New AR 2ax Restoration

[npt3]

So, my uncle gave me his pair of 2ax' on long-term loan. I needed a fun project, and this seems eminently doable. It's the later model with the four-screw mount woofers and black 3/4" tweet. Oh, and the 'unfinished' cabinets, which were finished by someone else in an OK fashion (looks like a one-step Minwax stain), but we can do a lot better.

Here's what I'd like to do:

- strip the outside finish off, sand the sides down very well and apply a walnut veneer

- take a thin black laminate or contact sheet and apply it to the black painted front so it looks cleaner than it does now

- replace the original grille fabric with a more sonically transparent fabric and add velcro fasteners

- just ensure that the drivers all work as-is, i.e., I'll prefer not to re-cap it, clean the pots etc. In other words, first do no harm.

So, here's my first question: I need a replacement woofer on one speaker, since the first one apparently immolated (seriously) and was trashed. The only sign that this happened is a slight charring on the front lower cabinet edge, which I can fix - nothing inside the box. I've secured proper replacement woofers for the speaker pair.

What kind of fiber fill should I use, and how much? And, since I'm replacing both woofers, should I pack both enclosures?

[genek]

What's in them now? The last runs of the 2ax used a poly fill that is either impossible or darn near impossible to match today (the white stuff sold by Parts Express and most other speaker building dealers will not do the job). If you have this stuff (it's a bluish/purplish grey with multicolored strands or bits mixed in), I'd reuse it. If it's anything else, use fiberglass. The amount varies with design changes over the years. Look at your crossovers and post the number that's marked on the inductor coils and we'll be able to tell you how much you should be using.

[JKent]

So, my uncle gave me his pair of 2ax' on long-term loan. I needed a fun project, and this seems eminently doable. It's the later model with the four-screw mount woofers and black 3/4" tweet. Oh, and the 'unfinished' cabinets, which were finished by someone else in an OK fashion (looks like a one-step Minwax stain), but we can do a lot better.

Here's what I'd like to do:

- strip the outside finish off, sand the sides down very well and apply a walnut veneer

- take a thin black laminate or contact sheet and apply it to the black painted front so it looks cleaner than it does now

- replace the original grille fabric with a more sonically transparent fabric and add velcro fasteners

- just ensure that the drivers all work as-is, i.e., I'll prefer not to re-cap it, clean the pots etc. In other words, first do no harm.

So, here's my first question: I need a replacement woofer on one speaker, since the first one apparently immolated (seriously) and was trashed. The only sign that this happened is a slight charring on the front lower cabinet edge, which I can fix - nothing inside the box. I've secured proper replacement woofers for the speaker pair.

What kind of fiber fill should I use, and how much? And, since I'm replacing both woofers, should I pack both enclosures?

Sounds like a good project. I've restored 2 pair of earlier 2ax's, but have not gone as far as veneering the cabinets.

I'd recommend checking the caps before you decide to keep them. If they are the wax blocks they are probably way off. If they are Spragues they "may" be OK but why not replace them with new film caps? Then you'll know they are good.

I also disagree on the pots. Rather than "do no harm" you may be "doing no good." The pots tend to corrode. If they are not too bad, rotating the knob back & forth several times may wipe them clean.

I'm especially suspicious about the immolated woofer. I'll bet SOMETHING in the crossover of that speaker is shot--most likely the cap.

If you read the AR3a restoration manual you'll find a description of how to replace the grille cloth with Irish Linen. It's pretty open and transparent, and looks authentic. If you decide to use the modern knit grille cloth instead, there is a demo on the Human Speakers web site.

Yes--both boxes should be packed with the correct amount of stuffing. Someone (probably John) will be able to tell you the weight of the stuffing if it is fiberglass insulation. As Gene said, if it is something else, just re-use it (actually you can also re-use fg. The only thing NOT to re-use is rock wool).

Good luck

Kent

[genek]

Yeah, I don't think I'd bother to remove fiberglass and replace it with more fiberglass. I'd just pull the stuffing out, weigh it and check the inductor numbers, make sure a previous owner hadn't mucked up the amounts, and if it's still right just put it back in again (it's what I did with my 3a's).

