07-23-2026, 02:27 PM
I suspect that the metal caps were for the domes of the audio tubes in this set in an attempt to reduce microphonics, which was a common problem with "globe" or "balloon" envelope tubes had less physical support for the internal structure. This was one of the reasons the tube manufacturers adopted the S.T or "Shouldered Type" envelopes in the mid 1930s, and later the G.T or "Glass Tubular" style envelopes, something many audiophools can't fathom.
The speakers these sets used were high impedance, so you will need an audio output transformer to use one with a more modern 4 or 8 ohm speaker, otherwise a set of headphones, a horn, or magnetic cone speaker from the era will work with the set. The advice I read online is NOT to try operating one of these sets on a horn speaker with a 171A in the final output socket as it can damage the the driver, but using one with a later cone speaker should be fine, otherwise use a 01A or a 112A with the horn.
Regards
Arran
The speakers these sets used were high impedance, so you will need an audio output transformer to use one with a more modern 4 or 8 ohm speaker, otherwise a set of headphones, a horn, or magnetic cone speaker from the era will work with the set. The advice I read online is NOT to try operating one of these sets on a horn speaker with a 171A in the final output socket as it can damage the the driver, but using one with a later cone speaker should be fine, otherwise use a 01A or a 112A with the horn.
Regards
Arran
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