The Marco-boy main system, as of August 2020

[Marco]

Hi Alan,

I corrected the supply voltage that was rather low due to an out of spec resistor and also re-configured the heater wiring so it could be used without phono stage vales fitted if required.
This also enabled alternative higher heater current valves to be paired in the line stage, which wasn't possible before as you found out.

That must've made a big difference!

However, I'm not sure exactly what purpose/effect was intended by the latter, or why it would be considered as an upgrade. 6SL7s are superb valves for a line or phono stage. Could you elucidate on your thinking there, please?

Ta

Marco.