very happy with my PLX's. Never had a blip or burp, at all.

    Maybe one day I'll run across a Stewart but I doubt that I would be able to discern a difference either.

    Now back to the regularly scheduled thread. :)
     
  15. Never had a QSC problem, either. They are great.

    I just had my veteran Stewart World 2.1 apart twice yesterday. I used it last week for a small PA at a friend's Gallery opening, and halfway through one channel made a huge, ugly scratch noise and then went dead. We finished the event on the other channel.

    I found when I wiggled the banana jack for the affected channel, it comes back, goes away or emits horrible sounds. Inside there are lots of slip on type connectors, which are getting loose and dirty, and the harness is webbed so most of them are physically connected and under tension. I cleaned and tightened all I could find, but it still drops out when I bump the binding post hard.

    Aloha,

    Jonathan
     
  16. adouglas

    adouglas

    Jun 23, 2003
    Bridgeport, CT
    ...it sounds like the Stewarts sound just fine, but IF you're subjecting them to heavy gig use they'll pack it in.

    Is this a fair assessment of your experience?

    My usage is not as rigorous as yours and I bought the Stewart because it's got a pretty good rep for tone quality and because it's very light in terms of weight. I don't think I've scewed myself here, but I want to put the issue to bed...someday I might sell it, and I don' t want some search engine to queer the deal, yaknowhadimsayin?
     
  17. jobu3

    jobu3 Artist formerly known as Big Joe

    Feb 17, 2002
    Mountain Top, PA
    i thought about doing up a stewie mini-rig with rack bag and a 112 of some sort but i got scared off by all the stories of thermal shut-down and whatnot. why make it 1 RU if you need to surround it with open spots? a PLX may cost a bit more but you get that peace of mind AND light weight to boot. :spit:
     
  18. bben

    bben

    Feb 28, 2002
    Santa Fe, NM
    I sold my QSCPLX1602 and replaced it with a Stewart 1.2 about a year ago. The QSC was a nice amp but the Stewart sounded better to me; not a big difference but a bit rounder and fuller.

    The main reason I switched, though, was the loud fan on the QSC - I needed something quieter. I have my 1.2 in a three space rack bag with an Avalon U5 centered above it, so there is all sorts of air space above the heat sink fins. Haven't had any overheating problems, but I just use it to drive a pair of 1x12 cabs.

    I always run it bridged. I have two cables with banana plugs on one end and Speakons on the other. I plug both cables piggy-back into the 1.2. Amp manufacturers (including Stewart) generally recommend multiple connections to the amp rather than a jumper from one cab to another.
     
  19. lamarjones

    lamarjones Supporting Member

    Aug 27, 2002
    Raleigh, NC
    For some reason, I thought that running from the amp into one cab, and then running from that cab into another cab was a series connection. I guess I am off on that? I got to do the same with an sm 900, and I got a banana into a 1/4", which I will run into one cab and that cab into another. They are both 8 ohms, so hopefully it will be a 4 ohm load. I thought it was gonna be 16.
     
  20. adouglas

    adouglas

    Jun 23, 2003
    Bridgeport, CT
    Depends on how the jacks are wired. You CAN get it to be 16 ohms, but AFAIK most if not all cabinets with more than one jack have them wired in parallel. It's the standard way of doing things.