JSE Infinite slope crossover rebuilb

[chucksrt]

I have a pair on model 1.8a floorstanding infinite slopes that I love. I had the woofers redone by Miller sound, he put new surrounds on them and dynamically balanced the cones. I would like to have the crossovers rebuilt. Does anyone have a recommendation on who I can send them to. I would like to have these speakers for another 20 years.

 

[TLS Guy]

I have a pair on model 1.8a floorstanding infinite slopes that I love. I had the woofers redone by Miller sound, he put new surrounds on them and dynamically balanced the cones. I would like to have the crossovers rebuilt. Does anyone have a recommendation on who I can send them to. I would like to have these speakers for another 20 years.

Why do the crossovers need rebuilding? Do you have a circuit for the crossovers? Generally crossovers do not need rebuilding, that is largely, but not always Audiophool BS.

 

[highfigh]

Why do the crossovers need rebuilding? Do you have a circuit for the crossovers? Generally crossovers do not need rebuilding, that is largely, but not always Audiophool BS.

But, but, but, caps age badly! Some guy said they need to be rebuilt and upgraded! Audio Karma members posted bad things about anyone who uses original crossovers........

OTOH, some speaker companies threw crossovers in as a way of saying "Yeah, we could have done better, but we didn't". The only crossovers I ever needed to repair had 25V caps and the users thought going WOT with a ≥100W amplifier would be OK.

 

[TLS Guy]

But, but, but, caps age badly! Some guy said they need to be rebuilt and upgraded! Audio Karma members posted bad things about anyone who uses original crossovers........

OTOH, some speaker companies threw crossovers in as a way of saying "Yeah, we could have done better, but we didn't". The only crossovers I ever needed to repair had 25V caps and the users thought going WOT with a ≥100W amplifier would be OK.

That was why I asked for a circuit. Some electrolytic caps can wander out of spec. sometimes, but foil and ceramic very, very seldom. My rears and surrounds have crossover that are thirty years old now and I don't intend to touch them! I do not use electrolytic caps in my crossovers.

 

[Speedskater]

I recall that the JSE Infinite slope crossovers were far from typical crossovers.
If the crossovers are rebuilt, use new parts with exactly the same specs.
Do NOT do ary parts upgrading.

 

[TLS Guy]

I recall that the JSE Infinite slope crossovers were far from typical crossovers.
If the crossovers are rebuilt, use new parts with exactly the same specs.
Do NOT do ary parts upgrading.

I have never seen a circuit for one, but I have had a long curiosity about them. He used what he called Cuadra filters, and patented them. They have 100 db per octave slopes. I have seen measurements of those speakers, and there is a lot of ringing at the crossover regions, as I think you would expect. So probably not a good idea.

The time smear is enormous.

The ringing at crossover is monstrous.

Which all goes to show, that an FR plot is not the whole story.

S

 

[D Murphy]

I have never seen a circuit for one, but I have had a long curiosity about them. He used what he called Cuadra filters, and patented them. They have 100 db per octave slopes. I have seen measurements of those speakers, and there is a lot of ringing at the crossover regions, as I think you would expect. So probably not a good idea.

The time smear is enormous.

The ringing at crossover is monstrous.

Which all goes to show, that an FR plot is not the whole story.

S

I've never seen the crossover either, but I believe it relies on interactions between the inductors to achieve such a steep slope. So any rebuild would have to keep the orientation of the inductors exactly as on the original board.

 

[TLS Guy]

I've never seen the crossover either, but I believe it relies on interactions between the inductors to achieve such a steep slope. So any rebuild would have to keep the orientation of the inductors exactly as on the original board.

I have always thought it to be a nightmare Frankenstein system.

 

[highfigh]

That was why I asked for a circuit. Some electrolytic caps can wander out of spec. sometimes, but foil and ceramic very, very seldom. My rears and surrounds have crossover that are thirty years old now and I don't intend to touch them! I do not use electrolytic caps in my crossovers.

I haven't seen any charts showing the drift in caps over time, but I would think the % would be greatly affected by the margin between voltage in actual use vs rating- electrolytics that are used for HV applications can fail catastrophically without the rated voltage being exceeded whereas, crossover caps usually fail because they were under-spec'd or the rated voltage was exceeded.

That said, it's probably not a bad idea to test the components after a couple of decades if practical, just to find out how close to the rating they are. OTOH, a lot of good caps are rated ±5%. Many of the non-polar electrolytic caps I have seen were rated ±10%. I'm sure someone has info on drift/time.

 

[Swerd]

I haven't seen any charts showing the drift in caps over time …

Not all old non-polar electrolytic (NPE) caps drift or fail with time. I depends on how well or poorly those NPE caps were made. I've seen very old NPE caps from the 1970s that were fine, and I've also seen caps made roughly 20 years ago, that did drift or fail.

See Capacitor Plague
https://en.wikipedia.org/wiki/Capacitor_plague

Over the years, the idea that all NPE caps drift or fail with time became standard fodder on audio forums, such as AudioKarma. That is only partially so. It depends on who made the cap and when it was made. Back in 20th century, film caps, such as the metalized polypropylene (MPP) caps, were expensive and less common. So NPE caps were the standard. Now MPP caps are cheaper and more available. So, on new construction, I'd look for MPP caps. But on older speakers, the NPE caps may or may not have drifted. To know for certain if they have drifted or failed, you have to remove the cap from the crossover and measure it. Once you do that, you might as well replace it.

But it is important to remember that not all older NPE caps go bad.

 

[highfigh]

Not all old non-polar electrolytic (NPE) caps drift or fail with time. I depends on how well or poorly those NPE caps were made. I've seen very old NPE caps from the 1970s that were fine, and I've also seen caps made roughly 20 years ago, that did drift or fail.

See Capacitor Plague
https://en.wikipedia.org/wiki/Capacitor_plague

Over the years, the idea that all NPE caps drift or fail with time became standard fodder on audio forums, such as AudioKarma. That is only partially so. It depends on who made the cap and when it was made. Back in 20th century, film caps, such as the metalized polypropylene (MPP) caps, were expensive and less common. So NPE caps were the standard. Now MPP caps are cheaper and more available. So, on new construction, I'd look for MPP caps. But on older speakers, the NPE caps may or may not have drifted. To know for certain if they have drifted or failed, you have to remove the cap from the crossover and measure it. Once you do that, you might as well replace it.

But it is important to remember that not all older NPE caps go bad.

I don't follow the adage that if it's a certain age, it should be replaced and I hate the fact that so many are gouging others by insisting a piece of equipment has to be recapped, the amount they charge, the fact that they don't set the others straight and the stupid prices for equipment that wasn't great when they were new. C'mon, $1500 for a Pioneer SX-850?

I asked the service manager at a local AV store for his opinions on recapping vintage equipment- he chuckled and said "If it ain't broke, don't mess with it".

I recently replaced a woofer in a Polk speaker and found that the caps were more than 10% from the value on them, but the owner didn't care. I used a crossover calculator and that variance won't cause problems, so they were left in place.

 

[chucksrt]

But, but, but, caps age badly! Some guy said they need to be rebuilt and upgraded! Audio Karma members posted bad things about anyone who uses original crossovers........

OTOH, some speaker companies threw crossovers in as a way of saying "Yeah, we could have done better, but we didn't". The only crossovers I ever needed to repair had 25V caps and the users thought going WOT with a ≥100W amplifier would be OK.

I will try to take a picture of the crossover and post it. I know it is not a typical crossover design. These speakers are over 30 years old, so I want to be proactive and do any maintenance I can to keep them going.

 

[lovinthehd]

I will try to take a picture of the crossover and post it. I know it is not a typical crossover design. These speakers are over 30 years old, so I want to be proactive and do any maintenance I can to keep them going.

Just curious, is this particular iteration so important compared to more modern offerings? I can appreciate keeping old stuff going, but sometimes....

 

[TLS Guy]

I will try to take a picture of the crossover and post it. I know it is not a typical crossover design. These speakers are over 30 years old, so I want to be proactive and do any maintenance I can to keep them going.

