New Tubes for my Supro Amp ?? Tube savvy question

[KevWind]

I purchased a Supro Titan 1X10 50 watt combo a little over a year and 1/2 ago. And honestly because of my having to use my practice amp and headphones most of the time because of family being in the house
I have probably only played it between 15 and 25 hours total.
Yesterday while playing it about 1/2 volume for an hour or so , I noticed that the volume all of a sudden dropped way down and there was a fairly loud humm . I looked at the back and noticed one of the two 6L6 tubes had a bright orange glowing line about 1/8 inch wide going down the entire center of the tube (the other one just had a little orange at the bottom and top like usual ) and it was extremely hot (like almost burn my finger hot) on the metal chassis right above the tube. ( the tubes are Sovtek 5881 / 6L6WGC ) Seems like they should be good for quite a bit longer but ?


I shut the amp off let it cool for about 1/2 hour and then turned it back on and everything seemed normal played a little bit .
I then shut it off and when it cooled I pulled both tubes and did a continuity test on the number 2 and 7 pins (as per a youtube video suggestion) and both tubes tested OK . So it appears to be related to heating up over time ?

Any way I am shopping around for a matched pair at the TubeStore and was curious about two different replacement types
One is the Tung Sol 6L6 GC-STR
And the other seems to be A TubeStore Preferred Series 6L6GC
Any thoughts or experience ???

[Steve DeRosa]

This might help with your decision, Kev:

http://www.thetubestore.com/Resource...-Reviews-Chart

As I'm sure you recall I'm a big fan of the Preferred Series tubes as a whole - their 7025's and EL84's turned my Bugera V22 into a real tone monster - and IME the tubestore.com folks are dead-on with their evaluations, so I'd trust their 6L6GC to be everything they say it is. That said, there are some very interesting things coming out of Tung-Sol these days, including a reissue of the near-impossible-to-get 7581A:

http://www.thetubestore.com/Tubes/6L...Tung-Sol-7581A

A direct replacement (with appropriate re-biasing) for 6L6 applications, this one is rated at 35W (versus 25W for a typical 5881 and ~30W for most 6L6 variations), and in its original '60s incarnation was TMK the secret weapon of the big-name acts using piggyback Bassman/Showman/Twin-based rigs; should give you tons of clean headroom - great as a pedalboard platform or for rhythm/cleaner lead styles straight into the amp...

In either event, I'd see a tech first - based on your test, make sure there isn't something else going on in there...

[Watt]

Originally Posted by KevWind

I purchased a Supro Titan 1X10 50 watt combo a little over a year and 1/2 ago. And honestly because of my having to use my practice amp and headphones most of the time because of family being in the house
I have probably only played it between 15 and 25 hours total.
Yesterday while playing it about 1/2 volume for an hour or so , I noticed that the volume all of a sudden dropped way down and there was a fairly loud humm . I looked at the back and noticed one of the two 6L6 tubes had a bright orange glowing line about 1/8 inch wide going down the entire center of the tube (the other one just had a little orange at the bottom and top like usual ) and it was extremely hot (like almost burn my finger hot) on the metal chassis right above the tube. ( the tubes are Sovtek 5881 / 6L6WGC ) Seems like they should be good for quite a bit longer but ?


I shut the amp off let it cool for about 1/2 hour and then turned it back on and everything seemed normal played a little bit .
I then shut it off and when it cooled I pulled both tubes and did a continuity test on the number 2 and 7 pins (as per a youtube video suggestion) and both tubes tested OK . So it appears to be related to heating up over time ?

Any way I am shopping around for a matched pair at the TubeStore and was curious about two different replacement types
One is the Tung Sol 6L6 GC-STR
And the other seems to be A TubeStore Preferred Series 6L6GC
Any thoughts or experience ???

Can't help you, but let us know how it turns out. I'll have to replace the tubes in my Titan at some point.

[KevWind]

Originally Posted by Steve DeRosa

This might help with your decision, Kev:

http://www.thetubestore.com/Resource...-Reviews-Chart

As I'm sure you recall I'm a big fan of the Preferred Series tubes as a whole - their 7025's and EL84's turned my Bugera V22 into a real tone monster - and IME the tubestore.com folks are dead-on with their evaluations, so I'd trust their 6L6GC to be everything they say it is. That said, there are some very interesting things coming out of Tung-Sol these days, including a reissue of the near-impossible-to-get 7581A:

http://www.thetubestore.com/Tubes/6L...Tung-Sol-7581A

A direct replacement (with appropriate re-biasing) for 6L6 applications, this one is rated at 35W (versus 25W for a typical 5881 and ~30W for most 6L6 variations), and in its original '60s incarnation was TMK the secret weapon of the big-name acts using piggyback Bassman/Showman/Twin-based rigs; should give you tons of clean headroom - great as a pedalboard platform or for rhythm/cleaner lead styles straight into the amp...

In either event, I'd see a tech first - based on your test, make sure there isn't something else going on in there...

Hey thanks again great info as usual

[KevWind]

Originally Posted by nkatsonis

Can't help you, but let us know how it turns out. I'll have to replace the tubes in my Titan at some point.

I will definitely update this thread.

