innovine Posted February 16, 2015 Share Posted February 16, 2015 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... That's Bogners tighter tolerances for you (aka the only way they could get it to work without melting the tubes every few weeks) Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 17, 2015 Author Share Posted February 17, 2015 That's Bogners tighter tolerances for you (aka the only way they could get it to work without melting the tubes every few weeks) Maybe, maybe not. There's only 3-4 tubes in these things. They could probably get similar results with looser tolerances only if they went with more gain stages of lesser gain per stage (i.e. more tubes). Did you see the stuff in the other thread, in particular the article by the guy from Mesa-Boogie who says only buy Mesa tubes for Mesa amps due to exacting tolerances? (same deal, right?) I can't wait for my new 12AX7s to get here so I can see if my noise floor will drop off. It worked for spaceatl so it should work for me--and maybe for you too? Should be any day now. I will definitely report my findings! Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 18, 2015 Share Posted February 18, 2015 I can't wait for my new 12AX7s to get here so I can see if my noise floor will drop off. What did you go with for the 12AX7 replacement tube>? Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 19, 2015 Author Share Posted February 19, 2015 What did you go with for the 12AX7 replacement tube>? i believe you can use any 12ax7. for my dt50 i went with a mullard for the boost and a groove tube sag-ax7-mpi (matched phase inverter). i can't say it helped as i'm now getting a ground buzz which i hate even more than the noise floor. I put the eh's back in and the noise seems less but the buzz is still there. maybe the buzz is sucking the noise? much more info toward the end of this thread: http://line6.com/support/topic/8112-which-12ax7-socket-is-the-phase-inverter-on-a-dt50/ Quote Link to comment Share on other sites More sharing options...
BigBob-Irwin Posted February 23, 2015 Share Posted February 23, 2015 If you are getting hiss or noise through it might not be the output valves as you have probably discovered but over the years I have used a quick and easy test to check whether the pre amp or PI tubes have gone noisy or are micro phonic and that is switch the amp on in clean mode take the back off and gently tap each 12ax7 (ecc83) with a pencil if you hear the tap come through loud change that tube. Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 23, 2015 Author Share Posted February 23, 2015 If you are getting hiss or noise through it might not be the output valves as you have probably discovered but over the years I have used a quick and easy test to check whether the pre amp or PI tubes have gone noisy or are micro phonic and that is switch the amp on in clean mode take the back off and gently tap each 12ax7 (ecc83) with a pencil if you hear the tap come through loud change that tube. I'll give that a try! Thanks! EDIT: I put the amp in full power mode with channel volume maxed, with gain and master volume at 70%. I heard very little coming out of the speaker, and that's with me trying to get my ear down and directly in front of it. How much hiss and buzz are you folks getting? With all volumes and gains at zero, in Voices II and especially III does it raise any red flags for you? Quote Link to comment Share on other sites More sharing options...
BucF16 Posted February 23, 2015 Share Posted February 23, 2015 Replaced my power tubes with E34L's from Svetlana (had a tech do it). Been over a year of heavy use and they're both doing fine. Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 24, 2015 Share Posted February 24, 2015 Yeah, mine sounded good with JJ's. Some low hum, but nothing that seemed too off. Definitely not silent, but no hiss. Had them nicely cranked, tried the JTV split inputs (variax mags / variax models), and I do like that sound alot! I use two amp models and make them the same amp model. I turn the mixer down slightly on the mags side, and use a wah, comp, and drive on each amp channel before the models. I set the full 8 FS, and use 5-8 for the two comps and two drives. I use FS1 for the fx loop, FS 2&3 for the two wahs, and FS4 for a ping pong delay. I set both wahs to use the Mission exp pedal, and I set the HD500 onboard exp to control the delay mix. So for now, JJ's are fine, but not something that was so much different from the stock EH's, so most likely whenever I retube these down the road, I will probably go back to the stock EH EL84's and some decent option for the 12AX7, probably EH. Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 24, 2015 Author Share Posted February 24, 2015 Replaced my power tubes with E34L's from Svetlana (had a tech do it). Been over a year of heavy use and they're both doing fine. Very interesting, both of you! Results with non-EH tubes varies so widely. If I'm remembering it all accurately, it seems like the people who put in non-EH the tubes themselves have issues, but when a tech does it there are no problems. Some of the reasons why this may be are scattered in other threads I've posted in, so I'm gonna get lazy with the typing and not be repetitive here. Quote Link to comment Share on other sites More sharing options...
