My Nomad's giving me some problems

[Bleak]

Hey all,

Figured it'd do me some good to post here and see your thoughts on this before anybody else, so here goes.

Nomad 55 2X12 Combo. I've got EL-34's in it.
Long story short, I had an issue about 2 weeks ago with the amp making really loud popping noises in succession - regardless of where the master volume was set. Obviously, it didn't take too long of late night practices for this to drive me up the wall. I figured it would be a power section issue since the master volume didn't seem to change the pops. Put in a brand new set of EL-34's (even though the ones in it were only a few months old), and I hadn't had any more problems with it.

Then comes tonight. Again, playing at very low volume, my amp decides to start buzzing/rattling. It wasn't coming out of the speaker - something in the back was doing it. I shut the power off as quick as I could get to it and haven't messed with it since in fear of screwing it up even worse.

If anyone can help out, I'd really appreciate. I just can't afford a trip to the tech for awhile, so if I can avoid being ampless, it'd mean the world.
Thanks in advance!

 

[Monsta-Tone]

Can you describe the 'Buzzing' noise?

Does it happen only when you hit a note, or does it happen all the time?
Could be a mechanical vibration. Combos are notorious for this sometimes.

You could try tightening all of the screws on the speaker baffle.
Also, you can tighten the nuts on the speaker, but DO NOT over-tighten them!
Take a look at the screws that hold the back cover on as well! If the sound is coming from here, you can use a little bit of weather stripping between the cab and the panel.
If it's the metal bar across the back (can't remember off hand if the Nomads have this), you can use weather stripping.

If the sound happens all the time, then you might have transformer buzz. My Heartbreaker and DC-10 both have this. It is a low level buzz that happens when the amp is on. It cannot be heard over the sound of the amp when I'm playing and does not increase in volume.


If none of these help, or if the buzzing increases with the master volume, then you may need to take it to a tech.
I always change the Phase Inverter tube when changing power tubes because it takes quite a beating.

 

[Birdy]

I just re-tubed my 55 1x12 Nomad(6L6 power tubes) but I also did all
12ax7a tubes. I had some weird *ghost echo* noise thing happening before
I did it. Gone now....clean....dead silent even with headphones on for late night
practicing.
Maybe try your pre-amp tubes Bleak.

 

[Bleak]

I did a number of things that both of you had posted, and everything seems to be sorted out for now

Thanks a ton!

 

[Monsta-Tone]

Right on! I love it when it's easy to fix!

 

[DWAKO]

I have I minor Nomad issue for my Nomad 100. I did the reverb mod and I was very happy with it. But the thing is if I don't have the food switch plugged in, the reverb works great, but the instant I plug in my foot-switch and I hit the reverb button nothing happens, the foot-switch lights up, but no reverb. At first I thought the was the fact I used a 5-pin cord connecting the foot-switch to the Nomad. So I bought a 7-pin cord from Mesa, I plug it in, no difference. I took the foot-switch apart and nothing appeared to be wrong, so I am really confused. I feel like I'm missing something really obvious... but I don't know what. Any advice?

 

[DWAKO]

I JUST realized my issue... and I feel kinda stupid but oh well. I bought my Nomad used and it came with the standard Nomad footswitch, not the Nomad 100 footswitch so it doesn't allow me to use the reverb... oh well, it still performs all the basic functions. I really don't feel like forking out the extra $139.00 for a new one.