Instead of using a high impedance speaker, I would like to connect an output transformer and pm speaker to the output tube, in this case a type 01A running at 135 volts. I have several old radios (battery, AC/DC) from which to pull a transformer and speaker. In coming up with a match, is the load resistance or impedance? more critical than the plate resistance? Are there certain output tubes I should select a radio to pull from that would work better?

Brian

Just about any output transformer will work. If you have a choice I would use one from a radio with 6V6 or battery output. An AC/DC radio output impedance will be only 2000-2500 ohms.

Norm

:Instead of using a high impedance speaker, I would like to connect an output transformer and pm speaker to the output tube, in this case a type 01A running at 135 volts. I have several old radios (battery, AC/DC) from which to pull a transformer and speaker. In coming up with a match, is the load resistance or impedance? more critical than the plate resistance? Are there certain output tubes I should select a radio to pull from that would work better?
:

Thanks Norm.

:Brian
:
: Just about any output transformer will work. If you have a choice I would use one from a radio with 6V6 or battery output. An AC/DC radio output impedance will be only 2000-2500 ohms.
:
:Norm
:
::Instead of using a high impedance speaker, I would like to connect an output transformer and pm speaker to the output tube, in this case a type 01A running at 135 volts. I have several old radios (battery, AC/DC) from which to pull a transformer and speaker. In coming up with a match, is the load resistance or impedance? more critical than the plate resistance? Are there certain output tubes I should select a radio to pull from that would work better?
::
:
:

You can get a miniature xfmr and P.M. speaker, and stuff them in the base of your horn speaker - after removing the old reproducer.

Unfortunately, I do not have a base for my horn, but hope to make a wooden box on which to mount it. Apparently, some horns did have a squarish wooden base.

:You can get a miniature xfmr and P.M. speaker, and stuff them in the base of your horn speaker - after removing the old reproducer.
:

You will obtain the best audio from a 6 or 8 inch speaker in a suitable cabinet for good bass response.

You can further improve the power and tone quality by changing the output tube to a '71A, which takes the same voltage and current as a '01A.

T.

Norm,

What would the DC resistance be on the primary of a suitable output transformer? I have found severalin 400 to 600 ohm range.

:Brian
:
: Just about any output transformer will work. If you have a choice I would use one from a radio with 6V6 or battery output. An AC/DC radio output impedance will be only 2000-2500 ohms.
:
:Norm
:
::Instead of using a high impedance speaker, I would like to connect an output transformer and pm speaker to the output tube, in this case a type 01A running at 135 volts. I have several old radios (battery, AC/DC) from which to pull a transformer and speaker. In coming up with a match, is the load resistance or impedance? more critical than the plate resistance? Are there certain output tubes I should select a radio to pull from that would work better?
::
:
:

The DC resistance is irrelevant. It's the turns ratio that reflects the speaker's impedance back to the radio's output tube.

Just put in a junk audio output xfmr.

:
:What would the DC resistance be on the primary of a suitable output transformer? I have found severalin 400 to 600 ohm range.
:
::Brian