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| [#4485] QUAD ESL speaker Please make sure that there is an active preamp for comparison. Shall I bring along the Nagra from DW to drive the GM20? |
cpsjj 正式會員219.xxx.xxx.124 |
2007-09-12 17:17 | |
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| [#4486] QUAD ESL speaker My initial understanding: 1) Colin will pick up Gingers and drive to my place. 2) CP will pick up Hon at HK island, follow by Patrick at TKO then join Limage at Limage's pastry shopfront to come by Taxi. A long drive. How about all meeting at my place, say 10:00 am.? Hope that sounds acceptable to you We may consider late lunch at 2:30 pm to avoid peak time congestion. Please correct me if I'm wrong. |
dkyyu 正式會員 210.xxx.xxx.23 |
2007-09-12 17:26 |
| [#4487] QUAD ESL speaker I and my domestic helper hear no sound coming out from the speaker anymore _________________________________________________________________________________ dkyyu, It seems it's always your maid helping you out with your audio game. Somehow there must have been a rapport established between you two. Is she particularly good at music appreciation or there's a menage a trios going on here?:-) |
cpsjj 正式會員 219.xxx.xxx.124 |
2007-09-12 17:29 |
| [#4488] QUAD ESL speaker Welcomed. I guess you are coming by taxi. Can you manage to arrive safely? |
dkyyu 正式會員 210.xxx.xxx.23 |
2007-09-12 17:30 |
| [#4489] QUAD ESL speaker Revision: 1) Colin will kindly pick up Gingers and drive to my place at 9:45am 2) CP will meet Limage and come by Taxi at 9:45am 3) Dkyyu will pick up Patrick at TKO at 9:00 am 4) Dkyyu will pick up Hon at KRC duty free shop at 9:30am. I hope that sounds OK to you. Sorry the above sounds like a flock of boyscout planning a day out; or are we 童子軍跳彈床? |
dkyyu 正式會員 210.xxx.xxx.23 |
2007-09-12 17:47 |
| [#4490] QUAD ESL speaker CP, My maid is just old enough to be my daughter. Usually, philipino has strong sense in music and I need her pair of younger ears to comment on treble quality. |
dkyyu 正式會員 210.xxx.xxx.23 |
2007-09-12 18:13 |
| [#4491] QUAD ESL speaker Limage: I live in Saiyingpun, far away from Jordan, but thanks for your kind offer. CP: It is very convenient for me to catch a bus to Hung Hum, I don't think I need a lift. Thanks. Dennis: I'll meet you at KRC duty free shop at 9:30am Regards Hon |
hifienthusiast 正式會員 219.xxx.xxx.113 |
2007-09-12 21:22 |
| [#4492] QUAD ESL speaker limage Would you please bring along yours to come?? John :)  |
Gingers 正式會員 221.xxx.xxx.254 |
2007-09-12 21:34 |
| [#4493] QUAD ESL speaker No, of course not. Sa Ding Ding is strictly for private use only!!! |
limage 正式會員 219.xxx.xxx.29 |
2007-09-12 22:01 |
| [#4494] QUAD ESL speaker Sa Ding Ding is strictly for private use only!!! ----------------------------------------- Sound like Sa DingDing becomes limage's exclusive domain :-) |
Gingers 正式會員 221.xxx.xxx.254 |
2007-09-12 22:22 |
| [#4495] QUAD ESL speaker Hon, Please do. Let's meet at 9:30am. Please prepare, I am going to surprise you with my many newly acquired stuff since your last visit. Dennis |
dkyyu 正式會員 210.xxx.xxx.23 |
2007-09-12 22:25 |
| [#4496] QUAD ESL speaker Dkyyu, Sorry I can't come. Enjoy your time together! Besides, I just want avoid the Sa Ding Ding Cd, too poisonous! :) |
rcwy 正式會員 221.xxx.xxx.253 |
2007-09-12 22:45 |
| [#4497] QUAD ESL speaker Richard, No problem. We know you and King will be engaged on Friday. I knew your 27M is great stuff and I am most horny to hear how well it perform with the OTL amp together. I agree with Gingers's saying it would be meaningless without you or King attending in the 27M party. Let's fix another date. |
dkyyu 正式會員 210.xxx.xxx.23 |
2007-09-12 23:00 |
| [#4498] QUAD ESL speaker Gingers, I think it might be too much on the plate to have the 50C and the cow. May be we should wait for the 27(B) to compare in another session. We should also empathetically leave our enthusiastic host a peace of mind to avoid a vintage preamp driving the vulnerable OTL. |
cpsjj 正式會員 219.xxx.xxx.65 |
2007-09-12 23:58 |
| [#4499] QUAD ESL speaker Sa Ding Ding is strictly for private use only!!! ________________________________________________________ limage, Your immaculate choice of words this time seems irreverent and a suggestion of blasphemy! |
cpsjj 正式會員 219.xxx.xxx.65 |
2007-09-13 00:07 |
