I made big progress yesterday on the DSL40C. I had to abandon my theory and accept results. For some reason, the DSL40C has a gain knob that goes from zero to 10. However, at anything much past 12 noon, the gain isn't usable. It becomes to "gainy" and loose. In reality, you get the best tone and clarity at somewhere between 9:30 to 10:00 on the gain knob. Why Marshall allows so much higher, yet utterly unusable gain levels, is a mystery.
This is an anomaly I verified in other DSL's and also TTR forum member Don O verified the same condition on his own DSL40C. - High gain is available, but at increased gain levels, the amp sounds muddy, "pillowy," like a clogged up drain. The attack of the guitar note on palm muted passages is like a "splat, or a "farting noise."
Currently, I am running a Russian Genelex B759 (highest gain available) in V1 with a Marshall Red Label ECC83S in V2, a JJECC83MG in V3 and a JJ5751 in V4.
I chose this setup, based on tubes that I had on hand. It made sense to my head that the gain should start high and descend or 'cascade' to a lower value as the signal moved from V1 towards V4. Not sure there is any science behind that, but that's how I did it.
Here's my current settings. I'm using the 'Lead 1' position (this is red or drive channel #1 which is a lower gain setting) because 'Lead 2' really increases the gain level and things start to get undefined rather quickly:
As you can see, my gain knob is set to dial position 3. This is where I have the greatest clarity, even though I would like more "gain" or more saturation in the tone, I'm sticking wit this setting for the greatest clarity.
I started using the Tube Screamer TS-9 (on loan from TTR chum ChasFred) with drive at 10am and level full-up for a sort of clean boost, and this works very well. It does slightly - ever so slightly - increase the gain, makes the tone seem bigger, but doesn't squeal and feedback.
I also found a very cool setting....which gives a very Ratt/Robbin Crosby rhythm tone.
'Tone Shift' in, which is said to give a slight mid scoop, but I hear a high cut...which I counter with mids full-up. Then, I crank 'presence' and add 'resonance' to just dull the edge so it is tolerable to the ear at volume levels of 4-5.
The result is a very 3 dimensional sound, almost like two guitars are playing at the same time - one clean and one distorted...although it certainly sounds like it has less gain on tap than Crosby's tone.
The end result is a much better, much more usable tone, but only if I keep my gain settings really low...
More to follow...