[NJARC] In search of an 8 inch zenith electromagnet speaker, 2150 ohms.

[Thomas Lee]

Hi John,
I just thought that the correct speaker was the one callled for in the 
schematic.  Also Tom provost has the same model with the speaker stated in 
the schematic.  Would the ohms differ by that much and not make a 
difference?  (Calls for 2150 ohms, has 1000ohm).

What did that set use, a single 6F6 for output?
Yes.  The tube lineup is...

6F6 Power
6Q7 2nd Det/1st Audio
6K7 I.F.
5Y3 Rect.
6A8 1st I.F.

Tom



Tom,
Perhaps that's just a production variant. Do you have any evidence that the 
speaker was not original to the set? Plus the sechmatic could be wrong. And 
even it it's not, manufacturers frequently made mid-production changes.

Also, don't worry too much about feed coil speakers. Exact replacements can 
be difficult to find. And from what I remember, you *don't* need the 
speaker, just the output transformer (for which a replacement from AES or 
Radio Daze is easy to get and fairly cheap). Also, a transformer from a 
parts set should work. What did that set use, a single 6F6 for output?

My advice for replacing an electrodynamic speaker is to replace it with a 
permanent magnet speaker and use a filter choke (or sometimes a resistor) in 
place of the field coil. You're fortunate that the speaker is still good, I 
think.

JR


 > Visit our web site - See http://www.njarc.org
 > _______________________________________________
 > Hi John,
 > the speaker that the radio has is not what the
 > schematic calls for, it's a
 > model 49-166X 1000 ohm, the schmatic calls for a
 > model 49-152, 2150 ohms.
 > Should I keep the speaker and add a resistor in
 > series once I find a
 > transformer?
 >
 > Thoughts?
 >
 >
 > Tom
 >
 > btw go to sleep :)
 >
 >
 >
 > Tom,
 > If this is the radio we were working on at the
 > clinic, you DON'T NEED the
 > speaker -- you need to replace the OUTPUT
 > TRANSFORMER which is physically
 > mounted on the speaker. The speaker field coil is OK
 > (we tested that at the
 > clinic), and I think we tested the voice coil and
 > it's OK too. But check it
 > to make sure.
 >
 > It should be easier just to replace the transformer
 > -- it will be much
 > harder to locate a matching speaker. The primary of
 > the output trasnformer
 > tested *open* (or you've got a broken wire
 > someplace, but I doubt it).
 >
 > JR
 >
 >
 > --- Thomas Lee <thomas_v_lee at hotmail.com> wrote:
 >
 >  > Visit our web site - See http://www.njarc.org
 >  > _______________________________________________
 >  > if you have one send a pic, and a price :)
 >  >
 >  > thx
 >
 >
 > _______________________________________________
 > NJARC mailing list
 > NJARC at mailman.qth.net
 > http://mailman.qth.net/mailman/listinfo/njarc
 >



       
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