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BigRiver

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  2. Acoustic Research ar5 rebuild questions/opinions

    in Acoustic Research

    Posted

    6 minutes ago, JKent said:

    Glad to help. As I said, Mouser is a very good source but not for speaker capacitors. Those 72uF WIMA caps from Mouser are expensive and huge. NPEs from PE will work fine for 2 or 3 or 4 decades.

    I created a little firestorm in another thread by being too flippant about capacitor values. But yes--you can caps that are close. Most modern caps are almost spot on, even when rated +/- 5%. So it's fine to use a cap that's 5% or even a little more off the desired value. For your speakers, 25uF is a perfectly good substitute for 24uF. 75uF is fine for 72. I just rebuilt a crossover using 3.9uF for 4uF and 15uF for 16uF. No need to get all OCD about differences of 5% or less.

    The pots are your call. They seem pretty solid and they are sealed (unlike the Ohmite pots I used in my 3a's) but I'll just say that virtually all the people on this forum have been won over by cheap L-pads. AR used L-pads in later versions of the AR-3a.

    And there is a small chance that the issues with your speakers may be with the actual tweeters and mids, in which case you'll want to save some money to have Roy or Chris do rebuilds.

    Kent

    Ahh, that's a good point.  I have removed the tweeters and mids from the first and they are right around 6.5 ohms, though the mid jumped around a bit before settling at 6.3, which made me nervous, though now it seems to be a pretty solid reading.  Seeing that so many have used the L-pads, and given the cost difference, that just may be the way to go.

  3. Acoustic Research ar5 rebuild questions/opinions

    in Acoustic Research

    Posted

    19 minutes ago, JKent said:

    Here are the L-pads. https://www.parts-express.com/speaker-l-pad-attenuator-15w-mono-3-8-shaft-8-ohm--260-248 Just be sure to ask us about the wiring if you go this route.

    And while you're ordering from PE get some of this  https://www.parts-express.com/parts-express-speaker-gasketing-tape-1-8-x-3-8-x-50-ft-roll--260-540

    Wow JKent above and beyond!  Thank you so much for these recommendations, though I might just spring for the pots, haven't totally made up my mind on those.  

    The 72uF's will save me a small stack alone as I was looking at these:  https://www.mouser.com/ProductDetail/505-DCP5-72-1100-10/

     

    So I gather from the above that it is O.K. to use caps that are as close as possible to the original values but not necessarily exactly matching if it is difficult to match.

     

     

  4. Acoustic Research ar5 rebuild questions/opinions

    in Acoustic Research

    Posted

    Hi,

    I just picked up a set of ar5's in decent shape for what I would consider an o.k price, not great and not too bad. I have three days to decide if I want to keep them, and they are going to need work, I just am not sure if this set is worth the expense.

    One speaker works pretty well as in sounds is coming from all three drivers, the other side as very soft/muted sound coming from the high and mid. From initial research I assume this is a pot issue ( and that I should do the soak/clean/etc. that I have seen.  The other option I am seeing are to buy newly manufactured ones on that auction site made specifically for the ar's - but it's $120 for all 4 of them.  

    It seems likely that these needs a recap since I have read that they can be pretty excellent, right now they just sound like cr@p.  I am having a bit of a hard time finding the 4uF - 24uF - and 72uF all in one place.  Found the 72uF at mouser but again $$$$ and the same with the 4uF from parts Xpress.

    Does anyone have experience with these, have any advice or things to specifically look for, ideas on better pricing on the caps, etc?

    Thanks,

    Dan

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