The claim is that it "virtually eliminates the universal problem all tubes have of stray electrons bouncing off the plate by manipulating (the suppressor) grids."
It's been out there for over a year; also known as the Hazen modification, after the Decware technician who thought it up. I have not tried it but it appears simple and cheap enough, easy to implement and totally reversible on Dynaco amps with their chassis-mount (rather than PC board-mount) output tube sockets and using the EL34 tube (Mk II, Mk IV, ST-70). It consists of breaking the external connection between suppressor grid and cathode, and replacing it with a nonpolar 0.1uF capacitor. What I'm wondering: would be its applicability to a higher-powered push/pull Ultralinear amplifier be the same as to a low-powered triode amp?
I may try it next time I have my Mk II amplifiers out for service, but in the meantime, has anyone else here attempted this modification?
Announcement by Decware as a modification for THEIR amps:
Part Two: an attempt to explain the modification:
The Decware forum, in which ONE member "Veryoldcat" reports trying it on his ST-70 with positive results: