I can attest to that. I bought a pair of 898's for € 250 and Wout rebuild them for me. Best speaker I ever had, as we say in The Netherlands: 'They are playing the stars off the sky' 😎
BTW, I rely heavily on measurements to verify my rebuilds. Ears are worthless for catching subtle changes in the speaker response from various electronics and panel issues.
Sheldon
Sheldon
May I reanimate this thread?
While repairing and completely rebuilding a Quad ESL63, having taken the stack of all 4 panels apart. And then, before re-stacking ... has anyone stacked them in a different order?
My question is - why not placing the both single-signal panels as base panels, and then, as the two upper panels, the panels with the circular phase delay structure? This would make for an asymmetric array, shure, but might provide to a vertikal upshift of the virtual point source by some 20cm? Which some people like to archieve by lifting the original Quads upon a stand. Think of this modified stack construction as a truncated Quad 2912, less it's two top unisignal panels.
Has anyone tried this at home yet? Drawbacks? Benefits?
While repairing and completely rebuilding a Quad ESL63, having taken the stack of all 4 panels apart. And then, before re-stacking ... has anyone stacked them in a different order?
My question is - why not placing the both single-signal panels as base panels, and then, as the two upper panels, the panels with the circular phase delay structure? This would make for an asymmetric array, shure, but might provide to a vertikal upshift of the virtual point source by some 20cm? Which some people like to archieve by lifting the original Quads upon a stand. Think of this modified stack construction as a truncated Quad 2912, less it's two top unisignal panels.
Has anyone tried this at home yet? Drawbacks? Benefits?
Nope, I've never seen anyone do it.... you might be the first. I guess for most people it is easier to put them on a stand rather than extend the wires etc. Also, I'm probably wrong here, but I understood that all panels got all frequencies in the 63s, so the delay panels in the middle still see the low frequencies.
I've done it and I can dig up some measurements I did that showed that I didn't mess up the tonal balance by doing it. I think it's a great idea and eliminates the need for stands in a lot of cases. You'll need to rewire from the delay lines up, but that's not hard.
Sheldon
Sheldon
I thought about that when replacing the panels in my 63s. Never dared, but it's quite simple, solder and shrink tube. On the six panel models maby it is enough to lift the "eye" one panel only.
While the panels structure is open and disassembled ...
To stiffen the floppy panels aluminium-L-carrier-profile support I resorted to carbon profiles 2mm x 20mm which I epoxy'd at the backside of the aluminium-L-carrier-profiles. This was a full success.
Then I also glued 4mm diameter circular carbon rod along the cenetral front and back grill spacers. This made them a bit more robust.
And then ...
... I did something partially inconsiderate: I also epoxy'd 10mm diameter carbon rods into the main side aluminium profiles. Because in theirs non-built-in state, these main aluminium profiles do resonante quite heavily. As a result, this indeed damped the Q of the resonance a bit. But, as meant as a damping approach, I better had them glued with a damping, viscous PU-product instead of expoxy. This would have provided a better damping. And then, I had to mill a notch of these carbon rods out again, because the dust covers frame plastic profiles did no more fit: It was no more possible to "snap" them in.
I wonder now wheter it would be useful to include some more bracing measures to further fix/damp the panel's assembly.
To stiffen the floppy panels aluminium-L-carrier-profile support I resorted to carbon profiles 2mm x 20mm which I epoxy'd at the backside of the aluminium-L-carrier-profiles. This was a full success.
Then I also glued 4mm diameter circular carbon rod along the cenetral front and back grill spacers. This made them a bit more robust.
And then ...
... I did something partially inconsiderate: I also epoxy'd 10mm diameter carbon rods into the main side aluminium profiles. Because in theirs non-built-in state, these main aluminium profiles do resonante quite heavily. As a result, this indeed damped the Q of the resonance a bit. But, as meant as a damping approach, I better had them glued with a damping, viscous PU-product instead of expoxy. This would have provided a better damping. And then, I had to mill a notch of these carbon rods out again, because the dust covers frame plastic profiles did no more fit: It was no more possible to "snap" them in.
I wonder now wheter it would be useful to include some more bracing measures to further fix/damp the panel's assembly.
