Moderator: VelvetGeorge
bulldozer1984 wrote:Hey guys,
After ripping the AFD ish mod a year ago, I've come full circle back to it again. I have tried everything under the sun Including my own circuit that was bits of this and bits of that. Now I'm looking for that AFD tone again but with less top end. Herbvis, your last clip sounded spot on ! What did you have going on there
It sounds so authentic. Good job man.herbvis wrote:bulldozer1984 wrote:Hey guys,
After ripping the AFD ish mod a year ago, I've come full circle back to it again. I have tried everything under the sun Including my own circuit that was bits of this and bits of that. Now I'm looking for that AFD tone again but with less top end. Herbvis, your last clip sounded spot on ! What did you have going on there
An awesome spec! lol
For less top end with that spec, you probably need to increase mids and bleed some treble. More specifically increase your 2n2 1st stage coupling cap to 22n and fit a 2n2/470k peaker and a 1n bright cap. Increasing the 2nd stage cathode bypass cap should help too. Capacitor types can also effect the amount of top end. As far as bleeding off treble, try some 500p's over the 100k plate resistors on the 2nd and/or 3rd stages, the same as you've done on the 1st stage. Grid stoppers on the 2nd and 3rd stages of between 100k to 150k can also help keep things more controlled.bulldozer1984 wrote:Now I'm looking for that AFD tone again but with less top end.
Yeh I have done all that, but I can't help but feel that the circuit topology was wrong to start with. The amp sounded good, but it didn't have the X factor once I had smoothed it out. I forgot to mention that it has 68k grid stoppers one the first 2 stages.BRMSlash wrote:For less top end with that spec, you probably need to increase mids and bleed some treble. More specifically increase your 2n2 1st stage coupling cap to 22n and fit a 2n2/470k peaker and a 1n bright cap. Increasing the 2nd stage cathode bypass cap should help too. Capacitor types can also effect the amount of top end. As far as bleeding off treble, try some 500p's over the 100k plate resistors on the 2nd and/or 3rd stages, the same as you've done on the 1st stage. Grid stoppers on the 2nd and 3rd stages of between 100k to 150k can also help keep things more controlled.bulldozer1984 wrote:Now I'm looking for that AFD tone again but with less top end.
What can I expect going from 68k grid stopper to 150k ?BRMSlash wrote:68k on the 1st stage is too much. You need cathode bypass caps on every stage and probably a 2k7 or 3k3 resistor in series with the cap to tame the gain a bit on the 2nd and 3rd stages. Also get rid of that treble bleed on the 1st stage and use a 250V or 400V MKT368 cathode bypass cap instead.
bulldozer1984 wrote:What can I expect going from 68k grid stopper to 150k ?BRMSlash wrote:68k on the 1st stage is too much. You need cathode bypass caps on every stage and probably a 2k7 or 3k3 resistor in series with the cap to tame the gain a bit on the 2nd and 3rd stages. Also get rid of that treble bleed on the 1st stage and use a 250V or 400V MKT368 cathode bypass cap instead.
BRMSlash wrote:68k on the 1st stage is too much. You need cathode bypass caps on every stage and probably a 2k7 or 3k3 resistor in series with the cap to tame the gain a bit on the 2nd and 3rd stages. Also get rid of that treble bleed on the 1st stage and use a 250V or 400V MKT368 cathode bypass cap instead.
Cheers thanks for your feedback, no one puts specs up anymore, but start with a 34 + extra gain stage. & tweak from there,snakepit86 wrote:
duuukeeeee OMG spects now please!!!!
yes 39, i have the right scheme, & i have done a few small changes, thanks for the infosnakepit86 wrote:benny did.... why no one shares anymore?
im i wrong or you wrote 39 instead of 36?
Ibeen working on some 39, last year a client brought his jmp 76 with the 39++ mod on it... im working on some schematics, its a very complete mod with 3 channels but its not the AFD sound, its de Lynch/Demartini/Aldrich sound.
If you what to try some real confirmed #39 spects take of the 2n2 cap on the #34, put a 680n on the second cathode insted of the 100n and a 680n on the CF
Not particularly, only what's been posted on this forum and trying ideas from similar mods and experimenting.snakepit86 wrote:oh sr well played i see you have looked at tim caswell's work too...