talwilkins Posted February 25, 2015 Share Posted February 25, 2015 Very interesting, both of you! Results with non-EH tubes varies so widely. If I'm remembering it all accurately, it seems like the people who put in non-EH the tubes themselves have issues, but when a tech does it there are no problems. Some of the reasons why this may be are scattered in other threads I've posted in, so I'm gonna get lazy with the typing and not be repetitive here. I have put in Tung Sol myself without any problems. Thw EH's I put in before actually melted (literally). Well, one of them. I have also tried a couple of JJ's. Didn't have issues but didn't use them very long. I took them from my Peavey 50/50 and used them until I got some new ones. The stock tubes were finished after about half a year of playing. Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 25, 2015 Author Share Posted February 25, 2015 I have put in Tung Sol myself without any problems. Thw EH's I put in before actually melted (literally). Well, one of them. I have also tried a couple of JJ's. Didn't have issues but didn't use them very long. I took them from my Peavey 50/50 and used them until I got some new ones. The stock tubes were finished after about half a year of playing. how many hours per week do you play? So the stock tubes lasted 6 months, and since then you've put in EHs, JJs (one or 2 sets) and Tung Sol, correct? Do you adjust the DC bias voltage when you change tubes? Do they all seem to last about the same length of time? Quote Link to comment Share on other sites More sharing options...
talwilkins Posted February 25, 2015 Share Posted February 25, 2015 how many hours per week do you play? So the stock tubes lasted 6 months, and since then you've put in EHs, JJs (one or 2 sets) and Tung Sol, correct? Do you adjust the DC bias voltage when you change tubes? Do they all seem to last about the same length of time? I play about 4 hours per week at high volume and sometimes a couple of hours at low volume (not low volume mode, I just turn the master on the DT-25 and POD down and it sound pretty darn good that way). First the stock lasted about 6 months. Then I only used the JJ's for a month or two and put them back in my Peavey Classic 50/50 power amp. I then put in EH's that lasted only 4 months before one melted (see picture). These I replaced with the Tung Sol which are still going good after more than 12 months. I always adjust the DC bias as close to 25 as I can, So up to now my experience hasn't been too good on EH\s lifespan. I can't say much about JJ except that I found them not sounding as good as the EH's (hence the return to EH). To me the Tung Sol's sound at least as good as the EH's, maybe better and they seem to last. I bought 4 of them at the time so the next batch will also be Tung Sol :) . Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 25, 2015 Share Posted February 25, 2015 These I replaced with the Tung Sol which are still going good after more than 12 months. To me the Tung Sol's sound at least as good as the EH's, maybe better and they seem to last. I bought 4 of them at the time so the next batch will also be Tung Sol :) . I just noticed there is a link to the EHX website from the Tung Sol website. What is the correlation between the two companies? The website says "Tung-Solâ„¢ is a registered trademark with Electro-Harmonix".. Are they made in the same factory in Russia? Quote Link to comment Share on other sites More sharing options...
talwilkins Posted February 25, 2015 Share Posted February 25, 2015 I just noticed there is a link to the EHX website from the Tung Sol website. What is the correlation between the two companies? The website says "Tung-Solâ„¢ is a registered trademark with Electro-Harmonix".. Are they made in the same factory in Russia? Interesting. i have no idea. The tubes themselves don't look exactly the same but they could well be from the same plant. I actually just mailed the question to Tung Sol. I'll keep you posted B) Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 25, 2015 Author Share Posted February 25, 2015 Interesting. i have no idea. The tubes themselves don't look exactly the same but they could well be from the same plant. I actually just mailed the question to Tung Sol. I'll keep you posted B) Being the EH owns the brand, I think it's a safe bet that they're made in the same plant. In fact, now that I think about it, I believe I read in these pages a post from a Line 6 Tech who reported that all russian tubes are made at the same factory. The EH tubes are held to a narrower spec which works for the Bogner design. Some kind of arrangement between Line 6 and EH was implied. So there's a 50/50 chance that the tung sol tubes are simply EH tubes with a different logo painted on them. Perhaps this is true sometimes but not always--might be the tung sol brand is whatever russian tube is handy/available/overstocked at the moment. Russia and China are both that way. You must have a DT25. I wonder if the same luck can be found in my DT50, which has a bias voltage of 36mv. My guess is that higher voltage means hotter, so it could be more critical in the 50s. Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 25, 2015 Share Posted February 25, 2015 I should find out if the EH tubes are specifically selected for the Line6 products, or will any matched pair of the correct EH tubes work - do they set aside certain EH tubes just for Line6, and if so, is there some way to either get those from Line6, or specify that when ordering the "correct" EH tubes? Quote Link to comment Share on other sites More sharing options...
