Actually... after owning the SR-404/SRM-313 for a long time, I do have to agree with Jazz - there is this coloration. There is also a tonal imbalance in this combo - the midbass and lower midrange sounds recessed while the upper midrange and lower treble sound too pronounced.
Note: this next bit is all hearsay! I don't have any actual experience with these combos!
I don't recall seeing these kinds of sentiments about the SR-Lambda Pro/SRM-1 Mk II combo, and I have been told that pairing the SR-404 with the SRM-717 amp eliminates a lot of this tonal imbalance; this makes sense in the light of the fact that the SRM-717 has a more pronounced midbass/lower midrange and a softer high end than the SRM-313 or even the KGSS. Supposedly.
So, assuming these observations are valid - I do believe that a) a lot of the fault for the above tonal imbalances rest with the SRM-313 amp, and b) the synergy between the SR-404 and SRM-313 is not the best. I think that an amp with a "tubey" sound signature would fit the SR-404, and similarly the SR-303 and SR-202 much better than the SRM-313.
I
would, of course, answer a lot of these questions first hand if Peter McAlister
would, of course, ship my amp sometime this year. Supposedly he did, but it's been 2 weeks and I've seen no sight of it. What the hell is going on?!?