| [#4500] Amplification for driving QUAD ESL speaker Excerpt from http://www.onethingaudio.com/FOR/QUA/57/9512-QUA-57-REV-AMP-CS-1.htm " All amplifiers sound the same " Peter Walker " Amplifiers DO sound different " Martin Colloms The question about the ideal amplifier for driving the Quad ESL-57 speaker is not easy to answer. It is well known that the '57 offers a very difficult load, because it is highly reactive and changes from approximately 60 ohms in the bass to 1.8 ohms in the treble region. The popular stacked pairs present an even worse load, because when connected in parallel, the impedance falls to 0.9 ohms ( at 18 kHz) which is almost a short wire. In addition to the problems mentioned above, the original Quad speaker has mediocre efficiency ( approximately 82 db/Watt ) AND limited power handling : Original Quads will flash up immediately when the voltage on the input terminal exceeds 33 Volt (peak-peak). From 1990 onwards a protection circuit (a diode rectifier bridge) was suggested by Quad-UK, quite similar to that used in the new ESL-63, though it protects only the treble unit and not the bass panel. Models which include that protection circuitry can be used quite safely with powerful valve and solid-state amplifiers, although long overdrive has to be avoided ( a different protection mode with a gas discharge tube is available from Sheldon Stokes ) Generally valve amps are not upset by an awkward load as presented by the '57, but many solid-state amplifiers give up in a cloud of smoke. Some of these items even damage the delicate Quad speaker before they die. The biggest crap I ever encountered was the BGW series 200 , a "professional " power amplifier : The manufacturer had stated in its manual that model 200 was stable into electrostatic speakers - unfortunately it was not ! Within milliseconds the BGW went into oscillation and killed the treble units. The "Audio Critic" wrote about the BGW : " This one is a disaster…." How true ! On the other hand a Marantz integrated (model 1060), whose manufacturer definitely excluded such a difficult load, worked quite well with the Quads for over a decade. Similar reports can be heard about the original Naim Nait integrated and the NAD 3020 ( designed by Bjorn-Eric Edvardson) , both handle the Quads with ease. The Acoustical Manufacturing Company (better known as QUAD) usually recommended only their own amplifier designs, as they could not guarantee the performance of other brands on their fragile ESL-57. The valved Quad amps of yesteryear were great designs and ideal for driving the ESL, but unfortunately some of their solid-state successors were not masterpieces. Many audiophiles have tried other products with the ESL-57 and came to even better results than with Quad's own stuff. The original Quad amps and alternative products are discussed here. Chapter One : QUAD Huntingdon, England QUAD II mono amplifier, 1949-1970 Valve (KT 66) These ones are real classics. Maybe not the most accurate sound from these mono valve amps, but sweet and euphonic . In one word : MUSICAL ! The II use the legendary KT 66 as power tube, produced by GEC and Mullard. Only 15 watts or so, but this is just right for the ESL57. Used IIs can be found in British magazines for 500 £, modification kits are available from several sources . In 1996 a special 40th Anniversary edition was available , albeit at a price. Both versions are collector items , like the original Quad ESL. Highly recommended ! QUAD 22 Valve The matching preamp to the II's. Funny optics. Sweet sound, but a little dated. Should be overhauled with modern parts. No moving coil input. QUAD 303 (1968-86) Solid-state (discrete) The solid-state successor to the II, a rather compact 2-channel amp. The design reflects Peter Walker's conservative thinking with only few power in loads lower than 8 ohms, but it was a rather stable and robust design and was used by several recording studios and music groups (e.g. Pink Floyd). It is a fine amp for driving the ESL57. There was also a mono version available, the 50E, which was dedicated to pro-audio applications. Avondale Audio can supply a complete overhaul which betters its performance a lot. QUAD 33 (1963-82) Solid-state (discrete) The matching preamp to the 303 and the successor to the valve 22. Similar optics , maybe a somewhat dated sound. Very clever filter design. No moving coil input as standard. Avondale Audio offers a complete overhaul of the 33 which betters its performance a lot. QUAD 405 (1976-91) Solid-state (discrete + Op Amps) The Quad 405 has caused several hefty disputes, because some guys think that the 405 is one of the best amplifiers around, whereas others ( Angus McKenzie, Martin Colloms, John Curl, Anthony H. Cordesman, Haden Boardman, Steve McCormack ) have expressed some criticism. The main problem with this amp is that it contains some rather bad electronic parts and a crummy protection circuitry . The operation amp at the input is type LM 301, a mere noise and distortion generator. In addition the Op Amp is powered by an unregulated DC line. The design of the output stage is rather conservative, because the amplifier can supply its suggested power only into a narrow band around 8 ohms. Beyond