Hi everyone, love the place! so I scored some 91's

[Darren James]

Found an orphan pair for cheap money. 

As usual the owner replaced the woofers with some aftermarket JL audio woofers.

At least they got the Ohm correct. I found a pair of correct woofers.

Question, would you replace the caps on principal?

What an ugly crossover! LOL

Darren

[Stimpy]

Congratulations.  Great speakers.

As to capacitors, if your 91s have the red/black Callins caps, I'd replace those, as they usually didn't hold up well. AR also used Unicon caps, and they still sounded fine, in my AR-58S speakers.

Your speakers have 4.0, 8.0, 24, 40 and 100uF capacitors.  The series caps are the 4.0 tweeter cap, and the 24 mid dome cap.  The others are shunt caps.  I usually use poly for the series caps, and electrolytic for the stunts.  To me, that's the best bang for the buck recap solution.  Parts Express, Parts Connexion, Sonic Craft, Meniscus Audio, and Madisound are all good sources for capacitors; electrolytic and film.

Good luck!

[Darren James]

Thanks Stimp,

They are "elcap" black with red ends... the 100 is a blue metal cap "elcap"

 

Darren

[JKent]

Hey Darren. Welcome to CSP.

I love my 91s. 

Regardless of the brand--they could be Callins, Whale, Temple or, apparently elcap--those black and red caps have to go. Below is a shot of one from a KLH Seventeen. 

IIRC according to John O'Hanlon the reason they are prone to leakage and failure is because of the material they are made of. The black is PVC, the red is something else and the 2 parts expand and contract at different rates.

The metal cans may be fine but why not replace them with NPEs? They're cheap enough and will give peace of mind.

Kent

[JKent]

Here are two 91 xo's. I did mine with all film caps and ones for a CSP member with NPEs for the larger values.

[Stimpy]

I'd definitely replace the "black and red" caps.  They tend to drift out of spec, and often leak.  Those same caps, in my 90s, were sounding very veiled and opaque.  Distorted too.

The metal caps seem to hold up a bit better.  Most report that they usually test ok.  But, to me, they're still very old, and I replaced those as well.  No need to go in twice.

Now, the controversial part, which caps to use?  They used NPE's, and new NPE's will be fine.  Sound great, though they can sound better than great.  I own AR-90's, AR-58S's, AR-1MS's, AR-92's, and AR-18's.  I once had TSW410's.  On the 90s, I used Mundorf film.  The 58S got ClarityCaps, the 92's have a mix of Dayton and Mundorf NPE's, and the 1MS, Dayton as well.  The Mundorf film sound best to me.  Very clean and clear.  Huge depth and presence.  No distortion.  The Clarity's are next.  But they sound very different to the Mundorf caps.  The ClarityCaps are much warmer in tone.  Relaxed.  Not as resolving as the Mundorf's, but no one will consider them too bright.  The Dayton's split the difference.  They sound balanced to me.  Not too warm or too bright.  In the middle.  Very good sound, for the price, but for me, occasionally sibilant.  Spitty.  Not on all music, just every once in a while, enough to be noticeable and annoying.  I added a film and foil bypass cap, which helped clear that up.

All only my opinion.  Not all agree with using expensive caps.  I guess I like to play around, out of curiosity.  Compare, to hear any differences.  For fun, and more importantly, for a love of music.  So, go as crazy as you want.  Spend a little or a lot.  I won't judge.  But, our AR's are worth the effort.

[Stimpy]

5 minutes ago, JKent said:

Here are two 91 xo's. I did mine with all film caps and ones for a CSP member with NPEs for the larger values.

ClarityCaps and Erse...!  Nice.   

I have a set of AR91 crossover boards that I want to swap into my 58S speakers, one of these days.  That'd give me level switches too.

[ra.ra]

1 hour ago, Darren James said:

They are ... black with red ends....

Yup, those caps gotta go ..... pic attached is from 1972 Smaller Advents with two caps paralleled to make 16uF - - - when I removed the tape to confirm the value, it could be seen that the 12uF cap had cracked and split lengthwise. 

13 hours ago, Darren James said:

I found a pair of correct woofers......What an ugly crossover! 

 You're getting some good advice on re-cap process. If you could, plz post a couple pics of new woofers and crossover.

[JKent]

33 minutes ago, Stimpy said:

ClarityCaps and Erse...!  Nice.   

Thanks. FWIW here's a thread on that restoration: http://www.classicspeakerpages.net/IP.Board/index.php?/topic/6565-ar91-restoration-project/

There's also a 0.1 Jantzen on the Erse 3.9 and some nice 1uF Epcos caps I had on hand to bring the 39uF up to 40. Those adjustments were totally unnecessary but also added a "bypass" feature. The Clarity is 25uF, replacing the 24. Again, no biggie. I happened to have them on hand at the time.