Another option to firm up the panels is to put a 1/2" long standoff between the "L" shaped panel mount and the aluminum extrusion at the middle of the bracket (where the two mid panels meet on the bracket). That connects the "L" bracket to the outer extrusion and the whole thing becomes very stiff (like the very early 63 outer extrusions). This is particularly important on the 989's because that "L" bracket is quite floppy with the added length and mass of 6 panels.
Sheldon
Sheldon
Some thoughts
- Why wouldn't have Peter Walker done that if it was better. So simple.
- Why break the d'Appolito set up.
The result is an absence of any sudden change in directivity with frequency.
- IMHO the effect would be reverse, you're sound would be directed more down because of the influence of the bass panels.
- Even more (unwanted) bass coupling with the floor.
- The stands are mostly for decoupling from the floor, not for bringing the image up. Again my opinion and I might be wrong.
- What about the bass corners on the mid/high panels? Two of them are now what, dangling at the top of the speaker.
- A good recording has fine height information, so the singer (or main instrument) is at ear level or where the engineer wanted it. No shift needed.
- 6 panel Quads like the 2912 are still d'Apolito, so it is not a truncated 2912 you create. A 2912 is an extended 63. I have seen people make it symmetrical by putting the mid/high panels one slot higher. Again in my opinion not a good idea.
Seems the ESL63 experts are all gathering here, so i think it's a good place for my hopefully small problem: i am the happy owner of a freshly repaired pair of 63's from 1989, and they sound(ed) just wonderful. But since two weeks or so, volume on one of them is significantly lower, changed sides / amplifier etc but the problem persists,. Sound quality is still fine though. Could this be the HV supply?
Will check the diodes and caps tomorrow (too late for today). Just in case, any recommendations for the caps and diodes types for replacement? Thanks a lot!
Quick look at the neons, they are blinking roughly every 15sec or so, same on both. Turned them off now and will measure the components first thing tomorrow.
All 4 panels runs bass. the center segment gets really all frequencies. there is a slight attenuation of the highest frequencies on the outher segment, then the bass panels are fed by some resistors, and acts as an RC filter reducing the highest frequencies.
I have also tried to elaborate with the placement of the panels. Get your self two or four spare panels and add those to increase low frequency output as in 989. But remember ALL panels are bass panels. But not all are treble panels 🙂 This is why you gain so much dynamics of this speaker when you add an electronic crossover and add dipole subwoofers. You can easy play 10dB higher when you cross at 100Hz (Gradient style) i have experimented with 200Hz and that will give you some extra dB as well. But... the cleanliness and low distortion capabilities of the QUAD´s in the 100-200 Hz region will be lost, and no subwoofer is even close to play so good. I think 100Hz is close to ideal, but it requires 2x15" woofers of good quality, or 4x12" woofers (per channel that is). 20 years ago i made a two towers of 6x15" woofers that was made as a H shape, quite deep ones so that there was less cancellation between front and back. The towers was also attached to the roof for stability. They had to go for non audio reason... unfortunately.
I have also tried to elaborate with the placement of the panels. Get your self two or four spare panels and add those to increase low frequency output as in 989. But remember ALL panels are bass panels. But not all are treble panels 🙂 This is why you gain so much dynamics of this speaker when you add an electronic crossover and add dipole subwoofers. You can easy play 10dB higher when you cross at 100Hz (Gradient style) i have experimented with 200Hz and that will give you some extra dB as well. But... the cleanliness and low distortion capabilities of the QUAD´s in the 100-200 Hz region will be lost, and no subwoofer is even close to play so good. I think 100Hz is close to ideal, but it requires 2x15" woofers of good quality, or 4x12" woofers (per channel that is). 20 years ago i made a two towers of 6x15" woofers that was made as a H shape, quite deep ones so that there was less cancellation between front and back. The towers was also attached to the roof for stability. They had to go for non audio reason... unfortunately.
Have you got a high voltage probe by any chance?
All the advice seems to say that the caps in the voltage doubler don't give trouble, but the diodes more often need replacement. There is also a Mox resistor on that board which rarely enough gives trouble, and there is an electrolytic cap on another board that sails very close to the voltage its rated for that can go. There is also a film cap on that board that rarely enough gives trouble.