and below that load the output power is drastically reduced, partly because of severe current-limiting. Actually the Quad 405 can only supply only 17/18 watts into 2-3 ohms ( Hugh Ford, Hifi-Choice). The instantaneous peak current is only 3 amperes, which is very low for a 120 watter . In comparison the 15 watt "strong" Naim NAIT offers a healthy 10 amperes output . Actually the '57 would not need much power, but as the impedance falls to 0.9 - 1.8 ohms in the treble region, the amp can only drive this load with the supply of current - otherwise it gets into hefty clipping . To play safe the 405 also included an optional limiter (switched in via a wire jumper) which lowered output power even more. With the limiter in, the 405 had only 40 watts into 8 ohms , 20 into 4 ohms and almost nothing into 2 ohms. The limiter was thought to be essential when driving the 57, but actually it was difficult to destroy the delicate speaker even without that limiter. Anyway, the diode rectifier bridge that was suggested from 1990 onwards is much better in protecting the delicate treble unit. One gets the impression that Quad wanted to manufacture a single amplifier that should please BOTH professionals and audiophiles. Now the expectations for a professional power amp and for an audiophile amp are rather different : the pro-audio amp has to have huge power, cooling and lot of protection circuitry. The domestic "audiophile" amp needs only low power and almost no protection. Quad tried to make both in one design and failed. But the standard 405 as supplied by Quad proved to be a trusty workhorse and was used successful by several recording studios and broadcasters. As explained above, a real "audiophile" design it was not. Unfortunately many ESL owners still use it with the ESL-57 or 63 and never hear what their speakers are capable of. QUAD 405-2 Solid-State ( Op Amps) As the critics could not be overheard even in Huntingdon, Quad decided to overwork the protection circuitry / current-limiting of the 405 and fitted an improved IC (TL071 series) and other parts. The sound is much better than the original 405, but still not outstanding. As the original 405 it proved to be a very stable and robust workhorse and was used successfully in several pro-audio applications. MAC MOD 405 (1980 onwards ) The respected audio designer Steve McCormack , who now works for Conrad-Johnson, realized that the basic concept of the Quad 405 ("Current-Dumping") was great, but the idea was destroyed by crummy parts and drastic protection circuitry. In consequence he offered a modification kit for the 405. The ultimate Mac Mod were mono amps. The modification contained the following changes : * Current Limiting removed * Improved IC fitted (LM 318) * Faster Drivers ( Motorola MJE 15031 ) * Faster Output Devices ( Motorola 2N3773 ) * Improved Resistors (metal-film 1% by Resista Mk3 or Corning RN-60 ) * Improved Capacitors (Wonder Caps, Wima, dipped mica) * Improved Wiring (Audioquest) and Plugs (Tiffany) The Mac Mod 405 surpasses the original 405 in every respect : It was a great sounding amp which could compete with the most advanced high end amps in these days. Harry Pearson of the "Absolute Sound" magazine wrote an enthusiastic review about it. I still regard it a pity that Quad-UK did not overtake the Mac Mod as standard, because the improved 405 is an exceptional amplifier. The only caveat about the complete Mac Mod is, that the ultimate version (= mono amps) has too much power for the delicate ESL-57 (protection circuitry mandatory !), though power output is quite right for the ESL-63. Avondale Audio 405 (1990 onwards) England Mr. Les Wolstenholme, the owner of Avondale Audio, realized the potential of the standard Quad 405 and offered a similar modification as the Mac Mod which bettered the sound dramatically. In addition to Steve's modifications, Les fitted a special external power supply to feed the input OP . The designer argued that in the standard 405 the Op Amp is powered by an unregulated DC which is not at all good, because the Op Amp reacts quite strong on power line fluctuations. In consequence he designed a special external power supply with high-speed voltage regulators which supply a clean and stabilized +/- 15 Volt line to the Op Amp. QUAD 44 (1979-87) Solid-State ( Op Amps) The matching preamp to the 405 and 405-2. The idea behind the 44 was great, because it consisted of a motherboard and several modules, which could be exchanged as wanted (similar as Mark Levinson's first preamp, the legendary JC-2 ). Unfortunately the sonic performance of the 44 was flawed, because the same mediocre Op-Amp (TL071) as in the 405-2 was used. In addition these sensible Op Amps were powered by an unregulated DC line. The result was a rather