crossovers

[wrongway]

I'm attempting to re-build crossovers for my 43 year old ESS PS 5A speakers with the air-motion tranformer tweeters and 10 inch woofers. I'm trying to verify the value of the original caps to replace them with new ones. There are 3 caps as it is a 2 way crossover. The values are 7.5 microferads at 100 volts, 22 microferads at 75 volts and 26 microferads at 75 volts. They also have 10 ohm, 10 watt resistors. The crossover board is 4x6 inches. They are electrolytic caps. I only have room for these types on the board. My problem is that I can only find 33 microferad, 100 watt caps to replace the 26 microferad caps and 8 microferad caps to replace the 7.5 ones. I can get the 22 microferad ones as they still exist. Will these different values cause any issues? The original crossover is rated for 2400 Hz. The woofers have been replaced that can handle up to 200 watts RMS. Thanks, wrongway. PS. The caps have a 10% tolerance.

 

[j_garcia]

Yes, the different values will alter the characteristics of the x-over, how much you won't know until you do it and measure the results. Were the old x-overs dead or having issues?

As for the woofer, does the new driver match the other specs of the original driver or at least suit the enclosure it is now in? Replacing it with something dramatically different will result in unpredictable performance.

 

[lovinthehd]

So what happened performing-wise to make you want to do this?

 

[wrongway]

Yes, the different values will alter the characteristics of the x-over, how much you won't know until you do it and measure the results. Were the old x-overs dead or having issues?

As for the woofer, does the new driver match the other specs of the original driver or at least suit the enclosure it is now in? Replacing it with something dramatically different will result in unpredictable performance.

No. The old crossovers are still working and the new woofers sound great after breaking them in. I just figured the old caps don;t sound as good as they once did but that was along time ago. They still sound good to me with all kinds of music at pretty loud volumes. They fit the enclosure perfectly. They are GW 1038's. Ordered at Amazon cause Simply Speakers were sold out. The original woofers were rated at 6 ohms at 70 watts RMS and 140 total.The new ones are rated at 8 ohms and 130 watts RMS and 250 watts total.

 

[wrongway]

So what happened performing-wise to make you want to do this?

Nothing. My old woofers were re-foamed and they are going bad again and sound floppy not punchy. So I replaced the woofers. They seem tighter and more powerful.

 

[lovinthehd]

Nothing. My old woofers were re-foamed and they are going bad again and sound floppy not punchy. So I replaced the woofers. They seem tighter and more powerful.

If there's nothing wrong, why do this then? Did you replace with originally spec'd drivers?

 

[j_garcia]

The x-over needs to work with the drivers selected to achieve an overall sound. You changed one of the drivers, so that x-over will produce unknown response between those drivers. I asked about the woofer specs too (not power handling, which is almost irrelevant to the response of the speaker), if they aren't at least similar to the original driver, you can't tell how it will behave in that enclosure or the design. Slapping any old driver in a box doesn't make a good sounding speaker.

 

[wrongway]

Had to take a chance on the new bass driver that was recommended to me from another tech at Simply Speakers. My old drivers were re-foamed once before but are paper cones and I didn't want to re-foam them again. This is the closest I could find along with the Dayton DC250-8 10 inch Classics in the way of specs. The W-1038's are poly cones and have a higher power rating than the Dayton's at 8 ohms but seem to work well after breaking them in. These were the 2 models of bass drivers that were recommended to me and seem to have good reviews overall. Maybe new crossovers will make them sound even better? I know there is no perfect solution, especially with old speakers but at least I got some nice advice I'm sure.

 

[Eppie]

@wrongway If the caps are +/- 10% then the 8 micro-farad cap will be fine to replace the 7.5. For the 26 micro-farad cap, if you connect caps in parallel, the capacitance is additive. A 22 micro-farad cap in parallel with a 4.7 should get you close enough to 26.

The caps may not necessarily be bad but over time electrolytic caps will go out of spec. Whether or not this will be audible for your crossovers is subjective. You really need a proper capacitance meter and leakage tester to see if the old caps are still good, but after 43 years it's probably a good idea to replace them while you have access to them.

 

[wrongway]

Thank you very much for your response and advice. I thought parallelling them would be good too as the poly caps are just too big to mess with on the x-over board. I also have some sort of power supply metal disk on the crossover board that controls an attenuator dial on the rear of the speaker that can increase or decrease the sound of the speaker for room acoustics. It allows for brighter or more subdued sound from the drivers.

 

[TLS Guy]

Thank you very much for your response and advice. I thought parallelling them would be good too as the poly caps are just too big to mess with on the x-over board. I also have some sort of power supply metal disk on the crossover board that controls an attenuator dial on the rear of the speaker that can increase or decrease the sound of the speaker for room acoustics. It allows for brighter or more subdued sound from the drivers.

New crossovers need to be designed. Every driver is unique. The tech is wrong you can not replace one driver with another, and even use the same cabinet. So it requires a new design from scratch.

 

[Swerd]

The OP has 43-year-old ESS PS 5A speakers.
They have a 10" woofer and an aging ESS Heil Air Motion tweeter.
The speakers are a 2-way design, with a crossover at 2400 Hz.

