Bloodrock
Well-known member
Just wondering if anyone has done any mods to their Chupas, and if so what? I'm loving the crap out of my 50, but wouldn't mind thickening up the mids a little for a little more midrange growl.
FourT6and2
Well-known member
I dunno. My Chupa has plenty of mid-range growl. Just gotta adjust the EQ right. But I've been toying around with modifying mine. But haven't done it yet. But supposedly:
1. Changing PI Output Caps to 0.047 (if your Bias Grid Leak Resistors are 220k, then go with 0.022) will tighten up the amp a bit.
2. Changing "Fizz Cap" to 100pF will cut some top-end fizz.
3. Lowering the value of V1a Plate Resistor slightly will cut some high-end/harsh gain.
But not all the Chupas have the same values apparently. I've seen a few and they all varied slightly. But on mine, if you use these settings, you get some really aggressive mids and it's not harsh in the top-end:
Resonance: 9:00
Presence: 12:00 to 1:00
Bass: 9:00
Mid: 3:00 to Maxed
Treble: 12:00 to 1:00
Master: To taste
Gain Style Switch: To the right
Gain 2: 2:30
Gain 2 Switch: To the left
Gain 1: 12:00
Cain 1 Switch: Middle
I'd start there and play around.
1. Changing PI Output Caps to 0.047 (if your Bias Grid Leak Resistors are 220k, then go with 0.022) will tighten up the amp a bit.
2. Changing "Fizz Cap" to 100pF will cut some top-end fizz.
3. Lowering the value of V1a Plate Resistor slightly will cut some high-end/harsh gain.
But not all the Chupas have the same values apparently. I've seen a few and they all varied slightly. But on mine, if you use these settings, you get some really aggressive mids and it's not harsh in the top-end:
Resonance: 9:00
Presence: 12:00 to 1:00
Bass: 9:00
Mid: 3:00 to Maxed
Treble: 12:00 to 1:00
Master: To taste
Gain Style Switch: To the right
Gain 2: 2:30
Gain 2 Switch: To the left
Gain 1: 12:00
Cain 1 Switch: Middle
I'd start there and play around.