Gainclone & Quad ESL 63
Hi,
Newbie looking for some advice here....
I am currently driving my Quad ESL 63 pro with a 60w Class AB ss amp quite sufficiently in a 10" x 18" room.
Planning to build a LM3875 gainclone as my first amp project but would like to seek some advice here whether it can drive difficult load like my Quads.
Any help will be appreciated. TQ
Tham
Hi,
Newbie looking for some advice here....
I am currently driving my Quad ESL 63 pro with a 60w Class AB ss amp quite sufficiently in a 10" x 18" room.
Planning to build a LM3875 gainclone as my first amp project but would like to seek some advice here whether it can drive difficult load like my Quads.
Any help will be appreciated. TQ
Tham
I also have ELS-57s and these are actually not at all current hungry... Their impedance goes down to 2 Ohm at ?10KHZ? , but there is so little signal in that frequency range, that they don't demand that much current...
I don't know about the ESL67, but usualy it's the impedance dip in the low 20-400Hz range that can cause trouble with amps...
maybe an output inductor should be used to protect the amp from the capacitive load of the Esl67..
I don't know about the ESL67, but usualy it's the impedance dip in the low 20-400Hz range that can cause trouble with amps...
maybe an output inductor should be used to protect the amp from the capacitive load of the Esl67..
The more rational choice, imo.
The ESL57 is a more difficult load than the 63 on a decent SS amp that copes with a capacitive load, on top of that the 57 doesn't have over-voltage protection.
The ESL57 dips below 2 Ohm in the high freq. range, while the 63 remains above 3.5-3.6
It's a different story on the other side of the impedance curve, the 57 remains at very comfortable levels but the ESL63 drops well below 4 Ohm again at 20Hz.
The 63 needs a bulkier output stage, the later models are much more driver seat friendly.
A chip amp is a nice bench mark for ESL's though, goes to show how much difference in sound power amps really make, also again demonstrates how mediocre Quad amps like the 303s really were.
The ESL57 is a more difficult load than the 63 on a decent SS amp that copes with a capacitive load, on top of that the 57 doesn't have over-voltage protection.
The ESL57 dips below 2 Ohm in the high freq. range, while the 63 remains above 3.5-3.6
It's a different story on the other side of the impedance curve, the 57 remains at very comfortable levels but the ESL63 drops well below 4 Ohm again at 20Hz.
The 63 needs a bulkier output stage, the later models are much more driver seat friendly.
A chip amp is a nice bench mark for ESL's though, goes to show how much difference in sound power amps really make, also again demonstrates how mediocre Quad amps like the 303s really were.
why not use OPA549 or use OPA549 as current buffer output and high grade OP amp like OPA 445 or OPA 552 as voltage gain stage. You get a great deal of good current for low impedence ESLXX. The bandwidth will also much wider. The voltage gain stage should better be pulled down to -ve rail to create a single end class A stage. I trust this configuration will outperform more than 95% of commercial amp. Good luck
Quad 306
Quad ESL 63 pro? You lucky person I just have a normal Quad ESL 63, all this said, I would suggest you should build 4 amplifier channels and go for an active cross over at 100Hz. If you do this the low impedance at 20Hz is no longer an issue, your power and volume handling will go up greatly on the Electrostatic and you can use a conventional woofer with it where electrostatic speaker benefits are the lowest. Integration is so much easier than anyone on the internet says, I guess it is true if you don't High pass the Quad ESL 63 as it does have very nice and low bass at low levels and very dipole dispersion. I am using 24dB per octave active cross overs for the cross over and am delighted how the music above that frequency also sounds better as the ESL is more in its safe low power operating area, It also improves off axis sound considerably. For the Bass I am using a pair of 8" Linn Bass reflex speakers and its good enough, but I will build some speaker stands as 10" sealed boxes to go under the speaker in the near future as it may sound better and will look better.
100Hz high pass to the Quad ESL 63 is a very easy load for nearly all amplifiers.
Having never built a chip amp I cant say I know how good or bad they will sound. For driving Electrostatic speakers at least for me the most important issue before even sound quality is power supply rejection of spikes in the mains, This fortunately is not incompatible with good sound. I would suggest that this is an important question for the Chip amp users, and i would expect its a chip amp strength.
Personally I am tempted to build a JLH Class A monster for my ESL 63's but am happily living with a pair of Quad 306 amplifiers (cheap on Ebay UK) as they have better power supply rejection than my Quad 303 amplifiers (Cheap on Ebay UK). I once built a small JLH Class A and it was best amp I ever heard with the Quad ESL 57 until the under powered transformer started to Hum badly. This is pure luxury, expensive and other parts of the HiFi system need improving first, right now power management and boxes for my electronics are my HiFi priorities.
Good luck.
Owen
Quad ESL 63 pro? You lucky person I just have a normal Quad ESL 63, all this said, I would suggest you should build 4 amplifier channels and go for an active cross over at 100Hz. If you do this the low impedance at 20Hz is no longer an issue, your power and volume handling will go up greatly on the Electrostatic and you can use a conventional woofer with it where electrostatic speaker benefits are the lowest. Integration is so much easier than anyone on the internet says, I guess it is true if you don't High pass the Quad ESL 63 as it does have very nice and low bass at low levels and very dipole dispersion. I am using 24dB per octave active cross overs for the cross over and am delighted how the music above that frequency also sounds better as the ESL is more in its safe low power operating area, It also improves off axis sound considerably. For the Bass I am using a pair of 8" Linn Bass reflex speakers and its good enough, but I will build some speaker stands as 10" sealed boxes to go under the speaker in the near future as it may sound better and will look better.
100Hz high pass to the Quad ESL 63 is a very easy load for nearly all amplifiers.
Having never built a chip amp I cant say I know how good or bad they will sound. For driving Electrostatic speakers at least for me the most important issue before even sound quality is power supply rejection of spikes in the mains, This fortunately is not incompatible with good sound. I would suggest that this is an important question for the Chip amp users, and i would expect its a chip amp strength.
Personally I am tempted to build a JLH Class A monster for my ESL 63's but am happily living with a pair of Quad 306 amplifiers (cheap on Ebay UK) as they have better power supply rejection than my Quad 303 amplifiers (Cheap on Ebay UK). I once built a small JLH Class A and it was best amp I ever heard with the Quad ESL 57 until the under powered transformer started to Hum badly. This is pure luxury, expensive and other parts of the HiFi system need improving first, right now power management and boxes for my electronics are my HiFi priorities.
Good luck.
Owen
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