Restoring my 3's

[owlsplace]

Update. Back on the 3's now. Had to work on my amp for a while.

I took out the old cap in speaker 1 and the two values measured at 8 and 39 (supposed to be 6 and 24). Picked up another cleaned up pair of pots on the bay but they are no better than mine which are testing fine anyway. I am going to first re-attach everything in a temporary manner to see what I get out of the drivers that with the old pots were pretty much choked off. Need now to look at everyones examples of their crossover re-builds.

Making haste slowly is my motto

Just curious what amp because that is where I'm at, at the moment.

The auction site is always a crap shoot.

Roger

[DavidDru]

I was working on my Dynaco ST70 and my Pas2 preamp as well. The ST70 is up and running, but I still have the Pas2 on the bench replacing the volume control and then will replace the power supply. I really don't want to mess with the electronics end of this hobby as I would rather focus on finding fixing and trying speakers. But, I just have been uncomfortable with my electronics. The ST70 will be fine for when I want to run with tubes, but I am still not sure the ST400 will keep me happy for other stuff like the AR 3's and Maggies. Like you say getting gear from the auction site can be sketchy and frankly I keep thinking maybe I should just go with new gear for that end of things. Emotiva is probably where I would start if I went that route.

That Amp's for 3's thread we all chimed in on a while back still has some good thoughts on various options. I have been keeping my eye's open for an Adcom 555ii like Kent has. There is a GFA5500 here on Clist for $400 along with an Audio Research D110 for $700 so those are not great deals by any means.

Have you been looking at Bartertown over at AK or Audiogon? I think you can find some nice stuff on Bartertown from guys like us. I have picked up a phono cart for a great price as well as my ST400 from there and for prices I could never have got thru auction.

[owlsplace]

I was working on my Dynaco ST70 and my Pas2 preamp as well. The ST70 is up and running, but I still have the Pas2 on the bench replacing the volume control and then will replace the power supply. I really don't want to mess with the electronics end of this hobby as I would rather focus on finding fixing and trying speakers. But, I just have been uncomfortable with my electronics. The ST70 will be fine for when I want to run with tubes, but I am still not sure the ST400 will keep me happy for other stuff like the AR 3's and Maggies. Like you say getting gear from the auction site can be sketchy and frankly I keep thinking maybe I should just go with new gear for that end of things. Emotiva is probably where I would start if I went that route.

That Amp's for 3's thread we all chimed in on a while back still has some good thoughts on various options. I have been keeping my eye's open for an Adcom 555ii like Kent has. There is a GFA5500 here on Clist for $400 along with an Audio Research D110 for $700 so those are not great deals by any means.

Have you been looking at Bartertown over at AK or Audiogon? I think you can find some nice stuff on Bartertown from guys like us. I have picked up a phono cart for a great price as well as my ST400 from there and for prices I could never have got thru auction.

I am sticking with period gear at the moment but the Adcom looks like an excellent choice.

Working on old gear with discrete components has a charm to it -- sort of like looking at a town and seeing all the people rather than just seeing all the buildings.

I will take a look at Bartertown. Thanks for the tip.

[DavidDru]

Speaker 1 is back together and functioning! Temporary just to make sure all is as should be. Sound from drivers and tweet so thats a good thing. Sounds meh with no insulation and only 4 of the screws holding the woofer on and no sealant. I assume this is typical. Going to run it a few hours and let those new caps load up. (yeah, I couldn't resist) Used a Solen for the 24 and an Erse MpX for the 6. Going to leave the old wax cap in there for the hell of it.

[owlsplace]

Speaker 1 is back together and functioning! Temporary just to make sure all is as should be. Sound from drivers and tweet so thats a good thing. Sounds meh with no insulation and only 4 of the screws holding the woofer on and no sealant. I assume this is typical. Going to run it a few hours and let those new caps load up. (yeah, I couldn't resist) Used a Solen for the 24 and an Erse MpX for the 6. Going to leave the old wax cap in there for the hell of it.

Sounds grate I'm sure... need to limber up those old drivers at any rate... the old wax cap will add some ballast

[DavidDru]

They did limber up a bit over the next couple hours of listening and it did sound better. Could tell they like power.

So who here uses crimp connectors in their crossovers to connect to the pots and posts? I did solder connections to the caps and a few others.

[JKent]

Depends. In some cases crimps work well, in others solder seems to be the way to go. The 4x XO shown (with the Zen cap) was my first rebuild and I did not trust my soldering skill. The Cizek xo shows lots of paralleled "surplus" caps and lots of solder joints.

Whatever works for you. A good crimp is considered better than solder.

