Ceriatone Chupacabra mods

  • Thread starter Thread starter peterc52
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FourT6and2 said:
Nope lol. Ceriatone left out a 10K B+ dropping resistor. There should be one between the PI and V2. The one you circled is between V2 and V1. These resistors separate each section of the amp so they each get their own filtering. Without it, you have multiple stages sharing the same filter cap.

It's fine if you like that sound/feel. But if it were me, I would install it.
Have a look at one of their superlead layouts and you'll see it: https://ceriatone.com/wp-content/uploads/2016/08/Plexi50BassCeriatone.jpg

Just make sure you get the connections right, so if you do it... really pay attention to how it's wired.
Click to expand...
Damn. I will!
 
FourT6and2 said:
Nope lol. Ceriatone left out a 10K B+ dropping resistor. There should be one between the PI and V2. The one you circled is between V2 and V1. These resistors separate each section of the amp so they each get their own filtering. Without it, you have multiple stages sharing the same filter cap.

It's fine if you like that sound/feel. But if it were me, I would install it.
Have a look at one of their superlead layouts and you'll see it: https://ceriatone.com/wp-content/uploads/2016/08/Plexi50BassCeriatone.jpg

Just make sure you get the connections right, so if you do it... really pay attention to how it's wired.
Click to expand...
That haven’t updated the circuit still?

What does it do to the sound?

IMG_9870.png
 
peterc52 said:
That haven’t updated the circuit still?

What does it do to the sound?

View attachment 376103
Click to expand...

Correct. They haven't updated their circuit. I had a chat about this with Ceriatone years ago. But he wasn't interested in fixing it. You gotta realize that they don't design these circuits. They just copy them from schematics posted to forums. Those schematics are drawn by users who blueprint various amps they own or have seen. This particular amp is most likely a clone of a Fortin Jose mod that is in turn, a variation on a Cameron mod. So you've got a few moments where information can get lost in translation. Cameron —> Fortin —> forum member who drew up schematic —> Ceriatone. Sometimes key details like this get lost along the way. Schematics have mistakes, etc. Ceriatone wasn't interested in fixing this at the time. Maybe they have now, who knows.

Without a 10K resistor between the PI B+ node and the left side of that cap (as it's drawn in THIS layout), the PI and V2b (cathode follower) are sharing the same filtering. It's not "bad", per se. But it's not what many would choose to do in an amp like this, that is supposed to be a "hot rodded", higher-gain JCM800. Amp will be a little looser, flubbier, rounder sounding, and more squish/sag.

Adding that resistor will give each stage it's own independent filtering. This provides each stage with it's own reservoir of smoother DC/B+. So the amp will be a little tighter, faster attack, less sag, etc.
 
FourT6and2 said:
Correct. They haven't updated their circuit. I had a chat about this with Ceriatone years ago. But he wasn't interested in fixing it. You gotta realize that they don't design these circuits. They just copy them from schematics posted to forums. Those schematics are drawn by users who blueprint various amps they own or have seen. This particular amp is most likely a clone of a Fortin Jose mod that is in turn, a variation on a Cameron mod. So you've got a few moments where information can get lost in translation. Cameron —> Fortin —> forum member who drew up schematic —> Ceriatone. Sometimes key details like this get lost along the way. Schematics have mistakes, etc. Ceriatone wasn't interested in fixing this at the time. Maybe they have now, who knows.

Without a 10K resistor between the PI B+ node and the left side of that cap (as it's drawn in THIS layout), the PI and V2b (cathode follower) are sharing the same filtering. It's not "bad", per se. But it's not what many would choose to do in an amp like this, that is supposed to be a "hot rodded", higher-gain JCM800. Amp will be a little looser, flubbier, rounder sounding, and more squish/sag.

Adding that resistor will give each stage it's own independent filtering. This provides each stage with it's own reservoir of smoother DC/B+. So the amp will be a little tighter, faster attack, less sag, etc.
Click to expand...
Thanks for the explanation!
 
FourT6and2 said:
Nope lol. Ceriatone left out a 10K B+ dropping resistor. There should be one between the PI and V2. The one you circled is between V2 and V1. These resistors separate each section of the amp so they each get their own filtering. Without it, you have multiple stages sharing the same filter cap.

It's fine if you like that sound/feel. But if it were me, I would install it.
Have a look at one of their superlead layouts and you'll see it: https://ceriatone.com/wp-content/uploads/2016/08/Plexi50BassCeriatone.jpg

Just make sure you get the connections right, so if you do it... really pay attention to how it's wired.
Click to expand...
Good catch!!!!
 
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