Small Class A guitar Amp- old school-
Posted: Mon Aug 30, 2010 10:30 pmWell, I decided to see how some early versions of popular valves would sound for a small studio /practice amp. It had to be class A, use only real NOS valves from the great makers and not look like a guitar amp. Controls are minimal, Tone, Volume, switchable cathode bypass on the pre stage, switchable global feedback. Valves as shown are a 1947 Brimar 6L6G for output, late 40s Brimar 6SL7 octal dual triode, late 40s Brimar 5V4 full wave rectifier. Transformers are Hammond. The audio is in one sealed diecast box, Power supply and O/T are in a separate box with 2 cables. One carries heater and Gnd,the other HT, Feedback and Plate supply for the output bottle. HT is around 375 V, on the limit for original 6L6G. Sound is warm, has good bite. Power is around 7 Watts.
I also have tried it using a late 60's GEC KT66 and an RCA Black plate 6SL7 with an AWA 5Y3GT for the rectifier. This gives a bit more of a "mellow" sound.
Wiring is all point to point, caps are orange drop, silver mica and sprague electros.Sounds nice through a vintage JBL K120.
A fun little distraction...
I also have tried it using a late 60's GEC KT66 and an RCA Black plate 6SL7 with an AWA 5Y3GT for the rectifier. This gives a bit more of a "mellow" sound.
Wiring is all point to point, caps are orange drop, silver mica and sprague electros.Sounds nice through a vintage JBL K120.
A fun little distraction...
