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    Modern Made EL34 (or KT77) for Original ST70

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    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Modern Made EL34 (or KT77) for Original ST70

    Post by BNR_1 on Fri Feb 14, 2014 8:56 am

    Hello:

    So it has been a while since I read a recent update on your personel experience with modern made EL34 tubes for the older (original) Dyanco ST70 amps. My amp has been restored (removed selenium rectifier, new caps, etc.), and has the original transformers and uses a 5AR4 rectifier. The driver board is original with RCA 7199 tubes.

    I did a search on this topic but most of the recommendations are for the new VTA model ST70 that has a higher rated PT so I see the typical KT88s, etc; or if relevant to the older ST70s the recommendations are dated back to 2010 and 2011.

    I saw older postings of using the Russian made 6P3S-E and other variants of 6L6s. My prefernce is to stick to either a EL34 or KT77 tubes.

    The present tubes are SED Winged =C= which are no longer in production so prices are higher. My experience has not been all that great. Two tubes went bad after only 300 to 400 hours of use. In one tube the getter was white as snow and the other tube the getter was flaking off the tube. But my experenice with this tube is only once, and I have read numerous examples of positive results using this tube.

    Any inputs....good or bad?

    BTW, I know nothing can beat the older British and American made tubes but present budgets do not permit spending $300 to $400 for a quad. At this price point Psvane tubes are also out.

    Thank you

    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by peterh on Fri Feb 14, 2014 8:58 am

    BNR_1 wrote:Hello:

    So it has been a while since I read a recent update on your personel experience with modern made EL34 tubes for the older (original) Dyanco ST70 amps.  My amp has been restored (removed selenium rectifier, new caps, etc.), and has the original transformers and uses a 5AR4 rectifier.  The driver board is original with RCA 7199 tubes.

    I did a search on this topic but most of the recommendations are for the new VTA model ST70 that has a higher rated PT so I see the typical KT88s, etc; or if relevant to the older ST70s the recommendations are dated back to 2010 and 2011.

    I saw older postings of using the Russian made 6P3S-E and other variants of 6L6s.  My prefernce is to stick to either a EL34 or KT77 tubes.

    The present tubes are SED Winged =C= which are no longer in production so prices are higher.  My experience has not been all that great.  Two tubes went bad after only 300 to 400 hours of use.  In one tube the getter was white as snow and the other tube the getter was flaking off the tube.  But my experenice with this tube is only once, and I have read numerous examples of positive results using this tube.

    Any inputs....good or bad?

    BTW, I know nothing can beat the older British and American made tubes but present budgets do not permit spending $300 to $400 for a quad.  At this price point Psvane tubes are also out.

    Thank you  

    JJ EL34 works fine ( not E34L )

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by BNR_1 on Fri Feb 14, 2014 9:08 am

    Thank you peterh...now that is a fast response. Would you mine sharing why the JJ works well? Have you been using these tubes for a while with low rate of failures?


    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by peterh on Fri Feb 14, 2014 9:41 am

    BNR_1 wrote:Thank you peterh...now that is a fast response.  Would you mine sharing why the JJ works well?  Have you been using these tubes for a while with low rate of failures?

    Not only using, i sell them in sweden, and the failure rate has been below a percent, and those i caught myself during testing.
    At the moment i use 6550 in my vta-70, they will consume 400mA more in filament current together, so i would not recommend this in a stock st-70.

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by BNR_1 on Fri Feb 14, 2014 11:09 am

    [/quote]
    Not only using, i sell them in sweden, and the failure rate has been below a percent, and those i caught myself during testing.
    At the moment i use 6550 in my vta-70, they will consume 400mA more in filament current together, so i would not recommend this in a stock st-70.
    [/quote]

    Good to know. Thanks peterh

    arledgsc

    Posts : 330
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by arledgsc on Fri Feb 14, 2014 11:52 am

    In a guitar amp I used both JJ and Gold Lion KT-77s.   Liked both but felt the Gold Lions might be better for an audio amp.  Gold Lions are more expensive.

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by BNR_1 on Fri Feb 14, 2014 12:41 pm

    arledgsc wrote:In a guitar amp I used both JJ and Gold Lion KT-77s.   Liked both but felt the Gold Lions might be better for an audio amp.  Gold Lions are more expensive.

    If GLs are more expensive but the outcomes are better quality sound (to your liking) but provides the longevity factor then I think it is worth the increase in cost to a point.