[canerod]

As previously stated, you should see a tech. You may have other issues sending too much current to the tubes, causing them to overheat. That said, you'll most likely need new tube anyway. I, and several tech and amp builders I know, am/are a big fan of these:

http://www.tubeampdoctor.com/en/shop...M_Matched_2819

Good luck!

[Mr. Jelly]

I had to read this thread. I'm so old I remember going down to the hardware store to test my tubes on their tube testing machine. I'd steal the tubes out of old radios that were being thrown out.

[clintj]

Occasionally, a tube will die after just a few hours. Nature of the beast with newer production. Also, once a tube redplates like that it's generally trashed so you're right in shopping for new ones now.

I'd schedule a little tech time with that amp, just to see where it biases with the new tubes. Cathode biased amps are often touted as "plug and play", but different sets of tubes idle differently and some amps just run tubes really hot - Voxes and some Fenders like the Pro Junior are examples.

[KevWind]

Thanks for the replies people , I'll check out the TAD 's also

[Steve DeRosa]

Originally Posted by canerod

As previously stated, you should see a tech. You may have other issues sending too much current to the tubes, causing them to overheat. That said, you'll most likely need new tube anyway. I, and several tech and amp builders I know, am/are a big fan of these:

http://www.tubeampdoctor.com/en/shop...M_Matched_2819

Originally Posted by KevWind

Thanks for the replies people, I'll check out the TAD 's also

You might both find this of interest:

http://www.thetubestore.com/Tubes/6L...d-Series-6L6GC

From thetubestore.com website:

This 6L6 tube is a new version of the popular TAD 6L6GC-STR you might already know. Once exclusive only to TAD (Tube Amp Doctor) we contracted the Shuguang factory in China to produce a massive lot of these tubes to our specs. We think this is a better tube and at a better price!

- and based on my experience with both thetubestore.com and the Preferred Series tubes, I believe them...

[KY000]

My favorite 6L6's are the TAD 6L6WGC-STR and the Tung Sol 6L6 GC-STR. Vacuum tube quality control is not what it was 50 years. It's not unusual for tubes to fail at any time now.

[KevWind]

Originally Posted by Steve DeRosa

You might both find this of interest:

http://www.thetubestore.com/Tubes/6L...d-Series-6L6GC

From thetubestore.com website:


- and based on my experience with both thetubestore.com and the Preferred Series tubes, I believe them...

Hey thanks again actually I had read that about the Prefered , as I had noticed the link that canerod had posted was a EU link. And was doing some digging .... Although I had actually been leaning toward the Tung Sol 7581 A 's you posted about.

But I just got off the phone with Sweetwater Tech , they don't cover tubes obviously, but will check the amp out for any other issue and because I am still within the the 2 year warranty window they will send me a prepaid shipping label (really good because the shipping on a 47 lb amp will be spendy) They would then just charge me for new tubes and send it back on their nickel also...... And while I would rather have the amp checked locally I have no clue about any amp techs in my area (Denver and North). So I may just take Sweetwater up on the deal.

[muscmp]

i'd agree with clintj but did you swap the tubes around and get the same result? you'll still probably need new ones but that gives you more info about the tubes themselves. if i'm correct, those 5881s run a little higher voltage, do you have any 6L6 to test in it?

play music!

[KevWind]

Originally Posted by muscmp

i'd agree with clintj but did you swap the tubes around and get the same result? you'll still probably need new ones but that gives you more info about the tubes themselves. if i'm correct, those 5881s run a little higher voltage, do you have any 6L6 to test in it?

play music!

No I do not have any tubes other than the factory installed I believe they are (5881/6L6WGC - Sovtek) but I'll have to look again on the tube, but I will try swapping the position. The only thing I have done is pull them one at a time and test continuity which both had

[rockabilly69]

I know it seems like it would be an easier solution to have Sweetwater look at it. But me personally, I would just buy a new pair of tubes and call it good. If you have any problems after that, then maybe pursue having them, or better yet, a good Denver factory authorized tech look at it. The reason being, is shipping an amp can actually be hard on it, and you don't know how it's going to be treated both ways! And we're talking about glass tubes!!! The fact is, new production tubes are generally not famous for being that reliable. I've had failures from pretty much every available new production tube, so for me it's NOS all the way, they were just built to a higher standard! All of my amps are tube circuits so it cost me a bunch, but of the amps I use in my studio I haven't had a tube go bad in so long I can't remember!

I currently have a 1964 Deluxe Reverb, 1962 Ampeg Mercury, 1969 Fender Vibro Champ, 1962 Alamo Fury, Vox AC15HW, TopHat Club Deluxe, Mesa Boogie DC2, Victoria Regal II, Marshall 18 Watt custom build,and my Dirty Girl Reverb. In these amps I have El34, EL84, 5881, 6V6, 6973, and 6CZ5 power tubes, and in the last few years I haven't had one NOS tube fail! Although in my Boogie I had one NOS preamp tube go noisy on me.

This guy on ebay has 100% rating and offers a 60 day return policy for defective tubes and these look like a good pair of 5881 tubes...

https://www.ebay.com/itm/Matched-Pai...ss!84401!US!-1