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mtreehugger

DT Tubes--is there only one choice?

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As I write this, I'm listening to the whoosh of my DT50-112.  I should be hearing less of that, or nothing at all, I believe.  And I'm ready to try some new tubes, even though I don't actually need them at the moment.

 

From what I've seen here in this forum, the EH tubes from the factory are the culprits, but folks trying JJ tubes and other makes have experienced premature failure.  There was a post from a Line 6 tech who said that the el84s <EDIT--he did not cite EL84s, I believe he was speaking only of EL34s, which go only in the DT50> MUST be the EH tubes due to narrow tolerances required by Bogner's design, and that EH was the only tube known to be in compliance with the stricter standards.  <EDIT see below for the link to this quote>

 

Further confusing to me is the lack of discussion about the EH tube choices in the el84. <EDIT--SHOULD BE EL34 FOR THE DT50> If you look at MF or Amazon, you'll see that they come in 3 flavors:  soft, medium, and hard.  Which ones do the DTs ship with from the factory?

 

One poster opined that replacing the inverter tube and the other little guy (12ax7s if memory serves) helped with the noise floor.  Does anyone else concur with this?  Apparently any ole 12ax7 will work for these.  Should I stick with EH or is another brand better?

 

So what do you, oh community of DT players, have to say?  Care to share?

 

THANKS!

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I have to say my DT is a very quiet amp with the stock tubes in it. I've not tried anything else yet. That doesn't mean others wouldn't work.

 

You may have other issues if you have noise. Before I had warranty work done on my DT50 Head the noise floor was reasonable on every channel except topo III. When I got it back all the channels are quiet and it sounds great. I'll be sticking with the tubes it comes with.

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Doesn't the DT50 have EL34's?

 

Good eye! "T"!! The OP is talking about the wrong tubes although it's an easy mistake I would hope that error would be worked out when the tubes are actually replaced  I use EL34EH and 12AX7EH.

 

If anyone is going to replave the tubes in a tube amp you should really ask questions, read books related, know exactly what your doing and why or you should just have a qualified tech do it.

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Doesn't the DT50 have EL34's?

THANKS!  That woulda s_cked, as I was confident enough it was 84 that I probably wouldn't have double-checked.  

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I have to say my DT is a very quiet amp with the stock tubes in it. I've not tried anything else yet. That doesn't mean others wouldn't work.

 

You may have other issues if you have noise. Before I had warranty work done on my DT50 Head the noise floor was reasonable on every channel except topo III. When I got it back all the channels are quiet and it sounds great. I'll be sticking with the tubes it comes with.

 

"Quiet" can be subjective, but I doubt anybody would say mine's quiet.  It sounds like I have a fuzz box (i.e. distortion pedal, for all you young-uns) hooked in and running.  I did read that aging tubes can cause this.  I have no clue how old these are, but they look very new.  I also read that the EH tubes are noisey, so I curious if there is an alternative.  

 

Also wondering about the soft/medium/hard options EH provides for these tubes.  Anybody have any insight here?

 

THANKS!

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I probably wouldn't have double-checked.  

 

Try to get a habit of double checking when it comes to technical things. Sometimes I triple check and taking notes always helps to keep organized so you stay healthy and costly mistakes don't happen. Another key thing to success is to asking questions. The old saying "There's no stupid questions" hold true.

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Your Welcome,

 

http://www.mylespaul.com/forums/1490048-post6.html

 

The 'hardness' in this case would refer to how hard you can drive the tube before it distorts. The harder tube is cleaner. The softer tube has earlier breaku

 

 

Yes sound is always subjective. I can only testify it is definately quieter than it was when new.

 

Added: forgot to add the link to where I found that info, although I just asked this question on Amazom last week, lol.

 

"Quiet" can be subjective,

Also wondering about the soft/medium/hard options EH provides for these tubes.  Anybody have any insight here?

 

THANKS!

Edited by Brazzy

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I will report back when I get my DT25 back from the shop. Went with the matched pair of JJ's EL84's and the JJ's balanced triode 12AX7.

 

I didn't know the info about the stock tubes being the only options, for the Bogner specifications, guess I should have done more homework before I re-tubed! But other folks around here have used JJ's tubes in their DT amps and typically reported good things.

