AR5 Restoration

[dtafil]

Hi All - Just joined the site after coming across my first pair of Acoustic Research speakers - AR5's to be precise. These showed up in somewhat decent shape from 5 feet away, but the finish on the veneer was missing in patches, along with scratches, mostly on the bottoms, and a few small chips. I did hook them up to a Marantz 1060 briefly at very, very low volume, and noted all drivers were working, although the woofer surrounds were shot after peeking through the grills with a flashlight. A bit of oxidation in the pots as well, as moving them around a bit would cause one of the tweeters to cut out a bit. Even at low volume (and only for perhaps 30 seconds), I could tell that these were well deserving of a restoration, so I'm all in for this!

I ordered up some surrounds from Vintage AR, Dayton caps from PE, and got to work on the cabinets. Some before pics, and some in-progress ones of the cabs. So far, I both cabs have been carefully sanded down with 220 grit, being very careful of the edges. Went through about 4 sheets of paper for my hand sander, but I'd say 95% of the scratches are completely gone. Absolutely gorgeous veneer was hiding under there.

I've looked through the AR forum, I'm somewhat leaning towards a mahagony stain (wet sanded perhaps), and then 2-3 coats of Watco Danish oil (walnut) as it seems a few folks have gone that route. Any tips/tricks/thoughts from others? I'm really not a fan of Tung oil or boiled linseed oil... hoping to avoid those. Looking for a recommendation on the brand of mahagony stain ( Minwax?) as well as medium or dark Watco oil.

More to follow!

Dave

 

[ra.ra]

Welcome to the CSP forum..... and you seem to have a great pair of AR-5 speakers there. Your cabinet prep work thusfar looks terrific, and it is good to see you protecting those smaller drivers before you begin the sanding. You'll possibly receive a handful of opinions about wood finishing, and bear in mind that my comments come from the weekend warrior category rather than from the experienced skilled woodworker. Like yourself, I prefer a reddish hue to my walnut veneer, and I usually cook up a home brew for each project, mixing in varying amounts of Minwax mahogany stain with either a light walnut stain or maybe even tinting the light walnut or neutral Danish finishing oil. And I do like working with Watco products, too, even if some people blab about varnish or resin constituents in these "oils".   

No personal experience with this, but another angle to consider is using this product, as used very successfully by CSP member GD70.

http://www.homedepot.com/p/Minwax-8-oz-Wood-Finish-Gunstock-Oil-Based-Interior-Stain-223104444/202061434

Look at the pics to see if you like results, and make note of posts #96 and 116 for product ID.

http://audiokarma.org/forums/index.php?threads/just-picked-up-a-free-pair-of-klh-6s-from-original-1963-owner-pics.520806/page-6

[dtafil]

Hi there ra.ra -

Thanks for the pointer to the gunstock stain; actually looks pretty close to what I'm looking for... I may have to consider that one as well. I may grab a can of each and test on something similar to the cabinet, and see what it looks like in real life.

And yep, I'm a bit OCD with the cabinet prep... I actually have a plastic sheet with blue painters tape underneath that cardboard on the sanded cabinet... not taking any chances with those other drivers.

I did pull the rock wool (?) and fiberglass out of both cabs and stored separately per speaker to get the same amount back in both. I was amazed to see how the fiberglass was actually packed around the inductors, caps, etc. I grabbed a few pics of the crossovers if anyone is interested. I'm planning on replacing all 3 caps, but will grab ESR readings from all and post them here if anyone is curious as to how far the caps may have drifted. At least from the backsides, the pots look nice; but I'll be disassembling and cleaning as per a posting about using a white vinegar and salt dip. etc.. I normally use either Deoxit or CRC brand to clean most newer pots; sounds like these AR ones need a bit more attention.

I'll post up the serial numbers as well, they're almost sequential, off by 1, lol.

 

 

[ra.ra]

Thx for posting crossover pics - - they appear fully identical to each other except I think I detect an extra staple in one crossover panel . Cap replacement is a smart move, and the pots will undoubtedly require some overdue attention. AR-5 owners may chime in, but I think these woofers may benefit from the Boston filleted foam surrounds. 

[dtafil]

Well, I'm hoping the surrounds from Vintage AR are the right filleted ones (I read somewhere he had switched over to them), as the new foams are already attached to the cones ;-)  tomorrow night to the baskets with a test tone.

Just found the replacement L-Pads as a fall-back plan if I can't resurrect the old pots. Curious what resistor is correct for the new L-Pads, and how folks are adding it to the circuit to play nice with the original drivers. I think this one is correct:

http://www.parts-express.com/15-ohm-10w-resistor-wire-wound-5-tolerance--016-15

to go with these L-Pads:

http://www.parts-express.com/speaker-l-pad-attenuator-15w-mono-3-8-shaft-8-ohm--260-248

Hoping I won't have to find out though. Would love to keep the originals.

