Polk Model 7a's
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Hello All, I found these Polk 7a's for sale. They do have Peerless tweeters. The mid's and radiators look like they have a silver outer rim and I'm not sure if these are original or have been replaced. Maybe it's due to the lighting in the pic? Any input is appreciated, thanks.
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The early ones; 7, 7A, and earlier 7B do have the silver basket midwoofer and passive radiator. I would've sworn from the picture that these are 7B because they look just like mine.
Edit - Correction. My passive radiators have a considerably larger plateau or flat region in the center. Picture isn't super clear but those may not even have the flat region. It may be a hemispherical center region. So they probably are late 7As.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
He claims they are 7a's, though I haven't seen them in person yet. Do you like your 7B's? How's the bass?
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I love my 7Bs. Have had them since 1979 but after all the standard and then what I'd call ubermods, they are not something I would want to part with.
Bass wasn't great back then but I didn't have a good amplifier, just a Technics SA500 Receiver with damping factor of 24.
With a better amplifier with good damping factor rating it was fair.
With the Dynamat Xtreme, Xschop Semi-rings, and vibration isolation stands bass is excellent. I usually listen with a Martin Logan Dynamo subwoofer for assistance and I'd never go back to be honest.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
I thought the 7A had velcro grill attachment points?
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They do, or at least some do (edit - maybe just the 7 did?). Some 7A also have the 8" vs 10" passive radiator, I believe (edit - may have only been the 7). I'm thinking if these are 7A, they must be very late ones. My 7B are "fairly" early ones #197XX and look just like those above except for the passive radiator difference. They could be very late 7A or early 7B and just the first 7B I have seen with that passive radiator.
The 7A may have been very short lived, only like 1978. I haven't seen all that many examples of them so it is up in the air.
The frequency response is wrong in this below, and clearly what they give is the response with no dB qualifier, which would be -9dB according to Polk practices.
George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
The difference between a damping factor of 10 and 1000 is so negligible that it is a non-factor.
The frequency response of the Monitor 7 is as follows;
25 Hz to 25 KHz, 40Hz at lower -3db limit, 23KHz at upper -3db limit.
The bass response is better than a boat load of floor standers.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Whether the bass response was improved in whatever minor changes they made in going from the 7A to the 7B I do not know but the Polk quoted frequency response for the 7B is 33Hz to 20.5kHz +/-2dB. This is not in an anechoic chamber but what they called a "controlled reverberent field environment". The freq. response Polk gave for the 7 in 1977 (not 7A or 7B) was more like 40 Hz to 20.5kHz +/-2dB.
I think this is definitely another error below (should be 33 not 30 for the 7B lower lower limit. 30 was correct for the 10)
George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Found some pics of conradicles' 7A via the forum search. Hopefully he doesn't mind my posting. It does verify that there were "some" 7A that had the velcro attachment for the grilles. Maybe his are early ones? His also have the dual fuses and the crossover that uses the 4.7Ohm tweeter resistor vs. the 4.5Ohm one in the 7B. Probably to compensate for removing the Midwoofer fuse for the 7B. His also appears to be the passive radiator with the smaller center section which doesn't look flat but still not positive on that one. Definitely 10" not 8" though. Date code on the Gefco Matrecs Industries driver seems to be 32nd week of 77 and I think the date on the crossover is Oct 10th (1977?).
George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Here's another data point for you gardenstater.
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Enough with the speculation BS. They are obviously all original 7A's from 1978. Polk changed things on the fly back then. Stop asking questions, fix them up, then enjoy.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
@WestCoastPowHound Thanks! Yours must later 7A (10/10/78) and they have one fuse (no MW fuse) but still have the 4.7 Ohm tweeter resistor. The only thing I see different between those and my 9/17/79 7B is the passive radiator has the smaller flat center section vs. my larger one (probably different tuning) and the tweeter fuse on mine is 4.5 Ohm.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Isn't the sleuthing stuff fun?
Useful, too, for anyone interested in finding out all they can about this (or anything they like, really).
Keep on sleuthin' on, Polk Folk.The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * Ye Olde college stereo in the garage -
Waste of time because you'll never figure it all out and it really doesn't matter.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Polk had the Get 'er Dun engineering and assembly team to tackle any supply chain issue back in the day.Don't take experimental gene therapies from known eugenicists.
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plastic_avatar wrote: »Isn't the sleuthing stuff fun?
Useful, too, for anyone interested in finding out all they can about this (or anything they like, really).
Keep on sleuthin' on, Polk Folk.
Definitely fun. Even if it doesn't matter and some think it a waste of time. Although someone who has made over 47,000 comments on this site might have a warped idea of what is a waste of time! -
WestCoastPowHound wrote: »plastic_avatar wrote: »Isn't the sleuthing stuff fun?
Useful, too, for anyone interested in finding out all they can about this (or anything they like, really).
Keep on sleuthin' on, Polk Folk.
Definitely fun. Even if it doesn't matter and some think it a waste of time. Although someone who has made over 47,000 comments on this site might have a warped idea of what is a waste of time!
Contrary, my time here has shown me what a waste of time it is trying to figure out what Polk was doing 36 years ago. Welcome to the list.Post edited by F1nut onPolitical Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
And in other news, Idi Amin is still dead.The Gear... Carver "Statement" Mono-blocks, Mcintosh C2300 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD
“When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson -
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Brian
One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM -
@bcwsrt the guy is out of town. I am going to look at them soon, and will probably buy them but there are a couple of other people interested also. Hopefully I can get there first. -
Update.... I bought the 7a's this morning. Thank you all for the information and suggestions.
I need more speaker wire, any suggestions on gauge? I found 16 gauge Monster cable at Walmart for a good price. Any thoughts are appreciated.
The actual speakers are in good shape, though the cabinets are a little beat up, as two of the corners are smashed but the cabinet looks intact. I may try and repair the corners somewhat to keep the cabinet material from crumbling away. They sound very good, I am still experimenting with placement from the wall, etc. -
Bondo
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I need more speaker wire, any suggestions on gauge? I found 16 gauge Monster cable at Walmart for a good price. Any thoughts are appreciated.
Gauge is no way to shop for speaker cable and never buy anything from monster.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Supra Rondo or a good quality, budget friendly 14g OFC tinned.Don't take experimental gene therapies from known eugenicists.
