Stimpy
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Posts posted by Stimpy
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I believe the AR-9 schematic, that listed a 6.0uF cap on the UMR, was in error. Both the 9 and 90, should use the 8.0uF capacitor.
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17 minutes ago, meta_noia_fot said:
@DavidR I haven’t heard the 610’s (or any TSW speaker) but I imagine you’re right about the 91’s mid being better. The mids and tweeters from the 9 series are terrific.
@Stimpy Thanks for the info about the capacitor. Some previous tech really took care of these so I assumed they were left in position because they were still within spec
My wife used to have TSW 410s. A great speaker, with good dynamics. A more lively sound, with a slightly hotter high end, than our AR 9 variants.
Well, the 100uF Solen film cap would run over $55 dollars each. So, you'd spend quite a bit just to replace those 2 shunt caps. NPE's are fine there.
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On 8/19/2023 at 1:20 AM, blanddawg625 said:
I have to agree totally with how well the AR90s sound being pushed with a professional amp. I push mine with a fully restored Yamaha P2200, with the big vu meters and 350 watts @ 4ohms. I believe the weak link has been a little Aiyima pre/DAC that is surprisingly quite, but I think lacking in soundstage and imaging. I am currently awaiting the delivery of a Classe SSP25. Everything I have read about the Classe' tells me that it is a superb 2 channel performer. Can't wait to find out.
Good luck with the Classe preamp. I know a little Acurus L10 preamp really did wonders for my system, so I would think the SSP25 would be much better...!
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I've never heard the 91s, but I do have 92s, and the 91s bookshelf twin, the 58S speakers. And I agree with David, that they're a great find, and I'm sure they're wonderful.
Nice locating a recapped pair too. Plus, I wouldn't worry too much about the original 100uF electrolytic capacitor. It's a Unicon brand cap, and they tended to last much longer that some other brands that AR used back then. A Japanese manufactured capacitor, that sounds very good as well.
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12 hours ago, DavidR said:
Not what I asked. What frequency did you use when doing the test?
If you want send them to me and I can measure them and label them and send them back to you free of charge. PM me if interested.
Also, if they are 10% high then P.C. will correct the problem. So will Mundorf - free of charge.
Parts Connexion just changed their website. It's now Audio-Connexion. The new site isn't as easy to navigate, and it's more geared to audio equipment, and not parts. Parts Connexion now requires clicking on a link, within Audio-Connexion...! The PC site has been "updated" too, and not for the better. But, at least the same parts brands are there, they just take a little more effort to find...!
Edit: The new AC/PC site is very buggy. I can't even log into my existing account, to double-check the details of a previous parts order...!
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Here's a repost of the North Creek file. Hope it works...!
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The 90s have a fairly low impedance dip in the bass. Around 3.2 Ohms down there. Just where you're hearing issues. So, look for high current amps, that can handle low impedances. That's not necessarily high wattage amps.
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I've mentioned before, when I used my 90s in a HT surround system, my Yamaha AVR identified my 90s as being out of phase. Allowing the Yamaha to correct the issue, resulted in much better bass, with better balance to the rest of the speaker. At the time, my 90s were straight stock, purchased direct from the factory. So, I've always wondered if my woofers were mis-wired out of phase, when built?
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My 90's (bought direct from the factory, around '81) have the adjustment resistors mounted on a separate board. But, a pair of back up 90 crossovers I have, that I sourced from eBay, have the resistors soldered directly to the switches.
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1 hour ago, AR surround said:
4) The caps that AR used were known to have a very high ESR. You might find it necessary to add a small amount of resistance to tune the speakers to your taste. That is why my first question about the attenuation switches is so important. When I recapped a pair of Boston A70's with NPEs, I regretted replacing the old gray Unicon caps. The A70's had no attenuation switches, so I needed to add both a 0.5 ohm resistor and then a F&F bypass capacitor to achieve what I considered to be acceptable response.
A shame the Unicon capacitors aren't still available. Great sounding NPEs. Very dynamic.
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25 minutes ago, DavidR said:
I'd like to try some of the Alcap npe. I think I'll inquire about overseas shipping costs.
Alcaps come in some good AR values; with 6, 8, 30, 40, and 80uF caps. If you eventually try some, I'd love to hear about your impressions.
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1 hour ago, Markolone said:
I was thinking of doing the following:
- 1st step: I replace the capacitors on the first speaker in the version with Mcap on the midrange and I compare the result with the other speaker and with the pair of my old AR35bx which I'm currently using to compare performance
- 2nd step: I replace the capacitors on the second speaker in the version with Ecap on the midrange and I compare the result as above.