Brazzy Posted February 25, 2015 Share Posted February 25, 2015 I should find out if the EH tubes are specifically selected for the Line6 products, My understanding is they use "Line 6 approved tubes". This was the answer I was given in a support ticket along with the recommendation I get them from Full Compass. When I changed my tubes 4 months into the game I went with Ultra Matched power tubes EH's from "AMP HEADS", biased them the best I could, which wasn't that good. I had a 4 mv differance. I knew something was wrong as the 2 tubes should have been closer. A very short time after that it went in for the Main Board, TSB 059, and 2 tubes, lol. Works great now. Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 26, 2015 Author Share Posted February 26, 2015 My understanding is they use "Line 6 approved tubes". This was the answer I was given in a support ticket along with the recommendation I get them from Full Compass. When I changed my tubes 4 months into the game I went with Ultra Matched power tubes EH's from "AMP HEADS", biased them the best I could, which wasn't that good. I had a 4 mv differance. I knew something was wrong as the 2 tubes should have been closer. A very short time after that it went in for the Main Board, TSB 059, and 2 tubes, lol. Works great now. Never heard of "Ultra matched power tubes." Is this some kinda gimmick by a reseller? Line 6 says "only EH" and that those tubes are made to conform to Bogner's tighter specs (kinda what you said already, I know). However, I have been universally thwarted in my efforts to find out about the soft/medium/hard variations that EH offers. These variations have to do with how easily the tubes break up and distort. My guess is that any are fine, and the Line 6 installs the medium flavor, but nobody seems willing to confirm this. Quote Link to comment Share on other sites More sharing options...
Brazzy Posted February 26, 2015 Share Posted February 26, 2015 Never heaThese variations have to do with how easily the tubes break up and distort. My guess is that any are fine, and the Line 6 installs the medium flavor, but nobody seems willing to confirm this. i'm just going to get my tubes from Full Compass and make sure they know what kind of amp I'm putting them in, which is taking the advice from Line 6, after all they're the company who should know how to guide me in this area. I really don't want to modify this amp. I just want to enjoy it. So I'll follow the advice of Line 6 on this. Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 26, 2015 Share Posted February 26, 2015 However, I have been universally thwarted in my efforts to find out about the soft/medium/hard variations that EH offers. These variations have to do with how easily the tubes break up and distort. My guess is that any are fine, and the Line 6 installs the medium flavor, but nobody seems willing to confirm this. I think this extra set of variations is only available for the DT50, not the DT25? IE, the 'medium / soft / hard' EHX EL34 tubes.. I am guessing for the DT50 EL34's, you just need these: http://www.thetubestore.com/Tubes/EL34-6CA7-Tube-Types/Electro-Harmonix-EL34 I just started looking at prices for getting "backup" sets of EH 12ax7 and EL84 tubes for my pair of DT25's.. The Tube Store website still has the best prices; not sure how the total factors with shipping. They spell it out pretty straight forward, you choose if you want balanced/matched triodes for the 12AX7, and if you want the EL84's 'matched'. Two 12ax7's and Four El84's are subtotal of $91.70 + FedEx ground/ economy (3-5 days) is $9.95 or FedEx two day is $15.95.. My little experiment in doing the tubes on these amps is proving costly!! Anyway, have a pretty regular bunch of rehearsals coming up, at least 2-3 times a week, so will know pretty quick if I can live with the JJ's or if I will need to have them changed back out for the EH's.. Still wondering what to use for the 12AX7; I suppose I will use EH just to be consistent.. Not sure that matters as much, since it didn't have EH as the stock tube. 1 Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 26, 2015 Share Posted February 26, 2015 Interestingly, the Tung Sol (owned by EHX - same factory in Russia?) and the EHX EL84 tubes both give the same note on the TubeStore page: http://www.thetubestore.com/Tubes/EL84-6BQ5-Tube-Types/Tung-Sol-EL84-6BQ5 "Note: These tubes have a slightly larger diameter than other EL84 tubes so they can not be installed into some '90's era Marshall DSL201 or DSL401 amplifiers, some '90's era reissue Vox AC15 amps, and Bad Cat amps." http://www.thetubestore.com/Tubes/EL84-6BQ5-Tube-Types/Electro-Harmonix-EL84 "Note: These tubes have a slightly larger diameter than other EL84 tubes so they can not be installed into some '90's era Marshall DSL201 or DSL401 amplifiers, some '90's era reissue Vox AC15 amps, and Bad Cat amps." Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 26, 2015 Share Posted February 26, 2015 I thought I had copied this response from Partev Sarkissian (Line6 tech), might be in a different thread - but, for what it's worth: Sent 13 February 2015 - 10:33 AM Because of the way Bogner designs the tube portions of these amps, and that this is a hybrid and not the usual bill-of-fare tube amp, you should re-tube using the specified EH from Electro-Harmonix tubes. You can't use the EH bias spec on other tubes. The spec is dialed in for the EH's. All too often these come across our bench for no other reason than having non-specified tube inside (JJ's, Mesa, Groove Tube), using the specified bias. That does not work. They (JJ's, Mesa, Groove Tube) would have to be bias slightly different, because the characteristic curves from one to the other are not exact. That little of difference, makes all the difference. I've seen too many blown amps just because of that. It's a hybrid and a hot rod, don't mess with it. Stick with the specified EH's. Partev SarkissianRepair Technician, Repair DeptLine 6, Inc.26664 Agoura RdCalabasas, CA 91302phone: 818-575-3600web: www.line6.com 1 Quote Link to comment Share on other sites More sharing options...
Brazzy Posted February 26, 2015 Share Posted February 26, 2015 (edited) Anyway, have a pretty regular bunch of rehearsals coming up, at least 2-3 times a week, so will know pretty quick if I can live with the JJ's or if I will need to have them changed back out for the EH's.. I thought I had copied this response from Partev Sarkissian (Line6 tech), might be in a different thread - but, for what it's worth: Good stuff Colonel, Best Regards to your up coming rehersals! Was just on the horn with Line 6 David to ask about the tube replacement options. I had put new EH tubes in it and my bias reading (32mv~36mv) was 4mv differance between the 2 power tubes, This was just before the amp pooped out due to the warranty issue. He said that the differance was most likely due to problems with the amp and that it should've been much closer, I think he said within tenths of a mill volt. I'll check the bias of the amp soon as I'm starting to rack up some hours on it now. I would've done it right away but I really just wanted to enjoy the toy. Edited February 26, 2015 by Brazzy 1 Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 26, 2015 Share Posted February 26, 2015 Good stuff Colonel, Best Regards to your up coming rehersals! Was just on the horn with Line 6 David to ask about the tube replacement options. I had put new EH tubes in it and my bias reading (32mv~36mv) was 4mv differance between the 2 power tubes, This was just before the amp pooped out due to the warranty issue. He said that the differance was most likely due to problems with the amp and that it should've been much closer, I think he said within tenths of a mill volt. I'll check the bias of the amp soon as I'm starting to rack up some hours on it now. I would've done it right away but I really just wanted to enjoy the toy. Nice, yeah I should have researched more before I put the JJ's in.. I already emailed the shop with a copy of that note from Partev, see if they will do me a break on putting EH in place of the JJ's I just had them do... Everything is a learning experience; I suppose it could be worse, I spent the $$ on the JJ's tubes and the $150 for the rebias and swap. Another $100 in EH tubes + ??? in bench time to switch them back out... live and learn! 1 Quote Link to comment Share on other sites More sharing options...
Brazzy Posted February 26, 2015 Share Posted February 26, 2015 live and learn! As long as your doing the above you're alive and well! The older I get the more research I do when it come to new endeavors. Even when I have experience I can expect to learn something, lol. Quote Link to comment Share on other sites More sharing options...
