blindmouse
23 april 2007, 14:07
Sorry voor 't Engels, maar als autodidakt ben ik beter op de hoogte van de Engelse termen dan van de Nederlandse equivalenten.
Meningen graag over het volgende. Vond ik op firebottle.com
made the mistake once of putting 10k resistors on the screens of a push-pull 6V6 amp. It sounded so bad that it prompted me to experiment with screen resistance by using a 5 watt potentiometer, varying the resistance to see what happens. The amount of screen resistance made a big difference. I posted my notes from that test some time ago - here they are again.
6V6 screen grid resistance:
----------------------
1) 10k ohms: sounded terrible.
2) 1k ohms: not nice at all, artificial sounding, harsh distortion.
3) 470 ohms: some improvement, but still harsh and ugly sounding.
4) 220 ohms: starting to sound better, good clean tone with a smoother transition to better-sounding distortion.
5) 100 ohms: nicer still, guitar and amp sounding great, good clean sound, really nice distortion, still has some amount of compression.
6) 10 ohms: loving it
7) no screen resistor (like the 5F2 schematic): loving it
As long as the screen grid doesn't exceed maximum dissipation there should be no problem (although a resistor can offer protection in the event of a tube failure). Even with zero or minimal resistance the screen dissipation in my amp is within working levels.
Jan
Meningen graag over het volgende. Vond ik op firebottle.com
made the mistake once of putting 10k resistors on the screens of a push-pull 6V6 amp. It sounded so bad that it prompted me to experiment with screen resistance by using a 5 watt potentiometer, varying the resistance to see what happens. The amount of screen resistance made a big difference. I posted my notes from that test some time ago - here they are again.
6V6 screen grid resistance:
----------------------
1) 10k ohms: sounded terrible.
2) 1k ohms: not nice at all, artificial sounding, harsh distortion.
3) 470 ohms: some improvement, but still harsh and ugly sounding.
4) 220 ohms: starting to sound better, good clean tone with a smoother transition to better-sounding distortion.
5) 100 ohms: nicer still, guitar and amp sounding great, good clean sound, really nice distortion, still has some amount of compression.
6) 10 ohms: loving it
7) no screen resistor (like the 5F2 schematic): loving it
As long as the screen grid doesn't exceed maximum dissipation there should be no problem (although a resistor can offer protection in the event of a tube failure). Even with zero or minimal resistance the screen dissipation in my amp is within working levels.
Jan