[ra.ra]

Nice job, great project, smart research, good work all-around for only three posts here. These speakers are definitely keepers, and you appear to be fully on top of the situation. Keep us posted.

[RoyC]

5 hours ago, dtafil said:

Well, I'm hoping the surrounds from Vintage AR are the right filleted ones (I read somewhere he had switched over to them), as the new foams are already attached to the cones ;-)  tomorrow night to the baskets with a test tone.

Just found the replacement L-Pads as a fall-back plan if I can't resurrect the old pots. Curious what resistor is correct for the new L-Pads, and how folks are adding it to the circuit to play nice with the original drivers. I think this one is correct:

http://www.parts-express.com/15-ohm-10w-resistor-wire-wound-5-tolerance--016-15

to go with these L-Pads:

http://www.parts-express.com/speaker-l-pad-attenuator-15w-mono-3-8-shaft-8-ohm--260-248

Hoping I won't have to find out though. Would love to keep the originals.

Vintage AR sends the Boston filled fillet foam upon request only...better catch him before he ships.

Your link shows the wrong resistor to use with the L-pad. It should be 25 ohm, not 15 ohm.

Roy

[genek]

It's hard to tell for sure from the angle, but the long face shown appears to be pine. If these are pine that was previously stained and finished dark, once you have sanded you should apply a prestain sealer before you restain, because unsealed pine can absorb stain unevenly.

[stupidhead]

Nice find and project. My impression is they were choosier on the veneer used on the 5's and always beautiful faces on these. Caps, pots, surrounds (filled filet as previously mentioned) and these will sing. Post a pic of the surrounds from Larry and we can tell you which you have, describing can be confusing but basically the roll on the cone side will have a soft transition while the basket side is a 90 degree transition.

Hopefully the AP pots are reusable and you won't need to go the l pad route.

Good luck and welcome

[dtafil]

1 hour ago, stupidhead said:

Nice find and project. My impression is they were choosier on the veneer used on the 5's and always beautiful faces on these. Caps, pots, surrounds (filled filet as previously mentioned) and these will sing. Post a pic of the surrounds from Larry and we can tell you which you have, describing can be confusing but basically the roll on the cone side will have a soft transition while the basket side is a 90 degree transition.

Hopefully the AP pots are reusable and you won't need to go the l pad route.

Good luck and welcome

Thanks for all the feedback so far... happy to find this group!

I've added a couple pics of the surrounds I received, and reached out to Vintage AR for confirmation. They do appear to have a bit of a more gentle roll towards the cone, but I guess we'll see. IF anyone can give their opinion as well, I'd appreciate it. Thanks as well to Roy for the correction re: the 25 ohm resistor link.

4 hours ago, genek said:

It's hard to tell for sure from the angle, but the long face shown appears to be pine. If these are pine that was previously stained and finished dark, once you have sanded you should apply a prestain sealer before you restain, because unsealed pine can absorb stain unevenly.

Thanks! I'll add a few more pics later today of both cabinets with some close-ups; appreciate any tips on the veneer, and if a prestain sealer should be used.

[DavidDru]

Great work!

[dtafil]

Grabbed some pics of the cabinets to see what you guys think in terms of what these are, and if a pre-stain may be required. Thanks on advance for any comments/suggestions :-)

[RoyC]

dtafil,

"I've added a couple pics of the surrounds I received, and reached out to Vintage AR for confirmation. They do appear to have a bit of a more gentle roll towards the cone, but I guess we'll see. IF anyone can give their opinion as well, I'd appreciate it."

Your surrounds are not the FF surrounds. They are the conventional looking JBL 125A replacements (which are very compliant and will work fine). Larry does not send the FF surrounds unless they are requested due to some complaints from less technically minded customers who were more concerned about appearance.

Roy

[ra.ra]

Hmmm ..... your cabs pics are a bit perplexing. Pinkish-honey colored veneer with the very small dark knots makes me think cherry, but like genek has already noted, the (long-side) 6th and 8th pics in previous post almost appear to be pine.  Random cherry veneer pic attached.

[dtafil]

Thanks for the response Roy! As long as you think it's not worth re-doing (as the cone side is already attached), I'll just finish up the basket side. I'll make a note for next time (if I ever come across another pair) to ask for the Boston filled fillets next time.

Regards, Dave

[dtafil]

3 minutes ago, ra.ra said:

Hmmm ..... your cabs pics are a bit perplexing. Pinkish-honey colored veneer with the very small dark knots makes me think cherry, but like genek has already noted, the (long-side) 6th and 8th pics in previous post almost appear to be pine.  Random cherry veneer pic attached.

