I would like to restore the original connections of an LS-3 army louspeaker that
I had modified many years ago, but I am unable to find the connection diagram on
google.

Inside the speaker there is a high-to-low impedance transformer, but I am not
sure whether both the low- and the high-impedance connections were brought to
the exterior. Also, I am not sure on whether one of both transformer windings
were connected to ground.

Can any one please let me know the original connections of the input
three-contact jack?

Thanks & 73

Tony I0JX

I sent a couple of pics to you..
Let me know if you didn't get them
Hank
"Antonio Vernucci" wrote in message
.. .
I would like to restore the original connections of an LS-3 army
louspeaker that I had modified many years ago, but I am unable to find
the connection diagram on google.

Inside the speaker there is a high-to-low impedance transformer, but I
am not sure whether both the low- and the high-impedance connections
were brought to the exterior. Also, I am not sure on whether one of
both transformer windings were connected to ground.

Can any one please let me know the original connections of the input
three-contact jack?

Thanks & 73

Tony I0JX

Antonio Vernucci wrote:
I would like to restore the original connections of an LS-3 army
louspeaker that I had modified many years ago, but I am unable to find
the connection diagram on google.

Inside the speaker there is a high-to-low impedance transformer, but I
am not sure whether both the low- and the high-impedance connections
were brought to the exterior. Also, I am not sure on whether one of both
transformer windings were connected to ground.

Can any one please let me know the original connections of the input
three-contact jack?

Thanks & 73

Tony I0JX


The connector used is the 3-pin military mic connector, same as on the
front panel of the BC-312 and '342. The high impedance side (only) of
the transformer goes to the tip and ground. The low impedance speaker
winding goes to the voice coil taps, only. I have come across a few
LS-3's that used tip and ring but don't believe that's correct. Reason
is, the LS-3 was designed for the above receivers and BC-312 receiver
(only) has DC (filament) voltage on the ring connection. WA5CAB may
have add'l info as he sells new LS-3s. Hope this assists you.

de K3HVG



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yes, thanks very much

Tony

"Henry Kolesnik" ha scritto nel messaggio
...
I sent a couple of pics to you..
Let me know if you didn't get them
Hank
"Antonio Vernucci" wrote in message
.. .
I would like to restore the original connections of an LS-3 army louspeaker
that I had modified many years ago, but I am unable to find the connection
diagram on google.

Inside the speaker there is a high-to-low impedance transformer, but I am not
sure whether both the low- and the high-impedance connections were brought to
the exterior. Also, I am not sure on whether one of both transformer windings
were connected to ground.

Can any one please let me know the original connections of the input
three-contact jack?

Thanks & 73

Tony I0JX

Thanks Jeep.

even though it may not matter much, do you know whether the voice coil is
grounded on one side?

73

Tony I0JX
------------------------------------------------------

The connector used is the 3-pin military mic connector, same as on the front
panel of the BC-312 and '342. The high impedance side (only) of the
transformer goes to the tip and ground. The low impedance speaker winding
goes to the voice coil taps, only. I have come across a few LS-3's that used
tip and ring but don't believe that's correct. Reason is, the LS-3 was
designed for the above receivers and BC-312 receiver (only) has DC (filament)
voltage on the ring connection. WA5CAB may have add'l info as he sells new
LS-3s. Hope this assists you.

de K3HVG



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----------------------------------------------------------
http://www.Newsfeeds.com

Antonio Vernucci wrote:
Thanks Jeep.

even though it may not matter much, do you know whether the voice coil
is grounded on one side?

73

Tony I0JX




Tony, I looked inside a new one, just out of the original box. NO
speaker connections are connected to ground.



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----- Original Message -----
From: "K3HVG"
Newsgroups: rec.radio.amateur.boatanchors
Sent: Sunday, January 11, 2009 7:59 PM
Subject: LS-3 speaker


Tony, I looked inside a new one, just out of the original box. NO speaker
connections are connected to ground.

Thanks for your time Jeep.

By the way, my BC-191 works fine now, but I came to the conclusion that
operating with that dynamotor is really unpleasant. So I am in the process of
building an AC supply.

I hope that, with the AC-powered filaments, no hum will show up in the transmit
audio.

73

Tony I0JX

Antonio Vernucci wrote:
----- Original Message ----- From: "K3HVG"
Newsgroups: rec.radio.amateur.boatanchors
Sent: Sunday, January 11, 2009 7:59 PM
Subject: LS-3 speaker


Tony, I looked inside a new one, just out of the original box. NO
speaker connections are connected to ground.

Thanks for your time Jeep.

By the way, my BC-191 works fine now, but I came to the conclusion that
operating with that dynamotor is really unpleasant. So I am in the
process of building an AC supply.

I hope that, with the AC-powered filaments, no hum will show up in the
transmit audio.

73

Tony I0JX


Tony, From various reports, use of the dynamotor may well be better
than a.c. supplies in that the dynamotor MAY provide better regulation
than external supplies. If your a.c. supply is stiff and capable of not
sagging under voice peaks, etc. it will be just fine. Personally, I use
one with a pair of 6336B regulators. That really helps the residual
FMing of the signal. Also, try the "San Luis Obispo" fine tuning
procedure for the frequency you intend to use the most. That will also
quiet things down a bit.

Regards Jeep/K3HVG



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Tony, From various reports, use of the dynamotor may well be better than a.c.
supplies in that the dynamotor MAY provide better regulation than external
supplies. If your a.c. supply is stiff and capable of not sagging under voice
peaks, etc. it will be just fine. Personally, I use one with a pair of 6336B
regulators. That really helps the residual FMing of the signal. Also, try
the "San Luis Obispo" fine tuning procedure for the frequency you intend to
use the most. That will also quiet things down a bit.

Regards Jeep/K3HVG

OK Jeep, thanks for your advice.

I would not like to build a stabilized power supply, as that would be quite a
huge machine. Anyway I shall give a look to the diagram and see whether there
would be any simple way to feed just the oscillator tube with a separate
stabilized HV.

With regard to voice peaks, using big output capacitor should help.

I am more worried about CW because, even with a big output capacitor, voltage
will tend to decrease along the duration of a dash or a dot, and this may cause
chirp.

Going back to my original question, the first test I shall do is to feed the
filaments with a transformer, while keeping the dynamotor for the HV. I want to
be sure that powering filaments on AC (instead of DC) does not cause an
unacceptable hum on the audio.

By the way, I have been looking for a spare VT-25 (10Y) tube, but I could not
find one for less than $70. Apparently that tube is one of those that had the
disgrace to fall into the esoteric hi-fi aficionados circuit, who are prepared
to pay almost any price for the promise of a "warmer" sound.

73

Tony I0JX

Antonio Vernucci wrote:

I would not like to build a stabilized power supply, as that would be quite a
huge machine. Anyway I shall give a look to the diagram and see whether there
would be any simple way to feed just the oscillator tube with a separate
stabilized HV.

I know it seems like cheating.... but... consider a zener and TIP50 darlington.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."