Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

Hi

Is that the right part number? PT142 is 325-0-325 @ 50 ma.

http://antiqueradio.org/transmitter.htm

Transformer in this circuit shows 120 & 12 volts output. 12 volts is only used to light a lamp. This winding isn't needed. You should use an isolation transformer for 120 volts. N51X will work but it can be smaller.

Norm

:Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

Oops it's P-T442:Hi
:
: Is that the right part number? PT142 is 325-0-325 @ 50 ma.
:
:http://antiqueradio.org/transmitter.htm
:
: Transformer in this circuit shows 120 & 12 volts output. 12 volts is only used to light a lamp. This winding isn't needed. You should use an isolation transformer for 120 volts. N51X will work but it can be smaller.
:
:Norm
:
::Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

Oops it's P-T442:Hi
:
: Is that the right part number? PT142 is 325-0-325 @ 50 ma.
:
:http://antiqueradio.org/transmitter.htm
:
: Transformer in this circuit shows 120 & 12 volts output. 12 volts is only used to light a lamp. This winding isn't needed. You should use an isolation transformer for 120 volts. N51X will work but it can be smaller.
:
:Norm
:
::Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

Hi

That will work. The 117L7 normally draws more current but in this circuit only a few ma. This is mentioned in the writeup.

http://antiqueradio.org/transmitter.htm

Norm

:Oops it's P-T442:Hi
::
:: Is that the right part number? PT142 is 325-0-325 @ 50 ma.
::
::http://antiqueradio.org/transmitter.htm
::
:: Transformer in this circuit shows 120 & 12 volts output. 12 volts is only used to light a lamp. This winding isn't needed. You should use an isolation transformer for 120 volts. N51X will work but it can be smaller.
::
::Norm
::
:::Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

:Hi
:
: That will work. The 117L7 normally draws more current but in this circuit only a few ma. This is mentioned in the writeup.
:
:http://antiqueradio.org/transmitter.htm
:
:Norm

A question, if a may: It would seem that the 117L7 was a pretty unusual tube back in the tube days-I had one at a radio station to turn on the tower lights at dusk, it never quit and I never had to work on it-and that might make it hard to find and expensive. Is there a tube with the 117L7 pentode section specs that doesn't have the recitfier that, say, could be powered by the 12 Volt winding (or 6 Volts) of the transformer that would be easier to find and cheaper? Like a 6V6 or a 6AQ5? Then you could use a diode for rectifier. Just wondering.

Lewis L.

::Oops it's P-T442:Hi
:::
::: Is that the right part number? PT142 is 325-0-325 @ 50 ma.
:::
:::http://antiqueradio.org/transmitter.htm
:::
::: Transformer in this circuit shows 120 & 12 volts output. 12 volts is only used to light a lamp. This winding isn't needed. You should use an isolation transformer for 120 volts. N51X will work but it can be smaller.
:::
:::Norm
:::
::::Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

:Hi
:
: That will work. The 117L7 normally draws more current but in this circuit only a few ma. This is mentioned in the writeup.
:
:http://antiqueradio.org/transmitter.htm
:
:Norm

A question, if a may: It would seem that the 117L7 was a pretty unusual tube back in the tube days-I had one at a radio station to turn on the tower lights at dusk, it never quit and I never had to work on it-and that might make it hard to find and expensive. Is there a tube with the 117L7 pentode section specs that doesn't have the recitfier that, say, could be powered by the 12 Volt winding (or 6 Volts) of the transformer that would be easier to find and cheaper? Like a 6V6 or a 6AQ5? Then you could use a diode for rectifier. Just wondering.

Lewis L.

::Oops it's P-T442:Hi
:::
::: Is that the right part number? PT142 is 325-0-325 @ 50 ma.
:::
:::http://antiqueradio.org/transmitter.htm
:::
::: Transformer in this circuit shows 120 & 12 volts output. 12 volts is only used to light a lamp. This winding isn't needed. You should use an isolation transformer for 120 volts. N51X will work but it can be smaller.
:::
:::Norm
:::
::::Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

Hi Lewis

Sure thay could have used other tubes which would have worked just as well. Believed they used this one because filament can be operated directly off the AC line. There was an earlier circuit without the 120 volt isolation transformer.

