SWR Stereo 800 Running Hot

Discussion in 'Amps and Cabs [BG]' started by Soulbanana, Jul 14, 2005.

  1. Soulbanana


    May 7, 2004
    Hi there,
    I have a Stereo 800 power amp and it's always run a little hot. Anybody else with the same experience, and is this normal?

    I'm running it pretty loud, bridged mono but the red lights only come on occasionally. The fan doesn't always come on as well. I understand it's thermostatically controlled but is there a way of visually checking the thermostat when I open it up?

    Will running it stereo into 2 cabs put less strain on the amp compared to running the 2 8ohm cabs paralleled in bridge mode?

    Lastly, I assume this amp puts out 800watts @4ohms bridged. What would it's output be in stereo and bridged modes, at 8ohms?

  2. I think it's normal. I had a 900 that got so hot you couldn't touch it! I think SWR uses their external cabs and the actual 'heat sink'. They do get hot. It always concerned me though... I never had a problem with the reliability of my 900 over the couple years that I used it... but have heard others having problems. There's lot's of SWR threads that mention the 'hot' issue if you do a search.
  3. SWR themselves say that the case is used as a heatsink

    have a look at their website for reassurance!
  4. Funkengrooven

    Funkengrooven Turn it down? You gotta be nuts!!

    I have Three SWR's of various types and they ALL run hotter than I think they should.
    However the reason for this is based on the transistors they use as outputs. Without getting too technical their transistor configuration uses less transistors than a bunch of others and uses them more efficiently (apparently) and runs them harder (also apparently) than other manufacturers.
    The 120/160 Watt SWR Basic Black uses only TWO output transistors. The loudest two transistors I have ever heard.

    The spec on the transistor says it will toast when the JUNCTION temp is over 150 Deg F.
    That means if your cabinet is at 130F, where you can't really hold your hand on it, the transistors are probably fine.
    So don't worry and put your mid-gig snack on the amp to warm up during the first two sets.
  5. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    yup, swr amps run hot. I've never had one fail though.

    FWIW, running stereo into 8 ohms will give you 220 watts per side.
  6. Fred312b

    Fred312b What if I want to play jazz precisely? Supporting Member

    Apr 23, 2002
    Chicago, IL
    make sure you give it enough ventilation and you'll be fine :bassist:
  7. secretdonkey


    Oct 9, 2002
    Austin, TX
  8. Soulbanana


    May 7, 2004
    Many thanks everybody. This has put my mind a bit more at ease, but I have installed a desktop fan in my roadcase for peace of mind.

    One last thing. When my preamp and power amp are out of their roadcase and running, I don't get a low-pitched, low-volume hum that only appears when I'm using my roadcase. I've tried faffing around with the ground lift buttons on both, to no avail.

    Is this what those "Humphree" tabs are for, and is there a cheaper way of isolating the units, maybe coating the rack ears with electrical tape or something?