The Quad thread

[The Monkey]

I like this Kent.

[Craig Sawyers]

Great news! I finally got off my lazy ass and shipped the speaker to Kent, whose turnaround was very fast.

Awesome! I read somewhere that owning a Quad ESL is a bit like owning a classic MG car - great to own and a pleasure to drive, but you are always tinkering under the bonnet. Certainly the case for the '57s.

The really good news is that yours have been re-panelled. I was a bit surprised on my visit to One Thing Audio how many of the '63's suffer panel damage. They rebuild the panels for 400 '63's a year, and can't keep up with demand. And that is just the UK and mainland Europe mostly.

[spritzer]

All of the 63's (and the new speakers too I believe) suffer from glue issues inside the panels on top of the mylar aging (mostly because it is exposed to direct sunlight).

[Craig Sawyers]

All of the 63's (and the new speakers too I believe) suffer from glue issues inside the panels on top of the mylar aging (mostly because it is exposed to direct sunlight).

That figures. Perhaps that results in the film losing mechanical tension, because most of the dead ones I was looking at at One Thing had torn films - some spectaculaly so.

[Craig Sawyers]

I've got interested in putting dipole subs on the ESL57's. Gradient in Finland used to do one (with 8" drivers), but no longer do. Since 1995.

The guy who has published most on dipole speakers is Siegfried Linkwitz. I've followed his thinking off and on since the late '70s. His day job before he retired was designing microwave test equipment at HP.

Anyway, his website sets out design rules. The main issue seems to be aerodynamic noise from the voicecoil cooling vents on the magnet side of the speaker. You don't hear that in a sealed box, but you do on a dipole. He kept finding speakers that were good in this respect, and then they were discontinued by whatever manufacturer. The really superb one was called the Shiva by Adire Audio. Of course Adire is defunct. Figures.

So I bought a JL Audio 12" sub for trials, and I could get no more than 6mm excursion at 35Hz before it started chuffing from the magnet side. That driver is due for the dreaded e-Bay, unless anyone in the UK wants one for a car system, or a sealed box sub for the listening room. It would be great in a sealed (or vented) box. Brand new.

It turns out though that the Shiva still exists, made by Exodus Audio and called the ShivaX2. By the time it gets from the US to the distributor in Holland, and then to me in the UK, being punished by dollar and Euro rates all the way, this beast comes in at a hefty

[Hopstretch]

If anyone is interested in this beast, I'll take some pics.

Please do!

[n3rdling]

Very interesting! Do you think that sub will be able to keep up with the Quads though?

[Craig Sawyers]

Very interesting! Do you think that sub will be able to keep up with the Quads though?

I can't think why not - they will take over at around 100Hz, so peak accelerations aren't so great, at least in loudspeaker terms (5g or thereabouts). The ESL itself has a fundamental bass diaphragm resonance at 40Hz or so (which is the 35 ohm peak in their impedance), so it isn't behaving ideally itself down there. The key thing is a good strong motor and a grunty amp that will put the cone where it ought to be. All the substantial 14.5kg is in magnet and support structures - the moving mass is only 200 grammes (7oz).

Gradient do a dipole sub for the ESL63 (called the SW63). That apparently uses custom 12" Peerless drivers (or Tymphany as it is now). No idea of the driver spec.

Anyway, I'm a real mug for well engineered product - and the ShivaX2 certainly is that. Exodus do even stoopider drivers, like an 21" animal called the Maelstrom at $647 a pop, with an Xmax of 32mm, a resonant frequency of 16Hz, and weighing 53lbs. But I really don't want to blow the windows out

Craig

[Hopstretch]

Exodus do even stoopider drivers, like an 21" animal called the Maelstrom at $647 a pop, with an Xmax of 32mm, a resonant frequency of 16Hz, and weighing 53lbs. But I really don't want to blow the windows out

I was going to do dual infinite baffle subs with four of those in our HT, but then my microscopic attention span moved on to something else and ... ooh, shiny!

