Pro Junior OT question

[trem]

What is this series Cap/Resistor across the OT primary doing........ "balancing" high frequency AC or something.?
Thank You

https://www.thetubestore.com/lib/the...-Schematic.pdf

[Helmholtz]

Circuit?
Are you speaking of a Boucherot cell (aka Zobel network)?
https://en.wikipedia.org/wiki/Boucherot_cell
https://en.wikipedia.org/wiki/Zobel_network

[trem]

Circuit?
Are you speaking of a Boucherot cell (aka Zobel network)?
https://en.wikipedia.org/wiki/Boucherot_cell
https://en.wikipedia.org/wiki/Zobel_network

That Wiki link sounds like it.

Pardon me..... i edited my post to include the correct schem for the amp.

[g1]

When used on the primary side of the OT it is also often called a 'conjunctive filter' and the RCA tube manual calls it a 'corrective filter'.

[Helmholtz]

In any case it's a low-pass shelving filter.