DavidR

Must be 3 union workers

@lARrybody IIRC you re-capped 2 air of 9s and one was with NPE and the other with film. If so what were your impressions between the two ? @sWilly The Mundorf ECaps are a well made NPE. My meter allows me to test for things like Dissipation Factor, Quality and Theta (phase angle). The Bennic, MDL and Dayton NPE were all pretty much the same - minor differences, if any, for same capacitance. The Mundorf (F&T) measured better.

How many hours do you have on the new Jantzen caps? Some caps can take 200 to 400 hours to 'settle in'. If I'm using film caps in a speaker project I will always 'run them in' prior to installation by playing an audio signal thru them.

I've used the Parts Express caps in my AR90 and AR9 large value caps. Personally I'd combine the 47uF with a 2.7uF. This is where Parts Connxtion is good. An email to them saying you need a 50uF without being higher than 50uF. A buck a pair to match. No one else will do that at that price.

https://www.partsconnexion.com/capacitors-ele-mundorf-e-cap-ac-series.html scroll down the page. Part Express has larger values, too : https://www.parts-express.com/electronic-parts/capacitors/non-polarized-electrolytic-capacitors

I suggest you go with Non-Polar caps as were originally installed and not go the film cap route. The speakers will sound as they were intended/designed to. I have gone both routes with other AR speakers. One thing you can do is add a 0.01uF bypass film cap in parallel to the mid and tweeter series caps. You can get good NPE caps at https://www.partsconnexion.com/capacitors-ele.html Mundorf and Jantzen (both made by F&T, a German company) are of good quality. They will match caps for a $1 per pair. The president of the company is very helpful. Can't think of his first name atm but last name is Johnson. I've used the ECap70 Mundorf series. IIRC LARybody has used the Jantzen and has used both NPE and film in AR9s. I don't know if he ever gave his impressions.

@mnboland: if you don't have an LCR to read your capacitors and feel like a drive out to MetroWest I can do it for you. I'm minutes from Rt9/Mass Pike. Just PM me if you have interest.

I love my 10Pi but they are no match for the 90 or 9s

Nice work and good choice on caps.

A lot of people who cut/shape foam use an electric knife.

I've used (2) x 1000uF + (1) x 500uF NPE in parallel. I haven't detected any issues. From the (6) Callins 2500uF caps I've replaced only one was within spec for capacitance. I have no idea what the original ESR was.

Hi @frankmarsi, Most new Class AB amps, if not all, are known as 'current pushing' amps these days. They do a better job at driving difficult loads. As for wattage, high is not necessarily better. I had several of the M series Caver amps that were modified to develop more watts. The M1.0t had 460wpc into 8 ohms. It didn't do as good of a job vs my Emotiva/Sherbourne SA-250 at 250wpc, a dual-mono current pushing class AB amp.

The 2500uF. Can your amp handle/stable at < 2 ohm loads ? Your amp may not be happy and may release the 'magic smoke' The other drivers will not be affected as far as impedance. Doubt you will hear a difference. There are at least 3 other threads on this topic. Not recommended.

Solen

John, curious what cap you used in the UMR 40uF notch filter circuit? It could have played a role in the bad SQ.

My 90s began to sound dull and I was beginning to think the tweeters had dried up ferrofluid. Many of the caps measured in spec for uF but were acting like resistors.

My VTA ST-120 had 60wpc in pentode mode and would drive the 9s but not very loud. Output tubes were 6550 and KT88. Driver tubes were (2) 12AU7 and (1) 12BH7.

From the AR9 Owners Manual

I got rid of my Bob Latino ST120 tube amp after it arced 600vdc. Too close for comfort. I'm thinking it was a spider or cobweb on the pcb board; but that was enough. SS is easier. However, I still have my VTA SP12/PH14 Pre with some 'killer' NOS tubes and have used it with many speakers. I'm currently using it with a pair of MicroAcoustic FRMA-1 that I restored. Great match even with my 45wpc (80wpc 4ohm) A100 headphone amp.

They use the same components as other AR speakers of that era and those capacitors are going bad - so its time. I recapped my 91s with film and my 10Pi and 90s using NPE but added a small film 'bypass' cap on all the series caps. I plan on doing my 9s using film but have NPE on hand if the sound doesn't sound as the speaker was designed to sound. IIRC, A member here @lARrybody recapped 2 pairs of 9s; one with NPE and one with film. Hopefully he will give you his impressions of each.

I'd leave the wiring alone. I don't think you'll hear any difference.

@Ggutierrezm > They may have been 3a speakers but the tweeter and rear control panel has been modified/changed. The woofers and mids look to be original AR parts.

My anti-virus software stopped me from going there.

Great link Frank. I will look into some that I see. Shipping will probably be a killer. I found Larry's JBL stands on Music Direct. $330/pr. Look very nice and they'll work. $351 tax and shipping. I'm also going to try my local fab shop I found. No shipping involved.

Thanks Frank. Same stands as AR55 pointed out. They are a little beat up and kind of pricey for their condition.