My 2As Finally Finished...Almost

westmassguy

I doubt they'll ever be really finished, but they are sweet now. Last year I had built a Hybrid or "Franken-Polk" out some 2A crossovers and my monitor 10s. They came out very nice, full SDA effect, and performed beautifully. I recently picked up a pair of real 2As, that were in good to excellent condition. I tranfered my already rebuilt crossovers and RDO-194s over to the 2As. The bass was better, due to the larger cabinet, and larger PR. When I rebuilt the crossovers last year, I used Sonicaps and Mills for the Hi-Pass, and Daytons for the Low-Pass shunts, except for the huge 130 uf electrolytics, two per crossover. I couldn't afford them at the time, so I installed some fresh NP Electrolytics, to tide me over. Business has been good, so I decided to finally replace those Electrolytics. In addition, I'd also been reading Mathew Polks opinion on inductor upgrades, specifically the inductor connected to the negative terminal on the dimensional woofer and the amps ground. Although he references a later generation than my 2As, the theory should still apply. The problem with 2As is, they're already sitting at 4 ohms to begin with. My Carver can handle 2 ohm loads, so I wasn't worried. MP mentioned/recommended Laminated Steel Core Inductors. The original 2A inductor is 5.6 mh, 18 gauge, with a DCR of about 1.5 ohms. Erse makes a great Laminated Steel Core Inductor, so I chose a 14 gauge with a DCR of around .2 ohms. Instead of the 130 uf caps at $50.00 each, I opt'd for three 90 uf caps per side, which saved me $50.00. I used a break-out board to mount the three 90s, and used some 12 gauge OFC to wire up the Caps point to point. The inductor leads were long enough, so I was able to solder them directly to the crossover board in place of the originals, and mount the new inductor to the back wall.
While I was at it, I replaced the blade/blade connectors with Speakons, and made a new cable using some old 10 gauge OFC speaker cable I had laying around. As a final touch, I spiked them. I found a seller on Long Island that has some real nice quality gold plated copper spikes. They were only $26.00, including shipping, for a set of eight. Got everything buttoned up this afternoon, and I was floored by the difference. The bass which was good, is now exceptional. Not flabby, not boomy, just exceptional. It's like I just added two subwoofers. All the changes I made affect the bass, but my personal feeling is it's the inductor that made all the difference. Like MP said, if you amp can handle it, change the inductor.

TennMan

Thanks for sharing. I enjoyed reading about your mods. I'm still running Hybrid, "Franken-Polk" 10Bs. They sound good but I hope to find some 2Bs one of these day near me so I can get serious about doing some mods like yours.

westmassguy

TennMan wrote: »

Thanks for sharing. I enjoyed reading about your mods. I'm still running Hybrid, "Franken-Polk" 10Bs. They sound good but I hope to find some 2Bs one of these day near me so I can get serious about doing some mods like yours.

Hey Tenn, where do you think I got the original idea....
Seriously, these 2As, although considered by some inferior to later generations, are putting out some incredible sound.

TennMan

westmassguy wrote: »

Hey Tenn, where do you think I got the original idea....
Seriously, these 2As, although considered by some inferior to later generations, are putting out some incredible sound.

How did your hybrid 10s compare to the stock 2As before you did all the mods? Just curious.

westmassguy

The 2As were good, but had sl2000s and old caps. The 10s had a much better top end since I had done the crossovers and RDO-194s, but the bass was a tad less

TennMan

Thanks!

chandler9a

I gotta say, the 2A's do sound incredible and should not be considered a "lesser" model. I have modded 1C's now and they are excellent, but I would have a smile on my face with my old 2A's any day of the week, especially with the upgrades.

They are still in my family and will probably stay there for many years.

westmassguy

chandler9a wrote: »

I gotta say, the 2A's do sound incredible and should not be considered a "lesser" model. I have modded 1C's now and they are excellent, but I would have a smile on my face with my old 2A's any day of the week, especially with the upgrades.

They are still in my family and will probably stay there for many years.

I agree, I certainly don't consider them lesser, they out-perform my CRS+s in every area, and both received the same upgrades, except for the Inductor.

