[aferguson]

Hi

Thank you for the query. With reference to C15, this is an odd wee cap placed between 6 and 7 of the ECC83 in both of the amps that I have. The DPA-10, a close relative of these, is considered very similar to the Mullard 5-10, and does not have this capacitor. I don't know if it was a later addition to improve some aspect of performance. If this capacitor is removed, we are left with a circuit very similar to Mullard 5-10 and indeed 5-20 (see attached).

I'd be very grateful for comments form everyone on whether the circuits in my amps, reflected in the schematic (C15 removed in the attached), have been doctored along the way with resultant errors. They look to me pretty much like the Mullards other than C15.

Thanks

Andrew