EL34 thoughts

[Szar]

34's in anything = ROCK!

 

[myles]

I have a pair of old teslas(brown base), don't know the year, but they are so smooth. I haven't found a current production EL34 I have liked yet. I wish I had. But today I threw in and biased up a quad of Tung Sols and I thought they were okay....a bit tighter than I am used to. I took them out and threw the Teslas back in.

I have no idea what I am gonna do if they ever go out?

The real Teslas are darn spectacular.

 

[FortinAmps]

I love the Winged-C-. I have a ton of NOS Svetlana EL34s from 1999 to hold me over

I am hopefully that these guys will produce a great sounding and reliable EL34
http://www.techtubevalves.com/index.php

Cheers,
Mike

 

[myles]

I love the Winged-C-. I have a ton of NOS Svetlana EL34s from 1999 to hold me over

I am hopefully that these guys will produce a great sounding and reliable EL34
http://www.techtubevalves.com/index.php

Cheers,
Mike

I think we are all waiting for the Blackburn folks to produce something. We have been waiting a long time. I would not hold your breath as there are a lot of steps forward and backward that one has to take trying to bring a tube into production. GT took an already existing tube, the 12AX7 Mullard, and over a period of over five years never really got it right.

 

[70strathead]

Below is an email I received from my friend Bruce Egnater. Bruce is attempting to produce a great EL34 based amp and over at least a year if not more we have worked together to try to get a reliable amp. Bruce's amps sound great and are reliable but no matter how talented a designer might be and how carefully he builds his amps the issue of poor current production tubes surfaces a lot of the time.

In the case of some folks like Bogner and Rivera the use of real winged C Svetlanas is recommended. Bruce was looking for other options rather than have one single source for tubes. I thought that putting some of our dialogue here may be of interest to others.

_______________________


Hello Myles,
Sorry to bother you again. Svetlana is being very difficult to deal with. Any other decent EL34 you can recommend? I know that is an oxymoron (decent and EL34) but I need to find an alternate that will be....potentially reliable.
Thanks!!

Bruce Egnater
EHMP LLC
3833 West 12 Mile Road
Berkley, MI 48072
Tel (248) 541-9100
Fax(248) 541-9102
http://www.egnater.com
NEW EMAIL ADDRESS
bruce@egnater.com

Bruce,

I really have no other options other than NOS. The winged C Svet is the only tube that will work with any degree of reliability over 450 B+. If screen voltages are over 400 most all the others also fail.

There are also mechanical issues. The EL34 is somewhat of a lightly constructed tube and the current offerings are pretty fragile. Maybe they work in a studio or bedroom but when it comes to road travel they are pretty fragile.

Back in the heyday of Marshall even with great EL34s they still put 6550s in USA bound amps as the travel had a lot of amp arrive DOA due to tube failure and the light construction of the EL34 even back then. Things have gotten even worse.

The JJ is a nice strong tube that may be an option you can try but they are an aggressive tube in tone and have something of a hard edge. Hard rockers that use a lot of pedals and do not rely on the output section for smooth distortion like these but they do not have the creamy overdrive that a nice Siemens or Mullard will have. But, they are a strong tube physically.

The EL34 Mullard reissue from New Sensor shows the same sort of results, curves and performance of the older Electro Harmonix EL34. Soft vacuum, light construction, and the shortest life and lowest overall output of any current EL34. Using RCA/GE/Mullard test specs of 265 plate, 250 screen and -13.5 bias the test spec is for 100mA of plate current for an EL34. Most of these have a hard time breaking 75-80. Those that do make it to 90 or more have very short life and run very hot even when biased a bit cool. You can apply all of these findings to the current Electro Harmonix tube as well as this Mullard reissue.

The Groove Tubes EL34M xf2 double getter reissue of the Mullard is a Chinese tube and is wildly inconsistent. If a set is properly matched one day you may find one of the tubes in a duet or quad has drifted out of range from the other(s) in less than ten hours.

ALL of the tubes called 6CA7 fall into two categories. One category is a tube with nothing more than an EL34 with a different label. The other category are EL34 offerings that are assembled in a big bottle. None of these has the performance or reliability of an original GE 6CA7. The GT (Groove Tubes) attempt at making this tube failed drastically. Anything over 250 plate and screen volts will show over a 90% failure rate in less than an hour.

