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psarkissian

Tubes

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Dear group, I can not emphasize this enough,...do not, do not, do not use anything other than the specified tubes (valves) in these amps.

Power tubes must be matched sets. Use only the specified tubes. Please, I'm trying to keep your gear of of my repair bench, so you can

make music and rock out.

 

Thank you.

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I've listened! Purchased and put in inventory, just in case. Glad to see an engineer committed to the community, good job man.

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Thank you.

Have one on the bench now from someone who didn't listen.

A number of items to replace as a result.

It didn't have to be.

 

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Tubes choices to use for the DT Series,...

 

DT-50 Series:

12AX7EH Electro-Harmonix approved for the DT50 pre-amps.

EL34EH Electro-Harmonix (matched pairs) for the power amps.

 

 

DT-25 Series:

12AX7B China for pre-amps.

EL84EH Electro-Harmonix (matched pairs) for the power amps.

 

Power amp tube choices are crucial, and must be properly biased by a tech or Line 6 authorized service center who knows the product.

Don't do this yourself, the shock hazard is too great,... and it hurts when you get electric shock. Leave it to a tech trained who is for this.

 

These valve amps are particular about tubes and tube brands. Do Not use substitutes, No Mesa, Groove Tube, Tung-Sol or JJ substitutes. No hot rodding of an already Bogner hot rod.

 

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Sovtek is preferable. The Sovtek factory is owned by Electro-Harmonix.

The Sovtek may have "LPS" as a suffix, that's fine, it just means it's a low microphonic version.

And that's a good thing.

 

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"12AX7B China" --- is typically from China that we use. But you can also get the Sovtek/EH versions.

EH's are Sovteks that go through more scrutiny. And since EH owns th Sovtek factory,

it's all the same company. Some of our China "B"s are sourced through either EH or another

source (maybe Ruby Tubes, I forget who).

 

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hmmm...Sovtek does NOT have a factory...Just another New Sensor Brand Name for tubes that come from Xpo-Pul factory (Reflektor) Saratov, Russia.

 

ALL Mesa Tubes: New Sensor Xpo-Pul factory (Reflektor) Saratov, Russia

 

Sovtek: Xpo-Pul factory (Reflektor) Saratov, Russia

EH: Xpo-Pul factory (Reflektor) Saratov, Russia

 

SINO (CHINA):  factory Shuguang Electronics Group Co., China

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EH owns the factory in Russia. I have this chat with Mike Mathews (owner of EH)

every year at NAMM in Anaheim, CA. Chat about tubes and the the factory in Russia.

I make my rounds of the tube people booths every year as part of my info gathering.

 

Shuguang Electronics Group Co., China sounds familiar, see their name in tube info here and there.

 

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Actually, New Sensor owns the factory and the brands EH, Tungsol, Mullard, Genelex, Svetlana, Sovtek, Tesla and JJ....EH is nothing more than just another brand that is printed on the Russian tubes that ALL come from the same factory owned by New Sensor...

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I'll have to remind myself to ask Mike Mathews about that hierarchy, next time I see him.

I should have a chat with Dave Pearlman (Pearlman Micropnes) and Robert Moran a couple

of fellow tube freaks who keep up on this, on a more daily basis than I do. And maybe have

a chat with Aspen Pittman (founder of Groove Tubes) while I'm at it. I see them more often

than Mathews. Thanks for the feedback.

 

 

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No problem...This is fairly well known and documented in many articles...If it wasn't for Mathews, tubes would be way more expensive than they are now...He saved the Reflektor factory and put it in American hands. I do not know him, but I have followed this since the early 2000s when it all went down...

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I guess that my knowing the people in this, I don't bother with the articles, since I'm personally well acquainted with the sources.

But it sounds like I need an update. So many companies merging, selling off, getting acquired,... you need a score card to keep track

of the score cards. 

 

Hmmm,... Reflektor. I see Mathews once a year at the trade shows. But Robert Moran, Dave Pearlman and Aspen Pittman are Facebook

friends and local to me, so I have more virtual and face-to-face contact with them more often. I'll pick their brains about this. Thanks.

 

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Just swapped the tubes out again on my DT25. 4th set of EH replacements. I gig regularly and I was disappointed with the sound of the amp recently, volume and bass was down, and wondered if a new set of tubes would make a difference. 

I checked the bais of the old tubes before swapping. 24.9 mV and 34.6 mV. So something was clearly not right.  

