Amplifier Conversion Project

[David Sutton]

I have a cute little 25 watt amp that looks like it was designed in the early 70s ("all transistor!!"), nice aqua/silver speaker cloth over a 10" speaker. I want to set it up so that my daughter could plug an iPod in and sing along, or sing and play guitar.

The amp has 3- 1/4" phono input jacks, one off/on/volume and one tone control.

I would like to reconfigure it just slightly by changing one of the input jacks to a 1/8" mini phono, which I don't think would present any problems, and by changing one of the other two input jacks to an XLR (microphone) input.

Will this work? Can I just swap it out? I don't know much about electronics. I have heard the term "phantom power" in re: microphones, but I don't really know what it means or how it works. Does a microphone like a Shure SM58 have enough output?

If changing a 1/4" phono input jack to an XLR input jack is NOT a simple one for one, then is there something else that I can do to make it work?

THanks!

[surffrogg]

u cam buy an 3/4 to one 1/8 adapter at the dollar store no need to change anything...also mics come in both lo z (xlr) and hi z (1/4 inch jack) so 2 adapters will about wrap it up

[Ted Crocker]

David, what you want to do is possible, but depending on the construction of the amp it may be difficult. Many solid state amps have circuit board mounted jacks, making it difficult to replace.

Phantom power refers to the voltage through many XLR connected high impedance microphones needed to power internal circuitry (pre-amp). The SM58 is a low impedance microphone and can be plugged directly into most amps. Cables can be bought with an XLR connector at one and and a 1/4" plug on the other.

Like surf said, simple 1/8 to 1/4 adapters will work for the iPod. Or you could easily make a cable with a 1/8 plug on one end and a 1/4 on the other.

Good luck!

[surffrogg]

dang didn't think of maken a cable but was looking for the simplest answer

Ted Crocker said:

David, what you want to do is possible, but depending on the construction of the amp it may be difficult. Many solid state amps have circuit board mounted jacks, making it difficult to replace.

Phantom power refers to the voltage through many XLR connected high impedance microphones needed to power internal circuitry (pre-amp). The SM58 is a low impedance microphone and can be plugged directly into most amps. Cables can be bought with an XLR connector at one and and a 1/4" plug on the other.

Like surf said, simple 1/8 to 1/4 adapters will work for the iPod. Or you could easily make a cable with a 1/8 plug on one end and a 1/4 on the other.

Good luck!

[wesley carl]

go with the adapter I use em and it is the easey way plus if ya dont want the 1/8 all ya do is unplug the adapter