7b Refurbishment

rzeles1967
rzeles1967 Posts: 6
in Speakers
I picked the 7bs up fir $75. The drivers were marked 1978 so I’m thinking early 7b. New Dayton 5% caps and reveneered with walnut. Added a few coats of danish oil with a sand at the last cost with 800 grit then wax. I think they cane out pretty well. My second attempt at veneer. They have the peerless tweets. Breaking them in but sound pretty good. Not sure if I like them as my KLH 5 frankly but good sound. I have a pair of 7c as well.
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  • rzeles1967
    rzeles1967 Posts: 6
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  • rzeles1967
    rzeles1967 Posts: 6
    More pics.
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  • Faustin
    Faustin Posts: 1,149
    Looking good. Replace the resistors on the c/o as well. Not much money, and then you know everything is up to snuff. New grill cover cloth can be had pretty cheap as well. Oh, and welcome to Club Polk.
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  • Gardenstater
    Gardenstater Posts: 4,502
    edited March 2020
    Welcome and nice work! I got a lot of improvement by putting Dynamat Xtreme on the midbass drivers and passive radiators and it is well worth the money and effort!

    I'm halfway through with my crossover upgrade (Sonicaps/Mills) and can't wait to finish that after seeing what an improvement I got in the one speaker. Then I'm going to re wire with Cardas Litz and Neotech UPOCC and put Cardas binding posts in. Last will be Blackhole5 behind the midbass drivers.

    Enjoy!
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
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  • Dabutcher
    Dabutcher Posts: 2,596
    Thanks for sharing and welcome to Club Polk. I use my Sevens in my garage rig. I wish I had your skills.

    Love yours. D
    MIT Magnum MH-750, Monster HTS 5100MKII, Sony 77" Class - A80CJ Series - 4K UHD OLED,PS4, Def Tech 15” sub,LSIM 706c, Sunfire Signature Grand 425 x 4,Parasound hca 120, LSiM 702 x 4, Oppo 103D, SDA SRS 1.2, Pioneer Elite SC63 , Pioneer Elite BDP-05 “Why did you get married if you wanted big speakers?”
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  • rzeles1967
    rzeles1967 Posts: 6
    I bought the Dayton resistors and they were quite a bit longer and I was having trouble unsoldering the others and ended up just leaving them. Mills were like 5x the Dayton’s I think. Guess I can always get back in there at sone point. Letting them run to see if the break in as well. I have some 7c that sound pretty nice as well.
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  • rzeles1967
    rzeles1967 Posts: 6
    Basement setup. I have way too much stuff. [i
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  • rzeles1967
    rzeles1967 Posts: 6
    dfwe4bfgj285.jpeg
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  • Gardenstater
    Gardenstater Posts: 4,502
    rzeles1967 wrote: »
    I bought the Dayton resistors and they were quite a bit longer and I was having trouble unsoldering the others and ended up just leaving them. Mills were like 5x the Dayton’s I think. Guess I can always get back in there at sone point. Letting them run to see if the break in as well. I have some 7c that sound pretty nice as well.

    A solder sucker with a teflon tip helps a lot with de-soldering. Make sure any wirewound resistors are low self inductance types, which I know the Mills are. I deliberately left about 1/8" space between the board and the resistors to allow air circulation, and that allows you to bend the leads back underneath to match up with the existing holes on the pcb, even if the new resistors are much longer than the old. Also, the higher the power rating the better within reason. I went with the 12W Mills. It lowers the heat induced noise in the resistor.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
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