a solid state amp that is recessed in the treble

Try any class A biased, low-to-mid power, SS amp.
Electro monos, the small Plinius... Any well maintained vintage class A amp probably could bring on happiness.
Another good if unlikely candidate is a wide bandwidth amp: Spectral for example.

Stay away from Krell, M-Lev, & the like. Accuphase would probably not fit the bill either.

I'm guessing you don't really needed a "muted" amp -- just one that doesn't sound shrill to you in the 2-6kHz region... After all, well designed tube amps reproduce high frequencies very well indeed, so if these frequencies are muted you'll miss them... even if the 57s don't go up very high.

I have actually enjoyed 57s with class A SS amp, hence the blurb above.

Mrtennis,
I used to experience what you observe as "hard, shrill, aggressive and unpleasant" sound with my Marantz PM 15 (1993 model). I always thought the problem was with my components -- until I started concentrating on cables and tweaks. They were the key. I have no such complaints anymore.

Not sure that you are asking the right question. I think that the right question would be what solid state amplifiers would be a good sonic match, and avoid excessive brightness, with YOUR speakers.

The reason I say that is that in comparison with most tube amps, most solid state amps will tend towards brightness with those particular speakers, due to the interaction between their much lower output impedance and the impedance characteristics of the speakers, shown here and here. The Quad's huge impedance decrease that occurs as frequency increases, and the low impedance of the Maggies at high frequencies in comparison with its large impedance peak in the lower midrange, will cause an amplifier having low output impedance/high damping factor (such as most solid state amps) to sound brighter than one having higher output impedance/lower damping factor (such as most tube amps).

That said, back in the day the famous Mark Levinson HQD system paired his ML-2 pure Class A 25 watt amplifiers, having huge current capability, with the ESL-57 (and a separate woofer and high frequency tweeter). Perhaps the Pass XA30.5 would be a comparably suitable choice today. Some of the higher powered amps in the XA series, as were suggested above, may also be good choices, while perhaps also being better suited to the Maggies, but you would have to be careful to avoid overdriving and possibly damaging the Quads.

Regards,
-- Al

You may want to take a listen to a pair of Clayton Audio M-300's or M-200's. Another reco would be a Coda Model 15.0 or S100. The S100 is listed under discontinued products, but is still available upon special request. Good luck.

I have the Quad 57's in a "second system", and haven't wanted to spend to much on other components. After reviewing the experience of others, I found that the VTL Tiny Triodes pair very well (tube amps), and the Bedini 25/25 pairs well for solid state. No treble harshness there. Relative to the VTL, a small loss in midrange magic but a firmer bass. If you are having hardness with the Bedini, I think the issue might be something else. I've heard that the Pass Aleph 3 pairs pretty well too, but the Bedini is better. Quads and Maggies have very different amplification needs.