[Craig Sawyers]

Some pics of the ShivaX2

http://www.tech-enterprise.com/tekstuff/ShivaX2a.JPG

http://www.tech-enterprise.com/tekstuff/ShivaX2b.JPG

http://www.tech-enterprise.com/tekstuff/ShivaX2c.JPG

I must admit that given the price of these beasts, I think I'll buy a second one and try two sealed box subs, and trial a dipole. That should give me an idea of which approach integrates best with the ESL57's. The wood needed is cheap by comparison.

Thinking of ESL57's, two pics

http://www.tech-enterprise.com/tekstuff/QUADa.JPG

http://www.tech-enterprise.com/tekstuff/QUADb.JPG

And two of the rig. Second one is a close up of the KG tripde E/S heaphone amp, feeding the Lamdbas on the top of the CD player.

http://www.tech-enterprise.com/tekstuff/Riga.JPG

http://www.tech-enterprise.com/tekstuff/Rigb.JPG

Craig

[spritzer]

I love the filament transformer on the GES. Pure win!

[Knuckledragger]

/me tilts head.

I spy an LS3.

That rig must do a nice job of keeping you warm on cold evenings.

[Craig Sawyers]

/me tilts head.

I spy an LS3.

That rig must do a nice job of keeping you warm on cold evenings.

I do like the LS3 - it isn't really an Audio Research purist amp, since it is a discrete FET circuit - and it sounds really good.

The real killer for heat is the D125. There are eight 6550's in there with two upward facing fans. Quiescent power is 400W - so on a warm summer's day it can get a bit much!

I'm about to add to that thermal overload - I'm building KG's T2 clone. You'll notice that the rack is full, so I have a bit of a space crisis for that monster.

Craig

[postjack]

got my 63 back and it works perfectly. just really fantastic sound. before I had it fixed I remarked on how wonderful the bass and midrange was. now that there is no crackle I can hear how perfect the highs are. super crisp, never bright. still, I feel the most remarkable parts of the sound are the vocals and the bass. the vocals are the most lifelike I have ever heard, and the bass is loaded with layers of detail that I haven't heard in any other transducer.

I'm using my balance controls right now to match the speakers, but once I get brave enough I'll buy a soldering iron and swap the resistor on my other speaker. Kent sent me the resistor and very detailed instructions. if I can solder just a little without burning a hole through my hand I should be able to pull this off.

[Craig Sawyers]

got my 63 back and it works perfectly. just really fantastic sound. before I had it fixed I remarked on how wonderful the bass and midrange was. now that there is no crackle I can hear how perfect the highs are. super crisp, never bright. still, I feel the most remarkable parts of the sound are the vocals and the bass. the vocals are the most lifelike I have ever heard, and the bass is loaded with layers of detail that I haven't heard in any other transducer.

I'm using my balance controls right now to match the speakers, but once I get brave enough I'll buy a soldering iron and swap the resistor on my other speaker. Kent sent me the resistor and very detailed instructions. if I can solder just a little without burning a hole through my hand I should be able to pull this off.

That it great news! Lots of listening coming up in Mobile, I suspect.

[deepak]

got my 63 back and it works perfectly. just really fantastic sound. before I had it fixed I remarked on how wonderful the bass and midrange was. now that there is no crackle I can hear how perfect the highs are. super crisp, never bright. still, I feel the most remarkable parts of the sound are the vocals and the bass. the vocals are the most lifelike I have ever heard, and the bass is loaded with layers of detail that I haven't heard in any other transducer.

I'm using my balance controls right now to match the speakers, but once I get brave enough I'll buy a soldering iron and swap the resistor on my other speaker. Kent sent me the resistor and very detailed instructions. if I can solder just a little without burning a hole through my hand I should be able to pull this off.

Nice!!!

[Knuckledragger]

I think Posty owes us some pictures. Moar Quad pron!

As an aside, I must confess my Quad pedigree is weak. I use my 99 CDP-2 and 12L Actives all day every day, but I don't own anything vintage or 'static. \

[kirkwall]

I've got interested in putting dipole subs on the ESL57's. Gradient in Finland used to do one (with 8" drivers), but no longer do. Since 1995.

Craig

I had the Gradient bases with my 63s back in the day -- worked well most of the time, though the integration never seemed to be quite seamless, and I found myself preferring the Quads on their own. I came across this posting -- maybe another option for a dipole sub?

