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Will a pair of Manley tube amps be a good match for Martin Logan ESL 11A's?

I have been looking into the Manley power amps to drive a pair of Martin Logan ESL 11 A's. From Manleys specs they report a speaker load of 5 ohms is recommended. The Logans are rated at 4 ohms.
pvmike
mechans
3,048 posts
 
In general its frequently thought tubes are a bad amp for electrostatic speakers.  Something to do with current delivery that low ohm speakers require. On the other hand there are some tube amps that can do the job.  Perhaps a different combination would suite your needs better.
georgehifi's avatar
georgehifi
10,312 posts
 
The Logans are rated at 4 ohms.
They might be conservitally be rated at 4ohm, but they do dip to 1ohm in the highs, with "may" see a dulling/recessing of the highs with many tube amps, unless like the Roger Modjeski RM200 Ram Tube amps, that have 1, 2, 4, 8ohm transformer taps, then enough watts become an issue.
Because the lower you go in "tap ohmage" the "lower the watts become" also, so a 100w at 8ohm tube amp may become only 25w at 2ohm.

Cheers George
jafox
1,449 posts
 
In general its frequently thought tubes are a bad amp for electrostatic speakers.
I never heard this before.  Perhaps this is true for amps with rather  output transformers.  But any speaker that dips down to 2 or even 1 ohm is going to cause a lot of amplifiers, tube or SS some serious pain.

I have run Sound Lab A1's for 13+ years, and these too dip to nearly 1ohm at the higher frequencies.  The 220w Wolcott tube amps drove these speakers incredibly well.  And then I changed to CAT JL-3 amps, 150w rated, which also do not have multiple output taps, and the result is stunning.

Make a call to ML as well as VTL to learn if a particular VTL amp would be a good match for the 11A's.


bdp24's avatar
bdp24
9,510 posts
 

@georgehifi has given you a good lead in the Music Reference RM-200 Mk.2. It is the only tube power amp I know of that puts out 100 watts at both 8 ohms and 4 ohms (do the McIntosh amps also?). The common wisdom used to be that OTL amps were a great match for ESL’s, and the Futterman amps were often paired with old Quads, single and stacked. Lots of Atma-Sphere amps on Quads and SoundLabs as well.

MR’s Roger Modjeski, a very opinionated designer/builder, disagrees (and has no axe to grind; he builds OTL’s himself). If interested, go to the MR website for more details, and read Michael Fremer’s review of both the original and Mk.2 versions of the amp in Stereophile (and equally important, John Atkinson’s bench test reports).

bdp24's avatar
bdp24
9,510 posts
 
Oops, neglected to include the matter of tube amp output impedance. Many tube amps have a high enough figure to cause considerable roll-off or boost at either the bottom or top (or both) of the audible frequency range when paired with speakers themselves having very low or high impedances at some frequencies, ESLs being exhibit number one. 
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