Croft 25 Cathode Follower?

[fiddlemaker]

Thanks, Martin. My understanding is that the 25RS line stage circuit is different from the 25 and 25R, using an 12bh7a valve rather than an ECC83.

Does this also mean that the output impedance of the line stage in the 25RS is lower (because modified cathode follower circuit is implemented?) than 25/25R? And the question is how can I check? It would greatly increase my range of power amp choices if so.

I'm not aware of any SS amps with input impedance as high as 470k.