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Got a Ceriatone 36RP and it sounds frickin great, but I don't know why looking at the schematic. Usually I can look at a schematic before I hear an amp and have a pretty good idea what it's going to sound like and even what mods I'd probably do, but on this one, I'm stumped.
Forget the EF86 channel a moment (which also sounds great), the M style channel is a slightly tweaked Plexi type circuit where almost everything on the schematic tells me it ought to be similar but brighter to most Plexi circuits. It ain't. It's warm, not harsh in any way or overly bright, none of that brittle glass Plexis tend to exhibit when turned up, punchy, loads of fat midrange even with the 22k mid pot at noon, responsive, nicely compressed....
And it has as much gain on tap as any 2203/4, maybe more, in spite of having one less stage cascaded. It hits 80's George Lynch tones/gain levels at non-ear shattering volumes and with no pedal required to boost it. It's clearly standard Plexi staging of input stage, 2nd stage, cathode driven stack, albeit with a master tucked in at the end almost as an afterthought.
But looking at the schematic, I see .01uf coupling caps where .022uf caps generally are, a 1M/500pf combo instead of the usual 470k/470pf combination, an 820ohm CK bypassed by a 1uf cap (which has a higher knee than a 2.7k bypassed by a .68uf), 330pf treble cap instead of 470pf, 47k slope resistor instead of 33k. All those things would lead me to think "This will be brighter/tighter than a usual Plexi". NOT.
The only things I see that say "warm" are the 56k Rk on the cathode follower instead of 100k, and the voltages are somewhat on the low side on the preamp tubes (and were REALLY on the low side until I found/corrected a factory mistake, 470k dropping resistor where the 2.2k ought to be).
It is of course cathode biased with optional NFB (which does almost nothing), but I've played Plexi circuits set up that way before and they sounded pretty much like a standard Plexi, nothing like this sounds.
Any clever individual able to tell me why this thing sounds so different?
Forget the EF86 channel a moment (which also sounds great), the M style channel is a slightly tweaked Plexi type circuit where almost everything on the schematic tells me it ought to be similar but brighter to most Plexi circuits. It ain't. It's warm, not harsh in any way or overly bright, none of that brittle glass Plexis tend to exhibit when turned up, punchy, loads of fat midrange even with the 22k mid pot at noon, responsive, nicely compressed....
And it has as much gain on tap as any 2203/4, maybe more, in spite of having one less stage cascaded. It hits 80's George Lynch tones/gain levels at non-ear shattering volumes and with no pedal required to boost it. It's clearly standard Plexi staging of input stage, 2nd stage, cathode driven stack, albeit with a master tucked in at the end almost as an afterthought.
But looking at the schematic, I see .01uf coupling caps where .022uf caps generally are, a 1M/500pf combo instead of the usual 470k/470pf combination, an 820ohm CK bypassed by a 1uf cap (which has a higher knee than a 2.7k bypassed by a .68uf), 330pf treble cap instead of 470pf, 47k slope resistor instead of 33k. All those things would lead me to think "This will be brighter/tighter than a usual Plexi". NOT.
The only things I see that say "warm" are the 56k Rk on the cathode follower instead of 100k, and the voltages are somewhat on the low side on the preamp tubes (and were REALLY on the low side until I found/corrected a factory mistake, 470k dropping resistor where the 2.2k ought to be).
It is of course cathode biased with optional NFB (which does almost nothing), but I've played Plexi circuits set up that way before and they sounded pretty much like a standard Plexi, nothing like this sounds.
Any clever individual able to tell me why this thing sounds so different?
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