 

For what it's worth, my DT25 was about a year old with the stock tubes in it when I took it in to the shop last week, and the tech reported back to me that those tubes were pretty much done - though they had not given me any issues; I just figured it was worth a tube up tune up bias and whatnot before I lug the gear to studio to do some recording.

 

Oh yeah, and you are using the DT50, so as others noted; yours gets EL34's.

Got mine from the tubestore; here's links to what you would need if you go with JJ's tubes:

 

http://www.thetubestore.com/Tubes/EL34-6CA7-Tube-Types/JJ-E34L-EL34

 

http://www.thetubestore.com/Tubes/JJ-Electronics/JJ-ECC83-S-12AX7

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Mine has worked great for the last 7 months since I installed the JJ tubes.  I do have an issue with blowing both fuses, at the moment, along with a support ticket, but I don't suspect the tubes are the culprits at this time.

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I will report back when I get my DT25 back from the shop. Went with the matched pair of JJ's EL84's and the JJ's balanced triode 12AX7.

 

Oh yeah, and you are using the DT50, so as others noted; yours gets EL34's.

 

 

So THAT's where I got the (wrong) idea about EL84!!!  

 

Very much looking forward to your report!  From what I read, the JJs will sound better than the stock EH's, but lifespan may vary.  But that's just a few cases, hardly definitive.

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Thanks for the hardness clarification, Brazzy!  My guess is that Line 6 installs the mediums and it's okay to go with soft or hard as long as it's EH.  Anybody have any info on this?  Anybody want to talk about which they prefer and why?

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I really don't like EH 12AX7s....I think they are very noisy...Not only in the DT50, but also in my old ADA MP-1....They suck...But they are a decent tube for production...functionally reliable...seems like 8 out of 10 of them are noisy...Biggest noisefloor improvement comes from the changing both 12AX7s for something else...

 

I use a Mesa SPAX7 for the buffer and a GT-SAG AX7 balanced for the inverter....I had an SPAX7 in the inverter slot and I cannot tell the difference between the Mesa and the GT SAG....I tried JJs...not impressed...Not bad...middle of the road for me...

 

The EH power tubes (EL34s) are a completely different thing...I quite like those...I think they work quite nicely in the DT50...

 

Although the DT50 just screams, "Put Mullards In Me!"....I am not a JJ fan...take em' or leave em'...good tube...over hyped IMHO...

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I tried JJ's for a while. They sounded pretty good but went back to EH which sounded great but didn't last very long.

One actually melted!

Last year I put Tung Sol in my DT25 and I have to say I really love them and I think I will stick to them.

Nice, warm and clear sound with great distortion.

post-90313-0-41964200-1423731332_thumb.jpg

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I don't know if they meet Bogner specs but I'm running TAD-STR EL84 (in the DT25) and they sound great to me.  I've had them in about a year now and no trouble.  I checked the bias points a few nights ago and they were still 25 and 24.6 - so pretty dead on.  I've tried a bunch of power tubes and PI tubes.  With my pickups and style of music I've landed on the TADs at least for now.  As far as the PI spot - imho it can make a subtle differences - especially as you turn the amp up push it really hard.  I've had good luck with Sovtek 12AX7 LPS.

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My first pair of jj's were a great improvement in the noise floor of my dt25. Tone wise I don't know, a bit clearer and brighter maybe, but certainly no worse. They lasted about 3 months before one blew up. Second pair lasted about 3 months too (I play a few hours a week, always warming them up before leaving standby, properly biased, etc).

After that I wasn't too enthusiastic over buying a third pair. So I stuck the remaining, unmatched tubes in instead, and even tho they are off by a good amount they have lasted much longer, must be over 9 months on each tube now. There's a slight hum but otherwise no other side effects that I've noticed from being unmatched. Perhaps its only SOME jj's which blow up? The sound quality difference is enormous compared to the stock tubes. Bogner designed a piece of lollipop if the best the amp can do is a choice between sounding noisy, or burning out the tubes every few months.

