A little more information

The two main activities in my life: Helping the hungry in the late hours of the night and helping guitar players sound better one amp at a time.

I always try to remember that in order to do good one has to take action and actually do something.

I was born and raised in Los Angeles. I have watched the city and Southern California change for well over half a century.

I can be found on facebook at www.facebook.com/mylesr or on twitter at www.twitter.com/myles111us

As of late 2019 the music related links and prints noted on this page which had their links to by GAB (Guitar Amplifier Blueprinting) website are no longer accessible. I grew weary of updating my GAB website and let it go away. You can contact me on Facebook. Saunders Stewart Models continues full operation but we are not accepting new clients without a referral.

Los Angeles Architectural History

Los Angeles Architectural History
1935 Art Deco at some of its finest: No. 168 - Griffith Observatory- (click on the photo for information)

Monday, February 7, 2011

Vacuum tube post from the past - where they are made

I initially posted this as a note on Facebook in June of 2010.

There has been a bit of discussion on the post so I thought that some folks that subscribe to this blog might find this of interest.
Older photo which shows GT "made in USA" silkscreen. Aspen was called out on this with legal action so the silkscreen was changed to eliminate this statement.

Today I received an email from my friend Rob Hull over at TubeDepot. Rob is is their technical director. He is a great fellow and has produced a lot of terrific videos about amp service and videos on many technical subjects.
Below is Rob's letter and my reply. Feel free to write Rob with tech questions as he is a great resource.
--- On Wed, 6/2/10, Rob Hull wrote:
From: Rob Hull
Subject: GT 6L6 GE looking tube
To: "Myles S. Rose"
Date: Wednesday, June 2, 2010, 12:34 PM


Do you have a link to where you describe where the GT 6L6GC tube is being made?

I don't understand where these are being made and where the components came from. Any assistance you can offer is greatly appreciated.

Robert Hull
Technical Director


All the GT 6L6 tubes (6L6GE, 6L6CHP and 5881C) were from the Shuguang factory in China. The short bottle TAD also came from the Shuguang factory and at times there were problems when the Chinese took GT plates, bases and pins and used them in the TAD tubes. The Chinese would blacken the plates and punch vent holes in them but in the end it was just the GT 6L6GE.

The GT EL34M xf2 reissue was also from the same Chinese factory as was the 6CA7GE. The 6CA7 GE reissue never worked properly and was never produced as per proper design. One of the two grids was wound backwards and was in parallel with the other grid as most other tubes but the design of the General Electric 6CA7 had the two grids cross so alignment was not an issue. This was not done so the GT version was something of a time bomb (with a very short fuse as a side note).

The GT 12AX7M was also from the Shuguang factory in China. Early runs were great but each run was worse. In the few years of production the tube was the most unreliable and inconsistent 12AX7 ever made in the history of vacuum tubes. It also had the lowest gain of any 12AX7 ever made, in a high percentage of cases lower than the gain of a 12AY7. The plate resistance was typically below 35k ohms where spec is 62.5k ohms. This caused a lot of issues depending on amp design as side A and side B of the dual triode would let two areas of a circuit bleed into each other which caused crosstalk, jumping volume levels when the amp was turned down, clicks, pops and other problems. The low plate resistance also produced very high plate current with generated a lot of heat and also dropped the gain of the tube dramatically.

I am going to post this as a note on facebook as a lot of folks might also find this useful. I will post your contact info and website as well as you folks at http://www.tubedepot.com/ have a great selection of tubes, great prices, terrific matching and great service.

Hope this helped ...


[click "read more" as there is a lot more]
Update after Rob sent me another email - my response:

At one point GT would ship plate material ( 5 clad ) from the USA to China. Bases and pins were also shipped but these were not GE bases, they were bases used on all GT octal based tubes. The micas were originally stamped by the USA company that made the micas for GE back in the day but the supply train derailed all the time. The majority of the parts were Chinese, grids were wound in China and assembly was done there . At GT we tried to get the USA tube equipment operational but this really never happened to a scale which would support anything that one could call production quantities.  It was more of it being a matter of tons of iron that Aspen used for PR. The 6L6GE, regardless of where it was made, was a great tube. It sounded great and had a nice long life and the winged C Svetlana that always gave the GT 6L6GE a run for the money from many folks point of view.

