Mark III replacement tubes

[Seanboy]

The owners manual says to use Mesa brand tubes, just wondering if it's really okay to use other brands, will it actually sound better if I use the Mesa tubes? The amp currently has mesa brand preamp tubes, but the power tubes are not Mesa brand.

Thanks,
Seanboy

 

[tony777]

It's because of the fixed bias in mesa amps they advice you to use mesa power tubes, because they are in the range of current draw.
This doesn't apply to the preamp tubes.

 

[rvschulz]

if you really think you want to retube - contact Doug's tubes - he has a good handle on what pre-amp tubes will fit to your particular style of playing/

 

[daveg62]

+1 for dougstubes. Tell him what amp you have and he will hook you up!

 

[Seanboy]

Talked to Doug, he told me which ones to get. They just showed up today, can't wait to get home to install them and see if it makes any difference.

 

[Seanboy]

Okay.... Got something strange going on now. Just replaced all the power tubes, didn't replace any of the preamp tubes though. It was sounding good for the first few minutes until I turned up the lead master and the master 1. Turned it up just barely above 2, and as im playing I all of a sudden get some strange feedback that sounds like a radio static that you get when youre in between stations. The sound stops as soon as I mute the strings with my hand. Any idea what's going on?

 

[daveg62]

Don't know but you gotta rule things out. Might just be dirty sockets. Try pulling tubes back out and re-seating. Better yet, if you have some de-oxit or contact cleaner spray some on the tube pins and work the tube in and out a couple times and wipe pins off with a clean rag. If that doesn't help try the old tubes and see if the problem is still there or goes away.

 

[jpdennis]

Okay.... Got something strange going on now. Just replaced all the power tubes, didn't replace any of the preamp tubes though. It was sounding good for the first few minutes until I turned up the lead master and the master 1. Turned it up just barely above 2, and as im playing I all of a sudden get some strange feedback that sounds like a radio static that you get when youre in between stations. The sound stops as soon as I mute the strings with my hand. Any idea what's going on?

You can also search through this board for Mark III noise. You should find great info. If this didn't happen before can you put back in your old power tubes and make this "not happen"? For me to give any type of input I would have to know,

1) What were you old power tubes?
2) What power tubes are you now using?
3) Is your amp a Simul-Class?

But other things to consider would be what daveg62 said. I usually re-tention my pins for the power tubes and preamp tubes when I change out a set. And I have about 3 cans of De-Oxit because it works that good.

If you have reverb check to see if the grey wire is in the front most connector just in case you had taken out the chassis AND you have reverb [not knowing your amp I am shooting a little blind here].

Did you get preamp tubes as well?

Hope anything said in the thread concerning this will help you.

Dennis

 

[Seanboy]

I have the old tubes, I can put them back in and see if it still does it. The old tubes were Ruby EL34BSTR's and Sovtek 6L6WXT's.
the new ones are the ones that Doug's tubes recommended, Ruby 6L6GCMSTR and Ruby EL34BSTR's. I haven't replaced the preamp tubes yet. The amp is a mark III black stripe with simul-class and reverb. I didn't pull the chassis so don't thing the wire on the reverb is unplugged.

Thanks, Sean

 

[jpdennis]

I have the old tubes, I can put them back in and see if it still does it ... I didn't pull the chassis so don't thing the wire on the reverb is unplugged ...

Thanks, Sean. I asked about the reverb because I once reversed the wires and had a similar sound to what you described. Also, in your first post about this amp you had said you had a muddy static sound. Was that similar? Or is this just "off the wall" static? Put the old tubes in and see what happens. Also, using De-Oxit and retentioning the tube sockets is a good thing to learn. There are a lot of self-maintenance tips & tricks that helps out tube amps. I can't remember for sure but I think I found as much about that in this board as I did during web searches.

Good luck and let us know what happens when you put in the old tubes. Also, make sure the preamp tubes are secure and flat in their sockets. I have bumped them many times in replacing tubes.

Dennis

 

[Seanboy]

alright.... more nervous now. I used the contact cleaner and cleaned the sockets and retentioned them, put the new tubes in, turned on the amp in standby mode. as soon as I flip the standby switch , the amp makes a popping sound through the speaker and the tubes start glowing blue, there's also a humming noise and the tubes also start glowing a lot brighter. When I first got the amp I took it to a friends house who has been playing guitar for over 40 years and has a lot of experience with tube amps, he was surprised the the tubes never lit up real bright and never got too hot to touch, it does have a cooling fan, so we figured maybe the fan just keeps them that cool??. Is the brighter orange and blue glow normal? I've tried doing some searching on this site, but couldn't find much info.

Sean

 

[MrMarkIII]

alright.... more nervous now. I used the contact cleaner and cleaned the sockets and retentioned them, put the new tubes in, turned on the amp in standby mode. as soon as I flip the standby switch , the amp makes a popping sound through the speaker and the tubes start glowing blue, there's also a humming noise and the tubes also start glowing a lot brighter. When I first got the amp I took it to a friends house who has been playing guitar for over 40 years and has a lot of experience with tube amps, he was surprised the the tubes never lit up real bright and never got too hot to touch, it does have a cooling fan, so we figured maybe the fan just keeps them that cool??. Is the brighter orange and blue glow normal? I've tried doing some searching on this site, but couldn't find much info.