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My first pair of jj's were a great improvement in the noise floor of my dt25. Tone wise I don't know, a bit clearer and brighter maybe, but certainly no worse. They lasted about 3 months before one blew up. Second pair lasted about 3 months too (I play a few hours a week, always warming them up before leaving standby, properly biased, etc).

After that I wasn't too enthusiastic over buying a third pair. So I stuck the remaining, unmatched tubes in instead, and even tho they are off by a good amount they have lasted much longer, must be over 9 months on each tube now. There's a slight hum but otherwise no other side effects that I've noticed from being unmatched. Perhaps its only SOME jj's which blow up? The sound quality difference is enormous compared to the stock tubes. Bogner designed a piece of lollipop if the best the amp can do is a choice between sounding noisy, or burning out the tubes every few months.

 

Good to hear from you--I saw your earlier posts on this subject in an earlier thread, and have been wondering how your tubes are faring.  

 

So your noise floor got better swapping in tubes.  Sorry I'm not familiar with DT25.  Are you referring to the the little ones (PI and boost?) and not the power tube(s)?  Have you ever replaced the little tubes?  I think they're 12AX7's in your amp as well as mine...  Spaceatl points to these as the noise culprits.  I just ordered a GT balanced inverter and a mullard for the boost.  I'm expecting a very noticeable difference, but through Amazon, who knows how long it'll take.  Also, I'm tempted to try something other than EH power tubes, but still wary...  I have to find that post from the Line 6 guy where he says only EH can be used for the power tubes  (but so far no luck).

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 Before I had warranty work done on my DT50 Head the noise floor was reasonable on every channel except topo III. When I got it back all the channels are quiet and it sounds great. I'll be sticking with the tubes it comes with.

 

What specifically did they repair/replace?  What were your symptoms originally?

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What specifically did they repair/replace?  What were your symptoms originally?

 

You can check out the thread I created on it. They replaced the main board, did TSB 059, and replaced the power tubes. I'm pretty sure I had one of the DT50's that had issues only I didn't realize it utill 13 months later. Being my first tube amp I just wasn't sure. Now I have that experience under my belt I know qute a bit more than I did when I was a grasshopper, lol. It worked really good for a while then little things started to happen which was the problem happening only I thought it was tubes etc. Read the whole thread it's like a journal, lol.

 

I think Line 6 did a great job fixing it for me. It's a shame there isn't anyone around me that was capable of doing it.

Edited by Brazzy

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here's a great post from Line 6 Tony.  Apparently it's only the DT50 that comes with the EH power tubes, and the DT25 comes with Sovtek.

 

Q: What tubes ship in the DT50/DT25 amps?

A:
DT50: Electro-Harmonix 12AX7 preamps tubes (2) and Electro-Harmonix EL34 power tubes (2).

DT25: Chinese-branded 12AX7 preamp tube (1) and Sovtek EL84 power tubes (2).

 

 

Everybody who hasn't already should read the entire post:

 

http://line6.com/support/page/kb/_/amplifiers/dt50dt25/dt50dt25-faq-r144

 

This leads me to believe it's only the DT50 where, reportedly, it must be EH power tubes.

 

 

**********I STILL WOULD LOVE TO KNOW IF LINE 6 SHIPS SOFT, MEDIUM, OR HARD TUBES WITH THE DT50, AND IF ANYONE HAS EXPERIMENTED WITH THESE "FLAVORS" OF EH TUBES**************

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My dt25 came with ehx el34, so line6 tony is talking bulllollipop. Wouldn't be the first time..

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So your noise floor got better swapping in tubes.

Noticibly. Went from a loud hissing to totally silent (withtthe matched tubes). so quiet that at normal volume (enough to sing loudly against) it wasn't possible to tell if the amp was on or not from a foot or two away. Compare this to the irritating hiss from the stock ehx. I still have them, so a before and after recording could be easily arranged.

 

 

Sorry I'm not familiar with DT25. Are you referring to the the little ones (PI and boost?) and not the power tube(s)?

I'm referring to the two power tubes. El84's. I didn't change the PI and there's no boost on the dt25.

In my case at least, the el84s were producing a very high noise floor. The jjs are much, much quieter. And the signal louder and clearere so fantastic improvement in SNR. The hum I have now is due to the tubes not being matched, and is quiet enough for me to live with

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My dt25 came with ehx el34, so line6 tony is talking lollipop. Wouldn't be the first time..