shut-in sound quality. Specialists like Avondale Audio offer a complete overhaul : the TL071 Op Amp is exchanged against a modern type , separate voltage regulators are fitted . All these mods better the performance a lot. QUAD 306 (1987- 97) Solid-State A cute small amp that was designed for driving the ESL-63 and the 10L , Quad's only dynamic speaker . The 10L was built by the Spendor Company for Quad , actually it was quite similar to the well known BBC LS3/5A monitor. Quad did not recommend the 306 for driving the '57, because it had too much power . But with the new protection circuitry there is no fear that the delicate treble panels can be damaged. Incidentally several '57 owners ( e.g. Werner Ogiers) praise the combination a lot . QUAD 606 ( 1987-97) Solid-State This was a real power horse intended for driving the ESL-63 and professional monitors . It was a good design - utilizing an improved version of the patented "Current Dumping" circuit. Paul Messenger criticized a somewhat dated sound in "Hifi-Choice", but again building quality was great as with all Quad amps. Used by many professionals and broadcasters. The succeeding 707 and 909 are quite similar to the 606. QUAD II-40 (2000 onwards) Valve (KT 88) Quad-UK came financially into severe troubles in the 90ies. After a near death the Quad company was overtaken by the Verity group, and soon after, by the IAG group which consists of a Chinese venture holding. IAG's president, Mr. Stan Curtis, has been known for years for excellent designs ( e.g. for Cambridge ) and reviews ( for Hifi for Pleasure). He quickly realized that a rejuvenated range of electrostatic speakers AND valve amplifiers would be in urgent need, so they decided to bring out a new variant of the legendary II mono amplifier, the II-40 , and a completely new preamplifier called QC-24 (designed by Audio Note). These are rather good news because with these valve amps Quad finds the way back to its legendary roots. I could not evaluate the II-40s yet, but Ken Kessler did so and speaks very enthusiastic in Hifi-News "The best current all-tube rig below 3.500 £" . The new Quads are a peach match with the ESL-63 and the new 98 series, but they should also work fine with the original ESL. In the meantime mastermind Stan Curtis was discharged from his job , but obviously with the new directors the policy of "keeping the legend alive" is still valid, though the complete production run may come from National China in a not too distant future. Chapter Two: Audiophile amplifiers from japan Stax DA 80 , MA 80 , DA 300 ( 1972 - 95 ?) Solid State , Class A Stax has been known for their excellent headphones and earspeakers ( models : Lambda, Sigma) , but incidentally manufactured other audiophile products like electrostatic loudspeakers , unipivot tonearms , electrostatic cartridges (!) and Class A amplifiers. Latter were developed to drive their huge electrostatic speakers ( series ESS 3 A , ELS-8X, ELS-F81 and F-83 ) , which were indeed very hard to drive ( even harder then stacked Quads !) . The Stax Class A amps also worked a treat with both the Quad ESL and ESL 63. Unfortunately several years ago the production line of all amps and electrostatic speakers was ceased . Stax will stay alive but is now only active as manufacturer of electrostatic headphones. Pioneer M-22 Class A (1977 - ?) Solid State , Class A One would not think of Pioneer as high end company, but there were several items that were quite good. Especially the M-22 Class A amp was a marvellous device, built like a Swiss watch ( in comparison to the competition from UK and USA ) . Sound was a little dark and soft, quite nice with the Quad ESL. Nakamichi 420/ 620 (1977 - ?) Solid State Nakamichi is well known for their famous cassette recorders , especially for their masterpiece called "The Dragon" . It was indeed Nakamichi ( and not Philips) that showed that cassettes could be used for audiophile purposes. Aside to their famous machines Nakamichi also developed several amps that were stable into electrostatics loads . The tiny 420 power amp was a cute design , driving Quads with ease ( actually it blew my Quad 405 amplifier away). Additional recommended amplifiers ( that have to be evaluated yet by the author ) * Audio Note by Mr. Kondo * Shindo Laboratories * Wavac Triode Amplifiers Chapter Three: Audiophile Amplifiers from USA Atmasphere M 60 (?