The Sino Chinese tubes are unreliable and low in output. The Shuguang is much the same although Ruby Tubes has a tube built in China for them as an exclusive offering from them called the EL34BSTR that was one of the great EL34 tubes and if still available may be a contender. Tom McNeil at Ruby Tubes keeps tight reign on the Chinese factory and production and seems to be the only person capable of getting the folks over in China to follow direction and have good quality control, or it may be the testing at Ruby Tubes / Magic Parts just takes a lot of tubes and through their testing procedures yields great consistent results. You might want to give a call to Magic Parts and Tom McNeil as he may have some good thoughts and he is also a great fellow and easy to work with.

I hope this helped ....

Myles

I agree with most of this with the exception of the JJ/Tesla being hard and edgy sounding. I have not found them to be that way at all while they are still the only reliable EL34 in current production. Personally, i wouldn't trust any Chinese EL34's as I've been told by a good source that Chinese STR variants still have a pretty high failure rate. just my opinion of course.

 

[crwnedblasphemy]

Svetlana isn't making winged =C= anymore though right? Now SED only right? I am done trying the New Sensor stuff. I have tried them all, and was even thinking of trying the new Gold Lion KT77s, but they are New Sensor as well!

I broke off the damn guide post today flipping my chassis over on the original tesla! Thankfully the glass didn't bust and it fires up fine! They have lasted me almost 2 years now, and I better find another EL34 with dark creamy mids/sustain, or I am gonna cry! hahahahaha

 

[blackba]

Myles do you have any data on the physical dimensions of EL34 tubes? I need some tubes for my '66 Vox AC50 and the SED =C= EL34's are a bit too high. I have EH EL34's in there now. My plate voltage on that amp is high at about 487VDC

Height: 4.44 inches (11 cm)
Diameter: 1.5 inches (3.8 cm)
Those are the spec dimensions.

At 487 plate volts bias between 30-34mA or so for best results. Remember, as the plate current goes up your B+ may be dragged down a bit so it is a bit of back and forth for a while. It is not all that critical though, you can actually go from about 26-36 based on personal taste. On the higher settings though watch out for red plating as many tubes today even when biased within spec can still prematuraly redplate.

If biased too hot the amp will sound harsh and run hot. If biased too cold the amp will sound grainy and may not develop full power or have nice clean tones.


487 V
25 W

40% 50% 60% 70%

21 26 31 36

Thanks Myles, I am biasing the AC50 about 31mA per tube. I generally try to stick around 60%.

For the height is there a site that has the height from the base to the top of the glass? I e-mailed Dougs tubes, but he has been too busy to get back to me. The SED =C='s I have measure 99.2mm and the EH measure 94.5mm. The SED's are about 2 mm too tall. Its too bad cause they sound great, but with them in I can't put the chassis in the head box.

I am hesitant to go with EH EL34's again as my plate voltage is about 450VDC. I am planning to get a Weber Browner soon as the AC50 should run better at115VAC input.

 

[D-Rock]

I've had good luck with the regular Svetlana EL34's in my amp. I don't know much about them though, other than they aren't winged C's. They sound similar to the EH ones I had in there previously.

 

[steve_k]

I went to the SED Winged C's in all my 34 based amps. Haven't had one fail yet. If you want a Chines EL34BSTR, buy them straight off the Mesa Boogie site. They are branded for Mesa, but they will have been well tested and culled out for use in whichever amp you prefer.

Note that Peter Diezel just started retubing everything out the door with SED 6550's because of the Q/C with all brands of 34's and the less frequent failure rate of the 6550. I haven't given them a go yet, but may try them out. Maybe this is why Marshall used them for years.

Steve

 

[myles]

I went to the SED Winged C's in all my 34 based amps. Haven't had one fail yet. If you want a Chines EL34BSTR, buy them straight off the Mesa Boogie site. They are branded for Mesa, but they will have been well tested and culled out for use in whichever amp you prefer.

Note that Peter Diezel just started retubing everything out the door with SED 6550's because of the Q/C with all brands of 34's and the less frequent failure rate of the 6550. I haven't given them a go yet, but may try them out. Maybe this is why Marshall used them for years.

Steve

On the Mesa tubes ....

Mesa does very good matching. They have six color codes that all fall within a range of a good spec tube. Mesa needs to keep a tight range as their grid biased amps have a fixed bias and therefore expect a tube plugged into the amp to be a tube that meets design spec as tubes did "in the old days". Their color code is as follows: Red, yellow, green, gray, blue, white. The cross reference to GT stuff is that all the Mesa tubes fall into a GT 4-6 range with red and yellow bing a GT 4, green and gray being at GT 5 and blue and white being a GT 6.