There have been a number of comments on the original facebook posted note.  I responded to some of them.  I will copy these comments below up to the last comment.

Brad Spence


Thanks so much. I've always wanted to try the GT 6CA7GE. I've heard they sound great, but don't last. Now I know why.

As for the Chinese 12AX7s, I totally agree with your assessment. I've replaced them in all of my amps that had ...them. (Actually, only 2...) But BIG difference.

I haven't had any LAX overnights since I changed domiciles at work. But when I get one, I'll let you know. Hopefully, we can hang out for a few. Sushi and rum are on me!

Brad - the last runs of 6CA7 tubes would fail within 15 minutes at anything over 300 plate volts. Spec is 700+. The failure rate was over 90% on the final run. The 10% that did pass would fail at 350 plate volts. The bias was adjusted d...uring the test so the tube output was only at 70% of 25 watts of output. The 6L6GE though was a great tube and may go down in history as the only tube Groove Tubes brought to market as a reissue that worked. The Mullard Reissue ( EL34M ) was an xf2 reissue. It was a successful tube for some folks but in the last six months of GT being a company there were more complaints from some amp makers who tried to use the tube. Rick Benson, the sales manager at GT, would bring me tubes that failed and we were just getting to understand reported problems that looked as if they may have been caused by the factory changing things or switching to substandard materials perhaps. I never discovered the problem and GT closed its doors 8/15/2008 after Aspen pulled what may go down as one of the greatest smoke and mirrors acts in music history as he sold GT to Fender. This is just my own take on things and just personal opinion from my own observation. When Fender bought the tube test gear my first thought was .... reminds me of airplanes ... today there are only two folks in the cockpit and the engines, nav systems and fuel management is all computer controlled. FADEC, DDEC and all sorts of cool stuff. Today there are tube testing devices such as the Maxi-Matcher that match to 1/10 of a milliamp in moments where little expertise is required to run the machine. The GT system broke a spread of 100-150 milliamps or even a wider spread, into 10 rating numbers. Not very precise. The tubes had a 45 second warmup and were hit for half a second to be measured. Not great when tubes were unstable. Back to the airplane train of thought ... complex, old tech, inefficient and needing trained people .... Aspen sold Fender a fleet of old Boeing 707s and DC-8 airplanes, again from my own point of view which just might be shared by a few others :-)

Kevin Miller
So, Myles, what 6CA7 type tubes WOULD you recommend these days?

Myles Rose
NOS. The new ones are usually little more than big bottle EL34s and there is a bit difference. Maybe talk to Mike at http://www.kcanostubes.com/ as he may have some real GEs, Sylvania or Phillips.

Brian Dietrich
Guys. I have some NOS 1958 Brown Base Milspec 6V6's that will blow your minds. Contact me and we can work out an arrangement. I have RCA tube as well.

Kevin Miller
Hey, since we're talkin' NOS 6CA7s, any idea what type of 6CA7s Eddie Van Halen was running back in the early VH album days?

Myles Rose
Kevin - I can tell you exactly which 6CA7 he used ... the General Electric. He used to come to GT and buy them directly from Aspen Pittman. When GT closed there were a lot of originals in a dark red file cabinet in the warehouse area. Some of those originals were destroyed on purpose to be used with the original engineering drawings when GT tried to recreate the tube.

Gregg Hopkins
Miles - Great info. Thanks for posting. Would you agree that SOME productions of Chinese 12AX7s for Ruby have been good to great? Always interested to hear what those in the know think about current productions. NOS can only last so long and many out there are rejects that keep getting sold over and over.