You are correct about price. Back around 1960 117L7 & 117N7 were just about the highest priced receiving tubes.

Norm

::Hi
::
:: That will work. The 117L7 normally draws more current but in this circuit only a few ma. This is mentioned in the writeup.
::
::http://antiqueradio.org/transmitter.htm
::
::Norm
:
:
:
:A question, if a may: It would seem that the 117L7 was a pretty unusual tube back in the tube days-I had one at a radio station to turn on the tower lights at dusk, it never quit and I never had to work on it-and that might make it hard to find and expensive. Is there a tube with the 117L7 pentode section specs that doesn't have the recitfier that, say, could be powered by the 12 Volt winding (or 6 Volts) of the transformer that would be easier to find and cheaper? Like a 6V6 or a 6AQ5? Then you could use a diode for rectifier. Just wondering.
:
:Lewis L.
:
:
:::Oops it's P-T442:Hi
::::
:::: Is that the right part number? PT142 is 325-0-325 @ 50 ma.
::::
::::http://antiqueradio.org/transmitter.htm
::::
:::: Transformer in this circuit shows 120 & 12 volts output. 12 volts is only used to light a lamp. This winding isn't needed. You should use an isolation transformer for 120 volts. N51X will work but it can be smaller.
::::
::::Norm
::::
:::::Would the 12.6v 300ma miniature transformer part #273-1385 from R.S. work for the Lil7 transmitter same as the PT-142 from Antique Electronic Supply?

:Hi Lewis
:
: Sure thay could have used other tubes which would have worked just as well. Believed they used this one because filament can be operated directly off the AC line. There was an earlier circuit without the 120 volt isolation transformer.
:
: You are correct about price. Back around 1960 117L7 & 117N7 were just about the highest priced receiving tubes.

I just thought since there was a 12 V. tap on the transformer, forget the 117L7 and use a 12V6. I've worked around thousands of tubes in my life, and only one 117 Volt filament.

Lewis

117L7/M7 and N7 tubes aren't that expensive. They're under $10 a piece. If you want to use transformers from Radio Shack to power a 12V6, you can either use one for the filament, with the B voltage derived from the line cord, or you can wire a second transformer's secondary to the first transformer secondary, and use the second transformer's primary to get your B voltage.

T.

:117L7/M7 and N7 tubes aren't that expensive. They're under $10 a piece. If you want to use transformers from Radio Shack to power a 12V6, you can either use one for the filament, with the B voltage derived from the line cord, or you can wire a second transformer's secondary to the first transformer secondary, and use the second transformer's primary to get your B voltage.
:
:T.

::117L7/M7 and N7 tubes aren't that expensive. They're under $10 a piece. If you want to use transformers from Radio Shack to power a 12V6, you can either use one for the filament, with the B voltage derived from the line cord, or you can wire a second transformer's secondary to the first transformer secondary, and use the second transformer's primary to get your B voltage.
::
::T.

Yea, I was thinking of something like that. I may be starting something I hadn't orter, but what would be a low Voltage verson of the 117L7 without rectifier?

Hi

A lot depends on what tube a person has already. 12V6 was mentioned. Nothing wrong with that. 117L7 was used as audio output. Just check for other audio output tubes in a data book. A lot depends on how well a person understands changes. The article is already shown with 117L7 pin numbers and voltages.

Thomas, you are correct. 117L7 isn't that expensive now. In the 1950's it was selling for around $5.00. A lot of money in those days. Looking at a price list from 1953 most other tubes were in the $2 and $3 range. 5Y3GT & G, 34W4 were $1.35. Even a 45 was only $2.10.

Norm

:::117L7/M7 and N7 tubes aren't that expensive. They're under $10 a piece. If you want to use transformers from Radio Shack to power a 12V6, you can either use one for the filament, with the B voltage derived from the line cord, or you can wire a second transformer's secondary to the first transformer secondary, and use the second transformer's primary to get your B voltage.
:::
:::T.
:
:Yea, I was thinking of something like that. I may be starting something I hadn't orter, but what would be a low Voltage verson of the 117L7 without rectifier?

I see that both the 117L7 and 117N7 are available at www.oldradioparts.com for $4.50 - $5.00

How things have changed! Now it's hard to find a #45 for $2.

T.