-?) Valve ( Output Transformer less ) USA These are output transformerless amps, designed by Ralph Karsten. The various Atmasphere OTL amps are an advancement on the vintage Futterman OTL theme . Some Quad owners swear on them, others complain a slight incompatibility. As Mr. Karsten has no distributor in Europe it is rather difficult to evaluate his interesting designs. Bedini 25/25 and Model 10/10 (1980-onwards) Solid-State ( Class A ) USA A class A amplifier with 25 watts, maybe not as stable as the ML-2, but sound wise even better. The Bedini 25/25 was a peach match with the Quads. To quote the Audio Critic : "Nothing makes the Quad electrostatic sound quite as perfect as the Model 25/25". Building quality was not in the class of Levinson or Stax , and some Bedini owners complained about break downs. Joe Bedini closed doors of his company several years ago, but recently a new investor revitalized the name Bedini and started an new production line. Old Bedini amps can be serviced by the new company. DYNACO ST-70 (1950-...) Valve (EL34 ) USA Aside to Marantz the Dynaco Company could be regarded as the first "audiophile" company in the United States. The ST-70 tube amplifier was a design of the legendary Mr. David Hafler , who latter started his own company. Dynaco also offered their amps as building kits for DIYers. Aside to the classic EL 34 output tubes, the ST-70 used a rare 7199 "compound tube" which consists of a triode and a pentode. Many tuning companies ( Audio Research, Van Alstine, Old Colony Sound ) have been offering tuning kits for the ST-70 for decades and it is reported that with these modifications the ST-70 sounds even better. In the 90ies the Pandor Company offered a new version of the classic ST-70, though this time with solid-state rectifiers and different tubes. Both version are highly recommended, but difficult to source in Europe. Futterman H3 (1956-1985) Valve ( Output Transfomerless ) Julius Futterman , New York, USA The H3 and successors H3a and H3aa are output-transformer-less valve amps (OTL), a principle which does not work properly into low impedances. But Mr. Julius Futterman showed that it could be done - with the help of feedback. All Futtermans ( or is it Futtermen ?) work indeed a treat with the original Quad and Quad 63 despite its falling impedance . The only caveat were double Quads , where the impedance falls to 0.9 ohms in parallel drive. For such systems Mr. Futterman recommended series connection instead. He argues " For owners of double Quads I recommend wiring them in series and, if I may be allowed to boast a little, they sound fantastic". There are many enthusiasts who still argue that the Futterman OTL was the best for driving Quads, although building quality was rather shoddy (some amps even began to burn up!). Highly recommended, but difficult to source. Mark Levinson ML-2 (1980 onwards) Solid-State (Class A ) Mark Levinson Audio Systems, USA The ML-2 was one of Mark Levinson's first power amp designs and was a main part in the legendary HQD system, which consisted of 4 Quads, 2 Hartley subwoofers and 2 Decca DK30 ribbon units. The ML-2 was the mere counterpart to the Quad 405 (which boosted a 120 watts but never had - it actually had only 17 watt into 2 ohms ). The ML-2 on the other hand was rated at only 20 watts into 8 ohm (Class A), but doubled its power the impedance was halved. In reality it could drive ANY load. It was a peach match for the Quads, the maximum voltage output of 14 volts could hardly damage the delicate Quad. It is a pity that the ML-2 is not produced any more by the new owner (Harman). Mark had to sell the company because of financial troubles and then started the Cello company , together with his designer , Tom Colangelo. Cello made wonderful products ( e.g. the Audio Suite) , but went bankrupt recently . Mark's new company is Red Rose Music, dedicated to valve amplification. New York Audio laboratories OTL-3Q and OTL-4 (1985-?) NYAL, New York, USA After Futterman's death Mr. Harvey Rosenberg ( president of the "Quad ESL owners club" ) overtook the company and gave it a new name. Several version of the output-transformerless amplifier were available : OTL-1 ( massive monoblock monster with separate power supply), OTL-2 ( triode version of OTL-4 ), OTL-3 and OTL-4 . OTL-3 was available as a special "Q" version , custom built for the old Quads and Quad 63s. One pair of the output tubes were removed and an external capacitor box was supplied to roll off the bass below 100Hz. Model 4 also was a perfect match for the '57. Unfortunately the NYAL company went bankrupt in the early 90ies. There were ardent rumours that Harvey Rosenberg (now runner of the famous Meta Gizmo site) would manufacture again under the "Futterman" name. It was quite a shock for the audiophile community when his former site recently reported that Mr. Rosenberg had died in summer 2001. VTL TT-25 Tiny Triodes (1990-2001) Valve ( EL 84 triode/ tetrode ) California, USA Designer David Manley is one of the few masterminds as regards tube amplification. He was born in South Africa , then went to England to start Vacuum Tube Logic, but finally moved to California. In 