Sean

This all sounds like normal behavior. You don't say whether or not you plugged a guitar into the **** thing, which is a generally acceptable way to test an amp.
The only part of the tube that glows is in the center of the plate structure and the amount of glow or seeming lack thereof is not a big deal, and different for every tube anyway. Some tubes have a blue glow, some may not. It's all good. When you play a loud note, the blue glow may pulse along with your playing. Again, normal.
If the tube becomes very hot and the glow looks a great deal brighter (large amounts) than its neighbor, then it may be failing.

 

[Seanboy]

All the power tubes start glowing blue and only one of them starts glowing bright orange. The plates on the inside of the tube start glowing also. Is it strange that this only happens as soon as I take it off standby? I haven't left the amp on long enough to try playing the guitar. Im afraid of damaging the amp.

 

[JOEY B.]

All the power tubes start glowing blue and only one of them starts glowing bright orange. The plates on the inside of the tube start glowing also. Is it strange that this only happens as soon as I take it off standby? I haven't left the amp on long enough to try playing the guitar. Im afraid of damaging the amp.

The tube that is glowing bright orange is "redplating". It, or the one that it is paired with is the ****-eater. The tubes are paired in the "ABBA" fashion. Sorry for any 1970's disco flashbacks. :wink:

 

[jpdennis]

Seanboy,

Hmm, O.K. now for some more questions.

• Did you try putting the old tubes back in first?
• Is the tube that red-plating (glowing orange) an EL34 or a 6L6? (This is in reference to Joey's reply to you which would let us know what pair the problem child is in)
• As for the contact cleaner, what did you use?
• Did you make sure that all the contact cleaner was wiped from the tube socket bases and the tubes?
• What did you use to retention the tubes?

Thanks for any reply
Dennis

 

[MrMarkIII]

All the power tubes start glowing blue and only one of them starts glowing bright orange. The plates on the inside of the tube start glowing also. Is it strange that this only happens as soon as I take it off standby? I haven't left the amp on long enough to try playing the guitar. Im afraid of damaging the amp.

You don't specify which tube is red-plating, the old one or the new one from Doug's, although it might seem to be the old tube from reading the entire thread.

We just need to be sure we are all on the same page.

Which tube is red-plating?
Remember, the tubes are installed in a pattern of A, B, B, A.
The two outer pair of tubes ("A") are the EL-34s.
The two inner pair of tubes ("B") are the 6L6s.

So, looking at the amp from the rear, the Bad Tube position is either "Left A", "Right A", "Left B", Right B".

Which is the Red-Plating Bad Tube?

Replace the Bad Tube with one which is the correct model, either 6L6 ("B") or EL-34 ("A"). Mark the red-plating tube with a piece of masking tape so it doesn't get mixed up with the Good Tubes.

Then:
BE SURE A SPEAKER IS CONNECTED. ALWAYS. ALWAYS. ALWAYS.
Turn the amp on, let it warm up in Standby for 30 seconds, then flip it On.

What happens?

If the tube Red-Plates no matter which tube you out in that socket, then it likely is an amp problem, not a tube problem, and it's time to see the amp repair person of your choice, because you can't fix this at home.

 

[Seanboy]

As far as the contact cleaner, I used a brand called CRC, quick dry contact cleaner, plastic safe. I didn't wipe off any excess cleaner from the sockets or the tubes, wasn't aware that I needed to. I used a very small screwdriver to retention the sockets. I haven't tried putting the old tubes back in yet, that's the next thing im going to try. I did notice that the problem chili's the EL34 in the first socket. I pulled it and swapped it with the one in the 4th, the tube glowed bright orange in that socket also. Im thinking about putting back in both of the old EL34's and see what happens.

Sean

 

[jpdennis]

... I did notice that the problem chili's the EL34 in the first socket. I pulled it and swapped it with the one in the 4th, the tube glowed bright orange in that socket also ...

So are you saying the same tube glowed orange when you moved it to socket four? If so then definitely put in the other El34s and see if that makes a difference. It could be you just have some bad El34s (it does happen) from the supplier. And Joey is correct in that the tube that is red-plating isn't always the "bad" one in the pair. If you put in the old El34s and there is no red-plating as well as the removal of the static like hiss and feedback then great. If so Doug is very good about replacing these tubes. I don't know if you noticed the tube glowing orange prior to posting about the strange feedback and radio static, so ... I am just guessing here! :wink:

Dennis

 

[Seanboy]

Problem solved! Put in the old set of EL34's, amp sounds fantastic, no strange sounds, tubes lit up correctly. Guess all along it was a bad tube. Thanks for everyone's help. It's kind of frustrating being a Newby with tube amps, but with everyone's help, I'm starting to learn.


Sean

 

[MrMarkIII]

That's great news. Glad you sorted it out.
You are now an official Tube Amp Troubleshooter!
Now, go forth, my son, and proceed to crank it and spank it!