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AC plug in adapter question for Boss ME50B

Discussion in 'Effects [BG]' started by vicenzajay, Jan 14, 2005.

  1. O.K.

    I've spent several hours reading the ME50 threads, so I hope I'm not rehashing an old subject - I've enjoyed my ME50B quite a lot; however, I'm extremely tired of buying batteries. I've tried two AC adapters - the first one induced a serious hum into the system (then I actually read the fine print and found out it wasn't a "regulated" power supply).

    Now I have a regulated adapter - the hum is gone, however, the unit is noticeably more noisy through the amp than when it is powered with batteries alone.

    Any suggestions? The first thing that comes to mind is that it could be a grounding problem (the adapter is not of the three-pronged variety).

    Appreciate any help.

  2. On your manual, you should have power supply requirements, so you need to make sure the adaptor matches that...not just the voltage, but the current as well, generally in milliamps. Also make sure that you have the polarity right on the plug. There's a little diagram printed on the adaptor showing which part of the barrel is positive or negative.
  3. Thanks,

    They are correct - I've been using the manual to select the adapters - the unit needs 9volts DC and 140 milliamps - as I understand electricity, the unit will pull only the milliamperage that it needs, so as long as the adapter supplies 140 or more milliamps I'm fine. The only regulated power supplies at Radio Shack, etc. typically provide up to 1200 or so milliamps

    Let me know if I'm screwed up on this. We had to test out the polarity - the pin is negative in this case.

  4. Everything sounds right...is your adaptor cord crossing over any other power cords or your signal cords? Do you have any televisions/computer screens/flourescent lights on? Sounds like some sort of interference there.
  5. The answer is yes to the flourescent lights...would this cause a difference between the battery-powered sound and the A/C adaptor powered sound?

  6. I hook up my pedals with an adaptor in a garage with flourescents, and when I turn the lights on or off there's a little 'pop', so I think it the interference is either traveling through the electrical circuit of the house or some crazy electrical field in the air. Batteries don't have the interference problems.

    Most venues and rehearsal spaces (or intumescent lighted spaces) have better circuitry. Most.
  7. Thanks - I'm actually going to shield the actual adaptor and wire next rehearsal.

    Last question - would the proprietary adaptor fix this issue...I'm trying to see if maybe BOSS designed the unit to need a grounded (three-pronged) adaptor. I don't know anything about their power supply.

    Another thought - anyone have any luck with rechargeable batteries? Any suggestions?

  8. wyliee


    Jul 6, 2003
    South Hill, WA
    FWIW, I use a OneSpot with my ME50B and have never had noise problems. That includes playing in my garage with my cheap shop lights, in a school library and theater. Granted, it isn't the cheapest power supply around.

    You might want to try something other than a Radio Shack power supply. There are several out there.
  9. atldeadhead


    Jun 17, 2002
    Have you tried the actual BOSS adapter? I'll attach a close-up photo of the BOSS PSA adapter I have. You could try to get something with the same specs if'n you don't wanna shell out the money for the Boss adapter.

    Attached Files:

  10. Robman


    Mar 19, 2004
    Sherman, Texas
    You can get the Boss Adapter at GC or Musician's Friend...
    for around $18 + s&h... :)
    Jazzcaster89 likes this.
  11. altdeadhead,

    Great idea - but music123, etc. tell me that the PSA120 is not the adaptor for the ME50B. Didn't make sense to me as the voltage and milliamperage are correct.

    Do you use yours for the ME-50B? If so, is the plug a grounded one (three-pronged)...just trying to eliminate all the variables.

    Thanks again for the help.

  12. Just talked to BOSS/Roland and they confirmed that the PSA-120T is the adapter for the ME-50B.

    So....so much for music123 and another site's (don't remember which) advice on the issue.

    I also looked up the OneSpot - seems like an even better value given the fact that it is 100-240 volts (I've lived in Europe and may go back).

    So my course of action right now is this:

    - have the control cavity in my bass reshielded (17 years old)

    - try it out

    - Shield the current power supply I'm using

    - try it out

    - Return the power supply and buy a OneSpot

    - try it out

    - go with rechargeables

    Sounds like fun!!!

    Thanks again for all the help...

  13. Got my setup guy (Dave) to reshield the control cavity - tried the bass out again with the board at his store - no noise whatsoever (with my adapter).

    So...during practice this weekend, the noise was there (but still present from time to time). As a result, I've concluded it has to do with the flourescent lights/electricity/etc. in our rehearsal garage.

    Thanks to all for the help.

    OBTW - This pedal has a wicked delay - I like the 400-1300 ms one...lots of fun and useful as well.