Bobby Vogel
Hey man, I still own four matched quad sets of the Jan-Phillips 7581, 6L6. These tubes have never been in an amp. I can't find them anymore.
Gregg -
There are a lot of GREAT tubes out of China. Ruby Tubes has some spectacular stuff. They have an EL34 that has always been one of my favorites. Tom McNiel of Ruby Tubes works in concert with the Chinese and produces great stuff.  There are other folks that do not work well in concert with the Chinese and have history of problems when they try to impose their viewpoints and the most ugly side of the "Ugly American" culture on them. Not a good working relationship and not a good foundation when trying to develop a specific idea or product. If you look at the timeline of the 6L6GE which was a great tube to the later GT offerings you can see the inter personal relationship take a toll. As the GT relationship declined (this also applied to their microphones .... the ribbon mic was a failure big time ... and their high end audio gear (watch out for "the brick" as there is possible electrocution) .... the well established relationship that Ruby Tubes had with the Chinese stayed strong. Ruby has terrific stuff.
As far as NOS ... yes, we are hitting the bottom of the barrel so be sure to know and trust your vendor. I love Mike at KCA ... www.kcanostubes.com .... and for you Bobby Vogel, if anybody can find more of thise 7581s he can.
Kevin Miller
Re: Bobby Vogel- Oooh, I had some of them yeeeaars ago; they were awesome in the Fender Twin I put 'em in!
Bobby Vogel
I bought Mike's last quad set a few years back. I have 4 untouched and think I will hang on to them. Myles you once told me that tubes don' t have a shelf life.
Myles Rose
Bobby ... they do not have a shelf life. Look how many NOS tubes are out there which are older than I am and still "new" in how they work when plugged in. I am not new when I am plugged in anymore :-) As Toby Keith says .... I'm not as good as I once was, but I'm as good ONCE as I ever was.

Side note from Myles .... For those of you who do not know who Bobby Vogel is, he knows tone.  He is a stellar player.  He is also the music director for Loretta Lynn.

Leonard Rodriguez
Not knowing alot about tubes I use JJ's in my HR Deluxe. I hope im making a good choice. 

Leonard - the JJ 6L6 is a nice robust 6L6. I find them more suited to harder rock than some other 6L6 tubes as they have a bit of an edge. Folks who have Mesa Recto amps and 5150 amps tend to like them.

If you want a smoother and more vintage tone try a duet of real Svetlana, winged C tubes biased at 60-62 mA using the Fender test point which sums the two tubes.

For the rock tone with your JJs you can bias a few mA higher, 64-66 is nice.

Leonard Rodriguez
Where can one get real svetlana's. Are these readily available?

Myles Rose
Yes ... here is a good link...

http://www.tubedepot.com/ is a good one as this initial post was written after Rob Hull from Tube Depot and I had a discussion.

I also like www.kcanostubes.com and www.dougstubes.com Just tell them you want "real winged C" tubes. There are tubes with the Svetlana name that are not the same tube which come from a different factory.
John Clark

Were you referring to the Ruby EL34B-STR tubes Myles? I read your review on your web page about them & you really seem to favor them. Also, do you think the Ruby EL34's are as good or superior to the Svetlana Winged C EL34's for a vintage hard rock sound?


The Ruby EL34B-STR is one of my two favorite EL34 tubes that are in production. You mentioned the both of them.

The Ruby that I love had been around a while and as good as it is, Tom McNeil added a second EL34 offering. The EL34BHT tu...be. This is a more robust tube and higher output tube than the EL34B-STR. Think of this as a rock tube for the 80s and later and the B-STR for the more vintage tones from the 60s-mid 70s. That is just my take on it and other folks may make different conclusions.

Life expectancy is very high on the BHT. Life on the B-STR is about 10% lower than the =C= (about 300 hours less when my rig is set to kill an EL-34 in 3000 hours). In either case life is very long and the BHT may end up being longer once I get them tested. When I life test tubes I run them until the plate current drops by 15% or until the tube fails.

Data on Ruby's tests indicate used 600 V on the plates, 540 V on G2 and a bias setting of –54V. The tubes idled at 25ma each. The power output from a pair of EL34BHT tubes using these voltages was 70 watts at clipping.

As a side note, no EL34 made today other than the BHT can take more than 450 on the screen (G2). Anything over 500 volts on the plates of other tubes made today is risky even though EL34 spec is 800 volts.

These BHT tubes meet spec from the past. Here is a Mullard and Telefunken set of links to the respective data sheets:



There are some new high end rock amps that now supply the Ruby EL34 as standard issue and folks love it.

The =C= Svetlana is also a winner. It sounds and traces like a Siemens EL34 from the golden era of tubes. The Ruby traces like a Mullard xf4. Each a touch different. No better no worse, total personal preference.

Bobby Vogel
Hi Myles, interesting stuff. Myles I still have several matched quad sets of the Sylvania 7581 6l6 tubes. What do you think of these? Thanks, Bobby

Myles Rose
Bobby - those are all outstanding. 6,000 plus hours general life if you push them very hard. They sound great, are ultra reliable and just terrific in every way.

The above comments are some of the comments.

