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SWR SM-400 'sploded! Help!

Discussion in 'Amps and Cabs [BG]' started by Stevious G, Sep 11, 2004.

  1. Stevious G

    Stevious G

    May 5, 2003
    I recently pick'd up a used SWR SM-400 head at my local. Brought it oot to jam TWICE, and the darn thing frig'd oot on me.

    FYI, I am running the aforemention'd head, bridge'd to 400w, into a Peavy 4x10 cab. There is no power rating on the cab, but it seems pretty robust.

    The first time it happend, I was playing at a high, but by no means crank'd volume, when the amp just stop'd making any noise. No loud bang or pop. Just silence. Not even white noise from the cab. It was still clearly power'd on, however.
    I DID try testing it by touching the core of my cable, and multiple other cables that I tried in both inputs. Nothing. No response. I cross-check'd the cab by plugging the amp into a buddie's cab with a different cable. Nothing. The amp was definately the souce of the problem

    SO, a couple of days later, I broke'er oot again, thinking that MAYBE it just overheated, (the thing gets realllll toasty.)
    It werked for aboot 10 seconds. Then, THIS time I heard a quiet pop sound, (although the amp was turn'd down really low to begin with,) and the two LEDs, (compresser and peak clip limiter, I think,) both lit up steady. I don't THINK it did THAT the first time. However, like the time before, it was dead. Havn't tried it again since.

    Now, apperiantly it had just been re-tube'd before I bought it, (it's a hybrid, with one preamp tube. The rest is all solid-state.) And I'm pretty amptarded, so I don'even know if this could be a tube related issue.
    I also know perfectly well that it's probably gonna be making a trip to the shop. However, I'd like to have SOME idea of what happend.

    Here's the owner's manual, if that helps anyone at all...

    Thanks for anything that any of you can do.
  2. Bummer mate :(

    I've got the SM-400S variant, and it's never showed any signs of stopping (its '89 vintage). Best bet is to take it to a decent amp repair mob.
  3. Not to be an ass or anything but the way you type is pretty annoying, anyway try buying a new preamp tube. Most preamp tubes are cheap like 10-20 dollars for an alright one. If its not the preamp tube check all the connections to make sure none of them are loose or broken and if that doesn't turn up anything take it to a shop.
  4. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    South Shore MA
    Sounds like a problem with the power section, not the pre.

    On the back of the amp, see which, if any, of the fuses are blown.

    Does the Peavey cab check out ok with another head?
  5. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    whaat th' bloody'ell ya' talkin' aboot josh? :p
  6. KeithPas


    May 16, 2000
    This could be a heat related problem as well. The early versions of the SM400 had heat related problems which were solved by the addition of the cooling fan. Do you hear your fan working when you have been playing for awhile? (It is actually pretty loud so you would not be able to miss it). If you do not hear your fan after playing for a little while that would not be good and the amp can be shutting down in order to prevent burning up.
  7. KeithPas


    May 16, 2000
    I have really pushed my SM400s hard and I never have had any problems. If the head was a model manufactures without a fan (I'm not certain this was ever the case.) or if the fan is not working properly you might have some issues. Even though I have not experienced problems with my SM400s I will tell you that it gets HOT!!