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New AR5 Project


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Hello all. Happy New Year.  Just purchased a set of AR5s from the son of the original owner. Listening to them now..Tweeters, mids and drivers all working ok and they sound great (tweeters are fading in and out sometimes but I think this is the pot issue). I've read the AR3a restoration guide here as well as had a putter about in the forums.  Thank you all for the info and the guide. Keen to make these speakers work very well for another 50 years.  There is a tube amp repair and build guy that can help me (I've learned the hard way fixing old turntables that my soldering skills are not the best). He has asked me to source parts rather than him using his old stock or what can be purchased here.  Seems I need to order parts from the USA and before doing so wanted to check on general advice on the following:

- L-pads with resistors or something like this (https://www.ebay.com/itm/AR-3-AR-3a-AR-2-AR-2ax-AR-4-AR-4x-AR-5-AR-6-wirewound-potentiometer-pot/153936403748?_trkparms=aid%3D1110012%26algo%3DSPLICE.SOIPOST%26ao%3D1%26asc%3D20200420083544%26meid%3D626cb72158ef47f7bc45be79dcc7775f%26pid%3D100008%26rk%3D1%26rkt%3D12%26mehot%3Dpp%26sd%3D164155400493%26itm%3D153936403748%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DPromotedSellersOtherItemsV2WithMLRv3%26brand%3DAcoustic+Research&_trksid=p2047675.c100008.m2219)

- Caps - which company / supplier do you recommend. Tips for optimum performance

- Is there a way to use the serial numbers to determine the year / crossover board from a database (apologies in advance if it was missed on the threads)

- I can get yellow fibreglass insulation from building shops here.  I've read 20-22oz per speaker.  Is there a diagram for location inside the speaker (cutaway on AR3a guide drawing?)?


Thank you all in advance and hope 2021 is much better for everyone













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Welcome to the CSP!

The AR-5 is an excellent speaker so you want to do things right. The AR-3a restoration guide is a good starting point because the 5 is essentially a 3a with a slightly smaller driver. 

Where are you? I'm guessing not in the USA because you said you need to order parts from here. Not necessarily. There are outfits in Europe and the UK that sell speaker capacitors and I would assume you can also find L-pads. Members in the UK have mentioned Falcon Acoustics. I'm sure there are others. I believe each speaker has one 4uF, one 24uF and one 72uF capacitor. I looked at Falcon's site and they have 4.0uF Solen for £3.60, 25uF (close enough) Solen for £12.66 OR an electrolytic for £2.14 and a 72uF 100V electrolytic for £2.74. As an alternative, you can order from the USA. Parts Express should have everything you need. If you go with L-pads check back here for instructions on how to wire them. The pots you linked will also work but a set of 4, shipped will be about $125 USD and then you have to pay import duty I would imagine. Pretty expensive.

I confess I have not worked on a 5 so hoping others who have will chime in. 

Do not replace the stuffing. Remove it from each speaker and put it in 2 plastic bags, then re-use it.

If you have more questions we're here to help.


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OK. So I should have just accepted that you will be ordering from the US and not tried to steer you to other sources. Sorry.

As I mentioned, I have not been inside an AR-5 myself. I'd suggest you open one up and see what you have. If there are Sprague Compulytic caps they may still be good.

If you order from PartsExpress, I'd use their Dayton 5% film caps and their L-pads. The PE site seems to be having issues as I type this so I can't give specific links. If those speakers were mine, I'd use film caps even for the 72uF. They cost a lot more than electrolytics but will last forever. Some members here have endorsed Mundorf E-caps (electrolytic) https://www.partsconnexion.com/capacitors-ele-mundorf-e-cap-ac-series.html    They come in 22uF--close enough to 24 or you could parallel 10uF and 15uF. They also come in 68uF which is close enough to 72 but you could parallel a 3.9uF 'lytic or buy enough 4uF film caps to use with these plus the tweeter caps. If you order from that site they have Solen film caps, which many here use and won't break the bank.

If you order from PE, get your 8 ohm 15w L-pads and some foam speaker gasket tape. 

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  • 2 weeks later...

Hi. I have been tied up with family stuff for a couple of weeks but now want to order. I found this shopping list on another thread for AR5s here and the capacitors are different from the AR3a restoration guide?


My desired outcome is to order the capacitors and gasking material for a local guy to help me do the work. Any thoughts on a specific shopping list would be very helpful as I am a total novice but love these speakers.  Really appreciate the help. Is this the correct order of parts:

https://www.parts-express.com/Dayton-Audio-DMPC-75-75uF-250V-Polypropylene-Capacitor-027-445?quantity=1  (x4)

https://www.parts-express.com/Dayton-Audio-DMPC-50-50uF-250V-Polypropylene-Capacitor-027-443?quantity=1 (x2)

https://www.parts-express.com/Dayton-Audio-DMPC-6.2-6.2uF-250V-Polypropylene-Capacitor-027-427?quantity=1 (x2)




Edited by Ecjenkins
correction on a link
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NO NO NO DON'T ORDER THOSE They're for the 3a.

The reason the shopping list for AR-5 caps is different from the AR-3a guide is the 5 is not a 3a. Most of what's in the 3a guide is applicable to the 5 but not specifics such as crossover design. 

Cap values for the 5 are 4, 24 and 72. 

Also just noticed you've posted the same question on 2 threads. That's confusing. Please try not to cross-post.

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  • 2 weeks later...

Made some good progress this weekend with both speakers crossover caps replaced and pots with Eddie Wu who builds local valve amplifiers and is an all around great guy.  Need to clean up the cabinets a bit and replace the grills back to the linen sheepskin colour.  They sound fantastic in the house now (even my wife is enjoying it). 












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