Differences between Polk 7A and 7B

[Tim D]

Hmmm. I had some 5B’s that I bought new in 1981. Wonder if those 7A’s might have been sitting at the PX for a long time?

 

[moebuster]

The time frame stated was fuzzy at best...

 

[relaximus]

Hmm, my 7Bs (w/ Peerless Tweeters) have cabinet-mounted badges.

 

[Tim D]

I've got 7B's with peerless tweeters with the grill mounted badges. I had a set of 7A's with peerless tweeters. The obvious difference was in the shape/depth of the passive radiator and maybe the weight in the center of the passive radiator was heavier in the 7B (for a different resonance frequency perhaps). The cone of the passive radiator looked deeper on the 7A, but that might have been an illusion because of the smaller weight.

 

[mhardy6647]

There's nothing different about them having been purchased in Japan, they are what the early 7A's looked like. Yours are not the very first though, they had a plain paper passive radiator verses the doped paper in yours.

Indeed, my 7As look just like that. Mine, which I believe to be pretty early 7A (but I don't have serial numbers handy) have two fuses per loudspeaker on the back panel: tweeter fuse and system fuse. I believe later versions had only one.

Polkmonitor7Asn4900 by Mark Hardy, on Flickr


.

 

[Ron Z]

I found a difference. The passive radiator has a deeper cone on the 7A's. The weighted center is smaller on the 7A's too. I'll know more when I open them up to see if the crossovers are the same.

My 7b. Just recapped with Dayton’s, veneered with walnut and 3 coats of danish oil and some wax to finish them up.