Comments on: Fkkng magnets. How do they work?

By: chris

chris — Mon, 19 Sep 2016 15:37:40 +0000

In reply to Bobby Mack. There are many, many things that could be wrong Bobby. If you want to be able to do this work, you will need to eventually learn how to test and evaluate every component. Start by reading Aspen Pittman's "The Tube Amp Book." He offers an excellent primer on servicing gtr amps. Good luck.

By: Bobby Mack

Bobby Mack — Fri, 26 Aug 2016 22:15:56 +0000

hello,
I have a acquired a late 40s amp with an electro-coil speaker. Any information on this kind of speaker set up in a guitar amp would be greatly appreciated.
I am refurbishing this Vega amp. After updating most of the capacitors as needed I am still only getting low power. I’m suspecting the OT, but I don’t have enough knowledge to test.
Thanks , bbmack

By: Don Bell

Don Bell — Sun, 03 Jan 2016 15:59:11 +0000

Before the advent of permanent magnets, an electromagnet was the way most loud speakers were made to operate. The voice coil of the speaker was attracted or repelled by the magnetism in the voice coil gap. The electromagnet in early speakers was powered by using the coil as a filter choke in the amplifier power supply.
They were actually very efficient. Permanent magnets are a lot cheaper than a big coil of copper wire and don’t need big electric.

By: The Field-Coil Guitar Amplifier | Preservation Sound

The Field-Coil Guitar Amplifier | Preservation Sound — Wed, 13 Oct 2010 14:49:56 +0000

[…] In my previous post on field coil speakers, I went into some detail about this technology and its relationship to more modern speakers. Now the time had come to actually build a working audio device using this antique technology. […]