talwilkins Posted February 26, 2015 Share Posted February 26, 2015 I just got an answer from Tung Sol: The EHX and Tung-Sol trademarks are both owned by New Sensor Corporation. There are differences between the EHX and Tung-Sol tubes. Most of it has to do with the internal geometry and actual construction of the tube. Most of the Tung-Sol tubes are built to replicate the sound of the original Tung-Sol tubes. 1 Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 26, 2015 Author Share Posted February 26, 2015 Nice, yeah I should have researched more before I put the JJ's in.. I already emailed the shop with a copy of that note from Partev, see if they will do me a break on putting EH in place of the JJ's I just had them do... Everything is a learning experience; I suppose it could be worse, I spent the $$ on the JJ's tubes and the $150 for the rebias and swap. Another $100 in EH tubes + ??? in bench time to switch them back out... live and learn! I totally wouldn't take out the tubes if they're working fine. Did you bias these yourself? If so, then that's different, as articulated by Partev Sarkissian (Line6 tech) in response to my earlier query. I believe (but don't have proof so be wary) there are amp techs that are putting JJ and other tubes successfully into the DTs, and because they use a signal generator and oscilloscope they are able to bias the tubes correctly. The DC voltage arrived at would be different from that of the EH tubes. --wait--I just re-read your thread and you said a repair center put them in. I think a discussion is appropriate here. If they're any good, they did not simply follow the DC voltage spec but use the proper techniques to make the JJs work (assuming that this is possible, which I and others who know more than I believe). As for the 12AX7s, those can be any 12AX7 that you like. it's the power tubes that are critical. The Tube store doesn't seem that affordable to me. I bought a backup matched pair of EH EL34s for $34 with free shipping from Musician's Friend. I got a GT balanced inverter 12AX7 and a Mullard 12AX7 for the boost position (DT50's have a 4th tube) from Music 123. via Amazon for about the same. When I first saw the price at the Tube store, I wondered if that was for a single or the pair, since the pair option was selected. (I didn't put the tubes in yet because my amp has some issues and is in the shop for a diagnostic) Quote Link to comment Share on other sites More sharing options...
innovine Posted February 26, 2015 Share Posted February 26, 2015 What bias value will let me use jj's without them melting after a few months? I did indeed bias them to 25mv which is the dt25 bias for eh tubes. So maybe line6 would like to let me know what value won't blow my tubes up. What kind of magic knowledge does a repair center have to have to get this working? I have an oscilloscope, just no deep knowledge on power amp design. I'd be happy to calibrate my amp if someone could just let me know the process. The more I think about it the more I'm going to call line6 out for bullsiht on this one. If amp techs can calibrate the amp to use jj's without melting, the why don't line6 a) publish the bias voltage and b) use jj's instead of shltty eh's which are clearly noisier. Bogner could have designed the pow'r amp to work with jj's just as easily. I bet line6 just have some kind of deal with eh. Quote Link to comment Share on other sites More sharing options...
Brazzy Posted February 26, 2015 Share Posted February 26, 2015 What bias value will let me use jj's without them melting after a few months? I did indeed bias them to 25mv which is the dt25 bias for eh tubes. So maybe line6 would like to let me know what value won't blow my tubes up, oktnxbai Maybe it's not the bias voltage that's melting them. I'm no expert on the subject of tubes but the plate voltage is much higher. Quote Link to comment Share on other sites More sharing options...
innovine Posted February 26, 2015 Share Posted February 26, 2015 Maybe it's not the bias voltage that's melting them. I'm no expert on the subject of tubes but the plate voltage is much higher. Are amp techs messing with that too? Cos the only user tweakable value on my amp is the bias, apparently Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 26, 2015 Author Share Posted February 26, 2015 Maybe it's not the bias voltage that's melting them. I'm no expert on the subject of tubes but the plate voltage is much higher. There's no adjustment for anything other than bias, is there? Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 26, 2015 Author Share Posted February 26, 2015 What kind of magic knowledge does a repair center have to have to get this working? I have an oscilloscope, just no deep knowledge on power amp design. I'd be happy to calibrate my amp if someone could just let me know the process. +1 to that! Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 26, 2015 Author Share Posted February 26, 2015 What bias value will let me use jj's without them melting after a few months? I did indeed bias them to 25mv which is the dt25 bias for eh tubes. So maybe line6 would like to let me know what value won't blow my tubes up. What kind of magic knowledge does a repair center have to have to get this working? I have an oscilloscope, just no deep knowledge on power amp design. I'd be happy to calibrate my amp if someone could just let me know the process. The more I think about it the more I'm going to call line6 out for bullsiht on this one. If amp techs can calibrate the amp to use jj's without melting, the why don't line6 a) publish the bias voltage and B) use jj's instead of shltty eh's which are clearly noisier. Bogner could have designed the pow'r amp to work with jj's just as easily. I bet line6 just have some kind of deal with eh. I have a scope too. Need a sine wave, need a test point, then adjust the pot until the "notch' is gone. Due to the electrical shock hazard and dummies biting off more than they can chew, don't expect the needed info to be made available. Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 26, 2015 Author Share Posted February 26, 2015 Good stuff Colonel, Best Regards to your up coming rehersals! Was just on the horn with Line 6 David to ask about the tube replacement options. I had put new EH tubes in it and my bias reading (32mv~36mv) was 4mv differance between the 2 power tubes, This was just before the amp pooped out due to the warranty issue. He said that the differance was most likely due to problems with the amp and that it should've been much closer, I think he said within tenths of a mill volt. I'll check the bias of the amp soon as I'm starting to rack up some hours on it now. I would've done it right away but I really just wanted to enjoy the toy. Brazzy, did David read you the riot act about biasing your own tubes? He did so with me at the merest suggestion that I might be leaning that way, even though I never said such a thing. Quote Link to comment Share on other sites More sharing options...
