Problem using a cord with an M14A

dr_bob · Post by **dr_bob** » Sat May 12, 2007 10:16 am

I recently purchased an M14 A. After receiving it I put the tubes back in and turned it on. Power came on but no guitar -- only static and hum. Took the tubes out tried again same result. I plugged the same guitar with the same cord into a different amp and it worked fine.

So I took the amp to my local guitar store here in Saint Louis and they plugged in and the amp worked fine.

Brought it home and I got the same result as before -- no guitar, static and crackling noises as well.

Although the guitar and cord worked fine with a different amp, on a whim I switched cords and hooray the amp worked. It seems that the old tube amp doesn't like my expensive low noise cord with a gold-tipped jack plug. But the amp works just fine with a different (silver-tipped jack) and fairly cheap cord.

I'm trying to figure out why. Does anyone (calling all electrical engineers) have an explanation?

jsm610 · Post by **jsm610** » Sat May 12, 2007 1:03 pm

I'm not an electrical engineer, but put the tips of your two cords together side by side, and I'm guessing you'll find that they're not the same size...

dr_bob · Post by **dr_bob** » Sat May 12, 2007 5:43 pm

Thanks but they are the exact same size. I know my initial post sounds -- well I'm sure it makes me sound pretty ignorant. But I can't figure out an explanation why the one cord will not work in the M14A but works in my other two amps.

charlyg · Post by **charlyg** » Sat May 12, 2007 6:21 pm

You could compare resistances between cables if you have a meter.

Impedance cannot be measured statically, but you can at least make a comparison of resistance.