Peerless Corrosion

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motorcityguy
motorcityguy Posts: 49
in Vintage Speakers
I scored a pair of 7514 Denmark-made Peerless tweeters. I noticed they have some corrosion near the base of the terminals. See pic.

Should I be concerned? Or just gently flick it away with a toothpick?

Also wondering about desoldering/soldering these, as they appear to have a rubber or plastic insulator under the terminal. Any special tips on preventing damage during soldering?


rhyscvov7oei.jpg
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  • Tony M
    Tony M Posts: 11,017
    edited January 2020
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    A Q-tip and Pepsi for the corrosion maybe.

    The rest, I don't know...maybe cut the wire 3" or more away from the terminal.
    Most people just listen to music and watch movies. I EXPERIENCE them.
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  • Gardenstater
    Gardenstater Posts: 4,188
    edited January 2020
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    It seems like aluminum corrosion, being that it appears to be white fluffy deposits, or aluminum oxide. Isn't that mounting plate some sort of electrically insulative polymer though, since the wires are in grooves in it?

    No doubt you need to at least put one or two of those little aluminum soldering heat sink clamps on the base of that tab. I'd even try to get something on the attachment point of the tab to the wire.

    How much $ were the Danish Peerless?

    They certainly look like mine, although mine has the number under the gasket.

    What is the mfg. date of yours? Can't quite read it (maybe 6/2/79?)
    .
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
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    Logitech Squeezebox Touch Streamer w/EDO applet
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    Custom Steve Wilson 1m UPOCC Interconnect
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  • F1nut
    F1nut Posts: 49,805
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    Use DeOxit and a worn out soft bristle toothbrush to very gently clean the area.

    Do NOT attempt to desolder the wire at the terminal. Cut the lead wire well away from the terminal. Later solder the ends together and use heatshrink to seal the joint.
    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."

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  • motorcityguy
    motorcityguy Posts: 49
    edited January 2020
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    F1nut: Sounds like good advice to NOT try to solder directly to the Peerless tweeters. I hate having a splice in the wire, as it gives a "patched" look, but much better than messing up a valuable 7514 tweeter!

    I got these tweeters from a crappy pair of early Polk 5's that I bought and parted out... Really glad I left long leads on the tweeters!!

    Deoxit and toothbrush sounds good, for the corrosion. I'll give it a try!

    Gardenstater: Don't have them in front of me but, yes, I believe the tweets (and MW6500 mids) were all marked 1979. Sadly, one of the mids had a shifted magnet, so NFG.

    I harvested them from a beat-up pair
    of early Monitor 5's that I found locally. Cost was about same as a couple of large loaded pizzas, so I'm quite pleased. :-)
    Post edited by motorcityguy on
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  • motorcityguy
    motorcityguy Posts: 49
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    Gardenstater: Since you were interested in in the dates I went back and looked at all four drivers.

    The mids are MW6500, and both marked 8/31/78.

    It's very difficult to read the tweeters but it looks like "7514 2678". My understanding is the last two digits are the year (78). I'm just guessing but the first two digits maybe the week of the year? 26 would put it dead in the middle of 1978 which is reasonably close to the date on the mid woofers. I believe all four drivers are original to the speakers.
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  • Gardenstater
    Gardenstater Posts: 4,188
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    @motorcityguy I just looked more carefully at my Peerless tweeter picture and I have the same white crystalline deposits around the positive terminal (only) and it is on aluminum so I'm thinking some sort of galvanic corrosion that occurs due to the current and the disimilar metals.
    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
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  • JayMX
    JayMX Posts: 435
    edited January 2020
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    I have a pair of Monitor 4’s that had similar stuff on the tweeters. Only lots more... I was worried too, but I cleaned them up with a toothbrush. I use them daily in my office - sound great. No ill effects.
    https://forum.polkaudio.com/discussion/182778/peerless-corrosion
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (3x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • AdamSDCA
    AdamSDCA Posts: 18
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    I have the same on a pair of 10A’s I just picked up. Any functional concern?
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  • skipshot12
    skipshot12 Posts: 1,002
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    When soldering always use a heat shunt.
    Especially where molten solder can wick on certain braided/delicate conductors.
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