11-23-2025, 09:28 PM
Hi Dan,
Yes, the radio would play with only 1 of the two Push Pull output tubes working or only one of the 2 "legs" of the output transformer good.
Attached is a page of the RCA Receiving Tube Manual version RC13 from 1937, describing the "45" power triode:
Based on the info included in the above document, my rough guestimate is that a transformer with a primary impedance of 4KOhm - 5KOhm (plate to plate) will work. Impedance is not the same as resistance. Primary impedance depends on proper matching of the secondary's impedance to the speaker voice coil.
Unfortunately, the diagram does not have any specifications for output transformer, voice coil or field coil resistance or impedance. It is also quite difficult to determine how it is connected. By the early 1930s, the field coil was between the first and second filter caps and usually had a resistance of about 1KOhm.
Hope this helps.
Yes, the radio would play with only 1 of the two Push Pull output tubes working or only one of the 2 "legs" of the output transformer good.
Attached is a page of the RCA Receiving Tube Manual version RC13 from 1937, describing the "45" power triode:
Based on the info included in the above document, my rough guestimate is that a transformer with a primary impedance of 4KOhm - 5KOhm (plate to plate) will work. Impedance is not the same as resistance. Primary impedance depends on proper matching of the secondary's impedance to the speaker voice coil.
Unfortunately, the diagram does not have any specifications for output transformer, voice coil or field coil resistance or impedance. It is also quite difficult to determine how it is connected. By the early 1930s, the field coil was between the first and second filter caps and usually had a resistance of about 1KOhm.
Hope this helps.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55
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