AR-9 Refurbishment

[SHOKDU]

I do not believe that more expensive caps are better. I used Daytons with a bunch of bypass Daytons and could not be happier. I don't think I spent more than $350 in caps, new foam, and grille cloth. You can see the external results, but I sure do wish you could hear the results I got as well!

You do not need to add resistors to compensate for small capacitor differences. Most are 10% variance anyway.

Hi all,

I am a newbie here.

Just purchased a pair of AR9's and just considering changing the capacitors.

I am considering Clarity ESA caps.

Any opinions?

After replacing the caps, do I need to add resistors to compensate the difference in resistance between old and new?

Hence I am also looking at the resistor board.

Does anybody has the detailed procedure on how to take the attenuation/resistor board out - the one with the switches attached to?

Thank very much in advance.

David.

This. I love Howards RAF and FNW.

If you need a bit more sprucing up, several of us have had good success with Howard Restor-a-Finish. Wipe on/wipe off. You can also apply it with 0000 steel wool. After that, apply a coat of wax such as Howard Feed-n-Wax.

[SHOKDU]

So, I need to confess, out of curiosity, I added spikes to the speakers. I added the spikes and put the speakers back on the granite plinths. The speakers are angled at about 5* toed in. They sit about 8 feet from each other, 5 feet from one wall, and 25 feet from another wall. They sit 18" out from the rear wall. I have a vaulted ceiling and large, open space. Not a very ideal listening room to be honest. Anyway, before the spikes I felt like I was having a hard time getting to the super low bass notes like I wanted to. I tried different speaker positions, etc...everything I could think of and the speakers were just lack luster in the bass department. Not what I was hoping for. Well, spikes added, I cranked them up to about 600 watts RMS and the bass just flooded over me. I was sitting on my couch laughing as some incredible low bass from either the Tron soundtrack, or the Inception soundtrack pounded me with authority.

Needless to say, I am impressed. Never thought little spikes would do that for me. I have to completely eat my previous words about spikes...they are worth every penny (even though I bought the cheapest set I could find)!

[ar_pro]

The difference with spikes isn't subtle, is it?

Your good description exactly mirrors my experience with spiked feet on the AR-9 and AR-90 - improved low frequency impact !

[genek]

By the mid seventies, even "boiled linseed oil" was no longer just oil, but a mixture of oil and various solvents and spirits designed catalyze the mix to speed drying. Not a commercial varnish finish with resins added, but the catalytic action produces a hardened polymer that chemists do refer to as a varnish.

If you compare an AR speaker from the 70's with one from the 60's, the 70's finish definitely has a slightly harder feel and more of a "sheen."

Watco Danish Oil is an oil-varnish blend, which contains oil, catalytic spirits and varnish resins.

AR did not use varnish.

Kent

[DavidR]

Shokdu,

Very nice thread and wonderful work on your xover upgrade. It would be helpful to others and greatly appreciated if you could provide a parts list of the replacement caps and the various combinations used in by-passing.

Thanks, David

[Mach3]

Shokdu,

So how do you like the sound of the Emotiva gear? I have been considering that brand (the price is right) but have heard that the amplifiers are more than a little "crunchy" sounding. Is there any truth to this?

As for the more expensive caps being "better" - as long as you move to a film cap (Solen, Jantzen, Dayton for example) I would agree with you. More important than brand is the tolerance - the tighter the tolerance the better the crossover behaves. The effect of bypassing, to my analysis, is no more than lowering the ESR (two resistors in parallel approach).

Did you cut the 2500 uF cap out of the circuit? If you do - and the Emotiva has the "balls" to handle the resulting low impedance - your bass response will get about 100% better. Much tighter, much lower (now I hit 20 Hz without any problem) and far more tuneful. Do try it - it is amazing.

I only very lightly sanded my Nines (220 grit) and then rubbed them down with Teak Oil (catalyzing resins like all the "oils"). Did a pretty good job for a box that is > 30 years old (made by Boston Coffin by the way).

One of the best speakers ever made imo.

[SHOKDU]

Shokdu,

Very nice thread and wonderful work on your xover upgrade. It would be helpful to others and greatly appreciated if you could provide a parts list of the replacement caps and the various combinations used in by-passing.

Thanks, David

Thank you David.

Looking at my old receipts, here are the parts used in my refurbishment:

Madisound:

4ea m1000 Bennic 1000 mfd Electrolytic Caps $10.25ea, total $41.00

2ea 25r5.6 5.6 ohm, 25 watt Wirewound Resistor $0.65ea, total $1.30

Parts Express;

2ea 027-426 Dayton Audio DMPC-8.2 8.2uF 250V Polypropylene Capacitor $3.37ea, total $6.74

2ea 027-438 Dayton Audio DMPC-25 25uF 250V Polypropylene Capacitor $7.08ea, total $14.16

2ea 027-442 Dayton Audio DMPC-40 40uF 250V Polypropylene Capacitor $10.77ea, total $21.54

2ea 027-427 Dayton Audio DMPC-6.2 6.2uF 250V Polypropylene Capacitor $2.83ea, total $5.66

4ea 027-378 500uF 100V Non-Polarized Capacitor $7.25ea, total $29.00

2ea 027-446 Dayton Audio DMPC-90 90uF 250V Polypropylene Capacitor $23.35ea, total $46.70

2ea 027-441 Dayton Audio DMPC-33 33uF 250V Polypropylene Capacitor $10.14ea, total $20.28

2ea 027-421 Dayton Audio DMPC-4.0 4.0uF 250V Polypropylene Capacitor $2.01ea, total $4.02

22ea 027-452 Dayton Audio DFFC-0.10 0.10uF 400V By-Pass Capacitor $0.97ea, total $21.34

[SHOKDU]

Shokdu,

So how do you like the sound of the Emotiva gear? I have been considering that brand (the price is right) but have heard that the amplifiers are more than a little "crunchy" sounding. Is there any truth to this?

As for the more expensive caps being "better" - as long as you move to a film cap (Solen, Jantzen, Dayton for example) I would agree with you. More important than brand is the tolerance - the tighter the tolerance the better the crossover behaves. The effect of bypassing, to my analysis, is no more than lowering the ESR (two resistors in parallel approach).

Did you cut the 2500 uF cap out of the circuit? If you do - and the Emotiva has the "balls" to handle the resulting low impedance - your bass response will get about 100% better. Much tighter, much lower (now I hit 20 Hz without any problem) and far more tuneful. Do try it - it is amazing.

I only very lightly sanded my Nines (220 grit) and then rubbed them down with Teak Oil (catalyzing resins like all the "oils"). Did a pretty good job for a box that is > 30 years old (made by Boston Coffin by the way).

One of the best speakers ever made imo.

I don't know how people can review the Emotiva gear as "crunchy". It is clear, crisp, and analytical...yes. It is not the "warmest" sounding equipment, but I don't prefer that anyway. The Emotiva gear puts out what is put in, everything I have ever heard out of my system has sounded exactly as it should from it's source...in my opinion. For the price point I do not believe there is any competition. Is there better, yes, most likely...will I ever spend more money than I have on the Emotiva setup? No. The differences between other very high end solid state equipment and my low cost Emotiva gear is so subtle (if it's even there at all), that I can not justify ever spending more...my ears just aren't good enough...or I have not convinced myself that the difference is there just because a piece of gear costs 10-20x what mine does.

I did remove the factory 2500uf capacitor, but replaced them with two 1000uf and one 500uf capacitors in parallel. I will have to try removing the 2500uf capacitance network that I built and see if my Emo gear has got the "balls". That's going to be interesting.