Which Mono block amps for ML Summit Speakers?

I'd be hesitant with the ARC CL150 mono amps. I had these for over a year and their 150w rating was quite wimpy to drive Magnepan Series 3.x speakers. The 110wpc VT130 stereo amp that I had before controlled the Maggies quite well without shutting down like the CL150s did regularly. I ultimately changed to Wolcotts for the Magnepans which worked beautifully in driveability and the openness of a tube amp.

Perhaps the ARC VT150 mono amps would be super here. The incredible dimensionality of the VT130 stereo amp leads me to believe the VT150 monos would be even more in this direction and a great match with the MLs which have a lesser 3-dimensional, bloomy, volume-of-space presentation than the Magnepans.

When I got the CAT JL-3 mono amps a couple years later, also rated at 150w, I realized 150w does not equal 150 watts. The CAT 150w rating was able to drive the Maggies like the CL150's never could come even close to doing. There's a lot more to a manufacturer's power rating when it comes to driving many speakers.

Perhaps the ML's are not difficult loads, but if you want more headroom, I suggest you look into the VTL 225 & 450 or Wolcott mono amps....or even a pair of the BAT VK60's. All of these are in the $4-5k range with the VT150s closer to the $6k price when you can find them.

I still have the Wolcotts. If you are near Minneapolis, I'd let you borrow them and try them out in your home.

John

YBA

Not necessarily the mono-blocks (very expensive) but something like a Passion 700.

I would look at Blue Circle amps.
Gilbert the designer uses ML CLSiiz and Statement E2's as his reference speakers.
I think gilbert has owned about 15 pairs of Martin Logan's over the years.

Blue Circle amps are voiced to sound very good with ML speakers and have NO problems driving them. Do some reading about Blue Circle amps. I think they are just what you are looking for.

In you price range I would look at the BC202. It is a hybrid amp with 1 tube on each side on the input stage. Or if you want to go all solid state you could look at the BC26, but IMHO the 202 is much better.

www.bluecircle.com

Cheers,
Nick

BTW: You can get the amps in pretty much any color combo you want. Don't let some of the pics scare you off. That is just Gilbert's sense of humor. :)

I've owned both Maggie IIIa's using their passive xover and Martin Logan Monolith IIIx's. The latter used the Krell designed electronic xover, allowing one to drive the panels with a separate amplifier, not unlike the Summit's.

The ML panels are more efficient than the Maggies. An amp's current drive is generally not the big need for ML panels (which it is for the Maggies) but the ability to drive the load presented by the panel. For tube amps, this gets down to the capabilities of the transformer. If it can't handle the load and phase, you'll generally suffer from some roll-off of the higher treble range. Per ML, the impedance is .7 ohm @ 20khz but I've not seen the impedance curve over its operating range but my guess is that it's a lot friendlier than the Monolith's.

I'd also run this set up in balanced mode although this will eliminate some of the amps such as the older Deluxe VTL 225 and 300 which are single ended or after market modded. Regardless, the VTL's come with nice transformers which should be able to deal with the load. Same for the Manley's although new, they're more than you want to spend.

Personally, I would look at the following on the used market.

The ARC VT-200 will do a decent job and offer good reliability and a company which has been around for a long time, thereby ensuring good service. You can also go mono bloc with the VT130 or VT130SE. One thing to note is that ARC generally rates their power output at 16ohms where their amplifiers are most efficient. Unlike some SS amp designs, power does not double or increase as impedance goes down. Generally, you lose power depending on the design and transformer.

VTL MB250 or MB450 would be excellent choices as well and should be investigated. Their products are reliable and again, they're around to service their amp's should something go wrong.

VAC makes some very nice products but they're above your range. There are a pair of Standard 220's on Audiogon but I've not heard that model. I have a pair of VAC PA-160 II's and they drove the Monolith 'stat panels to high levels with ease. VAC makes excellent transformers.

My top choice would be Manley's Neo-Classic 250 but it's quite expensive and rarely shows up used.

Depending on the music you listen to and the size of your room, you only need about 120 watts/side of clean tube power to make those speakers sing. Good luck.

I am very happy with Meridian monoblocs on ML Aerius speakers.