EL34 thoughts

[Myles]

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
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

 

[glassman]

Re: EL34 thoughts

Myles,

In this day and age, it may be best to design around the least common denominator tubes out there rather than cross ones fingers that tubes that are up to the task remain available and consistent.

Do you remember the dirt cheap coke bottle Chinese 6L6s? I did many mods to Deluxe type amps 10 years ago (or so) to use them in place of the absolutely horrible 6V6s that were available at the time. I got great tube life and respectable reliability (as well as pretty darn good tone) from these tubes run at a lower level...food for thought...the lower level thought that is.

Jerry

 

[ksms]

Re: EL34 thoughts

You're right about the JJ's, but that's what I use. And you're right about the fact that I don't rely a lot on the output section for distortion.

 

[Myles]

Re: EL34 thoughts

Myles,

In this day and age, it may be best to design around the least common denominator tubes out there rather than cross ones fingers that tubes that are up to the task remain available and consistent.

Do you remember the dirt cheap coke bottle Chinese 6L6s? I did many mods to Deluxe type amps 10 years ago (or so) to use them in place of the absolutely horrible 6V6s that were available at the time. I got great tube life and respectable reliability (as well as pretty darn good tone) from these tubes run at a lower level...food for thought...the lower level thought that is.

Jerry

Jerry,

You make a very good point. Most big amp makers do just that. That is what Fender does actually.

Over at 65 Amps for another look at how some folks do things, every tube is tested and hand picked. If somebody is concerned that it may be hard to find a proper replacement if needed that is really not much of a concern as they have a stock of proper tubes on hand for replacement for folks with their amps. All the tubes are actually documented so if a replacement is needed a tube with the same range of transconductance, plate resistance, actual gain and plate current is available.

 

[Myles]

Re: EL34 thoughts

You're right about the JJ's, but that's what I use. And you're right about the fact that I don't rely a lot on the output section for distortion.

There are a lot of folks that love the JJ E34L and GT E34LS. Billy Gibbons, Joe Walsh, Joe Perry to name a few.

 

[glassman]

Re: EL34 thoughts

Myles,

Have you investigated the Ruby EL34BHT?

Jerry

 

[CaughtLikeFire]

Re: EL34 thoughts

I hope that by the time I've gone through my last 2 pairs of Siemens EL34s that there's going to be a decent modern production EL34. I can't afford to buy them anymore at current prices and it probably won't be long before they reach $200/pair.

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.

so that's why they disappeared. I had really high hopes for that tube too. any chance GT will try again?

 

[Myles]

Re: EL34 thoughts

Myles,

Have you investigated the Ruby EL34BHT?

Jerry

Jerry,

No... I have not tested that tube but I will call Tom at Magic Parts and get some to test and post a report when I get a bit of free time. The testing can take a bit of time as there is life testing involved at high voltages. Some tubes fail running within spec in minutes. Other tubes run for months. I can post initial results though and then update the life tests later after I get a set of tubes from Tom to test. I also generally send a few sets of whatever I am testing out on the road with a few folks so perhaps I will ask for volenteers here if there are folks in So Cal. I would pay for the tubes and give them to beta test folks at no cost which is my general practice but folks have to give me a bit of a writeup on their thoughts and get tubes back to me periodically to see if they have changed or drifted. I will bias the player's amp as a side note as no charge.

 

[Lake Placid Blues]

Re: EL34 thoughts

I also have been in kind of quandry about EL34's to retube my amps. I 'm an EL34 guy. I havn't ordered any yet, because I just don't know of a decent alternative to the Svet/=C= EL34 that I have used since the 90's. I understand that real =C= are a getting difficult to find and have heard about a Tung-Sol labeled Russian EL34 tube. I'm just afraid its just another re-badged Sovtek like EH. What do you know about these?

I'm thinking about getting a set NOS Siemens for recording but I don't know what to use for everyday abuse?

The Shug KT66 may be what I turn to for daily abuse as it has a little more of that midrange body of an EL34 than most 6L6 based tubes, but we need a good and affordable real EL34 for that classic tone and response.

 

[ES350]

Re: EL34 thoughts

'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.'

