Do Quads wear out "all at once"?

[godofwealth]

When using Audio Reseach tubes I always used the ESL63 with the 8 ohm taps. They are around 4 ohm only in the last octave where in general instrumental music has low power. VTL and conrad johnson were internally wired to around 5 ohm, so I had no choice!

I know some reviewers suggest the 4 ohm taps.

The 57s are a more challenging load than the later 63 based Quads. Quad’s instruction manual specifically forbade use of the 57s with anything but the Quad IIs, or the Quad 303. Legend has it many an otherwise good amplifier in the UK melted when faced with the 57s low 2 ohm impedance in the high treble.



This impedance plot however does not give the whole picture. The reactivity of the impedance makes a huge difference. Quads can be highly reactive (i.e., capacitive). In fact, even above 20 KHz, they can represent rather nasty loads, as an old Audio review from the 1980s showed. Needless to say, you need a power amplifier that is stable into low impedance loads. Quad amplifiers were highly stable, and you could even use the Quad 405 as long as it had the limiting switches installed in It for the 57s. The plot below gives the impedance for the 2912, which is not as nasty as the older 57s.



Of course, no Quad is as nasty a load as Martin Logan stats are, which can go below 1 ohm in the high treble! The plot for the Martin Logan CLS shows an impedance of 1.6 ohms in the high treble.

 

[Dogberry]

@microstrip Thanks. No great benefit from risking an experiment, then.

@godofwealth I see why the Quad 306 amps I have sport a button on the back to reset them after they come a cropper driving Quad ESLs!

 

[R Johnson]

My Quad 57 pair blew up a Dynaco Stereo 120 in about 1970.
I then happily used the Quad 303 for years with the 57. In 1999, the 57 pair found a new home with a friend who then had quad Quads.

 

[AMR / iFi audio]

The 2905 speakers are said by Quad to have an impedance variation of 4-20?, and nominal is 8?. I've wondered about connecting them to the 4? speaker outputs instead of the 8. Any advantage anyone knows of, or potential harm?

If they are indeed down to 4 Ohms it's gonna be okay. Higher load Impedance doesn't hurt the amplifier as long as it has a voltage headroom (and tubes have a lot of that). If it dips below 4Ohm tough, it will increase distortion first, then it can increase the wear on the tube. In extreme cases that can overload the amp and create a failure.

 

[Dogberry]

I'll stick with the 8? outputs. Have to look after my Sophia Electric KT88s!

 

[Mendel]

Thanks for the photos and story of your Quad repair! I do hope you end up with at least 10 years of good service. I agree that once you get a taste of Electrostatic sound nothing else will quite do. As a back up at least, perhaps you should consider a pair of the most durable electrostatics ever built. Of course I am referring to Acoustats. I don’t know exactly why they are so tough, but the panels seem to be nearly indestructible. The only problem they ever seem to have is the electrical interfaces lose bias current over a long period of time, but they are easy and relatively cheap to rebuild. Very worthwhile as well, as the interfaces used cheap parts that let down the quality of the panels.
Even though the company is long gone, there are thousands of working pairs still around. They can be bought for a song (often less than $1K) and when the interfaces are rebuilt (also under $1K) they sound very impressive indeed. The cost is a joke for the performance you end up with, and Acoustats can do bass ! The more panels per side, the higher the efficiency and the more bass you get. I have had mine for over a decade and they were probably 15 to 20 years old when I got them. Never a problem.
Sorry to highjack the thread, Quads are great also!
Cheers

 

[delm]

I am using Atma-sphere Class D mono amps with Quad ESL 63 USA panels with great results.

For improved bass and less work for the ESLs I use three 12" subs on DSP, xover 80 Hz single stage, and ESLs are on passive 80 Hz single stage high pass filter. No DSP for the ESLs. DSP setup software is REW and MSO. DSP hardware is MiniDSP 2x4 HD or Flex (adds a volume control useful for thin sounding vinyl).

 

[italia]

I am using Atma-sphere Class D mono amps with Quad ESL 63 USA panels with great results.

For improved bass and less work for the ESLs I use three 12" subs on DSP, xover 80 Hz single stage, and ESLs are on passive 80 Hz single stage high pass filter. No DSP for the ESLs. DSP setup software is REW and MSO. DSP hardware is MiniDSP 2x4 HD or Flex (adds a volume control useful for thin sounding vinyl).

Nice. Many incorrectly assume ESL-63's "need" to be paired with tube amps.

I've had my ESL-63 USA's for about 35 years, early on with NYAL Moscode amp, but for the past 30 years with an 85-watt solid state amp which has worked quite well for me.

Sure, they present an interesting impedance load, but capable low powered (50-100 watt) solid state amplifiers can bring out the magic as well - maybe not NYAL OTL level magic, but delightful nonetheless. Have you tried the Atma-Sphere M-60?

 

[delm]

Nice. Many incorrectly assume ESL-63's "need" to be paired with tube amps.

I've had my ESL-63 USA's for about 35 years, early on with NYAL Moscode amp, but for the past 30 years with an 85-watt solid state amp which has worked quite well for me.

Sure, they present an interesting impedance load, but capable low powered (50-100 watt) solid state amplifiers can bring out the magic as well - maybe not NYAL OTL level magic, but delightful nonetheless. Have you tried the Atma-Sphere M-60?

I have not tried M-60 tube amps.

 

[microstrip]

Nice. Many incorrectly assume ESL-63's "need" to be paired with tube amps.

Fortunately many feel the opposite. The real problem is that the protection of some ESL63 models would almost short-circuit the amplifier if they detected excessive drive to protect themselves. This would burn the transistors of most high-end amplifiers, that did not have short circuit protection, as it could affect their performance.