-Kent

[DavidDru]

Hey, what is this stamp on the inside of the cabinet? Both sides.

[ra.ra]

Yeah, Denny was a busy guy that year - - - he has shown up in two pairs of AR's of mine, including this very early AR-4 specimen.

There is also a second personal ink stamp that shows up occasionally inside other AR cabinets of similar vintage (see pic, also AR-4's).

[DavidDru]

So here is a question for those of you in the know. As I dig into speaker #2 and ply through the damn mortite putty to get the woofer driver off and gain access into the cab to service the pots and caps, why is this the only way in? Couldn't they have sealed the back of the cabinet or maybe even an access panel or something? I wouldn't undo the woofer driver if I didn't have to get in to get to the other stuff. Was AR in te mindset that these speakers wouldn't be around and getting this attention 50 years later so why bother? Or is it simply the only way to gt the seal they wanted?

[owlsplace]

So here is a question for those of you in the know. As I dig into speaker #2 and ply through the damn mortite putty to get the woofer driver off and gain access into the cab to service the pots and caps, why is this the only way in? Couldn't they have sealed the back of the cabinet or maybe even an access panel or something? I wouldn't undo the woofer driver if I didn't have to get in to get to the other stuff. Was AR in te mindset that these speakers wouldn't be around and getting this attention 50 years later so why bother? Or is it simply the only way to gt the seal they wanted?

David,

They made them that way to make sure you sent them in for factory service along with making the grills nearly impossible to get off

the early models anyway

No doubt it helped keep the price down I'm sure.

A side benefit for today's collector is that it is still possible to find speakers that no one has figured out how to get the grills off, let alone mess with the crossover

Roger

[iso]

Was AR in te mindset that these speakers wouldn't be around and getting this attention 50 years later so why bother?

It is bad business to make anything to last too long. Very few speaker manufacturers do stock correct replacement parts more than 10-20 years. Some companies like Spendor or ATC do rebuild also older drive units... but I do not know how faithful these rebuilds are to original specs.

Best Regards

Kimmo

[DavidDru]

In my search for parts the best source of wire I have found that Napa Auto has the best assortment of sizes and colors along with crimp connectors etc. The wire is manufactured by Belden. Here is what they identify as a sec for it. It's classified as Automotive primary wire. Will this be okay for use?

[ra.ra]

Not familiar with that exact product, but I've also had good luck locating small quantities of various stranded wire gauges at auto parts stores - - particularly, 18 ga. or 16 ga., that sort of thing. Better prices and selection of colors than what you find at Radio Shack, and not as heavy (12 and 14 ga.) as what I've found at Home Depot, where they sell it by the foot.

[DavidDru]

What should the resistance readings on the mid and tweet be?

[RoyC]

What should the resistance readings on the mid and tweet be?

Hi David,

I just responded to your PM. The AR-3 tweeter should be just shy of 2 ohms and the mid should be around 2.5 ohms.

Roy

[tysontom]

So here is a question for those of you in the know. As I dig into speaker #2 and ply through the damn mortite putty to get the woofer driver off and gain access into the cab to service the pots and caps, why is this the only way in? Couldn't they have sealed the back of the cabinet or maybe even an access panel or something? I wouldn't undo the woofer driver if I didn't have to get in to get to the other stuff. Was AR in te mindset that these speakers wouldn't be around and getting this attention 50 years later so why bother? Or is it simply the only way to gt the seal they wanted?

Mortite is a wonderful thing! It seals without fail, but it's messy stuff.

Preventing "easy" access to back of the cabinet—fifty years down the road—wasn't the purpose of sealing the back of the enclosure. They didn't have you in mind, David. This procedure was done to get a more solid cabinet and a perfect air seal on the back, sides and front insofar as Ed Villchur needed an acoustic seal (note: not a hermetic seal). Sealing the entire cabinet by gluing the back, sides and front was Henry Kloss' idea, by the way, so you have him to thank, but it was a very good solution.

Harken back (HB) to the years preceding the 1954 AR-1, and you would find that nearly all loudspeaker cabinets had a huge plywood panel screwed to the back the cabinet to gain access to the speakers—this was the normal way to do things before the advent of the wonderful Acoustic Research acoustic-suspension woofer. But there was a problem for Henry Kloss (he worked out many of the mechanical details of the first AR speakers under Villchur's designs), and it was how would he get the big woofer into the cabinet to screw it to the baffle board? Kloss was innovative if not particularly clever: he decided to put notches in the cabinet front, and he designed a jig to pass the speaker through the speaker hole (with special notches at the top and bottom) and then turn the driver around to fact the front and screw it to the cabinet. He struggled with this concept for a long time when Villchur came along one day and asked him if he considered routing out a recess around the speaker hole in the baffle board to drop the speaker frame flush with the baffle surface and mount it from the outside. Thus we get the lovely mounting configuration with eight machine screws holding the woofer in place.