    I am new tube stereo and the ability (i.e. experience) for me to distinguish the sound quality from one tube make (or type) vs another is not much. If the amp is running fine and I swapped out different make tubes but the same type, I doubt I can tell much difference assuming the amp is properly biased. But what is obvious is the longevity issue.

    My experience is in tube guitar amps where we seek distortion along with a lot of headroom. In that arena the 6L6GCs and 6V6s rule in my opinion. But stereo is a different animal.

    Thanks areledgsc

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by PeterCapo on Fri Feb 14, 2014 1:21 pm

    BNR_1, if you think you *might* have liked the reportedly warmer sound of the Winged C EL34, then the JJ EL34 types or even the JJ 6CA7 might be a good choice, sound-wise.  I have an older set of the JJ E34L that is definitely on the warm side, though I cannot say if current production sounds the same.  Besides this, nowadays JJ reliability can be a question mark.

    The Mullard reissue is also a good possibility.  Some of the Chinese EL34 are also said to sound warm, but, there are a number of varieties, which could make narrowing this down difficult.  If you decide to go with JJ, have a look at Tube Depot, which is the only seller to my knowledge that burns-in the JJ for a significant amount of time.

    It's kind of hard to say what is generally more reliable.  There are all kinds of reports online.  My guess at this point would be that among the warmer-sounding tubes, the Mullard reissue may be a better bet for reliability, and I believe Tube Depot has those, as well, and they burn them in.

    Zimmer64

    Posts : 112
    Join date : 2013-01-29
    Age : 52
    Location : Switzerland

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by Zimmer64 on Fri Feb 14, 2014 2:02 pm

    Hi there,

    I have one of Bob's VTA ST 70 and have tried Sovtek KT88, SED Winged C EL34, and Gold Lion KT 77.
    For my ears the KT 77 are the most pleasant and balanced. EL34 lack a bit of top end and the KT88 sounded a bit hard through the mid range to me.

    Best

    Michael

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by BNR_1 on Sat Feb 15, 2014 12:52 am

    Thanks PerterCapo & Zimmer64 for the suggestions.

    I have been reading overall positive comments on the GL KT77s.

    So I figured approaching this a little different. I poked around some of the Marshall amp forum sites since they are a big user of EL34s. Overall they had positive comments on the SED Winged =C= tubes. But was surprisingly were the positive comments on the Ruby EL34B-STR tubes. I have no experience with these tubes but I did note that they were of the Shuguang factory. Now the Psvane tubes are also from the Shuguang factory but goes through a much more thorough QA/QC. I also read positive results with the Shuguang brand tubes. Sorry if I am misunderstanding the location, factory, etc. But has anyone tried the Ruby EL34B-STR tubes with this amp?

    corndog71

    Posts : 444
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by corndog71 on Sat Feb 15, 2014 3:03 am

    I haven't tried the Ruby EL34s but I have used their 5AR4 rectifier tubes which have held up longer than any Sovtek or JJ. Ruby tubes are selected for quality but still reasonably priced.

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by PeterCapo on Sat Feb 15, 2014 12:50 pm

    BNR_1, I have a Ruby 5AR4 in my Cary AE3-MkII preamp, and it has been running well for a few years.  However, when I recently tried it in my Stereo 70, I got popping sounds through the speakers.  Obviously, it could not stand the strain in the Stereo 70, but it does fine in the preamp.

    But, this is probably not a reflection on the reliability of the Ruby EL34B-STR.  It is certainly an option.  I believe Doug’s Tubes http://www.dougstubes.com/power-tubes/el34-kt77-6ca7/ruby-el34-bstr.html has these, he checks Ruby’s matching and there is a 6-month warranty, which is pretty good for tubes.

    One thing is that Chinese tubes do not come with date codes.  I personally think it is a good idea to have tubes that are electrically matched while also being from the same or close production runs.  I expect that many would disagree as this does make tube buying and selling more inconvenient, but I stand by it.  However, if you do not listen critically, it probably doesn’t matter.

    Another issue is that every Chinese octal tube I have owned, and most I have seen pictured online, does not have straight pins.  They are often splayed-out.  This has on occasion wreaked a bit of havoc on my tube socket contacts, so I think it’s worth being prepared to deal with somehow.