Brazzy Posted February 26, 2015 Share Posted February 26, 2015 (edited) There's no adjustment for anything other than bias, is there? As far as I know there is just the bias pot. This is the only adjustment I'm interested in. Any further than that and I need to send it to someone qualified. I'm thinking about buying and building an amp kit someday. Brazzy, did David read you the riot act about biasing your own tubes? He did so with me at the merest suggestion that I might be leaning that way, even though I never said such a thing. He didn't do that with me. Although, I've been hearing that one since the first time someone threw a live condenser in my bare hands, lol. Oh wait, before that, when I would intentionally touch the bare spark plug wire on that old lawnmower of ours while it was running at full throttle, Hahaa...........oh wait, I forgot, since I intentionally cut a live end table light cord with a pair of barber scissors, ahahahaaaaaaaaaa!!!. That last one made my hair stand on end for a while and scissors were ruined, lol. The warning is part of life now, I don't blame them for mentioning it to someone. They probably have to do it as long as they're at work. I hpe when you get your amp back you have as much fun as I am with mine. Best Regards. Are amp techs messing with that too? Cos the only user tweakable value on my amp is the bias, apparently I'm not sure but I'm sure the expert techs can adjust this value if they feel it's needed. We should'nt need to play with plate voltage. Edited February 26, 2015 by Brazzy Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 26, 2015 Share Posted February 26, 2015 I totally wouldn't take out the tubes if they're working fine. Did you bias these yourself? If so, then that's different, as articulated by Partev Sarkissian (Line6 tech) in response to my earlier query. I believe (but don't have proof so be wary) there are amp techs that are putting JJ and other tubes successfully into the DTs, and because they use a signal generator and oscilloscope they are able to bias the tubes correctly. The DC voltage arrived at would be different from that of the EH tubes. --wait--I just re-read your thread and you said a repair center put them in. I think a discussion is appropriate here. If they're any good, they did not simply follow the DC voltage spec but use the proper techniques to make the JJs work (assuming that this is possible, which I and others who know more than I believe). As for the 12AX7s, those can be any 12AX7 that you like. it's the power tubes that are critical. The Tube store doesn't seem that affordable to me. I bought a backup matched pair of EH EL34s for $34 with free shipping from Musician's Friend. I got a GT balanced inverter 12AX7 and a Mullard 12AX7 for the boost position (DT50's have a 4th tube) from Music 123. via Amazon for about the same. When I first saw the price at the Tube store, I wondered if that was for a single or the pair, since the pair option was selected. (I didn't put the tubes in yet because my amp has some issues and is in the shop for a diagnostic) Yeah, I think you got it right; they "biased to spec", meaning they probably biased to the settings which are intended to match the EH tubes. Yes; I did go to a shop; no way I was trying to do that myself... Third Coast guitar & amp repair in (Northfield and Chicago) I emailed them today - they are being really awesome about it; and I copied that note from the Line6 tech, and he said no problem, they will do the swap back to EH tubes, and go easy on me for the price since I was just in there.. Feeling pretty much *foolish*... The one newer DT I should have left completely alone; the other had the tubes in it for a year, so I figured it would a good time to change them, and just jumped the gun doing both at the same time. Lesson Learned!! Good catch on the pricing... I sent a message to the TubeStore to see if they will take returns.. Even with a restock fee, that would help. Will look around more carefully for better priced options; the lessons continue to roll in... Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 26, 2015 Share Posted February 26, 2015 However, I have been universally thwarted in my efforts to find out about the soft/medium/hard variations that EH offers. These variations have to do with how easily the tubes break up and distort. My guess is that any are fine, and the Line 6 installs the medium flavor, but nobody seems willing to confirm this. Yeah, now I see those options - on the Musicians Friend website, they are sold with those three options... More confusion!! http://www.musiciansfriend.com/accessories/electro-harmonix-el84-matched-power-tubes Hard quartet / Medium quartet / Soft quartet Hard pair / Medium pair / Soft pair "Soft, medium, and hard style descriptions refer to break up modes of the tube for an overdriven guitar signal. Soft-rated tubes break up easier and have the least headroom, yielding a heavier, harder distortion. In comparison, hard-rated tubes break up easier and have the least headroom, yielding a heavier, harder distortion, while medium-rated tubes fall in between." Quote Link to comment Share on other sites More sharing options...
