replacing crossover caps, is it worth it?

[Guest grassulo]

Would it be worthwhile to replace the crossover capacitors in my 2ax speakers with modern poly caps, like the dayton ones from parts express? I'd heard someone had replaced their original ones awhile back on this forum with good results. The speakers sound GREAT at low volumes, but you turn the system up they ring like bells, almost like listening to a pair of lowther full ranges, very peaky, I've begun to think this is because of the Harman/Kardon 330c reciever I'm using to drive them with, being only rated at 15wpc rms, could it be that it's the amp suffering under the load? I'm going to repair my 40wpc Dynaco sca-80 integrated amp and I'll post back with the results. I remember someone saying that these older AR speakers needed a high powered amp to drive them because of their inefficient nature.

-Garret

[ar_pro]

The Dyna 80 might not be the best choice, either Garret. Both the ST-120 and ST-80 power amplifiers (upon which your SCA-80 is based) had an iffy track record with the larger AR systems, like the 2 variants, the 5, and especially the 3a. This was particularly true for folks who enjoy their music *loud*.

The 2ax speakers that I owned while in law school were powered by an original AR amplifier, which was rated at 60 w/channel, and provided lots of clean volume with no reliability problems. Many here have also suggested Adcom amps, which seem to always be available on eBay for bargain prices.

I've never replaced caps in a 2ax, but have done so with the 3a and AR-9, with very pleasing results every time.

[r_laski]

>>Would it be worthwhile to replace the crossover capacitors in my 2ax speakers with modern poly caps, like the dayton ones from parts express? I'd heard someone had replaced their original ones awhile back on this forum with good results.<<

Garret,

Just a suggestion about changing your 2ax caps with Daytons from PE. Buy enough caps for both speakers, but change one speaker first and compare it to the “original.” If you are not pleased with the result, return the unused Daytons and buy Solens. PE is excellent about accepting returns.

When I worked on a pair of AR90s cost was a consideration and I replaced some of the AR caps with Daytons. The result was disappointing. I found the Daytons to be “harsh” and no improvement at all. I returned the unused Daytons and bought Solens from PE. IMO the Solens are worth the extra cost.

Whether or not you change amps, I believe you will find re-capping your 2ax speakers “worth it.”

Rich

[Steve F]

I agree with this assessment of the SCA-80/2ax combo. I used an SCA-80 to power my 2ax's in the early '70's, and was never entirely satisfied. Dyna themselves admitted that the amp would only deliver 36 watts per channel into the 4-ohm 3's, and when the FTC regulated the whole watts-per-channel ratings mess in 1974 (which had really gotten out of control), Dyna was forced to reduce the power rating of the SCA-80 from 40 WPC (40 x 2, hence the "80" nomenclature) to 30, because the amp had difficulties with the new, more stringent testing procedures.

As to the caps, I never replaced mine, but unless yours are actually defective or out of spec, I see no overwhelmingly compelling reason to replace them--unless you simply want to go through the exercise for the enjoyment of experimentation, which is, of course, a perfectly valid reason.

Steve F.

[Guest Frank]

Hello, I,m in the process of changing the caps on my AR9's and it would be a big help if you could give me the part# you used when you changed yours.

Frank

[ar_pro]

Frank -

The large value caps came from Herbach and Rademan's outlet store in the early '90s - they carried a Honeywell or GE branding, and were spot-on replacements. It's doubtful that they would still be available, but you never know.

It seems that many rebuilders are now using combinations of caps to approximate the original values. You might want to give Bill Miller a call at (215) 412-7700, to get a take on what he's currently suggesting in regard to recapping the 9.

[Guest Sean]

"When I worked on a pair of AR90s cost was a consideration and

I replaced some of the AR caps with Daytons. The result was

disappointing. I found the Daytons to be “harsh” and no

improvement at all. I returned the unused Daytons and bought

Solens from PE. IMO the Solens are worth the extra cost."

I agree 100%. The Dayton brand of caps sound much more "metallic", "ringy" or "solid state" as compared to the Solen's. I would further suggest damping the leads where they enter the body of the cap on Solen's and other similar capacitor designs AND "forming" the caps prior to installing them into the crossover circuit.

"Whether or not you change amps, I believe you will find

re-capping your 2ax speakers “worth it.” Rich

Once again, i agree with Rich's comments 100%. Especially if one takes the time to let the caps fully form before installing them into the crossover. Otherwise, you get to listen to the caps "breaking in". If you don't form the caps, they will never operate to full potential because you'll never have enough voltage on them to fully form. Each time one raises the volume higher than the last time, the caps will under-go a slight shift in operating parameters due to increased thermal stress that it never had to deal with before. By forming or stressing the caps by running them up to rated voltage and cycling them up and down a few times prior to installation, most all of the break-in will be complete and performance will be more consistent. Sean

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[rrcrain]

Concerning cap breakin, I have to agree that it is real and has an audible effect on the speaker, but I've also experienced an odd behavior recently.

