Is this a Pye model MP - or not?

[pwdrive]

I was following you post on the other forum and would agree with what was said, the SP41 was an RF pentode designed for television RF/IF stages up to 45 mhz, I wouldn't have thought that it was a manufactures modification, that MO valve base is just planted on the top of the chassis, I would revert it back to a B7 base and fit a VP4B in it, that valve is vari mu for AGC control, I don't think the SP41 is.

Lawrence. EDIT: missed Alan's post