DIY 802 field coil drivers may be a reality!!

[mah]

mah,

I am plenty credible. And I offered sound and credible advice. Who are you, who probably has zero field coil listening experience, to contend that my comments are ill advised?? Me, and my closest of audio friends have direct experience with hundreds of such field coil drivers, over many years and many venues.

I was very clear in what I stated, that the coils buck each other. Everyone hears it, but not everyone recognizes what they are hearing.

This is just my opinion. I am free to state it up here.

No rigid theoretical proof, ( which may or may not be correct ), is needed. The proof of the pudding ......is in the eating.

You, and others, are welcome to have a different opinion, but it would be much more credible to me and others, if you had field coil experience..

This of little consequence to me. I am happily using an 802D, remagnetized by GPA in 2015, as the top-end on A7-800s. My system's wiring, and amplification, is at a level that very much pleases me.

This is an open Forum where we can share our listening experiences, hopefully for the betterment of all. Each individual reader has the mental capability to discern who or what ideas they prefer to follow in any audio discussion, ....it is a right we all have.

Now, for a fifth time, lets get back to the idea that "we two" do not post after each other in the same thread. Its a waste of bandwidth. Anyone can see that is needed. Are you willing to address that ??

Jeff Medwin.....Low Ohms.

LowOhms,

You make an appeal based on a call for openness and then expect me to forgo that openness because you don't like some of my comments. Huh?

Just take responsibility for what you say in public( i.e. the internet) and let this thread(and Forum) return to its original purpose.

Don't try to self-interestedly censor me again!!


Be very careful and relative, legally, with what you say in any reply.

[mah]

Bill, Because I can't get PM to you, I'll put this up on the forum.

Rusty voice-coil gap on compression drivers, if not too far gone, may respond to Ultrasonic Cleaning. If you have a metal cleaning specialist in your vicinity it could be worth a chat. Mention that the concentric phase plug is an aluminium alloy.

[gvasale]

Evaporust may be a little more effective than ultrasonic. You would have to try samples of both to find which is better. No special equipment needed for Evaporust.

[BillWojo]

Surface rust is not a real problem except that indicates that the protective coating (zinc or cadmium plating) is used up. The problem is when the rust is deeper and changes the physical dimensions of the gap. I don't have the math handy to prove it but I highly suspect that even a small change in the gap width will have a much larger change in the gap magnetic field strength.
Thanks guys.

BillWojo

[mah]

Bill, look what this project could lead to:

Western Electric 13A Horn


Western Electric 16A Horn

[BillWojo]

Marshall, thanks for the links. What I find very interesting is a bit of information in the first link.
Seems the Western Electric 13A horn was actually manufactured by the Victor Talking Machine Company. Look at the brass plate in the last picture.
I live less than 15 miles from the old plant. That's really cool that these were built locally. Now if I could only find a set. LOL

BillWojo

[GM]

The problem is when the rust is deeper and changes the physical dimensions of the gap. I don't have the math handy to prove it but I highly suspect that even a small change in the gap width will have a much larger change in the gap magnetic field strength.

I don't remember there being a simple ratio, but making the gap irregular causes non-linear distortion, though in a compression driver I doubt it's a mechanical issue, just increased VC heating. If the gap is narrower, then it can shift the frequency response lower with increased VC heating and vice versa, so tis better overall to increase the gap a tiny bit with proper tooling to make it uniform, clean, cooler running.

GM

[mah]

Inside shots: Field Coil conversion for JBL, Altec, and Western - diyAudio

[LowOhms]

LowOhms,

You make an appeal based on a call for openness and then expect me to forgo that openness because you don't like some of my comments. Huh?

Just take responsibility for what you say in public( i.e. the internet) and let this thread(and Forum) return to its original purpose.

Don't try to self-interestedly censor me again!!


Be very careful and relative, legally, with what you say in any reply.

- - - - - - - - - - - - -

LOL, I am now getting threatened with a lawsuit??


You really need to get a LIFE, other than this Forum.


My comments in post 32 of this thread applies : ie: that the possible differences between field coil and alnico drivers, is FAR overshadowed by the performance differences, and possible gains one obtains with :

(1) amplifier implementations

(2) system wiring and

(3) modern capacitor choices.

These three RULE the overall listening result, which IS the purpose of this Forum.

Amps I mention first, because, IMHO, and experience, these are the WORSE performing audio component in the whole chain.

99.9% of amplifiers... simply flunk, get a D- to F- on getting what is possible from our ALTEC drivers !!

Jeff Medwin