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Quick Tube Question

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Okay, I've been getting some noise when my DT25 combo is just starting up. It sounds like a cable is shorting on something odd like that BUT it goes way after the amp has been running a while. I've been noticing some odd sounding stuff from time to time as well. So original tubes, probably time replace them.  Plus when i removed them to inspect them one of them does look discolored on the glass in one spot.

 

Question one? Does that sound as if it could be tube problem?

 

Question two? I order the EHX EL84 as that's what's in the currently. I notice on EH tubes they a have numbers along the very bottom after the tube type after the branding. What to those mean?

 

e.g. on the ones I removed

"EL84EH"

"Electro-Harmonix"

"Made in Russia"

"1206"

 

What does the "1206" mean?

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get a "matched pair" of Electro Harmonix EL84 power tubes. Per a messaging conversation with a Line6 amp tech support recommendation, stick to the Electro Harmonix brand. Something to do with Bogner design tolerances.

 

The stock DT25 12AX7 tube is Chinese, but the stock DT50 12AX7 tubes are EH Russian. There are some lengthy threads, people have had mixed results with tube brands and blowing fuses.

 

I am in the process of getting mine retubed with all EH brand tubes. I recently tried JJ's tubes, but then I learned about the EH brand being required, so my amp shop is going to swap them back out for me.

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Yea, I've been reading those threads. I ordered a matched pair of EL84EH last night along with a EH 12AX7. I'm not crazy about Chinese tubes and it seems the 12ax7 does not matter as much. 

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Okay, I've been getting some noise when my DT25 combo is just starting up. It sounds like a cable is shorting on something odd like that BUT it goes way after the amp has been running a while. I've been noticing some odd sounding stuff from time to time as well. So original tubes, probably time replace them.  Plus when i removed them to inspect them one of them does look discolored on the glass in one spot.

 

Question one? Does that sound as if it could be tube problem?

 

Question two? I order the EHX EL84 as that's what's in the currently. I notice on EH tubes they a have numbers along the very bottom after the tube type after the branding. What to those mean?

 

e.g. on the ones I removed

"EL84EH"

"Electro-Harmonix"

"Made in Russia"

"1206"

 

What does the "1206" mean?

I do not know what that means.  Sorry.  They're made in Russia.  I bought some replacement EH EL34s for my DT50, and even though they're a matched set there are numbers on each individual box that are dramatically different, suggesting that my matched pair comes from different lots--but who knows?  One other complexity is that EH tubes are often offered in differing sub-variations, soft-medium-hard, which has to  do with how easily they break up into distortion (soft = more distortion).  We have no further info, though we're in the process of trying to find someone, anyone, who has experience or knowledge.

 

Your tubes will need to be biased.  Line 6 will tell you that only a Line 6 authorized service center can do this.  These amps are "hot-rodded," and apparently if the new tubes don't match, your amp could wind up on a tech's bench.  (seems this happened mostly involving tubes other than the EHs) 

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Line 6 will tell you that only a Line 6 authorized service center can do this.  

 

Which is what is funny about my experience; without intending to, I actually took my DT amps to an "authorized Line6 service center", and due to my uninformed request, they biased it with JJ's and sent me home! lol..I happened to look up "authorized L6 service centers" in the area, and realized the place my amps were actually being worked on is on the Line6 list.. (I dropped them off in Northfield, but the shop is in downtown Chicago near River North)

 

I think the bigger issue, is all of this amp tube tech info should be a sticky post in the DT forum so future DT owners retubing their gear can save time and cost doing it right the first time.

 

As for the soft / hard / medium, that question remains unanswered. The shop I am working with says they stock the medium, so that's what I am going with. Some online stores don't even give that option when ordering. Musicians Friend does for some reason.

 

I think though, that is why the amp shop are also being really cool to have me bring them back to do the swap back to EH tubes for minimal cost to me... I am going to give them one last spin with the amps with the JJ's tubes in 'em on Thursday night after work, then I'll drove downtown and drop them off on Friday on my day off. Thursday is my Friday this week -  today is me working day 6 of a total of 9 in a row... We're open seven days a week, and everyone only works five day weeks, but sometimes, like these two weeks, my days off are at opposite ends of a two week stretch..

 

Hence me spending random time daydreaming in the Line6 forums! :)

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My original tubes (DT25) didn't make it 90 days.  I replaced them with JJ's and it lasted for about 7 months with no problems.

 

Then I turned it on one day and there was a humming sound for a few followed by the AC line fuse blowing.  I replaced the AC line fuse and it worked for a few minutes and then the tube protection fuse blew.  Visually, the tubes look fine.

 

Line 6 has it right now and I'll be curious to see what their solution is and if it still has the JJ's inside when I get it back.

 

I'll keep everyone posted.

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My original tubes (DT25) didn't make it 90 days.  I replaced them with JJ's and it lasted for about 7 months with no problems.

 

Then I turned it on one day and there was a humming sound for a few followed by the AC line fuse blowing.  I replaced the AC line fuse and it worked for a few minutes and then the tube protection fuse blew.  Visually, the tubes look fine.

 

Line 6 has it right now and I'll be curious to see what their solution is and if it still has the JJ's inside when I get it back.

 

I'll keep everyone posted.

awesome!  can't wait to hear.

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Which is what is funny about my experience; without intending to, I actually took my DT amps to an "authorized Line6 service center", and due to my uninformed request, they biased it with JJ's and sent me home! lol..I happened to look up "authorized L6 service centers" in the area, and realized the place my amps were actually being worked on is on the Line6 list.. (I dropped them off in Northfield, but the shop is in downtown Chicago near River North)

 

I think the bigger issue, is all of this amp tube tech info should be a sticky post in the DT forum so future DT owners retubing their gear can save time and cost doing it right the first time.

 

As for the soft / hard / medium, that question remains unanswered. The shop I am working with says they stock the medium, so that's what I am going with. Some online stores don't even give that option when ordering. Musicians Friend does for some reason.

 

I think though, that is why the amp shop are also being really cool to have me bring them back to do the swap back to EH tubes for minimal cost to me... I am going to give them one last spin with the amps with the JJ's tubes in 'em on Thursday night after work, then I'll drove downtown and drop them off on Friday on my day off. Thursday is my Friday this week -  today is me working day 6 of a total of 9 in a row... We're open seven days a week, and everyone only works five day weeks, but sometimes, like these two weeks, my days off are at opposite ends of a two week stretch..

 

Hence me spending random time daydreaming in the Line6 forums! :)

 

Geez--all the chewing out we get about not using EH tubes and/or having a Line 6 authorized service center bias them for us... And this happened to you?  Wow!  No wonder they're so willing to give you a price break, they shoulda known about the Line 6 party "Line" (no pun intended).

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e.g. on the ones I removed

"EL84EH"

"Electro-Harmonix"

"Made in Russia"

"1206"

 

What does the "1206" mean?

 

FYI, I found the anwser to this, just in case anyone is curious. The 12 06 is a date code in YY MM.  So these I removed were manufactored in June 2012. 

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FYI, I found the anwser to this, just in case anyone is curious. The 12 06 is a date code in YY MM.  So these I removed were manufactored in June 2012. 

 

Nice, good catch! I took a photo of one of mine, said 13 05; (May 2013 it would appear) and I will have to take a look at the other stock tubes, and compare to what I get from the retube.. (taking them in Friday, not sure how long I will have to wait to find out..)

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