I stopped using Erse caps because the leads are often too short. 

[Darren James]

Money money money....... 

so best budget purchase is.... still $140 for both

2 of 2' uf Dayton for the 4

2 of 12uf Dayton for 24

1 Dayton 7.5uf and 1 Dayton .48 uf for the 8

1 Dayton 40uf for 40

and 1 Audyn 100 uf for 100

That was the most I wanted to spend... close to $400 investment so far...

woofers were $170 for the pair.... 200003 very nice surrounds all done by seller

[Stimpy]

All poly film is great.  But, you can also just use poly for the 4.0 and 24uF caps, to save money.  They're the series caps, in line with the drivers, and have the greatest audible impact.  Electrolytic can be used on the rest, if desired?

[DavidR]

My re-capped AR91 board >>>

[JKent]

7 hours ago, Darren James said:

Money money money....... 

so best budget purchase is.... still $140 for both

Madisound

• Bennic 3.9uF film $2.20 OR Solen PB 4 mfd Metalized Polypropylene $3.20
• MDL XPP Polypropylene 8.2mfd $2.37 OR Solen PB 8 mfd Metalized Polypropylene $5.50
• 2 x Carli MET 12 mfd Non-Polar Mylar @ $2.19 ea = $4.38 OR Solen PB 25 mfd Metalized Polypropylene $12.50
• Bennic 40uF NPE $1.20
• MDL 100 mfd Non-Polar Electrolytic Capacitor $2.29

Could be as little as $25 for both

 

[JKent]

Or PE

• Dayton Audio PMPC-4.0 4.0uF $3.98
• Dayton Audio DMPC-8.2 8.2uF $3.40
• Dayton Audio DMPC-25 25uF  $7.89 OR Solen 24uF 400V Polypropylene $12.97 
• 33uF 100V Electrolytic Non-Polarized  $1.04 AND 33uF 100V Electrolytic Non-Polarized $1.04 = $2.08
• 100uF 100V Electrolytic Non-Polarized $1.59

Could be $38 for both

[JKent]

Erseaudio.com

• 4uF PeX film $0.86 OR 3.90μF 250v PulseX - Metallized Polypropylene Film $1.33
• 8uF PEX film $1.48 or 8.20μF 250v PulseX - Metallized Polypropylene Film $2.08
• 24.0μF 250v PulseX - Metallized Polypropylene Film $4.36
• 40uF NPE $0.38
• 100uF NPE $0.71

Could be $16 for both

[Stimpy]

The 91s and 58s use the same crossover.  My AR-58S order from Madisound.  $65.68 total for both speakers. 

Items in this shipment

Bennic 40 mfd Non-Polar Electrolytic Capacitor 100V m40	$1.50 (Not Taxable)	2	$3.00
Bennic 100 mfd Non-Polar Electrolytic Capacitor 100V m100	$2.40 (Not Taxable)	2	$4.80
ClarityCap 25 mfd ESA Range Polypropylene Capacitor 250V ESA250V-25	$17.49 (Not Taxable)	2	$34.98
ClarityCap 3.9 mfd CSA CopperConnect Poly Cap 250V CSA-3.9	$9.10 (Not Taxable)	2	$18.20
Carli MET 8.0 mfd Non-Polar Mylar Capacitor 150V m8	$2.35 (Not Taxable)	2	$4.70

[Darren James]

awesome guys!! thank you!

[lARrybody]

On 11/2/2019 at 11:25 AM, Stimpy said:

I have a set of AR91 crossover boards that I want to swap into my 58S speakers, one of these days.  That'd give me level switches too.

I also have a extra set of AR 91 boards that I intend to swap into my AR58S speakers. I acquired a nice set last May. Almost in perfect shape except for rotten surrounds on the woofers.

I swapped in a set of Tonegen Woofers I had and have been listening to them since. I have subsequently refoamed the original woofers but have procrastinated on recapping the  91 boards since they sound so good with the original unicom caps and the replacement woofers.  Stimpy's comment got me motivated and today I worked on one board.

  

I had my choice of NPE or polly caps for everything except the 4uf tweeter cap. Here is what I went with. 4uf Dayton Percisission Poly, Erse 8.2 poly, 22uf and 2.2 mundorf Ecap Plain. for the 24uf midrange cap. All caps are bypassed with Dayton .01uf Dayton film and foil caps. I really wanted to use .01uf Vishay bypass caps, but the wire leads were too short. This is exactly what I used on my AR9's upper midrange as per ARpros recommendation, and have been very happy the results. Jantzen Premium Elko NPE 33uf paralleled with 6.8uf with .01 Dayton F&F bypass for the 40uf cap. Lastly Mundorf 100uf Ecap Plain NPE with .1 Dayton F&F bypass. The resisters were replaced with Vishy Mills wirerounds that are paralleled for the the three 20 watt  resistors. I used the Parts Express recommended binding post and installed new Parts Express switches which are  much nicer.The new caps are held to the board down with shoe-goo I used the original wires. masonite board and inductors. What do you guys think about these choices? 