[JKent]

Checked with RoyC on the FG. Here's his reply:

"the stuffing amount is 20oz fiberglass for his era 2axs"

Hope this helps,

Kent

[npt3]

What's in them now? The last runs of the 2ax used a poly fill that is either impossible or darn near impossible to match today (the white stuff sold by Parts Express and most other speaker building dealers will not do the job). If you have this stuff (it's a bluish/purplish grey with multicolored strands or bits mixed in), I'd reuse it. If it's anything else, use fiberglass. The amount varies with design changes over the years. Look at your crossovers and post the number that's marked on the inductor coils and we'll be able to tell you how much you should be using.

The fill that's inside is a yellowish (well, at least now it is!) fill, not like what you described (these are pre-Teledyne 2ax'.) Fiberglass it is!

[npt3]

Sounds like a good project. I've restored 2 pair of earlier 2ax's, but have not gone as far as veneering the cabinets.

I'd recommend checking the caps before you decide to keep them. If they are the wax blocks they are probably way off. If they are Spragues they "may" be OK but why not replace them with new film caps? Then you'll know they are good.

I also disagree on the pots. Rather than "do no harm" you may be "doing no good." The pots tend to corrode. If they are not too bad, rotating the knob back & forth several times may wipe them clean.

I'm especially suspicious about the immolated woofer. I'll bet SOMETHING in the crossover of that speaker is shot--most likely the cap.

If you read the AR3a restoration manual you'll find a description of how to replace the grille cloth with Irish Linen. It's pretty open and transparent, and looks authentic. If you decide to use the modern knit grille cloth instead, there is a demo on the Human Speakers web site.

Yes--both boxes should be packed with the correct amount of stuffing. Someone (probably John) will be able to tell you the weight of the stuffing if it is fiberglass insulation. As Gene said, if it is something else, just re-use it (actually you can also re-use fg. The only thing NOT to re-use is rock wool).

Good luck

Kent

I do have the wax blocks (Chicago Condenser). I'm really kind of skittish about replacing them; my electrical skills are not terribly strong and don't want to eff them up if they are in fact OK.

Point taken on the pots, Kent. Once I can hook the speakers up to a signal source I will be able to tell if they're in bad shape. If I've got to replace 'em, so be it.

I was in fact thinking of using the modern knit grille - with the box veneered, I think it would be a nice, more modern look.

And thanks for the info on the weight of the stuffing. Can I correctly presume that any conventional fiberglass insulation, like I can pick up at Home Depot, will be fine?

[npt3]

BTW, I found the AR-3a Restoration document elsewhere at CSP. Wow! I'll save my questions for the stuff I can't figure out, or that which isn't found in that doc.

One thing I tried last night was cleaning up the brass grille badges. I found that using brown jeweler's rouge with a special buffing tip on my Dremel works awesome! I just polished up a portion of the badge without lettering. Before I move on to the areas in and around the lettering, I'll need to mask the letters off so I don't polish off the red paint (probably will use Scotch tape, carefully cut to fit with an Xacto knife.)

[Carlspeak]

BTW, I found the AR-3a Restoration document elsewhere at CSP. Wow! I'll save my questions for the stuff I can't figure out, or that which isn't found in that doc.

One thing I tried last night was cleaning up the brass grille badges. I found that using brown jeweler's rouge with a special buffing tip on my Dremel works awesome! I just polished up a portion of the badge without lettering. Before I move on to the areas in and around the lettering, I'll need to mask the letters off so I don't polish off the red paint (probably will use Scotch tape, carefully cut to fit with an Xacto knife.)

Sounds like you have the better badges with the red painted recessed characters. The easiest way to polish these without harming the red letters or having to do what you planned (apply masking tape into the letter's shape) is to buy a can of liquid Brasso available from your local hardware store.

Get a clean cotton rag and apply a single layer of it onto a hard FLAT surface. Pour on a minimal amount of the Brasso and then rub the face of the plate hard into the Brasso whilst holding the brazed-on screw at the back. In about 5-10 minutes it will shine alot. Work the plate into the Brasso initially. Then move the plate over to a clean area of the rag - still rubbing it downward with pressure. The rag will turn black in those areas and you'll know the brasso is doing its job.

[JKent]

BTW, I found the AR-3a Restoration document elsewhere at CSP. Wow! I'll save my questions for the stuff I can't figure out, or that which isn't found in that doc.