GT would take tubes that had problems such as improper test results from being assembled wrong or whatever, tubes which fell outside design range and put them into their low range (1-3) or high range (8-10) and put something of a marketing twist on things describing that a low tube (weak tube) wouuld break up sooner (of course ... it was a weark tube out of spec) and was best for folks that wanted a strong amp to distort sooner. High number tubes (8-10) were best for clean players, jazz or bass as they stayed clean longer. Unfortunately, these out of spec tubes even when properly biased could and generally would exhibit problems more quickly than a tube that was assembled properly.

On Mesa tubes I prefer the blue and white color codes as they are generally the most close to design spec. of the tube type.

 

[myles]

Barron 55

Your make some great points. Yes, the 6550 and EL34 are very different indeed. There were complaints for years on how the 6550 vs EL34 amps were so different in tone, feel and dynamics. Many pieces of work were published on how to put back a 6550 amp to an EL34 amp via biasing.

Some folks love the 6550 though, folks that get their tone via pedals and want the amp to be as loud and clean as possible. A year or so ago Zakk Wylde had his little rig (14 Marshalls) all redone by Jimmy Wigle when he and I were at GT and they all have 6550s as he wants that "as loud as possible" thing going on.

 

[crwnedblasphemy]

14 marshalls....all retubed, and set up....that is some cash!

 

[myles]

14 marshalls....all retubed, and set up....that is some cash!

Especially when there are 14 quads of pricy 6550s

 

[Death by Uberschall]

The JJ is a nice strong tube that may be an option you can try but they are an aggressive tube in tone and have something of a hard edge. Hard rockers that use a lot of pedals and do not rely on the output section for smooth distortion like these but they do not have the creamy overdrive that a nice Siemens or Mullard will have. But, they are a strong tube physically.

I have to disagree with this also. I have JJ EL34 tubes in my Bogner Uberschall (rev2) and that amp sings with a very nice compression/sag in the power section. Not harsh at all, but thick and full. My overdrive comes from the amp, not pedals and all I get are people/players telling me how good it sounds. I think output transformers and filtering caps along with tone stack circuits play just as big a part of tone and feel. So don't rule out these tubes. I also have a set of JJ E34L tubes I'm gonna try in it.

 

[bruce egnater]

There are two major factors that affect an amp manufacturers' choice of certain tubes. One is tone and the other is reliability. Of course the tone is very important. Fortunately, as a player you can change tubes and experiment with tone as you wish. The other really important factor is reliability, hence my questions to Myles. Consider after months/years of saving your hard earned cash, you are finally able to buy that dream amp. You are in "la-la" land playing your new amp and...POOF...it stops working. You don't think to yourself, "oh it's just a tube". You look at your now dead amp and want to kill the guys that made it and sold you this P.O.S. You feel cheated and deceived. You expected it to work forever, and rightfully so. Point is, even though it's, "just a tube", you are pissed and now question if buying this amp was the right decision. EL34 tubes are, and have always been, fragile and somewhat unreliable. At this time in history, as happens about every decade or so, EL34 quality plummets and it gets hard to find good, reliable ones. As Myles pointed out, the fragile construction is a major cause for the failures. It is not really as much an issue of bias current or plate voltage, though of course both are very important, but just moving the amp around and physically bumping and jarring the tubes can/will cause failures. We stopped offering EL34 tubes in our Egnater/Modular models long ago and only ship with 5881s. We hardly ever have 5881 failures. Of course, the owner is free to install any tubes he/she chooses. So why all of a sudden does Egnater care about EL34s? Because we have new models that will use both 5881 and EL34 tubes with the mix knob. It makes me nervous knowing the current state of EL34 tubes but....ahhhh the tone. I guess we must weigh the risk factors vs. tone and hope for the best...........Lastly, don't misunderstand, all EL34 are not bad nor do they all fail, as evidenced by thousands of players who have never had any trouble. It's just that the EL34 failure rate is considerably higher than any other tube types (5881, 6L6, 6550 etc.) and this is something we must consider.

Bruce Egnater

 

[stephen sawall]

Great thread...
Cool to see you around here Myles
.... and thanks for the update.

 

[jasonP]

I went to the SED Winged C's in all my 34 based amps. Haven't had one fail yet. If you want a Chines EL34BSTR, buy them straight off the Mesa Boogie site. They are branded for Mesa, but they will have been well tested and culled out for use in whichever amp you prefer.

Note that Peter Diezel just started retubing everything out the door with SED 6550's because of the Q/C with all brands of 34's and the less frequent failure rate of the 6550. I haven't given them a go yet, but may try them out. Maybe this is why Marshall used them for years.