TennMan

westmassguy wrote: »

The 2As were good, but had sl2000s and old caps. The 10s had a much better top end since I had done the crossovers and RDO-194s, but the bass was a tad less

If the hybrid 10s were all you had would you be looking for more speakers to get that tad extra bass? The reason I ask is because that is where I am now. The 2Bs are the largest SDAs that I can use in my room due to height limitations. (see photo) In your opinion would going to a 2b be a big step that would be worth the effort over what I have? I need to decide that before doing any mods to xovers etc.

westmassguy

TennMan wrote: »

If the hybrid 10s were all you had would you be looking for more speakers to get that tad extra bass? The reason I ask is because that is where I am now. The 2Bs are the largest SDAs that I can use in my room due to height limitations. (see photo) In your opinion would going to a 2b be a big step that would be worth the effort over what I have? I need to decide that before doing any mods to xovers etc.

I got the 2As for a good price, so it was an easy decision for me. The improvement in bass over the hybrid 10 was was noticeable even prior to the all the additional crossovers changes I made. I have no doubt however, that if I changed the inductor and capacitors while the 2A crossovers were still in the 10s, the bass output would have increased substantially. Your CRS+ crossovers can be updated with lower resistance inductors too, providing your amp can handle the increased load. That would be a much less expensive and beneficial upgrade, than purchasing 2Bs, since you can always swap them back into their original cabs too.
Something to look into.

nspindel

Congrats on the upgrades. Pics or it never happened, of course!

WRT MP's comments on inductor replacement, don't I recall him recommending air cores, not steel cores? I'm using a Solen 16mH, and the smaller inductors are all Jantzens. Mine are all air cores.

tophatjohnny

Sounds like the 2A's were a great score. Let's see some pics!!

westmassguy

nspindel wrote: »

Congrats on the upgrades. Pics or it never happened, of course!

WRT MP's comments on inductor replacement, don't I recall him recommending air cores, not steel cores? I'm using a Solen 16mH, and the smaller inductors are all Jantzens. Mine are all air cores.

MP suggested HIGH QUALITY Laminated Steel as an Alternative, and Stu Lumsden backed up what he said. What I sould have said was he "suggested", not "recommended" High Quality Laminated Steel Inductors as acceptable in lieu of Air Core

westmassguy

tophatjohnny wrote: »

Sounds like the 2A's were a great score. Let's see some pics!!

Gotta get my camera back from repair, and remove the PR for pics.

westmassguy

Warning Audio ****

nspindel

Nice!

westmassguy

nspindel wrote: »

Nice!

Thanks nspindel. I just ordered some Architectural Style Grill Cloth to finish them off. The original is showing it's age. I may veneer them at some point, but just want to enjoy them for now.

In case anyone asks, the reason there's no ties on the other caps, is 3M Heavy Duty VHB Tape under each one.

littlewoodboats

chandler9a wrote: »

I gotta say, the 2A's do sound incredible and should not be considered a "lesser" model. I have modded 1C's now and they are excellent, but I would have a smile on my face with my old 2A's any day of the week, especially with the upgrades.

They are still in my family and will probably stay there for many years.

I am digging hell out of my modified 2A's. 2B's are easier to drive so based on that alone I would put the 2B as the preferable model. With correct power the 2A can sing and sing well

TennMan wrote: »

If the hybrid 10s were all you had would you be looking for more speakers to get that tad extra bass? The reason I ask is because that is where I am now. The 2Bs are the largest SDAs that I can use in my room due to height limitations. (see photo) In your opinion would going to a 2b be a big step that would be worth the effort over what I have? I need to decide that before doing any mods to xovers etc.

With your side wall spacings would SDA work for you at all? Sidewall spacing would be less than advantageous to say the least. You have no corner so expect to be down a bit on the lower registers.

I would update the tens if it were me.

westmassguy

littlewoodboats wrote: »

I am digging hell out of my modified 2A's. 2B's are easier to drive so based on that alone I would put the 2B as the preferable model. With correct power the 2A can sing and sing well



With your side wall spacings would SDA work for you at all? Sidewall spacing would be less than advantageous to say the least. You have no corner so expect to be down a bit on the lower registers.

I would update the tens if it were me.

TennMan is already running them as hybrid SDAs, and loves them.

littlewoodboats

What is a Hybrid SDA? If not interconnected it is not SDA

TennMan

littlewoodboats wrote: »

What is a Hybrid SDA? If not interconnected it is not SDA

I have a pair of CRS+ pin/blade speakers and a pair of monitor 10Bs. I installed the crossovers, including the terminal cup that has the connection for the IC, and the dimensional driver from my CRS+ into my 10B cabinets. That is the reason I refer to them as CRS+10B hybrids.

