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Eden WT550 Kaput from Generator Power?

Discussion in 'Amps and Cabs [BG]' started by slap_happy, Oct 12, 2019.


  1. A little diagnostic help needed if anyone has ideas.

    My WT550 is dead after being plugged into a generator at an outdoor stage at a gig earlier today. The EQ clip light is fully on whenever the amp is powered, and no output through speaker out, headphones, or DI. It never actually worked, just went into this state immediately when I turned it on. It was plugged into a power strip, which was plugged into the generator. No noise from the cabinet, and no smoke or electronics smell (that I could tell outside). I do hear the normal quiet thud from the cabinet when the amp is powered down, which suggests the power section is okay?

    I'm aware audio equipment doesn't like generators, especially small ones, but I've read this would more likely blow a fuse than blow something in the amp's circuitry. I've checked the fuse (looks okay) and swapped it just in case with no improvement (I found it odd that the amp powered up, with no output, but with no EQ clip light on, when the fuse was not installed?).

    I had this amp in the shop recently for a similar no output / clip lights on issue but that was after I accidentally kicked the speakon connection at the cab and there was a pop, smoke, and and smell from the head. I'd rather not part with another ~$350 bucks, hopefully there's a simpler, easier fix to this. Any ideas?

    Thanks.
     
  2. Wasnex

    Wasnex

    Dec 25, 2011
    If the power amp section is working, there should be a bit of hum and hiss that is noticeable through a tweeter or possibly even a woofer if you put your ear right next to it.

    To the right of the Gain control are two LEDs. The bottom LED is the "Set Level Indicator" and it lights up as you turn up the gain. It should be set so LED lights on your loudest notes. The top LED indicates the compressor is active. If neither of these LEDs will light, it could indicate a problem with the tube. It's possible the tube simply needs to be reseated, or it may need to be replaced.

    On the right side of the amp there are two more LEDs. To the left of the Master is the EQ clip. This should only light if you are overdriving the EQ. To the right of the Master is the Output Limit LED. The manual says: "Illuminates when the power section experiences undesirable operation and the inbuilt protection circuit is active."

    If you are not a technician, you can check the tube. If that doesn't fix it, take it back to the tech or replace it. If the amp has a fault, turning it on, may cause more damage.

    I checked schematics that I found online, and AFAIK there are no additional internal fuses. I reviewed the Zipped schematics in this post Eden WT550 need schematic
     
  3. gyancey

    gyancey Supporting Member

    Mar 25, 2002
    Austin, TX
    The EQ clip light and output clip light both have their cathode hooked to the -15V rail and could light up if the rail goes more negative than that. I suspect the something in the +-15V supply section. They didn't use simple 7815/7915 regulators like most would, but instead opted for something more complex involving a lot of discrete transistors and zener diodes, which I find are prone to dying. If one of the rails did go off the rail (hah) you might have to replace all the opamps, as TL072s are only rated for +-15V. They are cheap though (less than $1 each, and I think there are 6 or 7 of them total) and socketed so easy to replace. And if your tech does charge $350 either find a new tech or just buy a replacement WT550 as I've seen them for that used.
     
    Wasnex likes this.

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