Not being a tube amp expert, I turn to the more qualified DIY members. I have read several threads concerning grid stopper resistor types and values needed. There is a divided camp as to the need and the valued necessary if used. Here's what I would like to have help with. My amps sound "bright" to me(my opinion, It's not the mutiple sources or speaker systems, cable etc).
The driver/gain stage is a ECL86, with a 68k(IRC MF I think) grid stopper on the triode section, directly connected to the pentoide section. This is then capacitor coupled to the output stage consisting of EL34's operating in PP @ 645v/30ma with 100 ohm(MF) G1 stoppers. G2 is connected to 390v through a choke,in series through 4 tungsten lights, then to a 39 ohm(CC) resistor. G3 is grounded.
The amps are Lab Instrumentation refugees rescued from sure destruction(scrap heap). The spec sheet claims full power up to 40khz and strong operation up to 100khz.. I have checked many other circuits and 1k grid stoppers on G1 is common. There is lots of info concerning types of resistors, circuit configurations, inline components that make brighter sound, I would like to limit this discussion to real life grid stopper experience, and leave the engineering for another day.
My question;
Would raising the value of the stoppers tone down the amps? Some would say it is counter productive, but would it tone them down and what value would be a good starting point.
I am interested in the sound I enjoy, not technical correctness!
The driver/gain stage is a ECL86, with a 68k(IRC MF I think) grid stopper on the triode section, directly connected to the pentoide section. This is then capacitor coupled to the output stage consisting of EL34's operating in PP @ 645v/30ma with 100 ohm(MF) G1 stoppers. G2 is connected to 390v through a choke,in series through 4 tungsten lights, then to a 39 ohm(CC) resistor. G3 is grounded.
The amps are Lab Instrumentation refugees rescued from sure destruction(scrap heap). The spec sheet claims full power up to 40khz and strong operation up to 100khz.. I have checked many other circuits and 1k grid stoppers on G1 is common. There is lots of info concerning types of resistors, circuit configurations, inline components that make brighter sound, I would like to limit this discussion to real life grid stopper experience, and leave the engineering for another day.
My question;
Would raising the value of the stoppers tone down the amps? Some would say it is counter productive, but would it tone them down and what value would be a good starting point.
I am interested in the sound I enjoy, not technical correctness!