The OP has replaced the woofer with a different 10" that fits the existing cabinet cutout. And now, he wants to replace the crossover capacitors.

The OP doesn't seem to be aware that different woofers nearly always require different cabinet dimensions as well as different crossovers. I say 'nearly always' only because there is a slight possibility that the new woofers' T/S parameters closely resemble the old woofers'. That's another way of saying the new woofer has little or no chance of working as a drop-in replacement. The OP also seems to have little or no experience with building crossovers. His questions about capacitors lead me to believe that.

I'm not criticizing the OP's lack of awareness. No one is born knowing things like that. But it does seem like he will ignore the above advice and push on with his rebuilding project anyway. None of us is likely to convince him it is worthless.

Therefore, I'm aiming my comment at other readers who might want to try the same thing.

That old speaker, dating from 1980, tries to use a 10" woofer in a 2-way design, crossing to a tweeter at 2400 Hz. No 10" woofer can perform at frequencies that high. I doubt if it can perform at half that frequency. Even if it can make some sound as high as 2400 Hz, it will suffer from severe beaming. It will be heard only directly on-axis. It's off-axis performance at 2400 Hz will be absent. The speaker's overall sound will suffer from a large hole in the middle. No crossover can fix that. That's why very few speaker manufacturers now try to make 2-way speakers with such large woofers. 2-way designs with 8" woofers have the same problem.

Some readers will no doubt ask why should we care, as long as the OP likes the sound of his speakers. That's not my point. I hope other readers might learn what their old speakers are & are not capable of before they try to restore their faded glory. Many of those old designs were never that good to begin with.

 

[TLS Guy]

No. The old crossovers are still working and the new woofers sound great after breaking them in. I just figured the old caps don;t sound as good as they once did but that was along time ago. They still sound good to me with all kinds of music at pretty loud volumes. They fit the enclosure perfectly. They are GW 1038's. Ordered at Amazon cause Simply Speakers were sold out. The original woofers were rated at 6 ohms at 70 watts RMS and 140 total.The new ones are rated at 8 ohms and 130 watts RMS and 250 watts total.

Simply speakers do have exact remanufactured woofers for those speakers. They have the T/S parameters listed. I note it is a low Fs high Qts driver, that were common back then. This type of drivers are no longer in fashion, so it is very unlikely the woofer you have is a suitable replacement. So you need to worry about the driver and not the caps.

 

[wrongway]

Simply speakers do have exact remanufactured woofers for those speakers. They have the T/S parameters listed. I note it is a low Fs high Qts driver, that were common back then. This type of drivers are no longer in fashion, so it is very unlikely the woofer you have is a suitable replacement. So you need to worry about the driver and not the caps.

Did replace all the old caps and resistors in my old ESS PS 5A speakers with same microfarad values and a little higher voltages with new woofers that are rated better than the originals. And replaced the old spring loaded speaker posts with new 5 way biding posts. My friend helped me with the soldering as I did not trust myself. We tested the old crossover with the new and was very pleased with the sound of the new crossovers. The sound was fuller, brighter, and cleaner. Even my friend was surprised in the difference in sound quality. The 10 inch woofer I used was a mica- polypropylene cone with butyl surrounds that was tighter and full sounding in the bass region. Better than my original paper cone that was re-foamed but was floppy sounding. Now its much more punchier and accurate. The mids and highs were so clean especially with the ribbon tweeters. I don't claim to be an expert audiophile but I have been listening to all kinds of music since the early 70's on good stereo gear and these speakers sound great again! My first time doing crossovers but I learned a lot and had the time and patience to do this project and it was very worthwhile. Wanted to thank everyone with their knowledge and input. You don't learn anything till you try a new project. You Tube helped a lot as well.

 

[PWRmx24]

I don't want to steal this thread but just a quick request since crossovers was the subject. is there a place or listings of people who make prebuilt cross over mods?

 

[TLS Guy]

I don't want to steal this thread but just a quick request since crossovers was the subject. is there a place or listings of people who make prebuilt cross over mods?

I would hope not. All crossovers need to be custom to the drivers involved. Why do you ask this question anyway?

 

[PWRmx24]

I would hope not. All crossovers need to be custom to the drivers involved. Why do you ask this question anyway?

I don't think i have the time, patience, or expertise to build them myself right now. And hopefully I could find someone who has a way of knowing what's good for my specific speakers.

 

[TLS Guy]

I don't think i have the time, patience, or expertise to build them myself right now. And hopefully I could find someone who has a way of knowing what's good for my specific speakers.

That is a pipe dream, as it would take someone clairvoyant! Do you know the Thiele/Small parameters and acoustic responses of all the drivers involved? That is the minimum required for a design, and the bare minimum at that.

 

[isolar8001]

I don't think i have the time, patience, or expertise to build them myself right now. And hopefully I could find someone who has a way of knowing what's good for my specific speakers.

TLS Guy has pretty much told you what is good for your specific speakers....exact replacements.

The only reason to keep/repair/restore speakers that old is because you find them preferable to anything else or you have personal ties to them, which is fine.
Anything you do other than replace parts with exact replacements renders all that null and void.
Not that what you end up with is bad or unlistenable...it's just not what was intended.

 

[PWRmx24]

Ok. Thanks for the comments. That helps.