A lot of dynamic mics use step-up transformers to boost the signal. A dynamic mic element is almost the same thing as a guitar pickup except that the coil is attached to a diaphragm so it can move. Also there are fewer windings in the coil.
Would it work to boost the gain on an instrument with a weak pickup to use a transformer in the same way? I've been trying it, and so far it doesn't seem to make any difference, but I don't understand why not. Am I wiring it up wrong?
I don't expect it to be as dramatic as a preamp, but I think there should be some audible difference. Can someone explain this?
I'm using a transformer that came out of an impedance matching adapter for microphones (low to high Z or vice-versa depending which way you go).
Thanks,
Paul
Would it work to boost the gain on an instrument with a weak pickup to use a transformer in the same way? I've been trying it, and so far it doesn't seem to make any difference, but I don't understand why not. Am I wiring it up wrong?
I don't expect it to be as dramatic as a preamp, but I think there should be some audible difference. Can someone explain this?
I'm using a transformer that came out of an impedance matching adapter for microphones (low to high Z or vice-versa depending which way you go).
Thanks,
Paul
Hi - Yes, it is easily explained - A transformer cannot amplify, it can only effectively alter impedence.. The POWER you get from the secondary of a transformer will be the power you put into the Primary Minus the losses produced by the transformer.
Assume a perfect transformer - put 1V @ 1mA in, and for a 1:10 winding ratio, you can get 10V @ 0.1mA out -
Assume a perfect transformer - put 1V @ 1mA in, and for a 1:10 winding ratio, you can get 10V @ 0.1mA out -
Simple impedance mismatching methinks.
A guitar pick up is circa 1K to 2K dc resistance
whilst a microphone is circa 100R dc resistance.
But you'll find with the average controls in a guitar
a very high impedance load is required, in the order
of 100's of kohms.
So the matching transformer doesn't match anything.
🙂 sreten.
A guitar pick up is circa 1K to 2K dc resistance
whilst a microphone is circa 100R dc resistance.
But you'll find with the average controls in a guitar
a very high impedance load is required, in the order
of 100's of kohms.
So the matching transformer doesn't match anything.
🙂 sreten.
Another point, transformers are specified for respose with a given set of impedances. So that if it was designed to transform 2.2k to 200 Ohms, it might do a bad job transforming 110 to 10 Ohms at least in terms of frequency response. I think the 2.2k to 200 is what is in a lot of condensor mikes. Oktava and Nakamichi are two that come to mind.
thanks, guys
Fred, that makes sense. I suspected it was something like that. I always thought that transformers needed to be powered up-- it didn't make sense to get something for nothing. I think I'll just coil some new pickups for the damn thing
, use some NIB magnets this time for more power.
Fred, that makes sense. I suspected it was something like that. I always thought that transformers needed to be powered up-- it didn't make sense to get something for nothing. I think I'll just coil some new pickups for the damn thing
, use some NIB magnets this time for more power.- Status
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