One thing I tried last night was cleaning up the brass grille badges. I found that using brown jeweler's rouge with a special buffing tip on my Dremel works awesome! I just polished up a portion of the badge without lettering. Before I move on to the areas in and around the lettering, I'll need to mask the letters off so I don't polish off the red paint (probably will use Scotch tape, carefully cut to fit with an Xacto knife.)

You may want to apply a clear finish like lacquer to keep them from tarnishing.

Your pots don't have to be replaced. They come apart easily and can be cleaned with a little wire wheel in your Dremel. Maybe use a little De-Oxit, then apply a little dielectric grease.

My first speaker restoration was AR2ax and I had no idea what a capacitor was but I got a LOT of help here and they turned out great. Remember--your woofer burned up. SOMETHING is wrong. And those old wax caps are WAY beyond their life expectancy. You need two 4uF and two 6uF caps to do the pair. If you go to Madisound, 3.9uF (close enough) Carli caps are $1.15 and the 6uF are $1.50. Cheap. Or you could use Solens, but in any case I'd say replace them. If you're afraid of soldering you "could" use crimp connectors. I did that on my 1st pair (photo attached).

Have fun with it!

Kent

[genek]

You may want to apply a clear finish like lacquer to keep them from tarnishing.

Simpler approach: dip a soft cloth or some tissue in olive oil, wipe it onto the cleaned-off brass and then buff. Repeat once a year. No tarnish.

[npt3]

You may want to apply a clear finish like lacquer to keep them from tarnishing.

Your pots don't have to be replaced. They come apart easily and can be cleaned with a little wire wheel in your Dremel. Maybe use a little De-Oxit, then apply a little dielectric grease.

My first speaker restoration was AR2ax and I had no idea what a capacitor was but I got a LOT of help here and they turned out great. Remember--your woofer burned up. SOMETHING is wrong. And those old wax caps are WAY beyond their life expectancy. You need two 4uF and two 6uF caps to do the pair. If you go to Madisound, 3.9uF (close enough) Carli caps are $1.15 and the 6uF are $1.50. Cheap. Or you could use Solens, but in any case I'd say replace them. If you're afraid of soldering you "could" use crimp connectors. I did that on my 1st pair (photo attached).

Have fun with it!

Kent

I'm going to take the plunge and order new caps from Madisound (the Solens). I think I can handle the soldering just fine.

Wanting for something to do, I polished up the badges tonight. Didn't have any Brasso, but I have a set of MicroMesh abrasive sheets (1500-->12000 grit) that I've used for finishing pen parts. Worked like a charm!

[npt3]

I'm going to take the plunge and order new caps from Madisound (the Solens). I think I can handle the soldering just fine.

Wanting for something to do, I polished up the badges tonight. Didn't have any Brasso, but I have a set of MicroMesh abrasive sheets (1500-->12000 grit) that I've used for finishing pen parts. Worked like a charm!

Idle question while waiting for new caps - does it make sense to chamfer the edge of the tweeter/midrange opening in the grille frame; or would that really make no difference on the high/mid dispersion?

[genek]

Idle question while waiting for new caps - does it make sense to chamfer the edge of the tweeter/midrange opening in the grille frame; or would that really make no difference on the high/mid dispersion?

I wouldn't expect anything audible, what with the much deeper cabinet/grill lip right next to it.

[npt3]

What's the deal with the 2ax midrange, i.e., is it a cone driver; and if so, why the foam covering as well as the metal mesh? (or, to be tabloid-like, "what does the 2ax midrange have to hide?" )

[genek]

What's the deal with the 2ax midrange, i.e., is it a cone driver; and if so, why the foam covering as well as the metal mesh? (or, to be tabloid-like, "what does the 2ax midrange have to hide?" )

It's a cone. The fiberglass (not foam) pad is there to help tune the sound. AFAIK, the mesh is just there to hold the FG in.

[RoyC]

What's the deal with the 2ax midrange, i.e., is it a cone driver; and if so, why the foam covering as well as the metal mesh? (or, to be tabloid-like, "what does the 2ax midrange have to hide?" )

It doesn't have any more to "hide" than the famous AR dome mid used in the AR-3, 3a, 5, 3a Improved, 3a Limited, 11, 10pi, LST, and LST 2. As Gene said, it is just a form of "behavior modification" .