1995 he sold the company to his son Luke who is also a very talented designer. After the separation from VTL , David and his young wife Eve Anna established Manley Labs , dedicated to Professional Audio. The Tiny Triodes are wonderful little mono amps, using the EL 84 tube in either tetrode or triode mode (push-pull, not single-ended). Triode mode offers about 25 watts, tetrode 45 watts. Both the Absolute Sound and "The Electrostatic Doctor" state that these amps are ideal for driving Quads. The contemporary "Limited Edition" of the Tiny Triodes is beautiful crafted, but offers only a 6 ohm tapping of the output transformer. According to the "Vacuum Tube Logic Booklet" a special 16 ohm tapping for the Quad speaker would bring no further advantage with this design. Recommended USA amplifiers ( that have to be evaluated yet by the author ) * Audio Research Classic 30 ( and similar models) * Conrad-Johnson MV-50 ( and similar models) * Dynaco Mk III monoblocks * Marantz Model 8 stereo ( original or Renaissance series ) * Marantz Model 9 monoblocks ( original or Renaissance series ) * McIntosh MC 275 ( original or Renaissance series ) * Quicksilver monoblocks * Classe Audio DR-2 Class A * Krell KSA 50 Class A * Pass Aleph 30 W MosFet * Spectral DMC 50 Class A Chapter Four: Audiophile Amplifiers from Europe Braun CSV 60/ CSV 13 (1959- onwards) Valve ( EL 84 , PL 500 ) Frankfurt, Germany The German Braun company ( which ceased the manufacture of audiophile products in 1980 and now is only active in the razor/ hair-dryer business ) was the only company that was ever allowed to sell an OEM version of the legendary Quad ESL-57 speaker : the Braun LE1. The speaker was designed in 1960 by architect Prof. Dieter Rams and looked rather futuristic. Prof. Dieter Rams remembers : " The LE-1 was produced under licence by Quad. Fitted with large, very light membranes covering the whole front, reproduction quality was impressively clear and transparent, according to the music that was appreciated at the time: jazz, music by Bach, H鄚del etc. " Braun offered a range of matching valve amps for the LE1. The CSV 60 obtained the PL500 tube, whereas the smaller CSV13 obtained the classic EL 84. The CSV 60 integrated was also available as power amp. The sound of the Braun amps is similar to Quad II, very euphonic and sweet, but maybe not quite "accurate". Service may be a problem, as Braun do not offer spare parts any more, but Gehado Electronic Service or Quad-Musikwiedergabe may help. ELECTRO "2-Channel-Audio Power Amplifier" Solid-State (Class A) Norway This legendary amplifier had been developed by Mr. Matti Otala, a well known designer because of his former work for Harman Kardon ( Citation series ) and other companies. He caused a shock in the audio world , when he revealed that feedback may produce transient-intermodulation-distortion (TIM). With the design of the "Two-Channel-Audio Power Amplifier", he had a proof of his theory. The Electro ( or Electrocompaniet in some countries ) was a wonderful match with the ESL-57, power output of 25 Watts was quite right. The company offered more powerful successors to the "2-Channel Audio Power Amplifier" in recent years, sadly some of the magic sound of the original design got lost. Esoteric Audio Research E.A.R. 861 (? - ?) Valve ( Triode) Huntingdon, England Tim de Paravicini is one of the true masterminds regarding valve amplification audio , though he also designs solid-state amplifiers and is active in the professional audio scene (microphones, cutting lathes, tape recorders). Many recording studios and musicians (Paul McCartney, Kate Bush, Ry Cooder, Aerosmith) use EAR products. The cutting studio "The Exchange" in London cuts masters with EAR 549 amplification. He was born in Nigeria, lived several years in South Africa, where he started his own business with transformers for mains and audio use. As he was very successful in the business, he was invited by the Japanese LUX company to come over to Japan and design tube and solid state amps . In his time at Luxman he developed several amps : * Luxman C 1000 preamp (solid-state) * Luxman M 6000 , M 4000, M 3000 power amp (solid-state) * Luxman MB 3045 , MB 3600 tube amp (monoblocks) In 1976 he went back to England , together with his Japanese wife, where he started his own company ( Esoteric Audio Research ) and developed a series of monoblock valve amplifiers that are still regarded as one of the best ( EAR 509, 519, 529, 549 ). He also offered his custom design to other companies, e.g. Musical Fidelity. Actually it was Mr. Paravicini who redesigned the legendary Michaelson& Austin TVA-1 so that it really worked ! Tim has been a Quad ESL devotee all the time. One of his recent designs, the EAR 861, is a triode amplifier (push-pull) with 2x35 watts, ideal for driving original Quads. It is very popular in Japan where Tim got many prizes because of its superior sound and design. It seems that the Japanese love Tim and Tim loves the Japanese people (he is married with a Japanese ) Esoteric Audio Research : direct-coupled valve amp (? - ?) Valve ( DC coupled OTL) Huntingdon, England This is an extraordinary item : the EAR output transformerless valve amp is quite different to the Futterman OTL, as it drives the electrodes of an ESL direct. In consequence it is not a stand-alone unit but it is mounted inside the Quad speaker. The main draw back of conventional OTL is that they still need the voltage step-up via the input transformer of the ESL . Beveridge and Acoustat (USA) also had similar amplifiers in their electrostatic loudspeakers ( model Beveridge II, Acoustat X). According to Mr. Tim de Paravicini the EAR direct-drive amp is available again , albeit at a price ( 6.800 GBP). EINSTEIN "The Final Cut" ( monoblocks ) OTL Germany ( 2001 -) This could be the best of all OTL designs that were ever made , because it uses a rather advanced circuit design : Whereas all other designer offer variations of the vintage Cyclotron theme , Mr. Ralf Weiler has developed something new and special - the "Cross Coupled Anodes Circuit". At least the specs are impressive for a valve amplifier : * Power : 55 watt ( 4-8 ohm) * Bandwidth : 3 mega Hertz (!!!) * Distortion : 0.02 % * Output Resistance : 300 milli Ohm * Damping Factor : 70 I first though the Einstein could be a perfect match for Quads , but a recent demonstration of the Einstein OTL ( in a supermarket ) was not very favourable. There is a possibility that I can evaluate the Einstein on my Quads soon . One big caveat : The Einstein OTL is ultra expensive and you will need two of them ! Goldmund SRI Mimesis Switzerland This is an integrated amp, comprising of fast MosFet devices in the power stage . It is a very strong amp, therefore care should be taken when connected to the fragile '57 ( protection circuitry mandatory). It sounds very tight and fast , quite dissimilar to a vintage tube amp like the Braun or Quad II . Maybe not everyone will love this clear and undistorted sound , but one has to concur that the Goldmund is in a special class ( BTW Sandro Boccara "Dr. Quad" owns a SRI). Caveat : Recently the Mimesis technology was abandoned and a new power supply was invited called Job . According to several reports ( e.g. Studiosound ) the Goldmund amps utilizing the Job supply are not 100% stable into complex loads a la Quad. Electrocompaniet "2-Channel Audio Power Amplifier" (?-? ) Solid-State (Class A) Norway This legendary amplifier was developed by the great Matti Otala, who discovered the important TIM distortions. Mr. Otala is also known for the designs he did for other companies , e.g. Citation . The Electrocompaniet is a wonderful match with the ESL-57, power output of 25 Watts is quite right. The company offered more powerful successors to the "Two Channel Audio Power Amplifier" in recent years, sadly some of the magic of the original design got lost. GRAAF GM-20 (1998 - ?) OTL Italy Italy is normally regarded as the land of fast cars , but not of high end audio. By now the situation has changed and with companies like Sonus Faber, Chario, SAP and Graff there are a lot of high enders around. Mr. Giovanni Mariani, the founder and chief designer of Graaf, began with normal (= transformer coupled) valve amps, but recently he also designed some OTL stuff. The GM-20 uses the legendary Russian 6C33C triode that was formerly used in Russian MIG jets. Reviews indicate that the 20 watt strong GM-20 works a treat with original Quad , but unfortunately I could not get a item yet to evaluate it on my Quads. The GM-20 can also be switched into bridging mode , in this case you will need two GM-20 .There is also a bigger version available, the GM 200, which obviously sounds great on Martin-Logans and Quad 989s. ( caveat : the Graff OTLs are very expensive ) Naim Audio NAP 250 (1973 - onward) Solid State Salisbury, England This amp is still in production, though the contemporary production line probably sounds not as good as the original because of the odd consequences of the CE legislation (electromagnetic compatibility). Actually the NAP 250 was invented in the same time (1973) as the legendary Linn LP12 turntable, which too is still in production. Chairman Julian Vereker ( who recently died because of cancer ) was an admirer of Peter Walker and his art. Julian owned a pair of Quad ESL57 till his death . In an interview for Hifi-Review Julian Vereker said : Hifi-Review : If you were unable for any reason to use one of your own amplifier at home, which other amplifier would you buy , and why ? Julian Vereker : A complete QUAD valve system with their old electrostatic speakers - the bits I don't have already have could be purchased through second-hand pages in the hi-fi magazines. The NAP 250 amp offers 70 watts, is stable into any load, as long as a dedicated Naim speaker cable is used. The NAP 250 omits the Zobel network and needs some inductive damping from the cable ( similar things are reported about the Bedini 25/25). The original NAP 250 and other relative designs like the NAP 160 and NAP 120 work quite well with the original Quad speaker. Naim Audio NAIT (1983-93) Solid State Salisbury, England Because many customers asked for an integrated amplifier, Naim Audio developed such an item from 1983 onwards. Involved in the design of the Nait was Mr. Guy Lamotte , an ardent enthusiast of electrostatic loudspeakers . He had owned 5 pairs of Quad ESL57 , but was not completely happy with the fragile construction of it. So he developed an prototype electrostatic loudspeakers, codenamed FL-1, which was some kind of a battleship version of the '57. Press reports indicated that the FL-1 would be invited to the market in 1987 , but unfortunately Guy left the company without finalizing the speaker . Guy's successor ( Roy George) obviously had no idea of electrostatics and was not able to finish the ESL project, so Naim Audio choose to manufacture mediocre dynamic loudspeakers instead. The original NAIT (Naim Audio Integrated Amplifier) offers only 15 watts, but as it contains a rather stiff power supply, a massive Holden&Fisher transformer , it drives the Quads with ease ( Chris Beeching also praises the Nait in his "Quadfather" article ). Actually this little integrated blows the Quad 405 away, because it can supply up to 10 amperes into awkward loads, whereas the 405 fails with its mediocre 3 amperes output. The Nait was also available as single power amp, the NAP 90. Recently the production line was completely changed , the original Nait and its successors are no longer available. The current Nait 5 contains lots of ICs (integrated circuits) and is obviously not in the class of its legendary forerunner. Radford ST-25 (1960 onwards ) Valve ( EL 34 ) England These are classics from Great Britain , comparable with Quad IIs . There were many variants of the original amp, including mono blocks. Some enthusiasts like Ken Kessler rate the valve designs of Arthur Radford even over those of Peter J. Walker . It is difficult to source one of these amps as original , but in the early nineties the new owner of the Radford company offered a "Renaissance" series , which also sounded great on Quads. |
george1977 正式會員 58.xxx.xxx.156 |
2007-09-13 00:22 |
| [#4501] Amplification for driving QUAD ESL speaker Mr. Futterman recommended series connection instead. He argues " For owners of double Quads I recommend wiring them in series and, if I may be allowed to boast a little, they sound fantastic". ___________________________________________ That's why I kept calling the expert for advice. Would it be sensible if to run in series when OTL is on hand? Any comment on Pros and Cons? |
dkyyu 正式會員 210.xxx.xxx.23 |
2007-09-13 00:43 |
| [#4502] Mark Levinson HQD Levinson HQD system. Consisted of Dual Quad ESL's stacked bottom to bottom (forming an arc) with one Decca Ribbon Tweeter located in a space between the stacked units. Two separate, app x 3' x 3' x 6', sealed cabinets housing 24" or 30" Hartley woofers. Usually, back then, was purchased as a 'system' consisting of the speakers, Levinson electronics including Pre-amp, 2 electronic crossovers and 6 Class A amplifiers, approximately 15 wpc (I've forgotten the model number). Total cost was in the $30,000 range. An unforgettable sound though! I heard them at Christopher Hanson's in LA.  |
george1977 正式會員 58.xxx.xxx.156 |
2007-09-13 01:50 |
| [#4503] Mark Levinson HQD (II) Quoted from Stereophile Review for Mark Levinson No.20 written by John Atkinson May 1988 Mark Levinson No.20 I first heard the Mark Levinson HQD loudspeaker system some ten years ago, at the Festival du Son in Paris, in the days when it was a real hi-fi show. Perhaps even more so than by the speakers, however, impressive as they were with their stacked Quads, Decca ribbon tweeters and Hartley 24" woofers, all in beautiful beech woodwork, I was bowled over the amplification used: six Mark Levinson ML-2 monoblock power amplifiers. Capable of just 25W output each, these class-A monsters were the first true high-end amplifiers I had ever heard. The memory of effortless low-frequency reproduction, coupled with a magically liquid midrange, lingered on.  |
george1977 正式會員 58.xxx.xxx.156 |
2007-09-13 01:56 |
| [#4504] Mark Levinson HQD (II) Mark Levinson HQD  |
george1977 正式會員 58.xxx.xxx.156 |
2007-09-13 02:00 |
