Nice goal but letīs put it in perspective:
in a simplified explanation:
1) *all* amps clip, eventually.
The level at which they start clipping is called roughly "maximum power / rated power / etc.".
2) in your case,your amp is rated 50W because if you feed it a clean sinewave, it will be clean up to 49W and will be visibly clipping peaks at 51W. Ok, not so strict, but thatīs the general idea.
3) so the trick for cleanliness is to use the amp way below clipping level, or well below maximum power. (same thing)
4) BUT: you say that50 watts (just barely enough for one of my music projects)problem is than now you have to open volume to, say, 5 to reach overdrive channel level. (and I guess itīs not that clean by then).On the AVT 50H clean channel, to get any volume comparable to the overdrive channel, you have to open up the gain pot, even a little for any signal and then more for more volume. Problem is of course, the more you open the pot, the more gain I get. I would love to get this channel cleaner than clean as clean can be.
IF you lower gain inside the preamp, amp will be cleaner, but sound weaker :O , to recover lost volume you now need to set it to 7 or 8 and again get dirty.
Fact is, you do not have a gain problem but a power one.
To throw some numbers on the table, just as an example:
Your current amp is 50W RMS.
The distortion channel can use all of that; even if it reaches the clipping point who cares or even notices? ... signal is already dirty !!!!!!!
Now you switch to the clean channel, not only it can not reach the full 50W, but it will probably be usable only up to 25 or 30W ... because a guitar has dynamics, reacts to picking pressure, so "now" itīs a little louder, "now" a little smoother ... yet it must never clip, so your *average* level will be less than maximum.
So in practice youīd need "a 100W amp. *used* at 50W" so clean never ever approaches clipping.
OR: use clean as loud as you can, and *lower* dirty chnnel setting to match that, that way you can go back and forth without problem.
If volume is not enough, you can mike and reamp your amp.
Or get a louder head, say 100/150W, use distortion at about 50W and youīll have lots of headroom for clean sounds.
Small mods wonīt change that, because they will not increase maximum power.