My room is probably not perfect for SDA sound but it is adequate. The room is 20 feet wide and is 15 feet deep. It is open to an 8 foot wide foyer behind the wall where the speakers are located. I don't know if that hurts or helps. The speakers are 5-1/2 feet from each sidewall. The tweeters are 8 feet apart and in the seated position I'm about 14 feet from the front of the speakers. I know sitting that far from the speakers is not ideal but that is what the layout of our furniture dictates. On some songs I hear sounds coming well beyond the walls on the side of the room... at about a 45 degree angles from the centerline of my listening position.

I'm happy with the SDA sound that I get. I know iti's not perfect. I don't get sounds coming from 90 degrees to each side as some folks describe. If I move a chair closer to the speakers I get more sound coming from a wider area but I'm not sure I like it any better and it really doesn't sound natural to me. I'm sure I can get better sound with some mods and tweaking but for now I have to live with what I have to work with.

westmassguy

tophatjohnny wrote: »

Sounds like the 2A's were a great score. Let's see some pics!!

Not to steal my own thread, but tophatjohnny, you pm box is full

westmassguy

Got my new grill cloth in. I had forgotten how beautiful this stuff is. It's deep black, has a nice sheen to it, and an irregular texture. The most important thing is how sheer it is. Like night and day compared to the knit stuff that Polk originally used. The flash shows up the frame, however it's not visible with normal lighting.

Mr. Bubbles

Nice job. I love the 2A's.

westmassguy

Mr. Bubbles wrote: »

Nice job. I love the 2A's.

Thanks Mr. Bubbles. They do sound sweet. Lot more detail coming through the grills now.

pitdogg2

Westmassguy,
where did you pick up the grill cloth for future reference.
thanks Ivan

westmassguy

pitdogg2 wrote: »

Westmassguy,
where did you pick up the grill cloth for future reference.
thanks Ivan

eBay. I've not been able to find it anywhere else. I've bought from this seller many time over the years.
http://www.ebay.com/itm/360286206011?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

pitdogg2

westmassguy wrote: »

eBay. I've not been able to find it anywhere else. I've bought from this seller many time over the years.
http://www.ebay.com/itm/360286206011?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Thanks Man looks very good I saved him for later.

Just to let you know I'm going to steal that 260 cap board idea. When i did mine I just stacked them have always worried that they may come loose. I did zip-tie and hot melt though but for piece of mind when if i switch out the Axon caps for Clarity in the future.

westmassguy

pitdogg2 wrote: »

Thanks Man looks very good I saved him for later.

Just to let you know I'm going to steal that 260 cap board idea. When i did mine I just stacked them have always worried that they may come loose. I did zip-tie and hot melt though but for piece of mind when if i switch out the Axon caps for Clarity in the future.

It's 3/16" Masonite. I used some 12 gauge copper that was cleaned and tinned, for the side rails. I despise hot glue. It makes a mess, is unprofessional looking in my opinion, and doesn't hold up well over time. It should only be used for Martha Stewart craft projects. I prefer 3M VHB tape under the caps, Nylon Wire ties, and if needed, I use a brush-on Cyanoacrylate between the caps.
You should also look into the Inductor replacement, if your amp can handle ohms. The difference in my 2As was amazing.

Mr. Bubbles

westmassguy wrote: »

I despise hot glue. It makes a mess, is unprofessional looking in my opinion, and doesn't hold up well over time. It should only be used for Martha Stewart craft projects.

I agree 100%. Kinda funny many of these old Polks are assembled using a version of the stuff. I knew a guy when i was a teenager who used hot glue in his car stereo install. The finished job looked awesome until summer.

westmassguy

Mr. Bubbles wrote: »

I agree 100%. Kinda funny many of these old Polks are assembled using a version of the stuff. I knew a guy when i was a teenager who used hot glue in his car stereo install. The finished job looked awesome until summer.

LOL
The glue they used for the cabinet assembly is much different. The stuff they used on the crossovers is just awful stuff. Every Polk Crossover I rebuild, is covered in the stuff, and its separated, falling off etc. Even the wire ties they used back then were poor quality.