Auto Clean and the Compressor

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rbc
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Auto Clean and the Compressor

Post by rbc »

I've been tinkering with non-Rockman compression and distortion. I was kind of curious if anyone knows how Auto Clean works with the compressor. It seems like the compression would "fix" the distortion level within the bounds set by the compressor output. Does Auto Clean change the ordering of compression and distortion somehow?
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rbc
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Re: Auto Clean and the Compressor

Post by rbc »

I guess another part of the auto clean circuit, would be some kind of treble bleed circuit to restore the treble when you have the volume rolled off. I suppose that could be added at the guitar's volume pot, or in a volume pedal that's between the guitar and the rest of the rig.
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RockmanCentralBob
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Re: Auto Clean and the Compressor

Post by RockmanCentralBob »

From what I can see in the schematics, auto clean doesn't change how the compressor responds at all. That said, many of the Rev 20 changes are made in the compressor circuit, and I strongly suspect part of that was to improve the performance of the auto clean circuit.

The auto clean is all handled after the loop return prior to the distortion stage. Perhaps an over simplification, but it basically detects the signal level using an optocoupler just after the loop return. I'm not entirely certain (I'm not an engineer, so I'm speculating a bit about what it looks like it's doing) but it looks like the lower the signal level, the more signal gets shunted to ground. There's also some circuitry in there that looks like some frequency filters, so I would say it could be targeting specific frequencies to reduce the level of so that those frequencies don't hit the clipping LED's to cause distortion as easily (perhaps the highs?).

When auto clean is engaged, it also provides an alternate clean signal path in parallel with the distortion path, almost like a variable presence control on an old tube amp. Hard to say, but since they are in parallel, it looks like it's mostly allowing the high frequencies to pass through un-distorted (and most likely boosted), which would align with how it's described in the product literature.

I basically did the same thing with my Kemper profile I created from my Rev 20 Sustainor. When I back off on the morphing pedal, it lowers gain, reduces the pre-distortion 800hz mid boost back to flat, reduces the lows and mids in the stack (basically representing the EQ controls on the amp, which are post distortion), and boosts the treble and presence, all at the same time. I get a perfect clean sound just by rocking the pedal back.
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rbc
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Re: Auto Clean and the Compressor

Post by rbc »

Interesting, kind of a clean/distortion blend thing. That's one of the things about the Sustainor. It packs a lot of different capabilities into one unit.
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RockmanCentralBob
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Re: Auto Clean and the Compressor

Post by RockmanCentralBob »

For recording, all you need is a Sustainor and maybe a couple of EQ's.