Klemt M40 converting from Ultralinear to pentode

[888]

Hi,
I hope someone here has made this change to a M40 and could help.
I'm thinking of disconnecting the Ultralinear taps on the OT, and running in Pentode mode.
I've attached a circuit diagram to give an idea of what I was thinking....
disconnecting the tap connections on the OT,
then connecting the original 200ohm screen resistors together and then to what seems to be an unused tap off the HT (which is at a lower voltage than the HT at the centre tap of the OT)
hope someone with more knowledge of valves could point out any problems in doing this.
thanks

[mhuss]

That should work. 200R seems a bit low for screen resistors, but 'low' seems typical in EL84 guitar amps (AC30s used 100R). The series shared 2k2 will help.

[pdf64]

Yes, it should be fine.
The idle conditions will probably cool down a little, due to the 2k2 dropping the screen grid voltage lower than in UL.