Hello, I want ask if this is normal:
I integrated a Rockster Booster with anode voltage supply from B+5 wich is together with V1a. From there the voltage dropped at this kathode (1k5//22µF) from 500mV to around 260-300mV.
But what makes me concern is that this voltage rises slowly from around 200mV to around 300mV. Than it is stable. But it takes 30 seconds until it is stable.
Is this normal?
The Bosster is at V2 integrated (the empty triode).
As I said, no problem and the sound is ok, but this slow rising ? V1b has 900mV imediate and stable.
Though I find 250 -300mV (depends at the tube) is quite low - or not?
The Rocket has identical values like the schematic here in the Rocket pages.
Best
Hans-Jörg
slow rising kathode voltage at V1 a in Rocket
Moderators: pompeiisneaks, Colossal
Re: slow rising kathode voltage at V1 a in Rocket
Is the plate voltage also increasing like that? Tried a tube swap?
If it says "Vintage" on it, -it isn't.
Re: slow rising kathode voltage at V1 a in Rocket
Hello,
yes, shure I swaped tubes.
What happens is that the cathode jumps to 260mV and than slowly (1 minute) to the highest range, around 350mV.
When I change the V1 it jumps also to 260mV and than slowly to let´s say 305mV. Depends on tube.
The anodes are stable from begin. The other cathodes too.
Maybe the cathode resistor weak or the cap (22µF)?
Is this a known phenomen?
But: this triode is connected with the booster triode (by Anode share) wichis the last triode (V2B). Maybe therefore? Different grounds!
The Booster cathode ground is at the tube socket and potentiometer ground is at PSU Cap.
I guess it is nothing sirious but I never met with this cathode rising.
Best
Hans-Jörg
BTW: this Rocket ist sweet!
But I need it perfect because it is a Christmas present from me to my daughter (15) to use it in her first band wich she created now. Members all from her school class.
Therefore this amp must be save - you understand? I fullfilled all security rules for tube amps also a 100nF at the entrance, so that no DC can flow to Guitar, etc.
yes, shure I swaped tubes.
What happens is that the cathode jumps to 260mV and than slowly (1 minute) to the highest range, around 350mV.
When I change the V1 it jumps also to 260mV and than slowly to let´s say 305mV. Depends on tube.
The anodes are stable from begin. The other cathodes too.
Maybe the cathode resistor weak or the cap (22µF)?
Is this a known phenomen?
But: this triode is connected with the booster triode (by Anode share) wichis the last triode (V2B). Maybe therefore? Different grounds!
The Booster cathode ground is at the tube socket and potentiometer ground is at PSU Cap.
I guess it is nothing sirious but I never met with this cathode rising.
Best
Hans-Jörg
BTW: this Rocket ist sweet!
But I need it perfect because it is a Christmas present from me to my daughter (15) to use it in her first band wich she created now. Members all from her school class.
Therefore this amp must be save - you understand? I fullfilled all security rules for tube amps also a 100nF at the entrance, so that no DC can flow to Guitar, etc.