This moddifications intended to get a more natural, vintage sound from this amp. The mods included a gz34 rectifier, choke, and a negative feedback pot. Also a Pentode/Triode selector for the El84. Filtering alteration was made for the rectifier operation. One dedicated transformer was added for the rectifier.The internal speaker was swapped for a "greenback". the v1 tube was replaced by a 5751 NOS Jan (GE). Now this amp sounds great, and no need to mess too much with the design, even in the "infamous" chanel 2, in wich I am using a 12dw7 tube for a bit less pre- distortion.
As a combo I use it with a greenback in triode mode, and it cuts beautifully in a band situation. With an Alnico Gold the detail and natural compression are very pleasing, and the frequencies sound very well balanced for a small combo.
Edit: The tubes now are all NOS. A GE Gz34 for rectifier, on V1 I use a tungsram 12ax7, on v2 a 5751 jan, followed by a couple of rft ecc83 and a ge12ax7 long plate on the PI. The power section is a quartet of mazda el84. I biased the amp cooler and run it allawys on triode, with the tube rectifier.The speaker I use now is a G12H heritage. Nice sounding amp!