Audio Dipole sub

This thread makes me wish once more that I hadn't sold those Quads. Still the best speakers I ever owned.

best,

k

[Craig Sawyers]

I had the Gradient bases with my 63s back in the day -- worked well most of the time, though the integration never seemed to be quite seamless, and I found myself preferring the Quads on their own.

The crossover is somewhat naiive in the SW63. The dipole subs are rolled off at 18dB/oct and the ESL63's at 12dB/oct, which is never going to work. They need to be properly integrated with a +6dB/oct boost to compensate for dipole behaviour at long wavelength. They need a Linkwitz Transform to properly deal with the bottom end, and then a 2nd order L-R crossover with the ESL63.

I came across this posting -- maybe another option for a dipole sub?

Audio Dipole sub

Yes that is a good version, references Linkwitz's treatment of dipole speakers including subs, but like most of Linkwitz's recommended drivers the ones used are no longer available.

There is a good article on making the SW63 work properly here Homepage MT Audio Design and navigate through to Quad ESL tweaks. I've chatted by e-mail with this guy, and he knows his stuff.

I've got the circuit schematic for the SW63 as delivered if anyone is interested.

[penger]

I remember Monkey was asking about 9L actives and just saw this posted: Quad 9L Active Desktop Loudspeaker (Playback 30) | AVguide

[Craig Sawyers]

Did some sine wave tests with the ESL57's in preparation for designing the active crossover to the dipole subs. Microphone was a modified Panasonic WM61A (Digikey plus many other places). Flat from 10Hz to 20kHz+ and pennies each. Mod is on Linkwitz's site.

Anyway, even measured in-room at 1m they were astonishingly flat - within +/-5dB from 55Hz to 20kHz. Drops like a stone below 55Hz. But - quite a few buzzes and rattles from 300Hz and down.

Turned out to be two things - wiring behind the signal transformer in contact with right hand bass panel dust cover, and the hessian mat stuck to the rear grille sagging into contact with the bass panels. Wiring was easily sorted out by unbolting the transformer, moving foward and pulling the wiring well out of the way (tucking down the side of the transformer).

The hessian was more interesting. Originally it was stuck on with dobs of pitch/bitumen, presumably applied hot. In my case it has lost grip over the years at the top - hence the sag into the bass panels. I took the mats out of both speakers, carefully removing it from the bitumen dobs with a craft knife blade. I then hand washed them gently, since they are rather fragile (unbelievably filthy) and dried on the washing line and airing cupboard. Cleaned the rear grilles (unbelievably filthy). The hessian mat was then attached to the grille using spray carpet adhesive. I sprayed that onto the rear of the grille, and then applied the mat.

That has sorted the problem a treat, and has the added benefit that now the mat is firmly stuck over its whole area onto the grille, it damps it nicely.

Craig

[luvdunhill]

Did some sine wave tests with the ESL57's in preparation for designing the active crossover to the dipole subs. Microphone was a modified Panasonic WM61A (Digikey plus many other places). Flat from 10Hz to 20kHz+ and pennies each. Mod is on Linkwitz's site.

are you saying they're flat with compensation files that are usually provided, or without? I already know the answer, as I had a modded one calibrated

[Craig Sawyers]

are you saying they're flat with compensation files that are usually provided, or without? I already know the answer, as I had a modded one calibrated

The el cheapo WM61A (a couple of dollars/pounds each - in fact you buy ten of them and have plenty to play with) does not come with any calibration data, other than what is in the datasheet.

In any case, measuring in a listening room renders any quantitative measurement meaningless, which is why it is appropriate to use a cost effective measurement method rather than a calibration standard mike. The best you can hope for is a subjective peer at the data and look for obvious problems. I was actually more interested in the bass end since I'm building subs, and at least doing the measurement identified a few rattly/buzzy problems (now cured).

[luvdunhill]

There are a bunch of standard calibration files for the WM61A that get pretty close. They are not in fact flat from 10Hz to 20kHz+ though out of the box, that's what I was getting at

Edited April 23, 2010 by luvdunhill

[mypasswordis]

I look forward to your progress and eventual completion of the dipole subs, and how well they integrate with the 57. Are you ever considering building a direct drive ESL amp at some point in time? Yes I realize that wouldn't work so well with the subs so I think I answered my own question.