For the tests I will select songs that I know well and are well recorded, such as: "you and your friends" by Dire Straits. Classical music to highlight the separation of instruments in full orchestras, etc.
Regarding the bypass, I plan to apply it to everyone immediately, but I don't rule out doing a final test with and without a bypass.
I like bypass capacitors too. I use them on all values, series and shunt caps. Bypass caps seem to smooth out the sound, while still Improving detail retrieval.
Oh, HiFi Collective and Falcon Acoustics, both in the UK, are good sources of capacitors. They could be useful for future projects.
Good luck.
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38 minutes ago, Jab said:
OK, y'all convinced me. Surround kits are on the way from Simply Speakers. Nice folks. Super helpful. But....
I forgot to order dust caps, so this aint over yet! Could someone please post a link to the re-building video? It's been years since I did this on a set of infinities, and damn if I can remember what was involved in getting the dust cap off!
Thanks in Advance.
I've followed the techniques in this video, and didn't have to remove the center dust cap. Actually, with my M&K sub refoam, shimming the voice coil, still left a rub. Following the advise in the Simply Speakers video worked even better, since I could adjust the centering by feel.
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26 minutes ago, RoyC said:
ERSE is the only common npe crossover cap I have found to be inferior, but I think that company went out of business.
Roy
From what I've read, the owner passed away, and the family didn't want to carry on with the business. Now, it seems the Erse name is Chinese owned. I'm not sure if that means parts from the old Erse facility, or from China?
Edit: After a quick search, it seems the former Esre employees have started US Coils. They look to provide many of the same components once supplied by Erse. Good news, I hope?
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21 hours ago, lARrybody said:
If your 91 boards have the Unicon capacitors you might want to keep them. Mine didn't.
I agree 100%. The stock Unicon capacitors, in my AR58S speakers, still sounded great. But, out of caution, I replaced them. It took quite a bit of money, towards very decent poly caps, to improve upon the Unicon caps. I wish those caps were still made, as they would be my go to NPE.
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Also, don't discount the use of bypass capacitors. A small value (0.10 or 0.01uF) poly film cap, in parallel with the NPE, can really open up and improve the sound of the electrolytic capacitors. They've been mentioned here, and aren't expensive. The Dayton film & foil bypass caps, that I use, are around a $1.00 each. Very affordable to try.
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25 minutes ago, uarnutz said:
That's kind of what I expected to hear. In fact, I had bought new caps before I even knew what was in there. I probably would not have done so if I had known. The one thing that may be worth it is that 24mfd cap based on these forums. Replacing with a Munsdorf e-cap has been an improvement for some.
I am definitely a fan of Mundorf caps. Their E-Caps too. But, hang onto what you've ordered, and when you feel there's a true need for an upgrade, you'll have the parts at hand.
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My AR58S speakers came stock with Unicon caps. The sound quality was still very acceptable. Actually, very dynamic in tone. I did a recap, for safety's sake, but truth be told, the Unicon's were equivelent to the poly caps I used. It would take boutique level capacitors to better the stock caps, IMO.
Oh, the Callins capacitors in my AR90's, were horrible before a recap. Rolled off, muted, and distorted. The AR58S Unicon's exhibited none of those issues.
Good luck.
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Falcon has Alcap 7uF caps, to parallel for the 14s. A 20 as well, so nothing extra needed there. Plus, if the old capacitor leads are long enough, just clip the old caps off, and solder the new caps using the old leads.
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Since you're in the UK, I'd use Falcon Acoustics. They're UK based too, and offer their well respected Alcap brand. The Alcaps are available in tight tolerances too, for a NPE.
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Those four screws hold the faceplate and tweeter diaphragm together and in alignment. If you want to clean them up, only remove one screw at a time, so nothing shifts out of place.
Capacitors can be daunting. Hard to decide how to replace, and with what? I used poly for the series values, (4, 6, 24, and 80), and NPE for the rest (8, 30, 40, and 350), to save a little money. You'll most likely have to bundle 2 caps in parallel, to add up to the needed values. That's unfortunately a common solution. Good capacitors can be found at Parts Express, Parts Connexion, Madisound, Meniscus Audio, and Sonic Craft. Prices vary, so be warned...!
AR-9 and AR-90 UMR crossover differences
in Acoustic Research
Posted
There is an extra inductor in there...!
AR-90