New ones biased to 25mV, gig last night and order is restored. Checked the bias again this morning and made a minor tweak. 

But the tone is back. That Laney 30BL is gonna have to wait. 

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If I buy my replacement tubes for my DT25 from you/Line 6 will I get the correct tubes?

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Yes, that's all we would have are the correct tubes for our product.

The tubes I listed above for the DT series can also be acquired from other tube retailers.

 

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You check with Customer Support, but if it's not in our online store, then I would

think we would not sell directly to end users for that item. It's more for service techs.

 

https://www.fullcompass.com/prod/236797-electro-harmonix-t-el34eh-matchpair-pair-of-matched-el34-preamp-vacuum-tubes

For the EL34 for the DT50 power tubes.

 

https://www.fullcompass.com/searchresults.php?search_simple=true&txtAll=Electro-Harmonix+12ax7

For the 12AX7EH pre-amp tubes.

 

 

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As always, have a Line 6 authorized tech do the biasing of the power tubes. 

There is a specific procedure for bias and other calibrations that are required. 

 

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I blew A fuse on my DT 50H. I'm figuring it was from age and not tube related as there were no symptoms of the tubes failing. If blowing fuses becomes regular I'll replace the power tubes my self. Will I need a dual test probe? I know it has only one bias adjustment, so do I average the mv between the 2? I know the it supposed to be 36mv. Tube recommendation above is acknowledged. 

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Take it to a Line 6 authorized service center.

It's not a self repair problem.

 

Which fuse is it?

 

 

 

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20 hours ago, psarkissian said:

Take it to a Line 6 authorized service center.

It's not a self repair problem.

 

Which fuse is it?

 

 

 

1A/250, output fuse I think. But, it appeared in tact and I believe it may still be good. I replaced the fuse (finally arrived) and it would not power up. I'm quite sure now the transformer is the culprit. For me taking it to a service center isn't feasible. My nearest one was in Lynn Haven, outside of Panama city. I'm pretty sure they aren't there but will be rebuilding courtesy of Hurricane Michael. A bud has family there and they are rebuilding, he says not much was standing afterwards. My second service center is in ATL and a 4 - 5 hour drive. I haven't opened it up as of yet to check the other fuse because I'm willing to bet I'll have to order it as well. The down side of living peacefully in a rural area! Its really a shame, I bought this amp the later of 2016. I bought a house and spent the next 18 months getting it like I want it before I took time the time to play any at all with the exception of an hour or 2 here and there. I bet this head doesn't have 50 hrs max on it.  I may end up going this route ( https://mytubeaudio.com/tag/new-transformer-line-6/ ) because all the research I have done has led me to believe that the OEM is a faulty design with low quality control. Biasing with dual probes will be out of the question and I will have to find someone with an oscilloscope after replacement. Its a great head, a true tone monster! Its me second one as I was forced to sale off all my gear several years back. I can't justify OEM after reading all the other horror stories! 

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I'm looking at the serial number.

Take it to a Line 6 authorized service center.

It's not a self repair problem.

 

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Yeah, must be one of the bad ones that the bulletin was about I take it? So, I drive 5 hrs to drop it off and 5 hrs back and wait a few weeks. drive 5 hrs to pick it up and pay a few hundred to have to fixed since its out of warranty. Then if I'm lucky, it'll last a couple of years. Ever get the feeling you've been hosed??? LMAO... This is giving me a great excuse to build me a 2204 or a JTM 45. I've been down this road before with only one other amp. It was a from the mid 60's. No matter what was done to that amp, it would blow tubes within 10 - 20 hrs. I think I had that thing in the shop so much it was practically rebuilt. The only saving grace was a guy loved it and offered me a lot of cash for it. I think I got a Mace or Deuce... not sure, it was the 70's and I acted accordingly! :P

 

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I just talked to the guy at Pro tech services in Lynn Haven, they are open but the guy said they had problems getting parts from you guys and there were issues between you? Nevertheless, The tech that knows the gear and does the work is out and will call me when he gets a chance. Since I'll most likely end up paying I might as well have a transformer wound and have it put in instead. I really wish I had bought a back up amp instead of that JTV69S last month. I just hooked up with some guys and was trying to put something together. Such is life, huh?

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Certain parts are getting hard to get, other parts are more available.

Wish I had more control over that.

 

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