Wow...that's pretty bad. I still have about a half-dozen sets of Philips/Sylvania NOS 6CA7 stocked up, but no thanks to new production. I almost bought some of the GT's; glad I didn't. I've stayed away from EL34 for the unreliability and cost relative to performance.

 

[glassman]

Re: EL34 thoughts

Over at 65 Amps for another look at how some folks do things, every tube is tested and hand picked. If somebody is concerned that it may be hard to find a proper replacement if needed that is really not much of a concern as they have a stock of proper tubes on hand for replacement for folks with their amps. All the tubes are actually documented so if a replacement is needed a tube with the same range of transconductance, plate resistance, actual gain and plate current is available.

Myles,

My concern would be as follows...having owned a repair shop for several years, I would say that the run of the mill gigging musician (about 75% of my clients) opted for the most economical alternative when it came to fixing a dead amp or retubing. I limited my tube assortment to those that I deemed reliable and offered NOS tubes as well...only 5% of my clients would entertain the idea of going NOS.

With that in mind and the fact that Egnater Amps are available at places like Guitar Center...I forsee reliablity issues if the amps are designed around a more premium tube. Whether the warranty covers it or not, in this instance there is still the worries of reputation when a customer becomes dissatisfied even though he/she didn't follow manufacturer recommendations...which most probably won't.

Jerry

 

[Myles]

Re: EL34 thoughts

I also have been in kind of quandry about EL34's to retube my amps. I 'm an EL34 guy. I havn't ordered any yet, because I just don't know of a decent alternative to the Svet/=C= EL34 that I have used since the 90's. I understand that real =C= are a getting difficult to find and have heard about a Tung-Sol labeled Russian EL34 tube. I'm just afraid its just another re-badged Sovtek like EH. What do you know about these?

I'm thinking about getting a set NOS Siemens for recording but I don't know what to use for everyday abuse?

The Shug KT66 may be what I turn to for daily abuse as it has a little more of that midrange body of an EL34 than most 6L6 based tubes, but we need a good and affordable real EL34 for that classic tone and response.

I have stated in other places that the Tung Sol is much the same as the EH.

If you need winged C's here are two folks that can help although there are more out there but these are the guys I use:

www.dougstubes.com and www.kcanostubes.com

 

[Myles]

Re: EL34 thoughts

'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.'

Wow...that's pretty bad. I still have about a half-dozen sets of Philips/Sylvania NOS 6CA7 stocked up, but no thanks to new production. I almost bought some of the GT's; glad I didn't. I've stayed away from EL34 for the unreliability and cost relative to performance.

Hang onto those NOS 6CA7s!

As a side note, Van Halen used to come into the GT shop and buy NOS GE 6CA7s for his own amps in the past. That is one reason Aspen decided to try to copy the tube.

 

[Myles]

Re: EL34 thoughts

Myles,

My concern would be as follows...having owned a repair shop for several years, I would say that the run of the mill gigging musician (about 75% of my clients) opted for the most economical alternative when it came to fixing a dead amp or retubing. I limited my tube assortment to those that I deemed reliable and offered NOS tubes as well...only 5% of my clients would entertain the idea of going NOS.

With that in mind and the fact that Egnater Amps are available at places like Guitar Center...I forsee reliablity issues if the amps are designed around a more premium tube. Whether the warranty covers it or not, in this instance there is still the worries of reputation when a customer becomes dissatisfied even though he/she didn't follow manufacturer recommendations...which most probably won't.

Jerry

Jerry,

All your points here are quite valid.

I do not use NOS tubes on the road based on some of your logic .... price and availability. On the road when there is an issue one needs to be able to get tubes where they can such as a place like GC or a store that carries an assortment of afforadable types of the needed tube.

Most of the folks I have out on the road carry a very ample supply of new production tubes that have been tested and burned in which help on tour.

 

[glassman]

Re: EL34 thoughts

Jerry,

All your points here are quite valid.

I do not use NOS tubes on the road based on some of your logic .... price and availability. On the road when there is an issue one needs to be able to get tubes where they can such as a place like GC or a store that carries an assortment of afforadable types of the needed tube.

Most of the folks I have out on the road carry a very ample supply of new production tubes that have been tested and burned in which help on tour.

It's good to know that some traveling performers plan ahead!