Note the picture of the fine old early 50s Bozak B-310A Concert Grand (one of the best speakers of the refrigerator-size category). This has the "removable" back panel.

—Tom Tyson

[DavidDru]

Thanks Roy for the values. I measured so I thought I might as well check to see what it is supposed to be. Based on what I have read on various threads it seems like they either read correctly or not at all?

More great background Tom. Thanks. I just can't believe Ed and Henry weren't thinking of me when they came up with the design!

Here is a picture of my crossover re-do in case you can pick up on anything I got wrong. I am using the crimp connectors on the pots just in case I want to replace the pots yet. I think they are borderline okay after my cleaning and polishing efforts. They range okay 0-16 but feel rough and aren't exactly pretty. I will organize the wires when I replace the old insulation. I used a Solen for the 24 (400v Poly PB2400) and the Erse for the 6 (250v pulseX Metalized poly film). Left the old cap in for historical value and to allow me to keep the coil as-is. Also as ballast per Roger.

[ar_pro]

Very clean, very nice.

How did you secure your cable tie mounts to the masonite board, David?

[tysontom]

Very clean, very nice.

How did you secure your cable tie mounts to the masonite board, David?

I can't clearly see it, but I can tell you what I think he did and what anyone should do when mounting components with Ty-Raps:

By the way, the "Ty-Rap" was invented by Thomas & Betts, and their original version with the metal insert is still considered to be the best cable tie, by far, available. They are expensive, but they adjust better and have much greater holding capacity. A good tensioning tool is also important to install them properly. The best: T&B.

--Tom Tyson

[tysontom]

I can't clearly see it, but I can tell you what I think he did and what anyone should do when mounting components with Ty-Raps:

By the way, the "Ty-Rap" was invented by Thomas & Betts, and their original version with the metal insert is still considered to be the best cable tie, by far, available. They are expensive, but they adjust better and have much greater holding capacity. A good tensioning tool is also important to install them properly. The best: T&B.

--Tom Tyson

Add another good way to mount Ty-Raps & components to a wood (or similar) surface. This is the "Mounting-Head" type Ty-Rap, and a component can be easily mounted flush to a board or wood surface. When mounted, it is applied inversely, or the opposite from what might seem "correct."

--Tom Tyson

[DavidDru]

I wish I had the high end version Tom showed. But actually I used mounts like the one Tom shows but simply found a very short wood screw with a wide flat head. Plus the self adhesive sticky back of the mount. I suppose I could of added some better glue too if I was worried but the screws did the trick it seemed. If you cant find a wide enough head, a washer would have worked. Of course I was just able to get the cordless driver inside on an angle enough to get to it.

The hardest thing in the first speaker was one of the T nuts had stripped the wood out when I tried removing it and I was unable to get it to re set. I had to epoxy it to get it to hold until it tightened.

It also seemed like the insulation didn't fill up the cabinet as much as it was before I took it out although it was all the original stuff.

Overall it appears the AR 3 crossover is a fairly simple one. The 2nd speaker took me no time to do.

[DavidDru]

both speakers are back together. 2nd one went really quickly. I have not given the cabinets any attention yet.

Unfortunately they do not sound good. The mids are not up to snuff with considerably reduced output. Sounds like they are in a box or something. Sound like Miss Othmar in Peanuts, the teacher...WA wa wa wa Wa..WA wa wa wa.

So, Roy to the rescue. They are going out to him tomorrow so he can do his magic on them. I am sure they will sound great when he's done with them, so stay tuned.

[lakecat]

Roy is certainly the magic man when it comes to these drivers..... He saved the mids in my 3's and they sound simply awesome. Fixed a loose spider in my woofer also and owe him many thank you's as I listen to these great speakers.

[ra.ra]

Glad to hear that your pot restoration might be working out - - I've noticed that the range should run from between 0 and 1 ohm at one end to between 15 and 16 at the other extreme. When I re-use cleaned pots, I will typically apply a silicone spray and/or dielectric grease before re-assembly to attempt to retard future corrosive activity. At the very least, this provides a much smoother sweep when turning the control. Also, that sealant should work fine, David, but these two options each have one very di$tinct advantage, IMO.

http://www.homedepot.com/p/Gardner-Bender-Duct-Seal-Compound-Plug-DS-110/100212441

http://www.homedepot.com/p/Frost-King-E-O-90-ft-Grey-Weather-Strip-and-Caulking-Cord-B2/100152937