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.

  • @Aliendelarge
    2•1 year ago

    Not seeing a lot of specs for those products on line but I suspect you may need the preamp, which is not the same as the transformer. Are you certain the mic in is a TRS jack? It seems like the kind of product that may only have a don’t see any specifics about the mic preamp on the Aroma amp, which makes me suspicious. How did you hook the zoom recorder to the amp input? Was it a line out? If so and that configuration worked, I’d say that further points toward the preamp.

    I might need a Mic Impedance Transformer to get ‘power’/volume to the dynamic mic.

    Just erase that detail, its wrong one way pr another and windmills do not work that way.

    • SarsaparillaOP
      1•1 year ago

      The mic-in on the amp is a TS jack (most likely), but my cord is a TRS … shouldn’t matter though? Yes, I used the line-out on my Zoom, with a 3.5mm TRS to 6.35mm TRS adapter.

      The Aroma website provides little to no info on the amp, but here is a local music store that has some specs. And this is the mic - https://www.behringer.com/product.html?modelCode=P0E7P

      Here are the apparent specs of the input jacks on the amp

      • Channel 1 Input socket: 6.35mm jack Input impedance: 10Kohm EQ: Bass, Treble, Volume
      • Channel 2 Input socket: 6.35mm jack Input impedance: 1Kohm EQ: Volume, Echo
      • @Aliendelarge
        2•1 year ago

        If the amp is a TS input, it is unbalanced and needs a XLR to TS cable. It does matter going from balanced to unbalanced signal. Double check me on that though with. Multimeter or pinout diagram or something.

        • SarsaparillaOP
          2•1 year ago

          Hi and thanks for the advice! You are correct that:

          It does matter going from balanced to unbalanced signal.

          A standard mic cable has done the trick and I’ve been practicing all evening. Much appreciation for the help! 😎

        • SarsaparillaOP
          1•1 year ago

          It does matter going from balanced to unbalanced signal.

          That’s fair. I’m going to get a standard XLR-TS mic cable tomorrow and try that out. 🤞