Not all of 'em though! I have been called out on several occasions to fix a nationally touring acts gear after an unexpected breakdown...Jeff Pevar comes to mind. When he was touring with CPR, his Mesa Boogie (MK I if I recall correctly) puked on him and I had exactly 3 hours from the initial phone call to complete it. A local music store supplied a loaner and I delivered mid-performance. Super nice guy...and very appreciative that his "baby" worked again. I urged his guitar tech to get him some backup tubes for emergencies.

Jerry

 

[Luke Duke]

Re: EL34 thoughts

Thanks for the info Myles! It's very depressing, but us EL34 guys need to know.

I've got a 2204 Modded by Jeff Seal that I've been running Mullard RIs in for almost 2 years now. About 8 mos ago I bought the GT EL34M due to Mike Ks high recommendation, but I haven't tried them yet...now I'm worried.

Luke

 

[Koreth]

Re: EL34 thoughts

What about tubes from TAD? I thought their stuff was custom built to their specs in a Chinese factory, based on NOS designs. Aren't their tubes supposed to have tighter quality control than your run-of-the-mill Chinese tube?

 

[Myles]

Re: EL34 thoughts

Thanks for the info Myles! It's very depressing, but us EL34 guys need to know.

I've got a 2204 Modded by Jeff Seal that I've been running Mullard RIs in for almost 2 years now. About 8 mos ago I bought the GT EL34M due to Mike Ks high recommendation, but I haven't tried them yet...now I'm worried.

Luke

Luke,

If you got them from Mike at KCA you don't have to worry. He burns things in and matches very well.

The problem with the GT tested stuff was that their tube testers apply heater voltage for 45 seconds (warmup time, but many tubes do not stabilize for many minutes) and then hit the tube with grid, plate and bias voltage after than 45 second warmup for less than 1/2 of a second. If tubes are made well and do not have a lot of impurites (which most do) then the match is a stable match. If the tube needs burnin, and most do, then problems are not found which crop up later.

As a good example, the GT 6CA7 would pass the GT tests all day long but when tested for more than a few minutes where they were allowed to warm up they would fail in 90% of the cases. So ... a lot of tubes that were shipped are time bombs. The GT-EL34M did not share this design fault and if burned in a bit are very nice tubes. Mike at KCA does a great job of letting the tube burn in and become stable.

 

[Myles]

Re: EL34 thoughts

What about tubes from TAD? I thought their stuff was custom built to their specs in a Chinese factory, based on NOS designs. Aren't their tubes supposed to have tighter quality control than your run-of-the-mill Chinese tube?

I like a lot of the TAD stuff a lot.

When I was at GT there were a run of TAD tubes made where the Chinese illegally sold GT plates and other components to TAD. TAD carborized the plates to look different than the GT 6L6GE (made black plates) and vented the plates as well. The tubes were sold by TAD as the EL37. They were great! I had a set in a THD Flexi 50 for a long time.

Legal action was taken against the Chinese (TAD was not at fault as the Chinese offered them the parts). The last 400 or so of the run were sent to GT and GT sold them for a while as a 6L6C blackplate. They were very well received and when there was no more stock GT got the idea to take a generic 6L6 Chinese tube, make it a black plate and that became the GT 6L6CHP or Chinese High Performance blackplate. The TAD was a superior tube to the CHP in every way. The CHP is little more than a blackened plate Chinese 6L6 which was a decent tube for the money.

TAD has a few 6L6 types but this one is a GREAT tube in their lineup:

These are available from www.thetubestore.com and perhaps from other folks as well.

I am not a fan of their EL84 but that is just my personal taste. I have found they do not last as long as the JJ EL84 in cathode biased amps and they are not as defined or articulate but again, that is just my personal preference.

 

[NecroPolo]

Re: EL34 thoughts

Thanks for the great piece of info, Myles!




Those sweet Svets.. Still work great in my old Selmer that sports a full line of old Telefunken ECC83 tubes. After 15 years and lots of bumps. No issues. Why are they so dificult to deal with?


JJs are solid as hell. Considering reliability, they win. They have lots of old Tesla machinery and some clever development. Definitely, a good company with good products. Their ECC83 tubes are not for me, anyway. I don't like it smooth enough, I guess


A couple of years ago I switched to TAD in my Marshalls and kinda stuck with them. They can take bump-a-round pretty well and I like their open sound.