It is odd, as when they're inside (the 6th and 8th pics), they do look a bit different than all the other pics that were taken outdoors. I'm guessing they are probably cherry, as the middle pic you provided looks more like them in natural light. I'll see if I can grab a couple more pics of the sides inside the house with some more natural daylight coming through...

[dtafil]

Wierd! From the front of each speaker, both of the right hand sides do look different... pine? Maybe someone was having an off day at the factory? lol...

Pic1: Speaker 1, left side

Pic 2: Speaker 1, right side

Pic 3: Speaker 2, left side

Pic 4: Speaker 2, right side

 

Has anyone ever seen that before? If the two right hand sides are indeed pine, is there a preealer that someone might recommend before applying the Minwax stain?

Regards, Dave

[dtafil]

Took a quick run over to the local ACE Hardware. Grabbed some Minwax Prestain sealer and Gunstock stain, but the gentleman there recommended the Zar brand as well; supposedly thicker, and great for Pine and softer woods without botchiness or a presealer. I matched up the Minwax Gunmetal stain to the Zar Cherry stain... pretty close. Here's the options so far:

[lakecat]

Hi....nice work so far. Your color us fine for that veneer. It is probably cherry but could be pine. Personally, I would use a gell stain and Minwax has it. The more liquid stains are usually for new woods. You can even thin a gell stain a little if needed but on this older veneer, it will come out better. It also gets rubbed into the veneer and makes it come out nicer.

The liquids can leave blotches on this sanded older veneer. 

Another option is satin poly that Minwax has in spray cans. I use three coats and the speakers are good for years. I show AR 12's on here that was refinished and was done in poly. Good luck.

[dtafil]

5 minutes ago, lakecat said:

Hi....nice work so far. Your color us fine for that veneer. It is probably cherry but could be pine. Personally, I would use a gell stain and Minwax has it. The more liquid stains are usually for new woods. You can even thin a gell stain a little if needed but on this older veneer, it will come out better. It also gets rubbed into the veneer and makes it come out nicer.

The liquids can leave blotches on this sanded older veneer. 

Another option is satin poly that Minwax has in spray cans. I use three coats and the speakers are good for years. I show AR 12's on here that was refinished and was done in poly. Good luck.

Thanks for the tip - never thought about the Gel version of the Minwax stain... I'm guessing that would alleviate the presealer and save a few bucks. I'll have to check and see if they have that version in Gunstock as I'm actually favoring that color stain, but it looks like they do have it in Mahagony. I'm also guessing I can then use a Watco Danish oil over the top of the Gel stained cabs without issue...

[stupidhead]

great work. Roy has confirmed that not filled filet but acceptable. FYI the 10" in the 2ax would also benefit from the filled filet.

As for gunstock, I have used this stain on maple furniture and it is pretty dark. Depending on the look you want, it is a nice rich color but again a fairly dark end result. If you can find a piece of cherry to experiment with before diving in to the speakers it may help you decide on preference before committing. I have been struggling with what to do with some unfinished pine specimens I have been "experimenting" for too long now and still not sure where I will go with them.  

Looking at your original pics it did appear as some sort of varnish was used. I am not convinced as others have stated that all sides are the same species. Some of the early models were finished on three sides and one long edge left unfinished as they were marketed as bookshelf speakers, but I am not sure if that applies to the 5s.

Have you cracked open the pots yet?

[ar_pro]

Stupidhead beat me to the question.

Could this be an instance as in the AR-2, where one horizontal underside was unfinished?

Did AR do that with the AR-5?

[lakecat]

Here's an AR5 I done last year to show gel and poly combo.

 

[JKent]

Sure would be nice to hear from Tom Tyson regarding the wood.

btw, you might not want to use Watco oil if the wood is cherry. According to a sample of AR cabinet finishes from the mid-60s (courtesy of Tom), the Teak and Walnut cabs were oiled but the Mahogany, Birch, Cherry and Korina were lacquered. You could also get lacquered walnut.

Your OP seems to show worn lacquer on the cabs.

FWIW, I used to shy away from lacquer but have found that the Minwax brand in rattle cans does a very nice job and is easy to apply. I have been less impressed with other brands. I now do all of my KLH radio cabs in Minwax spray lacquer.

Nice work so far!

-Kent

[genek]

I'm going to go with pine as my guess, based on the two right face photos. The left faces and the tops like like they could be birch, but birch as the same soft/porous wood issues that pine does, so finishing goes pretty similar.

Gel is probably better than penetrating, even with a sealer/conditioner. Use a color a bit lighter than what you would like and apply multiple times until you get the shade you want.

One thing about gel is that it does tend to obscure the grain more than penetrating. Depending on how you feel about that grain, this could be good or bad.