 

 

[Stimpy]

1 hour ago, lARrybody said:

Stimpy's comment got me motivated and today I worked on one board.

Hey, don't blame me...!  

But, those new crossovers look great.  Very clean work too.  Well done.

I like your cap and resistor choices.  All very good, and reasonably priced.  As I noted above, I used ClarityCaps and Bennics.  When I recap the 91 boards, I might switch to E-Caps.  I hadn't tried those when I first modded the 58s, but I've used E-Caps since, and they're very good.  Oh, I use those same Dayton film & foil bypass caps and like them.  They do an awesome job.

One other thing, my AR91 boards turned out to be AR92 boards.  I guess people get confused by the labeling, and think they're the same and interchangeable?

Oh, before you recap the 2nd crossover, you should A/B them.  You'll be shocked how much better the new board will sound.  I just wired my boards to an amp, and used a dome mid on each.  There was a crazy difference, with the new crossover sounding so much better.  

[ar_pro]

That's really nice work, Larry - I especially like your positioning & management of the new resistors and stacked caps. The parts layout on the AR-91 crossover isn't ideal, and it can be tough to work with.

Please let us know how you wind up setting the new level controls on the AR-58S, and if you decide to keep the Tonegen woofers, or the original drivers. I think the Tonegens might not get the respect that they deserve - they are excellent woofers.

[ra.ra]

1 hour ago, ar_pro said:

That's really nice work, Larry - I especially like your positioning & management of the new resistors and stacked caps.

I totally agree - - the physical layout of these resto-upgrade crossover projects on existing boards can sometimes be the biggest challenge and these look terrific, and using high quality components. Really great write-up, Larry, and very impressive circuit assembly, too.

1 hour ago, ar_pro said:

Please let us know how you wind up setting the new level controls on the AR-58S, and if you decide to keep the Tonegen woofers, or the original drivers. I think the Tonegens might not get the respect that they deserve - they are excellent woofers.

More very good comments, ar_pro. A subjective evaluation of the level switches installed in the AR-58s is what I am curious about, too. And also, I think I agree about the Tonegen woofers - - despite my general preference for the originals, I've been unable to detect noticeable differences in AR speakers where I've encountered Tonegen drivers.  

1 hour ago, Stimpy said:

.....you should A/B them.  You'll be shocked how much better the new board will sound. 

Good point.... I agree - - with this amount of crossover replacement, an A/B comparison is essential. But still, I'd really like to hear Larry's own performance evaluation assessment of this transformation. With 22 new components installed on each crossover board, the cost of this installation enters the discussion relative to earlier posts, and the bang-for-buck debate deserves consideration in this evaluation. 

 

[DavidR]

9 hours ago, ra.ra said:

With 22 new components installed on each crossover board, the cost of this installation enters the discussion relative to earlier posts, and the bang-for-buck debate deserves consideration in this evaluation. 

I disagree. Not our $$$; not our gear, not our ears, not our concern.

[JKent]

12 minutes ago, DavidR said:

I disagree. Not our $$$; not our gear, not our ears, not our concern.

Yes, but Darren, the OP, did seem concerned about cost. And although I have used Mills resistors I seriously doubt they provide any audible improvement AND original 10w wirewound resistors don't go bad. Mundorf caps are pricey for NPEs but very high quality and not outrageous. Film caps will last "forever" but big ones are expensive. IMHO using film for low values, NPEs for high (40, 100) and keeping the original resistors is very cost effective.

So yes David, you are right but the OP is a relative newbie and was asking for advice.

[DavidR]

16 minutes ago, JKent said:

So yes David, you are right but the OP is a relative newbie and was asking for advice.

I believe ra-ra's comment was aimed at Larry's xover boards.

[Stimpy]

17 minutes ago, JKent said:

 IMHO using film for low values, NPEs for high (40, 100) and keeping the original resistors is very cost effective.

I don't necessarily disagree with this statement, but I also don't completely understand the thought process involved?  And I'm not bashing you either, as I read this type of statement in almost every recap thread I see.  For me, bang for the buck isn't just using film for the small values and NPE for the big stuff.  For me, if cost is a concern, I always use film for the series capacitors and NPE for the rest.  That guarantees good parts where they make the most audible difference, and the cost effective parts where audible differences are more subtle.  So, in my head, that's spending for bang for the buck results.