Vouais, tu arrêtes pas de le dire, c'est vraiment que ça doit déchirer
Je vais essayer de bidouiller la SHO pour en faire un trebleboost..
Par contre j'ai trouvé des petits tubes en laiton chez MrBrico (je bosse là bas, donc j'ai le temps de regarder à droite à gauche pour les fournitures), qui pourraient faire l'affaire pour des turrets, à la façon des vieux amplis.. Je cherche encore un support (bien qu'une plaque d'époxy ferait l'affaire), mais je pense faire ma pédale comme ça.. Plus propre qu'un câblage en l'air, et moins contraignant qu'un PCB..
Edit: petits mods en provenance de Freestompboxes:
"I note that the original schematic and layout specify that the triode at pins 1-3 be used for the voltage gain stage, and 6-8 for the follower.
This isn't usually the best way to do it with a 12A*7. With battery power or regulated DC going through the heaters, it doesn't matter which triode you use in which position, but if you're using AC or less-than-pristine DC, the triode at pins 6-8 will be quieter, due to the location of the heater pins on the tube. (You can find mention of this in the data sheets on many 12A*7 series tubes.)"
"I lower the coupling cap between stages for less bass."
"For lowering bass, you could try lowering the value of either the input cap, or the coupling cap between the two tube stages."
"I am bypassing the Valvecaster gain pot with a 2.2nf cap. This helps maintain some brightness when the VC gain is turned down. For the input cap on the Valvecaster I am using a combination of caps to give me 2.7nf. This helps tighten up the bottom end."
"To tame the gain I would lower R2 and R3. 220k and 100k seem pretty high for a low voltage circuit. Even in a regular high voltage amp the normal value is just 100k. So maybe cut them in half."
"if you bring down that 220k to 100k it will def lower the gain a bit. I built mine with both plate r's at 100k."
"A 1M gain pot allows massive, saturated gain. A little mushy in the bass frequencies, but pretty cool. I'm considering putting a "more" switch in, whereby it adds a resistor in series to the regular gain pot."
"Adding resistance to the plate resistors(R1 and R2) will increase gain. Adding resisitance to VR1, in series with the gain pot, will decrease gain."
"guitarx: replace the 100k resistor with 47k. Replace the 220k resistor with 100k. Beautiful cleans."
"To fellow Valvecaster experimenters -- I've currently got this circuit on a breadboard, switching out everything and I have some items of interest to report, especially for those looking for more gain.
The nicest clean sound I've found so far, is with the following mods:
R2 = 100k
R3 = 47k
C1 = 0.1uf
Remove C4 and VR2"
"Finally received that 7812 - mounted with the 100uF filter cap on the dc jack - hiss is just a memory...
put a 100uF cap across the DC jack (positive leg to positive rail, neg. leg to neg. rail), then, instead of connecting the positive rail directly to the circuit, connect it to the regulator's pin1, ground to pin2, and the circuit to pin3. Then screw it on the enclosure. It is a 7812."