I think its a case of turning it upside down and taking off the bottom cover and carefully and methodically taking some measurements.
All the advice seems to say that the caps in the voltage doubler don't give trouble, but the diodes more often need replacement. There is also a Mox resistor on that board which rarely enough gives trouble, and there is an electrolytic cap on another board that sails very close to the voltage its rated for that can go. There is also a film cap on that board that rarely enough gives trouble.
I think its a case of turning it upside down and taking off the bottom cover and carefully and methodically taking some measurements.
If your neons are both blinking bout the same rate, that would imply that both power supplies are about the same voltage. Obviously a HV probe would be a whole lot more quantitative... Could be the Triac in your clamp circuit. Could be the coating on your diaphragms. Did you let the speakers charge up for a long time?
An easy way to isolate panel vs electrical problems is to swap bases. It requires unsoldering three wires and pulling the antenna out. Then loosening 8 nuts and lifting the base off. I show a photo here: https://www.diyaudio.com/community/...storation-dustcover-frame.375972/post-6924305
IF the problem follows the base, its electronics, if it doesn't then its panels. Then you know where to dig in.
Sheldon
An easy way to isolate panel vs electrical problems is to swap bases. It requires unsoldering three wires and pulling the antenna out. Then loosening 8 nuts and lifting the base off. I show a photo here: https://www.diyaudio.com/community/...storation-dustcover-frame.375972/post-6924305
IF the problem follows the base, its electronics, if it doesn't then its panels. Then you know where to dig in.
Sheldon
Thanks for all the good advice! I am pretty sure it is not the panels (for gods sake 😀) as they had been reworked by a pro just 4 months ago.
Classical story - had them in storage for non-audio reasons as well, and when I reactivated them the sound was horrible - lots of distortion, ticking sound, etc etc so the panels had gone. I gave them to a company here in Germany (Sombetzki) as I do not have the workspace nor the materials to do it myself, and this guy did a great job. He apparently was Quad's service technician as well for many moons, clearly knew what he was doing. Wasn't cheap, but after getting them back, they played beautifully and with no problem at all. He also used a thinner Mylar foil (1.5um), I stand in awe before all good men (and women) who know how to handle that stuff and apply it wrinkle-free to that frame 😀
Have them in my living room now, they have been plugged in all the time and worked just fine, only up until a couple weeks ago volume on one side went down. So its not the rework , not the panels, I am thinking it is the HV supply. And I hope to find some time later today to check. Will report back here!
Classical story - had them in storage for non-audio reasons as well, and when I reactivated them the sound was horrible - lots of distortion, ticking sound, etc etc so the panels had gone. I gave them to a company here in Germany (Sombetzki) as I do not have the workspace nor the materials to do it myself, and this guy did a great job. He apparently was Quad's service technician as well for many moons, clearly knew what he was doing. Wasn't cheap, but after getting them back, they played beautifully and with no problem at all. He also used a thinner Mylar foil (1.5um), I stand in awe before all good men (and women) who know how to handle that stuff and apply it wrinkle-free to that frame 😀
Have them in my living room now, they have been plugged in all the time and worked just fine, only up until a couple weeks ago volume on one side went down. So its not the rework , not the panels, I am thinking it is the HV supply. And I hope to find some time later today to check. Will report back here!
After opening pandora's box, and measuring the HV cascade, it seems that one of the caps is the culprit, while not completely shorted it has a much lower resistance than the rest. Not sure if I can trust my DMM, but the resistance was in the range of 16MOhm while all others were "infinite".
While I am at it, I will replace all caps and diodes , not waiting until the next one goes... The board looks like it is coated in some kind of white, see-through wax, probably in an attempt to minimize leakage currents. I sense this will be a mess to remove 😀
Any suggestions what to use here, or even to coat at all?
While I am at it, I will replace all caps and diodes , not waiting until the next one goes... The board looks like it is coated in some kind of white, see-through wax, probably in an attempt to minimize leakage currents. I sense this will be a mess to remove 😀
Any suggestions what to use here, or even to coat at all?