NAD - Marshall JTM30 2x10

[waltschwarzkopf]

Hello, World!

I got a new amp today! I saw it on the classifieds and went to try it. The owner said that a maintenance and new tubes may be a good idea, so I managed to bring the price down.

A few thoughts and possible solutions:

1. Some of the nuts are missing - no biggie, I’ll find some.
2. It hums quite a bit even when on standby - Any ideas?
3. Some pots are a bit scratchy - I have some contact cleaner and will clean from inside.
4. The overdrive is a bit harsh, is it supposed to sound like that? - maybe new preamp tubes?
5. The sound comes and go. I didn’t notice this while testing it because I didn’t play it long enough. I tried it at home for like 30-45min on the clean channel and it was fine, then it started fading in and out. - Could this be the tubes too?

What do you think?

Overall I am happy with the amp, just this minor things that new some attention. The clean-crunchy sound is really nice, I like playing it ok the only edge of breakup and then pushing it with chords.

Cheers,
Walt

[jeremy]

i have the 1x12 version of that amp. its decent but not quite the same as some of the better models. i swapped the speaker which helped as did a tube swap, which was a bit of a pita since there is no way to adjust the bias easily. i usually use it with the clean channel dimed and dont use the dirty channel much, sounds a little buzzy on the high end as i recall. its been a while since ive plugged it in.

[Gtrjunior]

My JCM800 fades in and out when the lower tubes are getting g worn. That’s it’s first tell.
You’re playing it and you keep thinking you hear it fading but you’re not really sure…then over a little time it becomes apparent that it’s fluctuating.

First thing I’d do is swap power tubes and bias and then see where the amp is at.

You may want to swap preamp tubes, or not. They tend to last quite a while in many cases. I only change them when they fail. Which is seldom. Or if I’m looking for something tonally.

As mentioned a speaker swap will be the most drastic tone change. I’d suggest something in the greenback family.
I absolutely love the Splawn Small Block speaker. It’s 55w greenback clone made by Eminence specifically for Scott. I have a Few of them in some speaker cabinets. Love them and they are about $50 cheaper than a Celestion.

[Aceman]

I love punchy 2x10's, 4x10's etc...

That looks like a newer rather than older thing.

[chadd]

Those things had a ton of issues, many of them caused by the tube layout. The sound dropping after 30-40 minutes would definitely have me looking for damage to the board.

[stevie_bees]

That series of amps had a lot of issues with overheating, so many were modded to have a fan fitted to keep things cooler and more stable. Might help with the sound dropping out.