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Thread: NAD: 1986 Marshall JCM 800 4210

  1. #1
    Forum Member Don's Avatar
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    NAD: 1986 Marshall JCM 800 4210

    I heard that these were lousy sounding amps so I went and tried on out. I love it! The pots were so dirty that it was difficult to try and the guy didn't have a footswitch so I didn't get to hear the clean sound. I should probably be looking at replacing the 32 year old filter caps.

    I used to thing DeoxIT was expensive, but after getting an '86 Rat for $30 on Saturday and this amp for about half of what they go for and then making them both sound great with the stuff, it's actually pretty cheap!


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    Re: NAD: 1986 Marshall JCM 800 4210

    Good find, Don!
    I've started using the cleaner/lube first, just to see if the pots can be cleaned, before lubing them with the "good stuff". (We lost our Radio Shack, so I'm not sure where to get more!)

  3. #3
    Forum Member OldStrummer's Avatar
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    Re: NAD: 1986 Marshall JCM 800 4210

    Is this it? Ask the Gods of the Amazon, and you shall be rewarded.(Click the image to shop).


  4. #4
    Forum Member Don's Avatar
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    Re: NAD: 1986 Marshall JCM 800 4210

    That's the stuff. Some people like to use the green one with lubricant on pots. I don't. The track on a pot is usually dry from the factory (they use grease in the shaft for dampening purposes) and I like to leave it that way. I think the lubricant attracts dust. I made the mistake of using the non lubricated stuff on a slider once- it pretty much ruined it!

  5. #5
    Forum Member Don's Avatar
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    Re: NAD: 1986 Marshall JCM 800 4210

    The amp sounds a lot like the one in this video (this is not me or my amp). Believe it or not, the grill cloth on mine was once black and has faded- you can see it under the Marshall logo.

    https://youtu.be/8VqhP9V4Du0

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    Re: NAD: 1986 Marshall JCM 800 4210

    I have about a half a can of this left, (a little cheaper than the "good stuff").

  7. #7
    Forum Member CoyotesGator's Avatar
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    Re: NAD: 1986 Marshall JCM 800 4210

    Very cool Don.

    They can sound excellent.

    What speakers?
    What happend?
    Who let the magic smoke out?

  8. #8
    Forum Member Don's Avatar
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    Re: NAD: 1986 Marshall JCM 800 4210

    It's got what appears to be the original G12M-70 in it. It sounds fine though I have others I can try- a Celestion V30, Scumback M55-PVC 65w and an S75-PVC 65w.

  9. #9
    Forum Member Don's Avatar
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    Re: NAD: 1986 Marshall JCM 800 4210

    I replaced all of the electrolytics in the amp as well as the screen grid resistors (one was wide open) and the B+ resistors (they were fine, but I like flame proof resistors there).

    It sounds great as it, but I've got new Tung-Sol EL34B power tubes and a Sovtek 12AX7LPS phase inverter on the way. The EL34s that are in it are of unknown age and are not matched well.

    It's a cool amp. It doesn't just do all out Judas Priest sounds on the boost channel. You can get a good dirty electric blues sound too. At controllable volumes. The G12M-70 sounds fine, too.

    It's a blast to play! I like it!

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