Speaker Asylum

Posted by Frihed89 (A) on April 11, 2007 at 01:23:58

In Reply to: Amps for ESL-57s? posted by lipmanl on April 10, 2007 at 13:47:50:

Amplifiers for Quad ESL 57

Remarks : the original ESL-57 is difficult to drive, many amps give up in a cloud of smoke or kill the delicate treble units. A power rating of app. 25 watts is quite right , Class A or tubes preferred . It is highly recommend to use the protection circuitry (Schottky diodes) as suggested by Quad-UK , when the amplifier has a power output higher than 25 watts.

1. Recommended Vintage Stuff / Tubes ( no longer in production )

o Quad II monobloks
o Berning EA-230 Stereo (30W)
o Radford STA-25 ( STA-15 , MA - 15 , MA -25 monobloks )
o Futterman H3 , H3a, H3aa OTL
o New York Audio Laboratories OTL-3 Q
o Dynaco ST-70
o Esoteric Audio Research 509 monobloks
o Quicksilver monobloks

2. Recommended Vintage Stuff / Solid-State ( no longer in production )

o J.E. Sugden P51
o Electrocompaniet "The 2-channel amplifier" Class A
o Bedini 10/10 and 25/25 Class A
o Mark Levinson ML-2 Class A
o Goldmund Mimesis model 6
o Spectral DMC 50
o Classe Audio DR-2 Class A
o Stax Class A amps ( DA 80 )
o Nakamichi 420
o Pioneer M-22 Class A

3. Beer - Budget

o Naim NAIT integrated

4. Recommended Contemporary Offers

o Quad II-40 monobloks
o Vacuum Tube Logic TT-25 Tiny Triode monobloks
o Esoteric Audio Research 861 Triode
o Esoteric Audio Research 534 Pentode
o Atmasphere OTL amps ( M-60)
o Graff OTL amps (GM-20)
o Transcendence OTL

5. Not recommended for safe use with the Quad ESL-57 - AVOID !

Generally following items should be avoided in any case :

o Solid-state amps made for pro-audio applications (public address systems)
o Solid-state amps with capacitors in the output-stage
o Cheap integrated amps

In detail :

n BGW series 200 ( may go into severe oscillation and kills the treble units )
n ION Obelisk range ( not stable into electrostatic loads )
n Rotel RA 820 ( good integrated but not stable into the ESL-57 )
n Lectron JH 50 ( switch-on thump that may kill the ESL-57 )
n Job series by Goldmund ( not absolutely stable into electrostatic loads )
n Quad 405 ( stable , but mediocre sound - sorry Peter )

Amplifiers for Quad ESL-63 / ESL- 98 series

Remarks : quite a kinder load than the original ESL , although the 63 and its successors still need stable amplification with power and control. A power rating of 40-100 watts is recommended anyway , tubes preferred. Two protection circuits prevent possible damage when high output amps are used .

1. Recommended Vintage Stuff ( no longer in production )

o Futterman H3, H3a, H3aa OTL
o New York Audio Laboratories OTL-3 Q
o Esoteric Audio Research 509 / 519 / 549 series ( all monobloks )
o Goldmund Mimesis model 6 , model 9
o Spectral DMC 50 , DMC 100
o Classe Audio DR-2 , DR- 3 Class A
o Stax Class A amps ( DA 80 and MA 80 monobloks , DA 300 )

2. Recommended Contemporary Offers

o Quad II-40 monobloks
o Vacuum Tube Logic ST-85
o Esoteric Audio Research 861 Triode, bridged as monobloks
o Esoteric Audio Research 534 Pentode, bridged as monobloks
o Atmasphere OTL amps ( M-60, MA-1 )
o Graff OTL amps ( GM-20 bridged as monobloks , GM-200)
o Transcendence OTL
o Inner Sound ESL amp solid-state

3. Not recommended

o Quad 405 ( stable , but mediocre sound - sorry Peter )

Postscript :

The list does not claim to include all suitable/ unsuitable amplifiers for Quads available somewhere in the world, only those known to the author and colleagues . For instance , the author tried several times to get Jadis , Audio Research and Conrad Johnson amplifiers for evaluation on the Quad speakers, unfortunately this has been impossible, because the companies / distributors showed not interest .

On the other hand several companies / distributors have been very kind and helpful , for instance Quad , Esoteric Audio Research ( E.A.R ) and Vacuum Tube Logic ( VTL ).

Christian Steingruber , May 2001

Post Scriptum:

All ME amplifiers (ME Sound Pty. Ltd.) are suitable for use with both old and new Quads of whatever vintage. They are Solid State, but don't sound like it.

Gary Jacobson