    In any case, AFAIK, Doug’s Tubes checks Ruby’s matching, which is good because I suspect that a lot of places selling the Rubys just ship them with Ruby’s matching.  I am not sure this purported business of special attention to QA/QC for Ruby Tubes really pans out.  I called Ruby on a couple of occasions to discuss their procedures, and I was told that they pretty much are the same tubes as usual but with Ruby markings - at least that was what I was told, but who knows if the person I spoke with was really in a position to know for sure.

    arledgsc

    Posts : 330
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by arledgsc on Sat Feb 15, 2014 1:44 pm

    Contact our forum friend Jim McShane if you have questions. Sells Gold Lion and a bunch of other tubes. The Winged -C- EL34s are very highly regarded as well.

    http://www.mcshanedesign.net/tubes.htm

    corndog71

    Posts : 444
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by corndog71 on Sat Feb 15, 2014 3:25 pm

    PeterCapo wrote:BNR_1, I have a Ruby 5AR4 in my Cary AE3-MkII preamp, and it has been running well for a few years.  However, when I recently tried it in my Stereo 70, I got popping sounds through the speakers.  Obviously, it could not stand the strain in the Stereo 70, but it does fine in the preamp.


    That's odd. I've used them in my ST70 as well as a pair of MkIV's with no problems. Perhaps the socket in your ST70 isn't the greatest.

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by PeterCapo on Sat Feb 15, 2014 3:50 pm

    The socket is brand new as is the rest of the amp.  The internal voltages are on the mark. I even tightened and re-cleaned (isopropyl) the contacts and cleaned the tube's pins to no avail.  No problem with a different 5AR4.  I wouldn't think it's really odd for a variation like this.  Not every production sample will perform as well as another.  Mine is just one Ruby 5AR4, others of the same might be just fine.

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by BNR_1 on Sat Feb 15, 2014 5:09 pm

    PeterCapo wrote:BNR_1, I have a Ruby 5AR4 in my Cary AE3-MkII preamp, and it has been running well for a few years.  However, when I recently tried it in my Stereo 70, I got popping sounds through the speakers.  Obviously, it could not stand the strain in the Stereo 70, but it does fine in the preamp.

    But, this is probably not a reflection on the reliability of the Ruby EL34B-STR.  It is certainly an option.  I believe Doug’s Tubes http://www.dougstubes.com/power-tubes/el34-kt77-6ca7/ruby-el34-bstr.html has these, he checks Ruby’s matching and there is a 6-month warranty, which is pretty good for tubes.

    One thing is that Chinese tubes do not come with date codes.  I personally think it is a good idea to have tubes that are electrically matched while also being from the same or close production runs.  I expect that many would disagree as this does make tube buying and selling more inconvenient, but I stand by it.  However, if you do not listen critically, it probably doesn’t matter.

    Another issue is that every Chinese octal tube I have owned, and most I have seen pictured online, does not have straight pins.  They are often splayed-out.  This has on occasion wreaked a bit of havoc on my tube socket contacts, so I think it’s worth being prepared to deal with somehow.

    In any case, AFAIK, Doug’s Tubes checks Ruby’s matching, which is good because I suspect that a lot of places selling the Rubys just ship them with Ruby’s matching.  I am not sure this purported business of special attention to QA/QC for Ruby Tubes really pans out.  I called Ruby on a couple of occasions to discuss their procedures, and I was told that they pretty much are the same tubes as usual but with Ruby markings - at least that was what I was told, but who knows if the person I spoke with was really in a position to know for sure.

    PeterCapo my comment about the QA/QC was something I put together in my head. I have absolutely no proof, reference, etc. to indicate that the QA/QC are a much higher step up for the higher priced tubes coming out of Shuguang. I was just thinking that possibly since Pvane tubes are coming out of Shuguang then maybe (big maybe) Ruby was manufactured under similar QA/QC standards.

    So when you called Ruby you called to China?

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by PeterCapo on Sat Feb 15, 2014 7:10 pm

    No, I did not call China.  I called Ruby Tubes, a.k.a. Magic Parts, in California.  I should have mentioned that I also had originally formed the impression of Ruby quality being a step higher than garden variety tubes.  Perhaps in some way they are, hence the 6-month warranty.

    The way I read it, the information on the website for Ruby Tubes at http://shop.magicparts.com/about-us lends the impression that Ruby tubes are made to some kind of higher standard.  However, when I called, I spoke with someone who was processing a shipment of E34LCZ they had just got in.  I asked some specific questions and was told that the E34LCZ is the same tube otherwise sold under the source manufacturer’s name.  But, as I suggested in my previous post, this might not have been a comprehensive and definitive answer that applies to all Ruby tubes.

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by BNR_1 on Sat Feb 15, 2014 9:19 pm

    Thanks Peter for the info and link. I am slowly learning.

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Modern Made EL34 (or KT77) for Original ST70

    Post by PeterCapo on Sun Feb 16, 2014 1:16 am

    Me too.

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