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AR 3a... eliminating the level controls


Guest Americain

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Guest Americain

Hi everyone. I decided to restore my venerable old AR 3a's but with a slightly modern turn. I replaced the burned out AR tweeters with EMIT planar tweeters by Infinity. They fit perfectly in the mounting cutout and I think will perform well.

But first I want to eliminate the non-functioning mid and tweeter level controls. Can anyone give me a tip on which wires to cut and re-attach? Many thanks in advance.

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The new tweeters are more efficient than the old ones, and both are much more efficient than the woofer. If you remove the level controls, the speaker system will sound un naturaly top heavy. I would replace the old level controls with new L pads, or have the old level controls cleaned. The level controls premit you to talor the response to your room.

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Guest Americain

I suppose I could use some pot cleaner and do things that way. I guess that would be a better route than eliminating them altogether. What model of L-pad would the forum members here recommend?

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Guest Americain

OK, here's the plan. My tweeter level controls work just fine now but one of the midrange pots doesn't work at all. Since the mids are original AR units I can take the pot out of the circuit without too much of a problem. Which wires go where in order to take the midrange level control out of the loop? Many thanks in advance.

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If you eliminate it completely the mid will be very harsh. The only chance you may have of just "eliminating" it with hopeful results is not to disconnect the pot and simply put a jumper wire between pot terminal #1 and "B". That at least gives you the resistance (15 to 16 ohms) that the old pot provides across the mid and therefore some attenuation. It is the same as having the pot increased to maximum.

It would still be too much for me (especially with the new tweeter you are using) but who knows, you may like it. As it is, it is likely that the new tweeter is going to contribute to the midrange more than the old tweeter which rolled off very quickly.

Roy

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Guest Americain

Roy,

Thanks very much! You wouldn't happen to know the wire colors of #1 and "B" would you? When I look at the pot I think there's a green and a blue wire which go to the midrange from the pot. Which connection is "B"? Many thanks.

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The small inductor wire is attached to the #1 terminal on the midrange pot and the green wire from the 6uF cap connects to the #1 terminal on the tweeter pot. The yellow wire from the "T" (+) input is attached to both #2 pot terminals and continues on to the + sides of the mid and tweeter. A green wire attaches to the mid pot "B" terminal and the mid driver's negative side.

A black wire serves that purpose for the tweeter from it's pot.

Roy

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Guest Americain

>The small inductor wire is attached to the #1 terminal on the

>midrange pot and the green wire from the 6uF cap connects to

>the #1 terminal on the tweeter pot. The yellow wire from the

>"T" (+) input is attached to both #2 pot terminals and

>continues on to the + sides of the mid and tweeter. A green

>wire attaches to the mid pot "B" terminal and the mid driver's

>negative side.

>A black wire serves that purpose for the tweeter from it's

>pot.

>

>Roy

So just so I'm clear, I'm attaching the jumper wire from the small inductor wire to the green wire which goes to the + terminal on the midrange? Just checking.

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The jumper simply connects to the same pot terminals as the inductor wire (#1) and the green wire ("B") leading up to the mid driver.

The pot stays as it was, connected to everything it was connected to before.

The attached photo shows the mid pot wire connections. The red wire represents the jumper. The resistance between the #2 terminal (yellow wire) and #1 (inductor wire) is typically between 15 to 16 ohms and is usually not affected by the corrosion that prevents the pots from working.

Let us know how you make out with the sound.

Roy

http://www.classicspeakerpages.net/dc/user_files/458.jpg

post-3-1117044195.jpg

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Guest Americain

Bless your little heart Roy! That was just the illustration I needed. I have the jumper installed and it works just great. I always had my midrange turned full-on anyways so it's all good. In addition, I'm glad I left the tweeter controls in the circuit so I can adjust those EMIT planar tweeters. I had already refoamed the woofers to their original glory two weeks ago so it was nice to fire the 3a's up and hear their great sound again. And how do they sound? Fantastic. The bass is deep but not overpowering and the highs are sparkling. It's been 20 years since they've sounded this good and it's sure nice to have them back again. The planar tweeters add a nice airiness to the package which I need to explore further and I'm sure I'll enjoy doing so. Thanks Roy.

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Guest Americain

OK, I've had some time with the newly refurbished 3a's and they have not disappointed me at all. That same AR sound that I remember is back and it's astonishing to hear it all again. I did have to turn down the new tweets a tiny bit and once done it was just a brilliant and airy sound that remained from the new planar tweeters. But it was the bass that took my breath away, it was so full, so solid and was absent any tubbiness or phony midbass exaggeration. And here I was so worried about whether the refoaming job was adequate. Pffftttt! I A-B'd them with my Vandersteen 2's and the differences were slight. It was the solidity of the bass on the AR's that was the one thing I noticed. It was subtle but definitely noticeable yet both speakers could easily be used as a reference monitor.

Another thing I noticed was the "bigness" of the sound, even though the AR's are physically smaller than the Vandersteens they easily projected a soundstage just as big. It's been so long since I'd lived with an acoustic suspension loudspeaker that I'd forgotten what an advantage they can have in the size department. Big sound from a smaller cabinet. Once again, the bigness and solidity of solo instruments like piano and guitar was wonderful and voices were rendered without the very common boominess and shreiking. Very nice indeed.

One minor quibble. I noticed that my right channel has a tiny bit of harmonic distortion which I'd been suspicious of for a couple of years. So the AR's have allowed me to hear imperfections in my source electronics which is good and bad but it's nice to know how good the AR's really are. So it looks like the Carver M-400 cube will have to be refurbished soon. You'd think the dang thing would last longer than 25 years but NOOOOOOOOOOOOOOOO!! Anyway, these are some of my first impressions back with these wonderful old friends.

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