Re: Amp kicks out on Mic ONLY with 8 ohm to 70 V Xfmr on Amp output
Bill,
I get the impression that this is a case where you'd rather invest effort than money. If you have an unused lo-Z to hi-Z transfromer sitting around, you could try putting it between the wireless receiver's output and one of the Sherwood's aux inputs, in place of the phone preamp.
Most of the ones I've seen have a turns ratio between 6:1 and 10:1, which would give your mic signal a voltage increase of 15 to 20 dB, without the monstrous RIAA bass boost. I suspect you could then use the output pot on the wireless receiver to set a usable level.
I almost hate to admit it, but I have done such a thing using a 25-volt speaker transformer (!) for an after-hour emergency repair to a school stadium system. 1/4" hi-Z mic connector was wire-nutted to the 8-ohm winding, and the 1W/25V winding was wire-nutted to amp's aux input. I needed to bring a 30 mV signal up to 300 mV. When it's used as intended, the transformer steps the 25V line down to 2.83V, so I was pretty close to 10:1. I knew it wasn't ideal, but it got us through the game. (And the transformer introduced MUCH less distortion than I ever would have imagined!)
Hope you find a comfortable solution!
Best Regards,
Jim Thorn
