Personal
Introduction
Amplifiers
for Quad ESL 57
Amplifiers
for Quad ESL 63 / ESL 98
One Thing Audio
Quad
ESL 57, Reviews, The Good, the Bad and the Ugly
(by Christian Steingruber)
The Good News : ANY amplifier in the world can be connected to the Quad ESL speaker
The Bad News : most of them give will give up in a cloud of smoke ( self-destruction mode) or damage the delicate electrostatic panels .
Remarks : the original Quad ESL is difficult to drive, a stable power amplifier is mandatory. 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 )
- Audio Research Classic 30 , D-79 ( and similar models)
- Conrad-Johnson
- MV-50 Dynaco ST-70 ( original or Renaissance series )
- Dynaco Mk III monobloks
- Esoteric Audio Research 509 monobloks
- Futterman H3 , H3a, H3aa OTL
- Marantz Model 7 stereo ( original or Renaissance series )
- Marantz Model 9 monobloks ( original or Renaissance series )
- McIntosh MC 275 ( original or Renaissance series )
- New York Audio Laboratories OTL-3 Q
- Quad II monobloks ( original or Renaissance series )
- Quicksilver monobloks
- Radford STA-25 ( original or Renaissance series )
- Radford STA-15 , MA - 15 , MA -25 monobloks
2. Recommended Vintage Stuff / Solid-State ( no longer in production )
- Bedini 10/10 and 25/25 Class A
- Classe Audio DR-2 Class A
- Electrocompaniet "The 2-channel amplifier" Class A
- Goldmund Mimesis model 6 MosFet
- Krell KSA 50 Class A
- Mark Levinson ML-2 Class A
- Nakamichi 420
- Pass Aleph 30 W MosFet
- Pioneer M-22 Class A
- Quad 303 modified by Avondale Audio or Steve McCormack
- Quad 405 or 405-2 modified by Avondale Audio or Steve McCormack
- Spectral DMC 50 Class A
- Stax DA 80 Class A
- Sugden P51 Class A
3. Integrated Amps
- Naim NAIT solid-state ( original version only )
- Esoteric Audio Research 859 Single-Ended-Triode
- Jadis Orchestra Pentode
4. Recommended Contemporary Offers
- Atmasphere S-30 and M-60 OTL
- Esoteric Audio Research 861 Triode
- Esoteric Audio Research 534 Pentode
- Graff GM-20 OTL
- Nagra VPA Triode
- Quad II-40 monobloks
- Transcendence OTL
- Vacuum Tube Logic TT-25 Tiny Triode monobloks
5. Not recommended for safe use with the Quad ESL-57 - AVOID !
Generally following items should be avoided in any case :
- Solid-state amps designed for public address systems
- Solid-state amps with capacitors in the output-stage
- Amplifiers with switch-on-thumps or noisy switches
- Cheap integrated amps
In detail :
- BGW series 200 ( may go into severe oscillation and destroys the treble units )
- Ion Obelisk range ( not stable into electrostatic loads because of capacitor coupling )
- Job series by Goldmund ( not absolutely stable into electrostatic loads )
- Lectron JH 50 ( switch-on thump that may destroy the '57 )
- Quad 306 ( Quad-UK say it shall not be used with the '57 )
- Rotel RA 820 , RA 840 ( good integrated amps but not stable into the '57 )
6. Not recommended sound wise - though quite stable
- Quad 405 ( 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 or Class A preferred. Two protection circuits prevent possible damage when high output amps are used .
1. Recommended Vintage Stuff ( no longer in production )
- Audio Research D-79 A
- Conrad-Johnson MV-50
- Counterpoint SA 4 OTL
- Classe Audio DR-2 , DR- 3 Class A
- Esoteric Audio Research 509 / 519 / 549 series ( all monobloks )
- Futterman H3, H3a, H3aa OTL
- Goldmund Mimesis model 6 , model 9
- Marantz Model 7 stereo ( original or Renaissance series )
- Marantz Model 9 monobloks ( original or Renaissance series )
- McIntosh MC 275 ( original or Renaissance series )
- New York Audio Laboratories OTL-3 Q
- Krell KSA 50 , KSA 100 Class A
- Pass Aleph MosFet
- Quad 405 or 405-2 modified by Avondale Audio or Steve McCormack (monobloks)
- Spectral DMC 50 , DMC 100 Class A
- Stax DA 80 , MA 80 , DA 300 all Class A
2. Recommended Contemporary Offers
- Atmasphere S-30, M-60, MA-1 OTL
- Esoteric Audio Research 861 triode, bridged as monobloks
- Esoteric Audio Research 534 pentode, bridged as monobloks
- Graff GM-20 bridged as monobloks OTL
- Graff GM-200 OTL
- Inner Sound ESL amp solid-state
- Nagra VPA triode
- Quad II-40 monobloks
- Quad 909 solid-state
- Transcendence OTL
- Vacuum Tube Logic ST-85 tetrode
3. Not recommended sound wise - though quite stable
- Quad 405 ( stable , but mediocre sound - sorry Peter )
Christian Steingruber , June 2001
Member of Audio Engineering Society - Austrian Section
