Ashdown MiniRig transformer

Discussion in 'Amps and Cabs [BG]' started by a-1wave, Jul 31, 2009.

  1. a-1wave


    Jan 2, 2007
    So a couple of weeks ago I turned my amp on and the fuse blew. I went to Radio Shack and got the proper replacement fuse and put it in and turned the amp on. Instant blown fuse. My dad cracked it open and has determined that the transformer is shot.
    The transformer has a 120v input rating and a 31v output rating. How would I go about replacing it? Does it have to have the same output rating? Also, I have found sites that list different types of transformers like "power" and "output" which kind do I need?
    I'm not looking to spend a bunch to repair this amp, but if it's reasonable, I would like to get it working again.
  2. bongomania

    bongomania Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Without actually seeing it, I'm going to guess that it's probably a power transformer, not an output xfo. Generally these days only all-tube amps have output xfo's. Whereas almost all amps have power xfo's.

    You just need to find one that has the exact same values as the blown one, and make sure you solder the connections on the new one identically to the old one. Take a picture, write down lots of notes, tape labels on all the wires, do whatever you have to do to get it right.

    Also, be aware that you are courting death. It is very easy to get shocked badly, even fatally, by charge stored up in certain power supply components long after the unit has been unplugged.
  3. Hi.

    +1 for everything Bongomania said, especially the part about courting with death. Not kidding either.

    First of all, transformers seldom just blow without any apparent reason.

    Secondly, linked directly with the first, it's more than likely that You'll end up with yet another blown transformer if You just replace the old one without diagnosing the rest of the circuit first.

    You'll get the VA rating of the transformer You'll need from the amperage/VA rating on the back panel or by doubling the output wattage of the amp. The voltage can probably vary a bit, ~ +/- 2V IMLE.

    As the 31V is a "standard" IIRC, why not get the exact one? From Ashdown even?

    The amp isn't under warranty anymore, is it?

  4. BassmanPaul

    BassmanPaul Inactive

    I think it's highly unlikely that the power transformer has gone. Much more likely the output stage of the amp has blown shorting the supplies. Take the amp to a tech and get it checked out. Do not add more fuses - you could well make a bad situation worse.

  5. a-1wave


    Jan 2, 2007
    Thanks for the input fellas! I think getting it checked out is going to have to wait though, life's a little too hectic right now.
  6. rpsands


    Jul 6, 2007
    I'm gonna say: Time to get a new amp :) Probably gonna cost you more in time and effort than buying a used craigslist amp to replace it would.