Field Coil Speaker Mod

[gary sanders]

Just got a cool power amp,all octal,that used a field coil speaker and a HUGE 6k wire wound resistor in the supply.This thing has RCA 6L6G power tubes and Id like to ditch the field coil but I know I have to keep the B+ down for the plate and screen specs.What are my options to make this work?

[M Fowler]

You can add a choke instead of the field coil.

[gary sanders]

cool,arent you the one that talked to me about the eh150 a while back?I built that,really like it a lot!wasnt even thinking of that being so similar

[M Fowler]

Gary,

Yeah I built one, then Colossal built one followed by you, it's catchy

Mark

[Cliff Schecht]

The cool thing with a field coil speaker is you can vary the bias on the field coil to change the Gauss of the electromagnet. This essentially lets you "tune" the speakers sensitivity and response characteristics. I haven't messed around with this yet but I will one of these days..

[Cantplay]

Doesn't changing the field coil voltage also directly change volume?

I would keep it that way.

I believe this is what Fluxtone is.

www.fluxtone-speakers.com

John

[Cliff Schecht]

Doesn't changing the field coil voltage also directly change volume?

I would keep it that way.

I believe this is what Fluxtone is.

www.fluxtone-speakers.com

John

Yes the sensitivity is directly related to the volume the speaker puts out.

[gary sanders]

Doesn't changing the field coil voltage also directly change volume?

I would keep it that way.

I believe this is what Fluxtone is.

www.fluxtone-speakers.com

John

Yes the sensitivity is directly related to the volume the speaker puts out.

That sounds like something worth experimenting with.I have the speaker but its a Radio Shack Realistic .That was another reason I wanted to change it because I sure dont expect a Radio Shack speaker to do well in an amp.Havent heard it yet though,maybe it will sound ok

[Cantplay]

Despite their earned reputation on some items ratshak has used some excellent speakers in some things.

This includes Linaeum tweeters, and in some speakers Fostex drivers.

Give it a listen before you toss it at least.

John