I presume you mean ehx el84?

Otherwise the lollopop is on you ;)

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This is great news about the 25 vs 50 tubes, the EH being specific to the DT50! I was getting slightly worried.. I will be getting back my pair of DT25's from the shop today; went with all JJ's; matched pairs in both, and balanced 12AX7's in both. I will keep a close listen for any difference in tone, noise floor, and report back if they give me any problems down the road.

 

Dropping off both guitars when I pick up the amps, so won't really be digging in with these until next week.

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This is great news about the 25 vs 50 tubes, the EH being specific to the DT50! I was getting slightly worried.. I will be getting back my pair of DT25's from the shop today; went with all JJ's; matched pairs in both, and balanced 12AX7's in both. I will keep a close listen for any difference in tone, noise floor, and report back if they give me any problems down the road.

 

Dropping off both guitars when I pick up the amps, so won't really be digging in with these until next week.

 

I wouldn't draw any conclusions yet.  Innovine says his DT25 came with EHs, and he had JJs fail.  Also, we don't know for sure what to make of the conflicting statements from the Line 6 employees.

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I really don't like EH 12AX7s....I think they are very noisy...Not only in the DT50, but also in my old ADA MP-1....They suck...But they are a decent tube for production...functionally reliable...seems like 8 out of 10 of them are noisy...Biggest noisefloor improvement comes from the changing both 12AX7s for something else...

 

I use a Mesa SPAX7 for the buffer and a GT-SAG AX7 balanced for the inverter....I had an SPAX7 in the inverter slot and I cannot tell the difference between the Mesa and the GT SAG....I tried JJs...not impressed...Not bad...middle of the road for me...

 

The EH power tubes (EL34s) are a completely different thing...I quite like those...I think they work quite nicely in the DT50...

 

Although the DT50 just screams, "Put Mullards In Me!"....I am not a JJ fan...take em' or leave em'...good tube...over hyped IMHO...

 

I tried swapping my inverter and boost tubes and the white noise seems to have ramped up.  I was testing presets, and when I went from NFL-III the noise got really loud.  When I went back to NFL II the louder noise remained.

 

I suspect, without any knowledge of the circuit, that the inverter tube and the boost tube are unaffected by gain and volume knob adjustments.  (So then my symptom of having a relatively constant white noise roar regardless of volume and gain knob positions would be consistent with noisey tubes.)  Just making sure here--Is that correct?  

 

The noise is now killing me.  I think it may be getting worse every day, but having only owned the DT50-112 for a week, and due to the complexity of HD POD+DT et. al. and my experiment yesterday, I can't quite be certain of that.  

 

I've ordered a GT balanced inverter, a mullard for the boost, and a matched pair of EH "medium" EL34s.  

 

In the meantime, would it be advisable for me to pull my lone 12AX7 from my '70s-era Dual Showman and try it in either the boost or inverter positions of my DT50?  I'm caught between my obsession with the tone potential in my DT and a fear that such an experiment might harm this elderly vintage tube.

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I wouldn't draw any conclusions yet.  Innovine says his DT25 came with EHs, and he had JJs fail.  Also, we don't know for sure what to make of the conflicting statements from the Line 6 employees.

 

True; though I remain cautiously optimistic! It seems the DT50 is far more susceptible to non-EH tube related issues. I am guessing since the DT25 ships with non-specific / non-matched tubes, it's not as big an issue. I did ask the tech to save me the tubes, will give them a closer look as to what brand they are when I grab the amps tonight.

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I saved my stock tubes when I changed them - they were labeled EH EL84s.  After reading these posts I checked it last night.

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I saved my stock tubes when I changed them - they were labeled EH EL84s.  After reading these posts I checked it last night.

 

Interesting.. So it seems they may have moved over to using EH tubes in the DT25's as well. I am curious to check what was in my DT25's, one amp was around a year old, bought it from Zzounds; the other was purchased more recently, from Sweetwater. I asked the amp repair guys to save both sets of tubes, will be interested to see if they were the same, and which brand(s) I had.

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I presume you mean ehx el84?