The ESL 63 were designed to be used with solid state amplifiers. Considering their roller coaster impedance curve , using them with with tube amplifiers with low damping factor will affect significantly their frequency response. I have used them with both tube and SS, surely when used with SS they were more accurate. But tubes sounded very enjoyable!

 

[italia]

But tubes sounded very enjoyable!

So enjoyable! When I worked for an audio shop 40-45 years ago, we tried ESL-63's with so many amps. The NYAL OTL-3 brought the greatest joy in listening of my aural memory.

IIRC, my favorite 'system' of that time was fronted by a Linn Sondek LP12 with Ittok arm and ARC SP-10 preamp. Good times

 

[microstrip]

So enjoyable! When I worked for an audio shop 40-45 years ago, we tried ESL-63's with so many amps. The NYAL OTL-3 brought the greatest joy in listening of my aural memory.

IIRC, my favorite 'system' of that time was fronted by a Linn Sondek LP12 with Ittok arm and ARC SP-10 preamp. Good times

I also have great memories of the NYAL OTL-3 with ESL 63. A very good and gentle older friend, unfortunately no more with us, had them with an SP8 and Oracle/Koetsu. At that time, visiting him was almost a religious experience.

If it was not for the almost impossible to get 6LF6 tube I would find the occasional OTL-3 that pops in used sales hard to resist.

 

[kswanson27]

Fortunately many feel the opposite. The real problem is that the protection of some ESL63 models would almost short-circuit the amplifier if they detected excessive drive to protect themselves. This would burn the transistors of most high-end amplifiers, that did not have short circuit protection, as it could affect their performance.

The ESL 63 were designed to be used with solid state amplifiers. Considering their roller coaster impedance curve , using them with with tube amplifiers with low damping factor will affect significantly their frequency response. I have used them with both tube and SS, surely when used with SS they were more accurate. But tubes sounded very enjoyable!

I use a Benchmark ABH2 with my ESL63s and it drives them beautifully. I have a pair of Entec subs for the bottom end which, I believe, were designed to work with the ESL63s and they pair very well. I'm currently using an Anthem STR pre and am using it's ARC. I was reluctant to use DSP with the Quads but comparing the Anthem to my Benchmark LA4 pre with no DSP there seems to be no difference in transparency but the room correction helps a lot. I'm crossing the Quads over at 70Hz.

 

[italia]

I use a Benchmark ABH2 with my ESL63s and it drives them beautifully. I have a pair of Entec subs for the bottom end which, I believe, were designed to work with the ESL63s and they pair very well. I'm currently using an Anthem STR pre and am using it's ARC. I was reluctant to use DSP with the Quads but comparing the Anthem to my Benchmark LA4 pre with no DSP there seems to be no difference in transparency but the room correction helps a lot. I'm crossing the Quads over at 70Hz.

AH! I have been considering the ABH2 if I upgrade my amp. I also run Entec subs with my ESL-63 USA's - a pair of LF-20. Not only were they considered by many or most the best available mates for the 63's (30+ years ago), a lot people bought them to pair with Wilson WATTs as they preferred them to the Wilson Puppies.

 

[Kcin]

I also have great memories of the NYAL OTL-3 with ESL 63. A very good and gentle older friend, unfortunately no more with us, had them with an SP8 and Oracle/Koetsu. At that time, visiting him was almost a religious experience.

If it was not for the almost impossible to get 6LF6 tube I would find the occasional OTL-3 that pops in used sales hard to resist.

Not an OTL-3 but it's predecessor the Futterman.

Here are my pair of mint H-3aa's -mirror imaged and I have enough 6Lf6s to keep me going for some time I hope. I was still too young to afford OTL-3s when they were new -the Futterman always sounded as good or better to me. The notion of fireworks and run aways is pure hysteria in my opinion. Great on the ESLs.

 

[kswanson27]

AH! I have been considering the ABH2 if I upgrade my amp. I also run Entec subs with my ESL-63 USA's - a pair of LF-20. Not only were they considered by many or most the best available mates for the 63's (30+ years ago), a lot people bought them to pair with Wilson WATTs as they preferred them to the Wilson Puppies.

I can't reccommend the ABH2 highly enough for the Quads. My Entecs are 12-F20s. I'm told Keith Johnson of Spectral and Reference Recordings fame designed the servo system for the Entecs which cuts down on the sub's distortion and helps them keep up with the Quads. BTW if you need any work done on your Entecs I highly reccommend JRS Engineering in Gig Harbor, Wa.. They are Entec experts.

 

[Dogberry]

I am using Atma-sphere Class D mono amps with Quad ESL 63 USA panels with great results.

For improved bass and less work for the ESLs I use three 12" subs on DSP, xover 80 Hz single stage, and ESLs are on passive 80 Hz single stage high pass filter. No DSP for the ESLs. DSP setup software is REW and MSO. DSP hardware is MiniDSP 2x4 HD or Flex (adds a volume control useful for thin sounding vinyl).

Sometimes I fantasise about Atma-Sphere M-60's and then as my fantasy tones down towards feasibility the Class D amps come to mind. Might be useful for the summer where it is too warm to use the tube amps for long.
Years ago, I had a pair of Audio Electronic Supply SE-811 amps, putting out about 12W max, and they ran my Quads just fine, so whilst Quad says 40-100W amps recommended, they certainly sound fine with less. I do use a subwoofer between them, set to take over below 60Hz. I used to have a Marchand active crossover, but I think I must have given it away.