2/10/11 addition:
Here is a question from today on a forum and my reply:


Without going into what I've been going through the last year both physically and mentally, let's just say I've missed some things I've tried to keep up the best I can. One thing I missed is what happened to GT after Fender bought it. I know you went to 65 Amps and a lot of other guys left, but what happened to GT? I still see their tubes at GC and Sam Ash; the web site is still up and seems to be active. I notice that my Delta's favorite tubes (GT KT88SV) are $198 a PAIR from Amazon.

So are the tubes still the same quality? Are they still made in the same plants? Did the EL34LS that I have in my KT-45 and SRZ go away?

I've been buying my tubes straight from Bob at Eurotubes. I was just curious what the fallout from the sale of GT was.

GT was sold to Fender 8/15/2008. GT tubes are now being rebranded at Fender. Most of the GT exclusive tubes are no longer in production.

Rick and Kathi are at 65 Amps. I have my own shop in the 65 Amps complex where I continue doing consulting for amp folks and try to keep touring acts on the road with technical help and training of their staff.

Tubes are made by the same plants for the most part but as I said, some are no longer being produced.

Quality has generally dropped which is indicated by my testing and what I see every week. Bottom line .... KNOW your vendor/tube supplier.

The E34LS was a GT exclusive tube and not the same as the JJ E34L regardless of what some profess. Look at the plate structure and the difference is visible where the plate pieces join, there are heat sink wings. Fender still shows the tube on their GT website.

As a side note, on the http://www.groovetubes.com/ website Fender still lists the SAG kits. This is amusing as this was my product and these kits were made by me on my own equipment. I never passed on my number system or how the balance of plate resistance, transconductance, plate current and true gain in circuit were put into my formula. These kits were a Guitar Amplifier Blueprinting development prior to my days at Groove Tubes. Groove Tubes had no right to sell my own intellectual property to Fender but I am not surprised as the line of folks where Aspen Pittman sold or took credit for the ideas of others as his own is a long line. At least I am in good company.

This is only a partial list from a screen shot of some of the "SAG" tubes that are noted on the scrolling page of the Fender website.  If some lawyer wants to sue Fender or Aspen feel free :-)

The matching system that Aspen sold to Fender was a great system in 1985 and earlier. Today it is out of date and quite inaccurate. There are devices out there today that match much more quickly and are far more accurate.

8/1/12 Update:

The other day a very cool fellow sent me a very nice donation to buy snacks for the folks on skid row.  He is a amp tech and tube fellow.

He was asking for a copy of the conversion chart I made for a few of my vendor friends back in 2008 when Groove Tubes was being sold to Fender.  

I explained that the information was long gone but some of the folks that may still have the info are Mike at KCA, Doug at Dougstubes, Antique Electric Supply and C.E. Distribution.

I decided to look around in my email and voila ... there is was from June of 2008.  I don't save old mail but I saved this.

#6 GT rating used to mean something but today the 10 ratings of the past have been further reduced to three, red... white ... and blue or high, medium, low.  I am not going to repeat what I have written in detail before (on my blog in detail) in regard to high or low ratings.  These are nothing more than tubes that were made improperly and have internal defects.  Do not use them.

A 5-6 rating generally met design spec.

The letter:


Her is something I wrote in the past that was sent to Noreen after NAMM last January.  I updated it a bit.  I put some more simple versions of this out on a forum or two.

Feel free to do what you wish with this info but I would not publish the data as I would not want to have this all over the place with multiple folks trying to sell tubes from the info, I would prefer to have one point of contact (you), that has this data.  You might want to grab parts out via a little editing for your own advantage in your organization.

The info is below ....



Tubes and rating numbers

Most tube vendors that sell matched output tubes usually have some sort of rating number or number of some sort on the tubes they sell.  In the case of Groove Tubes there is a 1 to 10 rating scale as an example.  In the case of other vendors there may be a number such as "44" or whatever.  In the case of a number such as 44, this really tells one very little as one generally does not know the plate voltage and bias voltage that the tube was subjected to for this number to be created.

In most cases this "44" number is probably mA of current output.  In some cases this could also be a transconductance number but current output is preferable to use as that is what one uses when one biases an amp.  As an example, a Fender 6L6 blackface amp likes the bias set to about 30mA.

