Solid State Amps for Quad ESL 57?

I am curious this morning and questioning this ML_2 that has been mentioned.

There are two outputs coming out of my preamp. One goes to the RM10 which is run full out to the Quads. The second preamp line out goes to the Subs which are set to cutoff at 60 hz.

I am trying to understand how the ML_2 mono pair, not having heard them, and just based on specs.....can get the job done. if I was using them I think I would need to use a higher cutoff on the subs?  

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From nyame’s post

ML_2 Mono - Pair 25, 50,100 watts into 8, 4, and 2 ohms

this implies to me and please tell me if I am wrong.

2..............4.............8............16..............32 OHMS

100..........50...........25..........12.5...........6.25 ML_2.....Output Watts.

***So only 6.25 watts available at 32 ohms***.

The Quad 57 use approx 32 ohms to make 100 hz. See the graph that was posted earlier and here it is again.

http://www.quadesl.com/graphics/quadGraphics/quad_impedance_graph.jpg

Somebody explain this one to me please.

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Whart - would have loved to have met Peter Walker in person. Also John Bowers.

Cheers Chris

ct0517                            1-09-2017

I am not sure that ohms law is the correct tool to unravel the mystery of the Quad 57 which present a capacitive load. My own experience is that very little power is required to reach acceptable music levels in a small/medium sized room. A friend of mine drove his quads with a 12 watt per channel solid state amp at bass levels which surprised me. 

Roger Modjeski  had the same experience: "The RM-10 came into being in early 1990, when I noticed I rarely played music above a few watts on my Vandersteen 2C speakers. Later, I acquired a pair of the old QUAD electrostatics and achieved the same listening levels at even lower power."


 

Hi nyame
yeah,
I get the fact that the Quad 57 presents a capacitive load. Atmasphere also made this clear earlier. Also I do remember now, similar discussions with the OTL manufacturer who made the 200 wpc OTL amps I was using with my Acoustats.
    
btw - do your amps have a brand name ?

So I have a recommendation to unravel this Quad 57 mystery.

Nyame - you may send me your ML_2's.

Kalali - you may purchase those Quad II's you linked earlier, and send to me also.

or alternatively Whart;  can send me his Quad II's while his Quad's are being restored.

I promise to complete the shoot out with my RM10, post results here, and all equipment returned by April 1, or when boating season opens; whichever comes first. :^)

How's that sound ? My LP assimilation project can wait .  8^0 

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Bdp24 (Eric) Is it my correct understanding that Roger will only build RM9's now upon request, due to the cost ........or is this a myth too ?

Cheers 

Chris (ct0517), I believe the RM-9 is no longer available, even as a special order. I could be mistaken however. Roger has relocated to the Bay Area, and appears to be more involved in his Audio Engineering school than in running Music Reference. He has a right-hand man still operating out of his old Santa Barbara location.

ct0517                     01-09-2017

  " btw - do your amps have a brand name ?"

" No. The amp I refer to as "my amp" was a joint project with four other friends. Five amps were built, each one slightly different. Four stereo versions, each with separate power supplies, while mine was built as mono-blocks. " 
Four of the amps were used to drive Quads, and one was used to drive a pair of Apogees. Three were built to produce 40 watts per channel, which was thought to be safer for the Quads. My friend with the Apogees actually used 16 output transistors per channel. This lead to heated arguments between us.

I am no longer in possession of the amp.

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