I had a major electrical spike damage both of my stereo amps and while they were in the shop being repaired (again), I hooked my speakers (AR90) up to my projection TV. When my amps finally came home several months later and reconnected to the speakers, the speakers were extremely harsh, perhaps edgy would be a better discription, for almost an hour before they settled down.

I've seen this type of behavior with other speaker/amp combinations as well, where it takes from a few minutes to a few hours for the pairing to settle down with each other. Has anyone else experienced this, and if so, why does it occure?

BTW, my 90s have completely rebuilt crossovers using solen caps and coils.

[administrator]

A very similar thing happens when I blast Megadeth out of my AR 303a's. Things start out harsh, but my ears start going numb after a while. Then the police come.

Mark

[rrcrain]

I have to admit that my two amps together could possibly melt the voice coils in my 90s as well as the 9s to a puddle of goo if I weren't carefull, but megadeth? Nope, nada, never!

[soundminded]

Couldn't resist could ya? }( I don't blame you, I'd have done the same. RHIP.

I don't think megadeth was exactly what Edgar Vilcher had in mind when he set out to bring high accuracy sound reproduction into the home. However, being a shrewd businessman as well as a scientist, he saw that this kind of development created an entirely new lucrative market for him....in hearing aids. :-)

[administrator]

Yeah, yeah .. try something new:

1998 HDCD GRAMMY NOMINATIONS: Megadeth - Cryptic Writings - Best Metal Performance - Trust

Well, maybe that's a pretty obscure category.

Mark

[r_laski]

>>I had a major electrical spike damage both of my stereo amps and while they were in the shop being repaired (again), I hooked my speakers (AR90) up to my projection TV. When my amps finally came home several months later and reconnected to the speakers, the speakers were extremely harsh, perhaps edgy would be a better discription, for almost an hour before they settled down

I've seen this type of behavior with other speaker/amp combinations as well, where it takes from a few minutes to a few hours for the pairing to settle down with each other. Has anyone else experienced this, and if so, why does it occur?<<

Richard,

I've experienced something similar to what you describe, but the circumstances were different. When I've pulled speakers out of storage (a year of more) they can sound pretty awful for several hours before they "settle down." I'm going through something like that right now with a pair of AR9s. Same thing after recapping unless you "form" the new caps as Sean described.

Just a guess, based on past experience, since your amps went in for service, unless the tech working on them wanted to fry himself, he discharged the power supply caps before working on your amps. After repair /parts replacement, it took your amps a while to warm up and settle in (break-in). That's what you "heard."

Rich

[rrcrain]

Heck, the caps in those amps are puny things; Well, they aren't any larger than a coke can and only have 200 VDC across them.

I considered the possibility you suggested as well and whereas I'm not fully discounting it as it is a possibility (because it is), I'm not fully convinced either. Caps, especially electrolytics need to be reformed after they sit idle for a time. This is rather imperative with very old tube equipment before its powered up after sitting idle for a few decades. To what extent does this happen to modern poly caps? What effect, if any, will powering the speakers with a low wattage, low current source have on them after being initially formed for several months, and then being reconnected to a high current source?

[Guest Sean]

My guess is that it was your amps that were "settling back in", not the speakers. If you weren't using the rest of your audio system ( speakers were hooked up to the TV as you mentioned ), this too could come into play. Sean

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[r_laski]

Richard,

>>Caps, especially electrolytics need to be reformed after they sit idle for a time. This is rather imperative with very old tube equipment before it’s powered up after sitting idle for a few decades. To what extent does this happen to modern poly caps?<<

I was not limiting my “guess” to capacitors. In addition to recharging the power supply caps in your amps, I was also taking into account the fact (assumption) that in getting your amps repaired several components had to be replaced. I was suggesting that like capacitors, there is a period of “forming” for those newly installed electrical components.

>> What effect, if any, will powering the speakers with a low wattage, low current source have on them after being initially formed for several months, and then being reconnected to a high current source? <<

Great question! If one were to reword it slightly, you have a hypothesis:

Powering speakers with a low wattage, low current source will have “no” (or other premise word(s)) effect on them after being initially formed for several months, and then being reconnected to a high current source.

You have the equipment on hand to conduct the experiment to prove / disprove your hypothesis. Please share the results with us.

Rich

[rrcrain]

I'm not familiar with your speakers nor the caps from Parts Express your looking at, but I would say yes, replace them. Do consider a poly cap from Solen or another decent manufacturer rather than a generic. I've seen astounding improvements in inexpensive speakers with a single cap for their crossover when upgraded.