Hi There! I am a beginner to amplifiers and I purchased an Aroma AG-15a for busking, which has separate guitar and mic inputs. I purchased a dynamic stage mic (Behringer BA 85a) and an XLR to 1/4inch stereo TRS cord, but there is no sound when plugged in, even with both volume knobs on the amp turn up to full. I tested the dynamic mic on a different guitar amp (no mic input) and it worked, so the mic is not faulty.

I rigged up a connection to the problem amp with a battery powered Zoom H1N recording mic, and it worked, but this is obviously not the mic I want to use for performing. Everything I read says a dynamic mic is plug and play in this situation. I am finding it impossible to find information anywhere about whether there is something wrong with the amp, if I need a different mic, or I’m doing something else wrong.

So having watched a few videos, I discover that I might need a Mic Impedance Transformer to get ‘power’/volume to the dynamic mic. Is a Mic Impedance Transformer a type of Mic Pre-amp?

Should I buy a Mic Impedance Transformer or a Mic Pre-amp??

P.S. I made a connection via a Hum Eliminator, and actually heard the mic thru the amp for the first time, but it is still very soft.

How do I solve my problem?

PLEASE HELP!! I’m tearing my hair out!

Thanks in advance for your expertise in this.

  • AxisentialEnglish
    3·
    8 months ago

    Definitely something going on that doesn’t make sense here - input impedance of the mic input for that amp appears to be 1k, with the mic at 300ohm. Yes it’s mismatched, but not enough to cause zero signal.

    I’m guessing cable - can you borrow a standard xlr and try an adaptor, or get another xlrl to 1/4”?

    • Sarsaparilla@aussie.zoneOP
      2·
      8 months ago

      Thank you for the advice and for pointing out the input impedance of both the mic and mic input on the amp … I have better understanding of that now. Your guess was correct in that it was the cable … a standard XLR to TS jack did the trick! 😊

    • Sarsaparilla@aussie.zoneOP
      1·
      8 months ago

      Ok so impedance does not seem to be the issue, then. I’m gonna have to buy a xlr-ts mic cable or adapter tomorrow. Strangely, with all my cords and adapters, I don’t have THAT one, of course! Plenty of XLRs, just nothing to convert to the TS jack! Hopefully tomorrow, Aroma or the seller can get back to me with some idea, as well.