[R-390] Speaker

[Cecil Acuff]

Your right about patience.....I would give a novice doing a one off a near
zero percent of success in maintaining the Gap dimensions.  The thickness of
the windings that has to pass through the Gap in the magnet pole pieces.  If
not kept in tolerance rubbing will occur.  A 1000' of even #38 wire results
in a good bit more thickness that the original windings.  Then one has the
task of gluing the bobbin back onto the cone....and perfectly centered.

I have reconed many EV and various other manufacturers speakers over the
years...even with their recone kits that are specifically designed for the
purpose it is sometimes difficult.

I won't say it is not doable....just not something one would expect someone
who has never done it before to be successful at doing...especially just
once.

I have been thinking recently about maybe having a speaker maker doing a run
of 600 ohm speakers....maybe in a 10" or maybe 12".  One could build a nice
wooden cabinet and get a great sound out of our classic tube radio's...

I went to a tube guitar amp repair/restoration class out in Texas a few
months back and the guy that taught the class was having speakers custom
made for the amps he built.  For a speaker maker I wouldn't think 600 ohms
would be much more difficult that the 4 or 8 ohm speakers they normally
make...certainly they are equipped to do that type of work with great
success.

I could check with him and see who he uses...

What do ya think?

Cecil Acuff
----- Original Message ----- 
From: "Michael Murphy" <mjmurphy45 at comcast.net>
To: "James A. (Andy) Moorer" <jamminpower at earthlink.net>; "Charles B"
<ka4prf at us-it.net>; <r-390 at mailman.qth.net>
Sent: Thursday, September 23, 2004 5:19 PM
Subject: Re: [R-390] Speaker


> Good idea Chuck,
>
> Why not a 600 Ohm speaker?
>
> For extra credit, carefully detach the speaker cone and spider from the 8
> Ohm speaker voice coil. Unwind the voice coil. Now attach the voice coil
> form to a lathe which has been outfitted with a slip mechanism. Wind
> approximately 1000 feet of #38 wire in a back and forth pattern. Make sure
> that the winding occupies the same footprint as the original 8 Ohm
winding.
> You should measure around 500 Ohms of DC resistance. The AC impedance will
> be higher of course. Glue the voice coil back onto the cone and spider and
> reattach the leads. This technique may take practice.
>
> Mike M. WB2UID
>
>
http://www.vintage-radio.com/repair-restore-information/valve_philips-speake
> rs.shtml
>
> http://www.mwaspeakerparts.com/speaker_parts.html
>
>
> ----- Original Message -----
> From: "James A. (Andy) Moorer" <jamminpower at earthlink.net>
> To: "Charles B" <ka4prf at us-it.net>; <r-390 at mailman.qth.net>
> Sent: Wednesday, September 22, 2004 7:52 PM
> Subject: Re: [R-390] Speaker
>
>
> > Well, you can't really. The don't make them that I know of.
> >
> > I will be happy to sell you (or anybody else) a NOS military transformer
> > that converts 600 ohms to 8 ohms for $15, postage included (US only).
> (sorry
> > for the appearance of crass commercialism, but I don't really make any
> money
> > off this - I just do it as a service). Actually, the transformer is
marked
> > as 9 ohms, but that is close enough.
> >
> > James A. (Andy) Moorer
> > www.jamminpower.com
> >
> > ----- Original Message -----
> >
> > > Hi all,
> > >
> > > where can I find a 600 ohm speaker?
> > >
> > > Chuck
> > >
> >
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