Steve

On the Mesa tubes ....

Mesa does very good matching. They have six color codes that all fall within a range of a good spec tube. Mesa needs to keep a tight range as their grid biased amps have a fixed bias and therefore expect a tube plugged into the amp to be a tube that meets design spec as tubes did "in the old days". Their color code is as follows: Red, yellow, green, gray, blue, white. The cross reference to GT stuff is that all the Mesa tubes fall into a GT 4-6 range with red and yellow bing a GT 4, green and gray being at GT 5 and blue and white being a GT 6.

GT would take tubes that had problems such as improper test results from being assembled wrong or whatever, tubes which fell outside design range and put them into their low range (1-3) or high range (8-10) and put something of a marketing twist on things describing that a low tube (weak tube) wouuld break up sooner (of course ... it was a weark tube out of spec) and was best for folks that wanted a strong amp to distort sooner. High number tubes (8-10) were best for clean players, jazz or bass as they stayed clean longer. Unfortunately, these out of spec tubes even when properly biased could and generally would exhibit problems more quickly than a tube that was assembled properly.

On Mesa tubes I prefer the blue and white color codes as they are generally the most close to design spec. of the tube type.

I take it Myles you don't work for GT anymore?

What is a really good robust 6L6 that sounds good Myles?

 

[myles]

I went to the SED Winged C's in all my 34 based amps. Haven't had one fail yet. If you want a Chines EL34BSTR, buy them straight off the Mesa Boogie site. They are branded for Mesa, but they will have been well tested and culled out for use in whichever amp you prefer.

Note that Peter Diezel just started retubing everything out the door with SED 6550's because of the Q/C with all brands of 34's and the less frequent failure rate of the 6550. I haven't given them a go yet, but may try them out. Maybe this is why Marshall used them for years.

Steve

On the Mesa tubes ....

Mesa does very good matching. They have six color codes that all fall within a range of a good spec tube. Mesa needs to keep a tight range as their grid biased amps have a fixed bias and therefore expect a tube plugged into the amp to be a tube that meets design spec as tubes did "in the old days". Their color code is as follows: Red, yellow, green, gray, blue, white. The cross reference to GT stuff is that all the Mesa tubes fall into a GT 4-6 range with red and yellow bing a GT 4, green and gray being at GT 5 and blue and white being a GT 6.

GT would take tubes that had problems such as improper test results from being assembled wrong or whatever, tubes which fell outside design range and put them into their low range (1-3) or high range (8-10) and put something of a marketing twist on things describing that a low tube (weak tube) wouuld break up sooner (of course ... it was a weark tube out of spec) and was best for folks that wanted a strong amp to distort sooner. High number tubes (8-10) were best for clean players, jazz or bass as they stayed clean longer. Unfortunately, these out of spec tubes even when properly biased could and generally would exhibit problems more quickly than a tube that was assembled properly.

On Mesa tubes I prefer the blue and white color codes as they are generally the most close to design spec. of the tube type.

I take it Myles you don't work for GT anymore?

What is a really good robust 6L6 that sounds good Myles?

I left GT when it shut down August 15th last year. Somebody in another forum asked if I worked for CE Distribution and this was my reply that sort of explains things....

When GT was sold to Fender I felt I was old enough and had paid enough dues for three decades in the computer and data comm bizz that I never wanted to be a captive employee again for the rest of my life. At his point I just support my GAB client base and freelance and consult for folks. I have been living on the road for the most part since about September of last year and move around a lot and generally live in a motorhome although the stuff that some of you have seen and played at my place in the past is still there although I do not spend much time there anymore.

When GT was going away there were a lot of folks that relied on GT number this or that tubes and were worried about getting say, a #6 replacement of JJ EL84 tubes for their Z or whatever amp. I worked out a conversion system for C.E. Distribution, Doug's Tubes, KCA NOS Tubes, Antique Electric Supply, ARS and a few other folks. The conversion was documented and those folks have it now so folks that used a GT rating of something can have those folks supply tubes that match that GT rating number and a rebias should not be necessary.

By the way, I am happy to talk to any tube vendors if they want to do conversions from GT rating numbers. Many folks use a Maxi Matcher but as long as I know the plate, screen and bias voltage of their test equipment I can create a test conversion table for them and would be happy to do that for folks.

As far as your 6L6 questions .... I like the =C= a lot, the GT 6L6GE if they are still being made as they were in the past, the new Tung Sol / Sovtek 5881 reissue, the TAD 6L6WGC-STR are a few of the current offerings I like a lot. Fortunately there are a lot of great 6L6s out there.