I contributed the above post about the need for a full-range speaker with a lot of headroom and proper timbre to gets strings right. I was going to stay out, but I've seen the posts and follow-up question about Vienna Acoustics Mahlers and have something to add.
I ran Mahlers in first and second systems for over six years. They are a very good orchestral music speaker as they have a lot of headroom, having the same large (too large) midrange drivers as the Maxx II's, supplemented with a pair of ten-inch woofers. The above comment regarding bass wooliness, which was noted by Anthony Cordesman in his review of the speaker, is correct -- the bass drivers on the speaker are quite difficult to control, Cordesman not getting satisfaction even with Krell monoblocks. Rich Maez worked at Rowland for many years, and he once told me that one of Rowland's Colorado dealers achieved really good bass control using Rowland's Model 501 ICe amps (Rich liked the combination and was thinking of buying Mahlers). That makes sense, as ICe amps are fantastic with subwoofers and have bizarrely high damping factors (what they do with highs rule them out for anything other than home theater and subwoofers, however, in my opinion).
I ran Mahlers with a Bryston 4B-ST very briefly, with VAC Renaissance 70/70 and 140/140 zero-feedback triode monoblocks (using VAC 300-B's) and with Rowland Model 6 monoblocks. Bass control-wise, they were pretty much the same with the VAC amps and the Bryston, which was a bit surprising, especially because they should have been terrible with the VAC 70/70 run with no feedback. I lived with them with the 70/70 for about a year, however, in a medium-sized room -- it was acceptable sound. The best bass control was achieved with the Rowland Model 6's, which was not surprising given those amps have a fair amount of current and are otherwise very high quality. The best overall sound was achieved with the VAC 140/140's, which just sounded so good with strings that the bass looseness was an acceptable tradeoff (others may not find the tradeoff acceptable, however, and the VAC amps are very expensive).
My recommendation would be the Model 6's or, budget permitting, perhaps the darTZeel. Both are high-current, but are low enough in power that they stay away from the unnatural, mucked up sound that high-powered amps featuring a lot of output transistors give. I own the darTZeel, but never tried it with the Mahlers. A good friend of mine ran the darTZeel with Salons in a good-sized room (a speaker I used in my main system for three years that is also excellent with orchestral music, by the way) and listens almost exclusively to big orchestral (Gustav Mahler, the Russian 5), and despite the Salons being a good 4 db. less efficient than the Mahlers, he never lacked for power. Another suggestion would be the CAT amps, which would likely be magnificent with Mahlers, as they can control the woofers of virtually any speaker and are otherwise tremendous amps. Be very careful with tube amps and Mahlers, however, as most well-known high-powered tube amps would be awful with the Mahler's bass issues and don't sound particularly good in any event. With this speaker, go with the best solid-state amp you can afford (Rowland 6, 8 or 9 are all safe bets).
The above post about active speakers is of course correct, but my experience is that most active speakers or powered studio monitors lack the finesse of audiophile speakers (very good ones would likely be better than Mahlers, which are, at the end of the day, a good but not great speaker).