ColonelForbin Posted February 26, 2015 Share Posted February 26, 2015 Looks like we're not alone in this confusion regarding the soft/medium/hard questions!'brea On this thread some folks are saying - in line with what Musicians Friend says - that it has to do with headroom, and when the tubes will break up. One other commenter thinks it had to do with how much they vaccuum the air out of the tubes! So much speculation and misinformation... I sent Partev another message, see if he has anything to add.. Hard tube = most clean headroom Soft tube = least clean headroom Medium is in the middle? http://www.mylespaul.com/forums/squawk-box/77073-el84-tubes-hard-medium-soft.html "The level of vacuum in the valve will mainly determine its life expectancy. If it's gassy, it'll be short. The level of distortion is to do with the current draw. It is not to do with the vacuum. It is to do with how much current the anode can take before it is 'saturated'. That is measured in milli Amps (mA), which is charge per second. It is an indirect measure of the number of electrons that need to hit the anode (or 'plate' in American speak) before the anode can carry no more current. Maximum current. It has nothing to do with vacuum. Regarding vacuums, a good vacuum is called a hard vacuum. A poor vacuum is a soft vacuum. These are semi-technical terms that have been in use for a century. The confusion has crept in because of the valve vendors terms 'hard' and 'soft', which refer to distortion ratings. Bear in mind that distortion was NOT a design objective in audiophile equipment, and wasn't a design objective in guitar amps until the late 60s. The Fenders and early Marshalls were meant to be clean. So the use of the words 'hard' and 'soft' to describe the breakup characteristics of valves is a relatively recent thing. Since the 70s at the most. But these terms refer to the distortion characteristics of the valve. This is dertermined by current draw, as described above. Just because they use the same words - 'hard' and 'soft' - doesn't mean they are talking about the same phenomenon." Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 27, 2015 Author Share Posted February 27, 2015 I would just like to know which variation, soft, medium, or hard, Line 6 installs. That much should be easy to learn. It would also be very nice to know, given Bogner's stringent requirements, whether these minor variations could have a negative impact on the DT. Since we're being told that we can't just replace tubes, that they must be the exact tubes that Bogner specifies and they must be biased only by a Line 6 certified service center, it does seem theoretically possible that, for example, a soft EH power tube would fall outside the Holy tolerance range. Maybe it wouldn't sound as good in the DT, or wouldn't last as long. Or it could sound better than stock if you're going for a bit of dirt (like most of us). So far there is zero feedback on this that I'm aware of. Quote Link to comment Share on other sites More sharing options...
mtreehugger Posted February 27, 2015 Author Share Posted February 27, 2015 Looks like we're not alone in this confusion regarding the soft/medium/hard questions!'brea On this thread some folks are saying - in line with what Musicians Friend says - that it has to do with headroom, and when the tubes will break up. One other commenter thinks it had to do with how much they vaccuum the air out of the tubes! So much speculation and misinformation... I sent Partev another message, see if he has anything to add.. Hard tube = most clean headroom Soft tube = least clean headroom Medium is in the middle? http://www.mylespaul.com/forums/squawk-box/77073-el84-tubes-hard-medium-soft.html Thanks for the info! Quote Link to comment Share on other sites More sharing options...
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