#Vox ac30cc2 brilliance switch Patch#
#Vox ac30cc2 brilliance switch mods#

It didnВґt sound bad with the JMI 47pF cap. The tonestack coupling capacitor is fine at 56pF. But, because it is before an IC, I think they should be already tweaked to avoid clipping - even if at very low volume I have a little. I believe increasing R17 or decreasing R16 could help in that regard.

The other resistors right before the IC could be tweaked for more volume balance between channels. But, with the jumper we have more or less the same volume between channels with a bit more drive in the Top boost. It didnВґt sound bad with the 330k resistor in there. I was tempted to go up to 330K, but maybe that would be over the top and too compressed for a VOX. Yes, the plate resistor were the essencial gain modifications. All I wanted was to set them as close as possible to vintage specs, but maybe they have to be adjusted to avoid clipping. I was trying to understand about those resistors before the IC. Perhaps the Reverb could be a bit better and tremolo less noisy (If I put it into maximum, it amplifies hum even without playing). It may work well on a combo, but with a closed cab, some highs are already lost and the sparkle character was reduced, so I went back to 56pF.ДЄll else is original.

Both work well.Д¬hanged the 56pF coupling capacitor from the tonestack to 47pF vintage specs. I also reduced the bypass cap from the TB volume control from 120pF to 100pF. The suggested 68pF by other users was still very muddy sounding. In the end, I have 100pF or 200pF with the brilliance switch 'on'. I also placed a fixed 100pF cap in the normal volume control and another 100pF in the switch. I jumped R49 to get a bit more gain and even the signal from the two different channels.

#Vox ac30cc2 brilliance switch mods#

Then, I found some pages about several mods to the circuit, which, in my opinion didnВґt work too well, or at least, they might work for the combo version, but, not so much for the head version. Well, I changed R6 and R7 to 220K as it seemed too obvious for some extra compression. I use it through a 2x12 G12M greenback combo, closed back. I actually like it a lot and I am just trying to understand it better. PS - R23 seems to interact with the IC as well. But itВґs also not the first time I only see one of the channels with the capacitor, wehereas the other channel doesnВґt have any capacitor before the IC ! This is not the first time I see a capacitor right before the IC. Is C39 removing treble from the signal path and mushing the tone ? not to mention the new one (CC) has R49 close to the 'volume' pot which is also cutting the signal.Д«oth TB channel compared (old and new), it seems the old one passes more signal as well.ДЄlso, why the TB channel has a 220nF in C39 before the Fx Loop and those resistors? The normal channel doesnВґt have anything.

Looks like the normal channel has a 470K resistor and the TB channel uses a voltage divider which seems to me is only allows 36% of the signal through.Д«oth normal channels compared (old and new), it seems the old one passes more signal. I wonder If removing R16 and changing both R15 and R17 to 220K would hurt ? Were the values changed/adjusted to avoid IC clipping ?

#Vox ac30cc2 brilliance switch Patch#

The old ones seem to use just a 220K resistor in the signal patch for each channel before the PI. Also, in the 'CC' the signal goes into an FX loop, and whereas the old ones it doesnВґt. I was looking at both schematics and found a few differences, which IВґd like to understand better.ДЇor instance, in the 'CC' range, we have different resistors in the places of R15 and R16 when compared to a old model.