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Posted: Mon Apr 14, 2008 11:50 am
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The Copperhead is darker than the Ragin Cajun, but at the top end, not more bottom end. I think that a modeling amp works best with a broad-range speaker that covers everything, especially the top end. The RC is the best 10-inch speaker I've found. Even though it doesn't have the deep, round tone of the stock speaker, nothing else I've tried does, either! At least, not in a 10-inch speaker.

Listening to the stock speaker and the RC side by side, I don't miss the roundness. It can actually be boomy on some of the clean voices. The RC provides all the bass you can use in any practical sense.

Edited to add:

For the heck of it, I tested both Super Champ XDs side by side, with the stock one set on Channel 1, tone at 7 and 7. The RC's tone controls needed to be set at around 6 and 8 to cut the treble and boost the bass to sound more like the stock speaker. But it was louder and it still cut better.


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Posted: Mon Apr 14, 2008 5:18 pm
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Thanks, Bill, for all the effort. My credit card hangs above the keyboard, even as I type, and Guitar Center is about to make $65 in an online sale on a Ragin Cajun speaker.

Can I bother you for a coupla more questions?:

1) do those tone settings also qualify for the "clean" (no amp voices) channel too?

2) are your SCXD's modded with non-stock tubes, and will the same tone characteristics apply to the stock tubes?

3) there is a discussion in here that the 12ax7 pre-amp tube is actually a rectifyer circuit. Is it, or is it a true pre-amp? And...does the "clean" channel use the 12ax7 "cleanly" if the F/X Level is set to one, or is the solid state circuit always in the signal path?

Thanks, Again!
Bob


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Posted: Mon Apr 14, 2008 6:57 pm
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I did this last comparison test on channel 1, which is the clean channel, but it's actually a "voice." It's the same as the Blackface voice, voice 4, on channel 2. But yes, the 7 and 7 were applied to channel 1.

One SCXD is bone-stock, with EH 12AX7 and 6V6s. The other one is modified so it can take 5881s (6L6GBs). It can put out 26W in that configuration, 30+ watts if I swap in a different output transformer. But for the test, I popped the stock 6V6s back in, so it was more apples to apples.

Other output tubes (JJ, Tung-Sol, whatever) will have a minor effect on tone, despite the claims of some. Different 12AX7s will be a little warmer or crisper, rounder or cooler, but at the end of the day, it's half a notch on the tone control's worth of difference.

Much of the early stuff (even WikiPedia!) written about the SCXD and how it uses its tubes is just flat out wrong. People were guessing, wishful thinking, or just making things up.

So hit the reset button and forget everything that people thought they knew about the Super Champ XD (and the VCXD). Here's what happens, straight from the schematic:

The SCXD is a digital amplifier that is made louder by a set of tubes. Period.

The DSP is always active. It provides the Channel 1 Blackface voice as well as all of the Channel 2 voices and all of the effects.

There is no tone stack in the amp. All tone shaping is done by the DSP. There is no volume control that directly acts on the guitar signal. All volume and gain are controlled by the DSP. The actual amount of volume and gain, as well as the range of the tone controls, is different for each amp voice. So is the basic gain threshold and the amount of noise gating (on the high-gain voices).

When the effects knob is on 1 the effects are off. When the pedal is plugged in and engaged, the effects are off.

There is no straight-to-tube mode. The signal always goes through several op amp stages on the way to the DSP and a couple of op amp stages on the way to the tubes. There is no signal processing of any kind after the signal leaves the DSP.

The first stage of the 12AX7 is simply a buffer. It takes the signal from the DSP and makes it stronger. The second stage of the 12AX7 is the phase inverter. It drives the 6V6s.

End of story! And even though some people think that DSP is evil, the rave reviews and out-of-stock condition of this amp would say otherwise.


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