I would leave the crossovers alone. The designer kept his cards close to his chest, and never divulged what he was doing. So, if anyone meddles with them they will overwhelmingly do more harm than good most likely. They have enough significant defects no one was really interested in understanding what that bloke was up to.

 

[D Murphy]

I would leave the crossovers alone. The designer kept his cards close to his chest, and never divulged what he was doing. So, if anyone meddles with them they will overwhelmingly do more harm than good most likely. They have enough significant defects no one was really interested in understanding what that bloke was up to.

I turned pages at a chamber music concert during the '80's where a pair of these speakers was being used as recording monitors in a room adjacent to the concert hall. During warm-ups I could walk from the recording room to the hall and back and compare the live sound with the feed coming through the monitors. I remember being very impressed with how closely the feed match what I was hearing in the hall. I think these speakers may have worked better than some of the measurements would suggest. In any event, I would certainly like to see the crossover.

 

[TLS Guy]

I turned pages at a chamber music concert during the '80's where a pair of these speakers was being used as recording monitors in a room adjacent to the concert hall. During warm-ups I could walk from the recording room to the hall and back and compare the live sound with the feed coming through the monitors. I remember being very impressed with how closely the feed match what I was hearing in the hall. I think these speakers may have worked better than some of the measurements would suggest. In any event, I would certainly like to see the crossover.

Interesting. I never got near a pair or heard them. Like you I have always been curious as to how he got that 100 db per octave roll off. He kept that secret to the grave I suspect. It certainly has never been duplicated in a passive crossover to my knowledge.

 

[highfigh]

I will try to take a picture of the crossover and post it. I know it is not a typical crossover design. These speakers are over 30 years old, so I want to be proactive and do any maintenance I can to keep them going.

If they haven't had excessive voltage sent to them (meaning the voltage rating for the capacitors), the crossovers should need no service. The rest of the components in the crossover should have been able to handle the voltage, but caps and drivers may be less able.

The comment from the service manager that I posted came after close to 50 years working on audio equipment, including testing. If it works, don't mess with it. I cleaned the controls & switches in my old stereo receivers in the past week- one is from ~1973 and the other was a new model in 1978- both sound very good, neither hums or distorts and the only part replaced in the newer one was a regulator in the power supply. Aside from that, both have all of the original parts.

 

[chucksrt]

Just curious, is this particular iteration so important compared to more modern offerings? I can appreciate keeping old stuff going, but sometimes....

I apologize for the delay in sending the pictures of the crossover. Kids, sports, work and fear of messing something up. Lol. I want to be proactive and maintain anything that could affect the speakers performance.

 

[TLS Guy]

I apologize for the delay in sending the pictures of the crossover. Kids, sports, work and fear of messing something up. Lol. I want to be proactive and maintain anything that could affect the speakers performance.

View attachment 65827View attachment 65828

I reckon that bloke must have been a sparrowhawk in another life, to create that untidy bird's nest.

I just would not consider touching that mess.

The problem is that chap never explained that crossover, and according to Dennis locations and distances of the inductors are part of the design.

Now crossovers seldom give trouble due to age. However electrolytic caps can wander with time. That crossover has 10 electrolytic caps by my count.

However, anyone with an ounce of sense is not going to go near that crossover.

That is just a frightful amateurish looking mess, and I could dredge up more colorful expletives.

This is how I build my crossovers, and I do not use electrolytic caps, and don't have to worry about rebuilding ever.

 

[chucksrt]

I reckon that bloke must have been a sparrowhawk in another life, to create that untidy bird's nest.

I just would not consider touching that mess.

The problem is that chap never explained that crossover, and according to Dennis locations and distances of the inductors are part of the design.

Now crossovers seldom give trouble due to age. However electrolytic caps can wander with time. That crossover has 10 electrolytic caps by my count.

However, anyone with an ounce of sense is not going to go near that crossover.

That is just a frightful amateurish looking mess, and I could dredge up more colorful expletives.

This is how I build my crossovers, and I do not use electrolytic caps, and don't have to worry about rebuilding ever.

It's definitely not as well thought out as yours is. I guess I may have to contact Joseph Audio to see if they have recommendations for my units.