Roy

[JKent]

Here's what I'd like to do:

- strip the outside finish off, sand the sides down very well and apply a walnut veneer

- take a thin black laminate or contact sheet and apply it to the black painted front so it looks cleaner than it does now

- replace the original grille fabric with a more sonically transparent fabric and add velcro fasteners

Hi

I was looking over your OP. Here's a question: Why use walnut veneer? I've re-veneered old radio cabinets and the new walnut veneer lacks the character of the 50-year-old stuff. So why not something different? Oak with a black grille looks cool. You can get oak iron-on veneer in Lowes or HD. Are you skilled enough to use regular veneer or are you using the stick-on kind (that's what I used). Anyway, there are plenty of varieties and you could make your ARs really unique! Back in the day college kids bought the cheap utility cabinets and let their chemically-altered imaginations go wild. Psychedelic paint jobs! Decoupage! Groovy.

Just a thought.....

Kent

[genek]

It would probably be best to check with "Uncle" to see what he'd like them to look like when they come back from "long-term loan."

[npt3]

Hi

I was looking over your OP. Here's a question: Why use walnut veneer? I've re-veneered old radio cabinets and the new walnut veneer lacks the character of the 50-year-old stuff. So why not something different? Oak with a black grille looks cool. You can get oak iron-on veneer in Lowes or HD. Are you skilled enough to use regular veneer or are you using the stick-on kind (that's what I used). Anyway, there are plenty of varieties and you could make your ARs really unique! Back in the day college kids bought the cheap utility cabinets and let their chemically-altered imaginations go wild. Psychedelic paint jobs! Decoupage! Groovy.

Just a thought.....

Kent

I've always liked the classic look. I might alternately go with cherry or mahogany. I was indeed thinking of going with black grille cloth. I've done iron-on veneer before with good success, and self-stick would be a good call here too.

As I mentioned before, someone had 'finished' the cabs with a quickie one-step Minwax stain, and the outside is kind of beat-up too. What I hadn't mentioned is that these ARE in fact utility-cabinet 2ax' (unfinished plywood), hence my desire to clean them up a bit. I'll check with Uncle, but I think he'll approve. Not likely he'd dig any psychedelic paint jobs, though ;-)

[npt3]

Stupid Question Time (#1): Don't worry, I do plan on replacing the original caps with new Solens, but how do I (can I?) check the original ones to see if they're bad or not? I've got a multimeter.

[JKent]

Stupid Question Time (#1): Don't worry, I do plan on replacing the original caps with new Solens, but how do I (can I?) check the original ones to see if they're bad or not? I've got a multimeter.

There are no stupid questions.

You would need an LCR meter (actually just a "C" meter for capacitance) but don't bother. They're wax. They're old. They're shot.

No need to remove them--you can just snip the wires. Here is the schematic

http://www.classicspeakerpages.net/library..._schematic.html

Use the wax cap as a guide. The green wire is 6uF and the black wire is 4uF. The blue is common. If you leave the original wires soldered to the pots, one lead from each of your Solens can be connected together (common) and attached to the blue. You can solder, crimp or use wire nuts. Then the other lead from the 6 goes to the green wire and the other lead from the 4 goes to the black wire.

If you get stuck just ask here. Members have done LOTS of these.

Good luck

Kent

[JKent]

Oh. One more random thought. Be sure to look at your tweeters and inspect the 3 blobs that hold the center dome in place. These eventually dry out causing the tweeter to "pop its cork". If that happens the tweeter is shot. No worries--RoyC has come up with a very good replacement.

Kent

[npt3]

Oh. One more random thought. Be sure to look at your tweeters and inspect the 3 blobs that hold the center dome in place. These eventually dry out causing the tweeter to "pop its cork". If that happens the tweeter is shot. No worries--RoyC has come up with a very good replacement.

Kent

Blobs look good - I think we'll be OK there. On to re-capping...

[npt3]

Blobs look good - I think we'll be OK there. On to re-capping...

Recapping of the 'en fuego' speaker: success! Soldered in the woofer leads and all the drivers work!!

The pots, OTOH, are a different story - I'll have to clean them up, doodies. I was really hoping I wouldn't, but they are 38 years old, so, out comes the Dremel.

Question about re-stuffing the enclosure: does it really matter if I bunch up the new fiberglass I got the way the original stuffing was, or as long as the stuffing weight is correct, can I just lay(er) it in?