Otherwise the lollopop is on you ;)

Sorry, yes, el84. Must have been a brainfart.

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Also, we don't know for sure what to make of the conflicting statements from the Line 6 employees.

I know what to make of it, and it doesn't reflect well on the competence level of their support staff, to put it mildly.

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My amp just died. Seriously!? wtf!?! You think those l6 support guys I dissed have some kind of remote activated destruct button?

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I know what to make of it, and it doesn't reflect well on the competence level of their support staff, to put it mildly.

I reactivated another thread with the bench tech who says "only use EH."  It's bumped toward the top of the list of threads in this forum.  He just wrote today that Sovtek is the same factory as EH, but they scrutinize the EH to match (Bogner's) tighter tolerance requirements (not his exact words, but read all this guys posts) and paint the EG logo on the glass.  He also says that other tubes would need to be biased to a different voltage, which would to me indicate that if you have a tech with a sine wave generator and an o'scope you could probably use other tubes.  However, that is not recommended by this gentleman.  My take is that if you're swapping tubes and biasing yourself, stick to EH.  

 

Geez, I SURE hope the EH tubes I'm getting are quiet compared to the dull roar I'm getting now!!!

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Yeah, I will be the guinea pig here; I know others have reported mixed results with using JJ's, etc.

I can confirm, that the stock 12AX7 in both of my DT25's was CHINESE, *not* EH.

 

They say 12AX7B, and printed on them it just says "China"

 

However, the EL84's in both amps are Electro Harmonix, and they say made in Russia.

 

So... I may have to retube these sooner than anticipated if the JJ's cause me trouble, or blow out.

Wishing I had done more research before I took them to the shop, but oh, well it's done now!

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My amp just died. Seriously!? wtf!?! You think those l6 support guys I dissed have some kind of remote activated destruct button?

 

really???  oh man, that s_cks!!!  yeah, i do think it was your lipping off that brought it down on you.  (not really)  how long have you had the amp?  did you buy it used like i did?   did you try putting the old eh's back in?

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to match (Bogner's) tighter tolerance requirements

Or, to look at it another way, they couldn't prevent decent tubes from burning out. The best they could do was a noisy, hissy amp.

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Or, to look at it another way, they couldn't prevent decent tubes from burning out. The best they could do was a noisy, hissy amp.

 

I actually started a support ticket due to the white noise roar.  They replied that as a high gain amp there is a higher noise floor (picture "I cannot change the laws of physics, Captain!"), and asked me to record a clip, which I did.  Now I'm waiting.  

 

In the meantime I'm also waiting for 4 new tubes, and I'm playing loud enough that they can hear me outside the house to drown out the noise.  I can still talk loudly over my playing, but it's now audible outside the house to the point where the sound carries, which means that the teenagers who party with my permissive neighbor's children all night every night can now hear me play and might be inspired to explore just how lucrative selling hot musical gear can be.  (thanks to imports, not as lucrative as it was years ago)  

 

Assuming the noise I'm hearing is "normal" (and it sounds like it might not be based on Brazzy's reports), if I were playing with live drums I wouldn't mind much.  It would be like "Dude, turn off your Big Muff when we're talking, 'kay?" and I'd have to go to standby for any period of silence longer than 5 seconds.  Yeah, actually, I would mind.  Scratch that earlier sentence.  I don't recall this white noise from auditioning a DT50 at GC, or on the day I bought it 2nd hand, or the next day either, so I think it's a new development, possibly something that grows worse over time, but I can't be 100% sure of that being that my radar is up more now than earlier.

 

So did you get your amp running again?

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No, not yet. The fuse looks like it might have gone. They are unusual (thanks again, amp designer) and I've to order one on the net.

 

Do you use noise gates? It'll cut down on the high gain amplification of noise in your guitar signal, but won't do anything for the amps noise floor.

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No, not yet. The fuse looks like it might have gone. They are unusual (thanks again, amp designer) and I've to order one on the net.

 

Do you use noise gates? It'll cut down on the high gain amplification of noise in your guitar signal, but won't do anything for the amps noise floor.

 

I don't have a problem with noise -- except the noise floor.  I get that noise with no volume, no gain, no guitar cord plugged in...

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