Royal Atlantic dead.

UPDATE. Bad power tubes. The burning smell was just a tube. Amp sounds a lot better now as well.




I was getting ready tonight for a band practice tomorrow and WAS going to take the Royal but the amp started humming loud, then a burning smell, and now no sound. Just a tube issue?

Back in 1999 - 2003 I played literally hundreds of gigs with a IIC+ head and not ONE problem. Nothing! And I never brought along a backup amp. In the past few years I've owned a few Electra Dyne's and a Royal Atlantic and I've never left my home with them and I've had several issues. What's going with Mesa's QC? Or are the tubes these days ****?

Tubes don't usually fail with a burning smell so I'd expect that something else has gone wrong like fried screen resistors.

I don't think its any secret that current production tubes as a whole are not nearly as reliable as they once were.

So far after nearly 4 years and 3 Mesa amps including an ED and the RA I have not had a critical issue. My RA is on the stock original Mesa tubes and has had a ride in the car to gigs and practice at least once a week over the last year I have owned it. I have replaced the power tubes in both My Express and the ED as they started to make intermitant popping sounds after a year of 2 hour a day plus use each.

Anyway, hope are able to get it sorted soon.

J.J said:

Tubes don't usually fail with a burning smell so I'd expect that something else has gone wrong like fried screen resistors...

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+1

If it is a failed SGR, it is almost certain that it was a bad tube that caused the resistor to fail. The humming sound was probably an output tube(s) failing, which will often take out a SGR, or two. :idea:

You know, I don't think I've ever had an output tube fail on me in 25 years. All the tubes were lit up and nothing looked out of the ordinary. Well, the amp is at a Mesa repair center and it's covered under warrant.

The tube lighting up only means that the tube heater is working, and is not an indication of the tube's condition. Usually, a tube failure that takes out a SGR, is a short to the screen grid in the tube, leaving the heater unaffected.

Tubes do have a number of failure modes. As soon as I detect something is not right with any of my amps the power is shut off and the cause investigated. Still, if you have a shorted screen you only have a few seconds before the screen resistors are toast.

I think the RA has a separate fuse for the high voltage supply to the power tubes. The idea is that it will go out much more quickly than the main fuse when something goes wrong. Sounds like it wasn't fast enough in this case.

danyeo1 said:

Or are the tubes these days sh!t

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They don't make them like they used to. I think tube manufacturers do it on purpose so that people have to keep buying new tubes.

As for the burning smell, I've had that smell when a tube redplates due to the dust and finger oils getting cooked.

The good news is that Mesa warranties their tubes for 90 days. (I think that's right)

RA owners need to pay special attention to the HT Fuse. The RA is the first amp I've ever owned, or even heard of, to employ 2 fuses. The HT fuse is designed to fail first, so if your amp starts acting microphonic or hissing... put it in standby and look for the HT Fuse LED. It's designed to be a first layer of defense should a tube fail when you are using the power soaks, preventing further damage from having the amp maxed out (ie under High Tension). It will indicate that you've had a tube failure. Power down the amp, replace the HT fuse (its a 1 amp, not 4 like the main fuse) and replace the failed tube. I recently had my two inner tubes fail as a pair, and the HT fuse worked as advertised. I replaced the fuse, and ran the amp in 50 watts (the outer tubes) and finished the gig.