1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  
     
    TalkBass.com has been uniting the low end since 1998.  Join us! :)

Ampeg BA-115 power transformer, HELP needed!

Discussion in 'Amps and Cabs [BG]' started by Giacomo79, Dec 3, 2017.


  1. Giacomo79

    Giacomo79

    Dec 3, 2017
    Seattle, WA
    Hi,
    I'm trying to find a replacement part of my bass amp Ampeg Ba-115.
    The original is an SLME 94-291-01
    Can you help me to find the specs of this transformer?
    I would like to know especially the secondary output voltage, to find a possible replacement online without spending a lot of money.
    The schematic report a 100VAC 50/60Hz with a 2A thermal fuse for USA models I think, I suppose the voltage out of the secondary, should be +40 and -40 Volt I suppose, 40 VAC.
    Thank a lot for your help!
     
  2. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    I’ve got to ask: why do you think your PT needs to be replaced?

    Oh and welcome to Talk Bass. :D
     
    Two-Spirit and agedhorse like this.
  3. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Maybe because he's trying to use a Japanese 100V model on 120V US power and had an "accident"?
     
    tubestuff and JimmyM like this.
  4. Giacomo79

    Giacomo79

    Dec 3, 2017
    Seattle, WA
    Hi Paul,
    Nice to meet u!
    To answer your question: there is not secondary output voltage when the primary of the transformer is powered on by the board or AC. I also replaced the thermal fuse of the transformer but the result is still the same. I also checked the amp board with the multimeter applying a voltage to the circuit with an external power supply. When the power line from the transformer is bypassed everything is fine and I have voltages coming out from speaker connection.
     
  5. Giacomo79

    Giacomo79

    Dec 3, 2017
    Seattle, WA
    The amp is a USA model and not Japanese, it worked with 120 AC volt US.
    As for the service manual: The Power requirement is 100-120 VAC 50/60Hz, 50W.
    I'm just trying to find:
    1- the specs of the original transformer SLME 94-291-01, especially the secondary voltages.
    2- The VA of this model (70 I suppose but I'm not sure)
    3- I cannot find a replacement online, neither the original. I would like to try with mouser/digikey, but I need some help to find a replacement then could fit in the amp and be a good choice instead of the original.
    4- I also know that some Create bass amp could share the same transformer, but I do not know which models.
     
  6. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    I suggest you contact Ampeg customer support for a replacement if you have satisfied your mind that the original is open circuit.
     
  7. Is there a reason that you are trying to source a replacement that is not Ampeg OEM?
    I'm pretty sure the folks at Ampeg would help you either with a replacement, or the info you want.

    Welcome to TB also.
    BTW, if you list your location it might be helpful for folks offering advice.
     
  8. Giacomo79

    Giacomo79

    Dec 3, 2017
    Seattle, WA
    I'm living in Seattle, WA
     
  9. Giacomo79

    Giacomo79

    Dec 3, 2017
    Seattle, WA
    I'm trying to search for a replacement since online I don't know where to find the original. I contacted the suppliers in Seattle that are suggested by the Ampeg support webpage. They suggest me to look into another website where I didn't find the original transformer for BA-115.
     
  10. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    Best to call Ampeg yourself I think. And I also welcome you here!
     
    Old Garage-Bander likes this.
  11. Hello Seattle! :hyper:
     
  12. Check an outfit called Full Compass.
    They carry a lot of other OEM replacement parts for other amp companies.
    Don't know about Ampeg, but worth a try.

    Also, another check of your transformer...
    Completely disconnect all leads and check primary and secondaries for continuity.
    This would tell you if a winding is open. If no open windings but no voltage at the secondaries, there may be a problem elsewhere and not with the transformer. It would be a pretty expensive proposition to buy a new transformer only to find out that wasn't the problem.
     
    agedhorse likes this.
  13. InhumanResource

    InhumanResource

    Dec 28, 2012
    Not for anything, but these things are under $200 used...
     
    vin*tone and Old Garage-Bander like this.
  14. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    From what you have posted, which is full of errors, I'm going to suggest that you get some professional help from somebody familiar with this specific transformer (which is similar to a few other Ampeg transformers for amps of this style).

    The factory transformer is not 100V for the USA market (they use a universal primary transformer that is differently wired than most applications), the 100V wiring is strictly for Japan, the fuse for domestic & Japan is not 2A, etc.

    If you have the service manual and understand it, the data is there but you will have to do the calculations backwards to find out.
     
  15. BogeyBass

    BogeyBass

    Sep 14, 2010
    yeah crate BXR100 uses same transformer and mercury magnetics has a replacement CRT-BX100-P unfortunately its a 175 $ part

    search shows a Kustom KXB100 amp uses same part number. think that amp is still in production.

    Schematic shows 40 volt +- rail on the amplifier, with 2.5amp norm blo fuse on the AC

    so what we talking here with 110/120 volts 190 to 270 ish volt amps or plain jain 250 VA.

    with a 30-0-30 volt transformer id expect usual 40/44 volts after bridge depending on transformer VA
     
  16. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Except that this is incorrect according to the Anpeg docs I have.

    The OP really needs to find the correct part. Since this is a safety related part that's located across the primary supply. And because the primary winding is not standard nor typical, I will not attempt to lead the OP down a path that may put him and others in a dangerous situation.
     
    Last edited: Dec 4, 2017
  17. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Check this out.

    94-291-40

    The part is readily available in the US. The web site says that you can use the -40 in the BA115. Call ampeg customer service and ask about using it in your amp just to be sure.
     
  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    This transformer will work but you MUST contact them about the correct 120V connection which is not shown. Do NOT use the 100V connection.
     
  19. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    I should mention that texting short cuts are frowned upon here. :)
     
    Two-Spirit likes this.
  20. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    As suggested, contact Ampeg customer service, ask for a power transformer primary wiring diagram for the -40 transformer to verify. Also ask what fuse you should use.
     
    Last edited: Dec 4, 2017

Share This Page