NAD: 1981 JCM 800 2204 (Resolved)

Discussion in 'The Workbench' started by JoshuaD, Oct 3, 2020.

  1. clutch71

    clutch71 Well-Known Member

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    Have you considered cleaning the input jacks and pots? That may help
     
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  2. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    I did give it a once over with Deoxit. Will do that again, as well as check the Low input volume levels again.

    Incidentally, if I were to pick up some tubes for replacement, do you guys have some suggestions?

    As far as power tubes, I’ve got a line on some GE 6550As, but I’d also be interested in something less expensive as an alternative. What about preamps? There are JJs in it now. I’ve got an extra GT-ECC83/12AX7, but that’s all I’ve got for spares in that range.

    Thanks again for all the input. I will say that this forum has been pretty amazing with information and support. Might not be much, but I’m going to upgrade my membership to show my support to you guys and this forum!
     
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  3. Gunner64

    Gunner64 Emotional Support Animal Gold Supporting Member

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    Killer amp btw. My holy grail. In great shape as well. I'm with ya..I clean boost the front end with a ts9..it's the tone in my head. Priesty, Scorpy, Accepty, goodness..Balls to The Wall man!
     
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  4. anitoli

    anitoli Well-Known Member Gold Supporting Member

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    I use EHX 12ax7's in my 2203x and they sound fine.
     
  5. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    Alright, I think everything seems to be fine. In the low input, the amp stays fairly clean. I do have to turn the Pre-Amp volume up all the way, then, once the master is up to about 6 or 7, it starts to get loud. Just like you’ve all said. It is different than any amp I’ve had before, so I wasn’t expecting such a difference.
     
  6. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    Is there a spring retainer that better fits the 6550? These look like they are probably a better fit for EL-34s as I’ve seen in some other amps. Would that make you think that maybe there were 34s in this amp at one point?
     
  7. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    This is the first time I’ve had an amp where I can really tell the difference between OD pedals. I barely need the gain on at all to get some really amazing tone. Not only that, but the volume is so much more manageable than a lot of other amps I’ve owned. And, the low really gives some great cleans. I wish I picked up one of these amps a long time ago. I am loving it.
     
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  8. lonewolfsx

    lonewolfsx Well-Known Member

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    That is one of the first things I noticed on older/single channel Marshalls too! I have an SD-1, tubescreamer, and OCD clone and they are all clearly different through my JCM800 and JCM900 SLX. However on my Splawns for example, I can barely tell the difference between them if the gain/volume is set similarly. Not that those are bad amps, but there’s something to be said for transparency with the Marshalls, part of why they make such great pedal platforms (or so I hear).
     
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  9. anitoli

    anitoli Well-Known Member Gold Supporting Member

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    These are bigger:

    https://tubedepot.com/products/retainer-for-kt88-kt66-6550

    It very well may have had EL34's in it.
     
  10. JM5010

    JM5010 Active Member

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    It's normal for jcm 800's to do this. Try a different tube in V1, maybe even a higher gain tube.
     
  11. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    Is there a specific tube you would suggest or recommend?
     
  12. JM5010

    JM5010 Active Member

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    My 2203 clone has Tung sol's, they sound pretty well rounded
     
  13. anitoli

    anitoli Well-Known Member Gold Supporting Member

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  14. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    Thank you!
     
  15. Greg70

    Greg70 Member

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    I have a 1984 vintage 2203 that originally came with 6550's. Those look like the correct spring retainers for them. If you want to convert to EL34's it's very easy. Just swap one resistor and rebias. I have also noticed that the low input requires much higher setting on the volume controls than the high.

    Congrats on your purchase. That's a beauty!
     
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  16. FogDweller

    FogDweller Well-Known Member

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    I also have an 1981 2203 with the original factory GE 6550s, and the spring retainers on your amp look identical to the ones on mine. I’m guessing the 6550s in yours have never been changed to EL34s.
     
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  17. Ufoscorpion

    Ufoscorpion Well-Known Member

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    Seal the low input socket up with silicone sealant, problem solved , lol.
     
  18. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    As time has gone on, I am liking both channels for different reasons.

    I recently picked up two 1981 Marshall JCM 800 1935B Bass Series 4x12s (G12-65 with the 444 cones). I had the amp connected to both cabinets, and it was phenomenal. I don’t have the “Lead cone” speakers to compare them to, but these cabs just flat out rock with this amp.

    I also picked up some spare tubes. A couple sets of 6550s, and a few different 12ax7s to experiment with. One set of 6550s I picked up was a much more reasonably priced (compared to NOS stuff) set of Shuguangs to see how they fare.

    I had also been going through some threads and noticed that there was disagreement whether the “USA” version of the amps were actually modified for 6550s. I haven’t done a thorough examination, but after a brief look, I did see some alteration as per the schematics that had been posted everywhere. So with my limited knowledge of amp specific electronics, I would confirm the alterations exist and are there. At least in my amp.
     
  19. Crikey

    Crikey Well-Known Member

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    How does it sound in the high input? If it sounds good run with it
     
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  20. JoshuaD

    JoshuaD New Member Gold Supporting Member

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    It sounds pretty damn awesome!
     
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