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Thread: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

  1. #1
    Forum Member Don's Avatar
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    NAD (last night) 1982 Marshall JCM 800 4010 Master Volume 50 watt 1x12" combo

    I can't believe I finally have one of these! I've wanted one for a very long time! It's dirty on the outside, the pots were scratchy as heck, and it was making some odd noises and cutting out then sounding awesome, then cutting out again... I cleaned all the pots, jacks and sockets and replaced the preamp tubes and it sounds awesome!

    I'm going to replace the 39 year old electrolytics and B+ dropping resistors for the sake of reliability. I may leave the ancient GE 6550 power tubes in it and just check the bias. It's tempting to change it over to EL34s for a more authentic Marshall sound, but I've heard arguments that the 6550s sound better at lower volume levels and might actually be better for the type of blues rock that I play on an amp like this.

    I'm trying to figure out if the ribbed plate made in Japan ECC83s that were in it were original to the amp.





    They haven't made regular production Marshalls like this in a long time- since about 1984!



    39 year old electrolytics! Scary!



    Last edited by Don; 01-22-2021 at 09:00 PM.

  2. #2
    Forum Member phantomman's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    No nefarious ribbon connectors, that's always a good sign.

    Pretty clean overall, I'd say. Very low mileage.

    Ya done good!
    "When injustice becomes law then rebellion becomes duty."

  3. #3
    Forum Member Don's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Quote Originally Posted by phantomman View Post
    No nefarious ribbon connectors, that's always a good sign.
    Yes! I had a 1986 JCM 800 4210 channel switcher. There were no ribbon cables, but the pots and jacks were mounted on the PCB and they were the only thing that held the PCB in the amp!!! There were no standoffs supporting the PCB!
    Last edited by Don; 01-22-2021 at 07:18 PM.

  4. #4
    Forum Member dirtdog's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Very nice! That’s a classic for sure.

  5. #5
    Forum Member Don's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    This amp sounds passable with the master at 1, better set at 2, and roars like a lion at 3!

  6. #6
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Very nice!

  7. #7
    Forum Member DanTheBluesMan's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    I am so jealous you can plug into an amp and let it rip, even if you have to wait for your wife to go out

    I may ask to borrow it to serenade the people upstairs. They deserve to hear the song of my people at, oh, say in excess of 100 db.
    "Live and learn and flip the burns"

  8. #8
    Forum Member Don's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    I'm very fortunate to have a space where I can play at about 100-110db regularly. 3 on the master on this amp is louder than that!

  9. #9
    Forum Member ch willie's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    I love the photos. What a great score!
    If we'd known we were going to be the Beatles, we'd have tried harder.--George Harrison

  10. #10
    Forum Member Don's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    I replaced the preamp tubes and electrolytics and the amp sounds good- nice and quiet with no funny noises.

    Unfortunately, the power tubes are not even a close match- there's a 24mA difference between them. When one is at 68% max plate dissipation, the other is at 41%. The difference stays with the tubes if I swap sockets.

  11. #11
    Forum Member phantomman's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    The idle-current differential is certainly more than I'd be comfortable with but if the amp sounds good and there's no sign of red-plating or other visual anomaly I wouldn't be too concerned. Remember, a power-tube mismatch is often responsible for those rich harmonics that we all crave. However, you might try installing a matched brace of 6550's just to see what audible difference the new bottles make.
    "When injustice becomes law then rebellion becomes duty."

  12. #12
    Forum Member Don's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Quote Originally Posted by phantomman View Post
    The idle-current differential is certainly more than I'd be comfortable with but if the amp sounds good and there's no sign of red-plating or other visual anomaly I wouldn't be too concerned. Remember, a power-tube mismatch is often responsible for those rich harmonics that we all crave. However, you might try installing a matched brace of 6550's just to see what audible difference the new bottles make.
    It doesn't sound bad, though I'm not really cranking the master. There is more hum than expected as I increase the master, though. My bigger concern is reliability- is one of the 6550s on its way out? They are 39 years old, after all.

    Unfortunately, I can't put a set of NOS GEs it it. Have you seen what they're going for?!?

  13. #13
    Forum Member phantomman's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Look into a pair of Tung-Sol re-issues.
    "When injustice becomes law then rebellion becomes duty."

  14. #14
    Forum Member Keefoman1's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Congratulations on a great score! I've got an '83 2205 head. In combination with a Silver Jubilee 4x12 cab with Celestion V 30s it sounds amazing!

  15. #15
    Forum Member Don's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Quote Originally Posted by Keefoman1 View Post
    Congratulations on a great score! I've got an '83 2205 head. In combination with a Silver Jubilee 4x12 cab with Celestion V 30s it sounds amazing!
    Thanks! I had a 4210 which is the 1x12" combo version of the 2205.


  16. #16
    Forum Member Don's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    A friend who's a hi-fi fanatic gave me a box of 12 lightly used 6550 power tubes to go through! Ten Winged C and two Svetlana. He used four in each of his mono block power amplifiers. He said to take what I need and return the rest when I can. I ran them through his Hickok 600 tester and picked the two strongest and closely matched and put them in the amp and set the bias. The amp sounds great!

  17. #17
    Forum Member DanTheBluesMan's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Quote Originally Posted by Don View Post
    A friend who's a hi-fi fanatic gave me a box of 12 lightly used 6550 power tubes to go through! Ten Winged C and two Svetlana. He used four in each of his mono block power amplifiers. He said to take what I need and return the rest when I can. I ran them through his Hickok 600 tester and picked the two strongest and closely matched and put them in the amp and set the bias. The amp sounds great!
    Noice
    "Live and learn and flip the burns"

  18. #18
    Forum Member phantomman's Avatar
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    Re: NAD (last night) 1982 Marshall JCM 800 4010 Master Vlume 50 watt 1x12" combo

    Quote Originally Posted by DanTheBluesMan View Post
    Noice
    +1!
    "When injustice becomes law then rebellion becomes duty."

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