Is this original Polk Monitor 7A driver?

Mystery

All other drivers I checked in other models have/had black metal basket but these have silver/brushed aluminum basket.
Is this original Polk Monitor 7A driver?
Terminals are soldered so either they came like that from factory or someone replaced woofers.
From their looks, they look like never been opened though.
Thanks

pitdogg2

most early models had silver baskets and soldered terminals. Weather THAT is original driver who knows but it shares that look.

Mystery

I see.
So MW6502 came in silver as well as black basket.

westmassguy

Mystery wrote: »

I see.
So MW6502 came in silver as well as black basket.

I've seen early Mon 10s, 7s and 5s all with silver baskets and soldered connetions. Don't assume it's a MW6502, check the DCR on the coil. Some early 5s I know came with 8 ohm nominal drivers,

Mystery

I see someone mentioned 7's also came with MW6500.
So it could be either 6500 or 6502.
There is no label on the driver.

westmassguy

Mystery wrote: »

I see someone mentioned 7's also came with MW6500.
So it could be either 6500 or 6502.
There is no label on the driver.

Check the DCR, that will narrow it down. 6502s are 4 ohm nominal, 6500s are 8 ohm nominal

mhardy6647

Looks like it - Here's what the front should look like :-)

Mystery

mhardy6647 wrote: »

Looks like it - Here's what the front should look like :-)

Yes with those thick gray paper gasket around the drivers that don't exist on later models.

Here is the pair I'm working on right now...
That woofer is from the right speaker.
I'll open the other one and check if it's same woofer even though they have different cabinets.

Mystery

Opened the other one and applied epoxy on both drivers.
However, I see that there was already epoxy bead all around the magnet both upside and downside so someone must have gone through it before.
Now I think of it, may be the crossover was also upgraded and I re-upgraded. :eek:

Drivers facing up:

Drivers facing down:
Both drivers are similar. One has number 22 and another 28.
The later one is newer or looks newer as it's more shiny.

Crossover before I upgraded/replaced:
Hopefully, these are originals. :redface:

westmassguy

The crossovers look all original

mhardy6647

Interesting... EIA code 1056.
The classical assignee of EIA code 1056 was Fisher (or, more accurately, I guess, a subsidiary called "United Speaker Systems", http://www.worthpoint.com/worthopedia/vintage-pair-rola-12-alnico-magnet-220174533 ), but there's anecdotal evidence that the 1056 manufacturer's code was re-assigned to... someone... Gepco? I cannot find a definitive link.

Mystery

westmassguy wrote: »

The crossovers look all original

Thanks.
One of them was really muddy before and now both are open and specially strings/flute type instruments sound really good.

mhardy6647 wrote: »

Interesting... EIA code 1056.
The classical assignee of EIA code 1056 was Fisher (or, more accurately, I guess, a subsidiary called "United Speaker Systems", http://www.worthpoint.com/worthopedia/vintage-pair-rola-12-alnico-magnet-220174533 ), but there's anecdotal evidence that the 1056 manufacturer's code was re-assigned to... someone... Gepco? I cannot find a definitive link.

Are you suggesting that these may not be original Polk drivers?

Toolfan66

Why 2 different cabinets? Did both crossovers have the same values in caps and resisters?

westmassguy

Mystery wrote: »

Are you suggesting that these may not be original Polk drivers?

Polk, like many other speaker companies, source their drivers from other manufacturers.
Those appear to be originals, from what I can see. The Early Polks had unpainted basket frames, and most didn't have labels like the later models.

mhardy6647

Mystery wrote: »

Thanks.
One of them was really muddy before and now both are open and specially strings/flute type instruments sound really good.



Are you suggesting that these may not be original Polk drivers?

Nope, not at all - The 1056 is the code of the OEM whose drivers Polk used. Most speaker system manufacturers do not make their own drivers; they use OEM drivers (but often made to their own specifications).

Mystery

Toolfan66 wrote: »

Why 2 different cabinets? Did both crossovers have the same values in caps and resisters?

Not sure why. I got them like this.
One of them has cream/brown colored baffle and back while other has black.
Both have two fuses on the terminal cap.
Vinyl cover and grills are same color though so looks matching from front with grills on.
However, one grill has grill pegs another has plastic stubs like velcro for grill to snap on and it's horribly tough to take the grills off.
Also, yes, both have exactly same parts, same color and exact values.
If you just take the crossovers out, there is no telling which came from which so exact clone.

westmassguy wrote: »

Polk, like many other speaker companies, source their drivers from other manufacturers.
Those appear to be originals, from what I can see. The Early Polks had unpainted basket frames, and most didn't have labels like the later models.

Oh I see.
I checked with meter while the cables are connected as I don't want to unsolder them and they read around 7.8 ohms.
My dmm is a cheapo brand and reads little higher so the drivers may actually be around 5.8 ohms suggesting they may be 6 ohm drivers.
But I'm not worried about what they are as they both work fine and I applied epoxy on top of previously applied epoxy. ;-)
I know I need a better meter. :redface:

Mystery

mhardy6647 wrote: »

Nope, not at all - The 1056 is the code of the OEM whose drivers Polk used. Most speaker system manufacturers do not make their own drivers; they use OEM drivers (but often made to their own specifications).

Okay got it.
Most other Polk drivers have sticker with model name but these don't so the confusion.

westmassguy

Mystery wrote: »

Oh I see.
I checked with meter while the cables are connected as I don't want to unsolder them and they read around 7.8 ohms.
My dmm is a cheapo brand and reads little higher so the drivers may actually be around 5.8 ohms suggesting they may be 6 ohm drivers.
But I'm not worried about what they are as they both work fine and I applied epoxy on top of previously applied epoxy. ;-)
I know I need a better meter. :redface:

Polk's MW6501 is actually 7.75 ohms, so if that's what's in yours, your meter isn't far off

Mystery

westmassguy wrote: »

Polk's MW6501 is actually 7.75 ohms, so if that's what's in yours, your meter isn't far off

Hmm...
I don't see any 7 schematics that mention 6501.
All I found was either 6500 or 6502.

westmassguy

Not surprising. Original Monitor 10 and RTA 12 used them

Mystery

Also, one thing to mention, these 7A cabinets are heavily stuffed with white polyfill.
I couldn't see drivers when I took terminal cup out and vice versa (Couldn't see crossover when I took mid woofer out).
Layers and layers of polyfill.
Is that normal or someone added that?

westmassguy

Mystery wrote: »

Also, one thing to mention, these 7A cabinets are heavily stuffed with white polyfill.
I couldn't see drivers when I took terminal cup out and vice versa (Couldn't see crossover when I took mid woofer out).
Layers and layers of polyfill.
Is that normal or someone added that?

The Dacron Batting is normal. The positioning has changed however. It's recommended that all the damping material be located in the upper portion of the cabinet, behind the tweeter and woofer. It should extend no lower than the top of the opening for the passive radiator. The area behind the PR should be clear of any damping material. It's easy enough to re-roll the dacron, and tuck it in above the PR. I tack the sides with a 1/4" staple to make sure the dacron doesn't fall down or move.

canadianicon25

does above post apply to all monitor? i am wondering about my mon5's.

westmassguy

The current thinking, is that the area behind the PR should be clear of any acoustic damping material. The exception, obviously would be the ported Monitor 4 and 5. You'll want to keep the port clear of any dacron or other damping material, as this could affect the operation of the port.