Tube Issue

[warjs]

So I was playing earlier today with my 5:25 Express with some overdrive and a clean boost, and suddenly my amp goes to about half volume. I replaced the tubes about a month ago with the same stock tubes, the EL-84's, so I wasn't sure what the issue was. I go to the back of my amp to check it out, and the tube on the left hand side of the amp is glowing red (as in the entire tube, including the metal part running down the center), while the one on the right is completely fine (just the normal glow). I then turned my amp off, let the tubes cool down, took the one that was glowing out to inspect it, and then reinserted it into the amp. After about ten minutes, the amp was working fine again.

What could the issue be? This has never occurred before, and my amp had only been on for about 30 minutes. Could the tube have overheated? Should I take it into a tech?


Thanks for your input.

-J

 

[NomadExpress]

Sounds like a Tube short to me.

50% of the EL84 Mesa tube sets I got do that. They always get replaced at no cost but 2 out of the 4 sets I had were returned for this reason. It either happens or not. I take care now to power teh amp down before I switch power modes, just to be sure and protect the tubes. I swear these EL84s are temperamental out of the box. They work or they don't.

 

[NomadExpress]

..... Should I take it into a tech?


Thanks for your input.

-J

You may need to, but here is my story....

Got my 5:25 and in 2 months I saw the behavior you experienced so I took it to the dealer I got it from. I first did my research and determined tube short, manual even points to it. Anyway the dealer was not a tech shop so they could prove the issue was a tube. Took it to a tech. They had it for 2 weeks and could not recreate it. I called Mesa and had tubes within a week, they worked fine. Flash forward 18 months and I think its time for a tube change and get a set (from retailer). This time - after 30 min like clockwork its toast. Returned the tubes to the merchant these new replacement ones are solid. Keep in mind the retailer can only replace tubes they sell under warrentee the ones that come in the amp need a certified tech or Mesa to make the replacement. weird but it makes sense.

Lesson... its the tubes. EL84s - Ive seen it, 6L6... never
Lesson.. Call Mesa be honest and they will send you the tubes, if they are under 6 months old.

 

[Krek13]

just use JJs and not crappy sovtek made mesa tubes...you can order from eurotubes, dougs tubes, tubestore, tubedepot or other shops that test their tubes to match the express bias...

 

[MrJackRozz]

Just experienced this with my 5 25, sounds becomes muddy and metallic and sometime volume goes down, turn off the amp for a little while and then the pb disappear the first times the pb occurs, finally the pb become permanent, muddy and mettalic almost instantly.

Just replaced my Mesa el84 by some Groove Tube el84, it seems to be solved.

 

[Newysurfer]

As has been noted many times on this forum the stock Mesa tubes are just ordinary quality Chinese one's (not Sovteks).
A few years ago I emailed mesa and they wouldn't say who makes all their tubes now but confirmed they are Chinese.
I wish they were Russian Sovteks - they're excellent.
Mesa Corp still rattle on about how they test each tube & match sets blah blah - sure they do - and so does every good tube retailer.

If you're having reliability prob's with mesa's tubes many of us have swapped to much better quality tubes from retailers like http://www.dougstubes.com and http://www.eurotubes.com. For around $100 you'll get better, smoother tones, much less amp hiss & often longer lasting. I just keep the Mesa tubes as spares and if I ever have a warranty issue I'll swap em back in before I send it in.

 

[Krek13]

As has been noted many times on this forum the stock Mesa tubes are just ordinary quality Chinese one's (not Sovteks).
A few years ago I emailed mesa and they wouldn't say who makes all their tubes now but confirmed they are Chinese.
I wish they were Russian Sovteks - they're excellent.
Mesa Corp still rattle on about how they test each tube & match sets blah blah - sure they do - and so does every good tube retailer.

If you're having reliability prob's with mesa's tubes many of us have swapped to much better quality tubes from retailers like http://www.dougstubes.com and http://www.eurotubes.com. For around $100 you'll get better, smoother tones, much less amp hiss & often longer lasting. I just keep the Mesa tubes as spares and if I ever have a warranty issue I'll swap em back in before I send it in.

you're wrong, mesa tubes are partly russian sovtek and partly chinese made, it says on the tube "russian" or "chinese" (check the preamp tubes for the label), powertubes are mostly made by sovtek, but sovtek tubes are not good quality tubes like JJs etc...

 

[Newysurfer]

As has been noted many times on this forum the stock Mesa tubes are just ordinary quality Chinese one's (not Sovteks).
A few years ago I emailed mesa and they wouldn't say who makes all their tubes now but confirmed they are Chinese.
I wish they were Russian Sovteks - they're excellent.
Mesa Corp still rattle on about how they test each tube & match sets blah blah - sure they do - and so does every good tube retailer.

If you're having reliability prob's with mesa's tubes many of us have swapped to much better quality tubes from retailers like http://www.dougstubes.com and http://www.eurotubes.com. For around $100 you'll get better, smoother tones, much less amp hiss & often longer lasting. I just keep the Mesa tubes as spares and if I ever have a warranty issue I'll swap em back in before I send it in.

you're wrong, mesa tubes are partly russian sovtek and partly chinese made, it says on the tube "russian" or "chinese" (check the preamp tubes for the label), powertubes are mostly made by sovtek, but sovtek tubes are not good quality tubes like JJs etc...

I said I emailed Mesa Corp 3 yrs ago and they told me all their tubes are Chinese made.
I did so cause I've never seen any Mesa tubes with any label other than the Mesa stamp on em.
It's possible they're changed suppliers in the past 3 yrs though.
And millions of happy Sovtek users will disagree with you about Sovtek tubes.
And they're sold and recommended by Doug from DougsTubes - http://www.dougstubes.com/brands/sovtek.html
So that's good enough for me

 

[assat012]

My amp is about 4 years old and has the original tubes fitted still.

The pre amp valves are indeed a mixture of Chinese and Russian. They are all marked "Mesa Boogie" but have made in China or Russia indicated.

The Russian ones are indeed Sovteks and the Chinese are no doubt Shuguang. Mesa told me they were selected for their respective slots and not to mix them up.

The output valves again look like Sovtek but no date of manufacture is included.

 

[Krek13]

I said I emailed Mesa Corp 3 yrs ago and they told me all their tubes are Chinese made.
I did so cause I've never seen any Mesa tubes with any label other than the Mesa stamp on em.
It's possible they're changed suppliers in the past 3 yrs though.
And millions of happy Sovtek users will disagree with you about Sovtek tubes.
And they're sold and recommended by Doug from DougsTubes - http://www.dougstubes.com/brands/sovtek.html
So that's good enough for me

I'm talking from my own experience, I personally got mesas russian labeled and chinese labeled tubes...so what you're saying simply cannot be true
sovteks can be solid, but their QC is bad so it's easy to get a faulty tube...it's ok to buy them from dougstubes or other similar sellers because they test each tube so you won't get the faulty one...but also soundwise sovteks are not a great purchase if you ask me, JJs are much better...

My amp is about 4 years old and has the original tubes fitted still.

The pre amp valves are indeed a mixture of Chinese and Russian. They are all marked "Mesa Boogie" but have made in China or Russia indicated.

The Russian ones are indeed Sovteks and the Chinese are no doubt Shuguang. Mesa told me they were selected for their respective slots and not to mix them up.

The output valves again look like Sovtek but no date of manufacture is included.

yeah, dont mix their positions, chinese ones are usually used in the phase inverter position so keep them there...and yes they are shuguang 100%...