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SWR SM500 getting extremely hot !!!

Discussion in 'Amps and Cabs [BG]' started by jarrod cunningham, Apr 16, 2009.


  1. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    in bridge mode on a 8x8 henry , my amp is getting scorching hot . the fan is on , there is a blank space above the head , plenty of ventilation ... is anyone else having this prob ? the sound isnt changed and i notice no problems but its hotter than any other amp ive ever owned . do i need a extra fan ? or replace the top lid with a piece of expanded metal ?
     
  2. chadds

    chadds

    Mar 18, 2000
    Is this amp new to you? How long have you had it?
    If it's new to you yes they get quite hot. I had two SM-400 that I gigged with for ten years even in direct sun. Never a failure. Once I dropped one in a case and the same one had a loose AC pwr connection about a month later. Never a failure due to heat as they were designed to have the chassis act as a heat sink. Your amp may need a bias though.
    Nice combination the Henry and an SM!:bassist:
     
  3. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    yeah the tone and punch is incredible !!!! im lovin my tone . yeah it is fairly new . i would guess a year or so old . i just got it last week . how can i tell if it needs a bias ?
     
  4. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    South Shore MA
    How long have you been running the head? Your bias might be due for an adjustment.

    Doh! chadds beat me to it!
     
  5. There's really no good way to tell unless you are a tech, sorry. But in general, if the bias is off, it'll get hot just sitting turned on doing nothing, in a half hour/hour or so. If the fan ever comes on while it's idle like that, it almost certainly needs adjusting.
     
  6. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    well it needs it cus the fan does come on at idle . now to find someone who can handle that adjustment .....
     
  7. Steve

    Steve

    Aug 10, 2001
    It's an aluminum chassis amp. The owners manual will tell you they can get hot as hell especially in bridged mode.
     
  8. KJung

    KJung Supporting Member

    +1 That's what SWR heads like the 500 and 900 do. As much as I knew they were 'supposed to do that', it never felt quite right to me.

    But yes, bridging into 8ohms (much less 4ohms) results in those amps running so hot so that you literally can't touch them.

    Therefore, to the OP, nothing to really worry about.
     
  9. pickles

    pickles Gold Supporting Member

    Mar 23, 2000
    Ventura, CA
    Many of us have done hundreds of gigs each at the end of which an SM-400 or 500 was hot enough to fry an egg, and it doesn't really seem to bother them at all. Mine only let me down once, and that was just a blown fuse, nothing to do with the heat.
     
  10. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Take the lid off and vacuum out any dirt and dust in the cooling system. Make sure that the vents are clear and open to the air. Do not replace the cover with a ventilated panel. You need a specific air flow path to keep the amp cool. In bridge mode the amp is working flat out and will get hot but nowhere near as hot as you describe..

    Paul
     
  11. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    a lot of different opinions here ....
     
  12. DanRJBrasil

    DanRJBrasil

    Jun 10, 2007
    are this unit racked?
     
  13. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    yep its racked
    with a blank space above it and planty of ventilation
     
  14. Steve

    Steve

    Aug 10, 2001
    I have an SM500 that I use bridged with a 4 ohm Berg 322.

    That thing at the end of a night is so hot that touching the end of the patch cord is a real "note to self:" moment as in, ok, let's not ever do that again.

    I've never had a problem with mine and it get's a lot of gig time.

    It is fairly unnerving I will agree. Just don't ask youself, "If the amp is that hot, I wonder how hot the cord end is?"

    if the fan is working and the vents are not obstructed you should be ok
     
  15. My 550x manual says to leave a rack space between the top of the head and any other components or the top of the rack. The aluminum chasis is supposed to draw heat away from the internal components. It struck me as strange too.
     
  16. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    yeah i have a blank 1 space panel above the amp . so it is free of obstuction . maybe i should try removing the blank panel ?
     
  17. jjk2007

    jjk2007

    Apr 16, 2008
    Austin, TX
    Yeah, I had an SM-900 going bridged (sometimes) into a pair of goliath III cabs. That thing would get so hot I would swear it was going to blow up or something. I always thought something was wrong with it but then found out that for those amps that is "normal".
     
  18. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    cool makes me feel better that the general consensus is that its the normal for my amp . ill take it in to a shop and get the bias looked at anyway ! many thanks to all of my tb friends !
     
  19. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    You should not put a blank panel above the amp. You want air to be able to flow around the chassis. Replace it with a perforated vent panel.

    Paul
     
  20. jarrod cunningham

    jarrod cunningham

    Apr 24, 2007
    sylacauga alabama
    spector basses
    yeah i need to do that . thanks paul ! ill get one on order . i also thought about installing a 1 space rack fan . will this help or hurt the internal fan ?
     

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