>Having jammed with some bands in the past few years I have lately come >across a problem when i either use my Shure Microphone or Astatic through >the PA. The Mics do not respond and there is no sound and I end up using one >of the band Mics and for health reasons I do not like doing this as you have >had lots of people singing into these Mics. I have tried putting my Shure >Mic on the bands lead but this does not work. Do PA's have a high and low >Impedance switch and is this the reason my Mic and lead are not compatabile. >I have just checked both Mic's and my lead on my Peavey Classisc 30 and >everything is oK. So it must be the PA. Any Comments would be appreciated.
Hi Tim and all! I remember this subject being fairly well discussed on the list some weeks ago. I believe there is a lot of info to get in the archives. But I'll put up what I know right here... You're right about there is an impedance mis-match between your mics and the PA system. PA mixers almost always only allows low impedance input. At least I've never seen any PA with an impedance switch... The high impedance mics are exclusively designed for use with hi-z equipment, like guitar amplifiers. First - thats why "bullet" type mics produces tiny - or none at all - sound trough a PA system. Second - there might be ways to use the hi z mic in a low z system, but it will require some sort of electronic device between mic and PA. The latest Kevins catalogue offers a small strap-on-belt sort of harmonica pre-amp that I think is useable for plugging into both amps and PA:s. Don't know the cost of that thing, but I know of another, really cheap way to go. On the other hand I really don't know if that way is safe for the PA... Here#001# it is: Somethimes I've plugged the mic into an old casette tape decks mic input, pressed "rec+pause" turned "rec volume" up a bit and put a lead from the earphone outlet of the tape deck into PA:s 1/4 input. What you get is a sound that will vary in distorsion with the setting of "rec volume". What I don't know a thing about is how the considerably high output effect from the tape deck may affect the PA system... I guess I have been lucky in my experiments - the PA still works...and I've got my Fender Champ 12 back in action. And that leads me into another thing - If you do a lot of more or less planned jamming, why don't you bring your amp to the gigs? I believe the Peavey classic 30 is about the same size of my Champ - which fits easily on any stage and does a good job even in bigger places when miked up.