If we go to the RCA Receiving Tube Manual and look up a 6L6 as an example, you will see that a tube that meets design spec will have a 72mA output at 250 plate volts and a -14.5 volt bias.  A number of "44" may be right on spec if the tube was tested at say 400 plate volts and a -48 volt bias as an example.  As I said before, those numbers that most people put on tube boxes mean little if we do not know the plate and bias voltages the tubes were tested at.  As a side note, if you want a copy of the RCA Receiving Tube Manual one great place to get one is at Antique Electric Supply ( www.tubesandmore.com )

There are many great amps from the past (and some current ones too) that do not have adjustable bias pot.  These amps worked great because tubes were consistent in the past and the amp designer knew what they were going to get from the tube maker.  Unfortunately this is not the case today.  Tubes are all over the place.  Tubes with low ratings or high ratings are not favored by me personally.  To me, these are tubes that are not within design spec.  There is something "wrong" with these tubes.  Grid spacing may be wrong or there may be other issues.  Just because you can adjust the bias to a proper level there is something still basically not right with the tube.  Bottom line here is; I prefer tubes that meet design spec.  Mesa Boogie selects tubes for their amps which fall into a narrow range as their amps have a fixed non-adjustable bias.  Many people have techs put adjustable bias pots in Mesa amps to use "any tube". 
My own Mesa amps are stock fixed bias even though it would take me a few minutes to install an adjustable bias pot.  I do not need one or want one.  I use tubes that fall within spec.

Below are a few little tables that may help with trying to figure out what numbers, ratings, colors or whatever you have or want.

A number of my favorite tube vendors use the Maxi Matcher to match output tubes.  This is a great device which is very accurate.  It can match within .1 milliamps or 1/10 of a milliamp.  A tube within 20% is considered an industrial match and within 10% a very good match.  In the case of a 6L6 in most amps that means that two tubes within 3mA of each other is darn good.  Output tubes that are over 20% difference may exhibit lower power, shorter tube life as they are fighting each other, loss of sustain and articulation and background hum.

The numbers I have in the maxi-matcher table are the numbers I prefer myself.
In the case of cathode biased EL84 amps these are also the numbers I use and a cathode biased amp with high numbers will do little more than run hot, sound harsh and generate a lot more heat. 

Maxi-Matcher to GT #6  (maxi-matcher settings)
6L6   20-25             400 / -48V
EL34  30-35             400 / -36v
6550  35-40             400 / -48v
KT88  38-40             400 / -48v
EL84  30-35             325 / -12V
6V6   28-32             400 / -36v

The above numbers are the plate current display numberrange that would correspond to a mid range (proper designspec) tube.  In this case a #6 GT rating was used to establish these numbers and the GT rating was verifiedby using published tube design data (from the RCA tubedata sheets).  As an example, a 6L6 spec tube would have been tested at 250 plate volts, 250 screen volts and -14.5vbias with a design target of 72mA plate current output asthe design expectation.  This tube on the maxi-matcher wouldhave a plate current readout of 20-22mA and would be a proper spec tube.

Mesa Boogie color scale to GT rating:
Red Orange   4
Green Gray   5
Blue White   6

Fender color scale to GT rating:
Blue      1-3 GT
White    4-7 GT
Red       8-10 GT

There are many original tube data sheets available on mywebsite at http://www.guitaramplifierblueprinting.com/datasheets.html

My preferred vendor for new tubes is Antique Electric Supply (for retail sales but they discount quite nicely) and C.E. Distribution for wholesale sales.  You can reach them both by calling  480.820.5411 (AES) or 480.755.4712 (CE).When you call ask for Steve Martin.  He is the one that understands howto make the proper conversions from one tube rating system to another andif there is any issue or question he is the one I will work with directly.

www.tubesandmore.com and www.cedist.com are their two websites.

Myles S. Rose

I copied the below piece from an area of my own Guitar Amplifier Blueprinting website:


Updated 8/5/05

We currently estimate that the demand for audio tubes is growing 10% to 20% per year. Audio tubes are over a $200+ million  dollar industry in the USA and possibly $500+ million dollars worldwide.

Note: this list shows all the small glass audio tubes believed in production at this time.(not counting exotic devices, such as photomultipliers and microwave devices)


Reflector Corp, Saratov
Makes most of the tubes marketed by New Sensor Co. of New York under the "Sovtek" brand name. Some of these are old Russian types, others are made especially for export. Types in production: 2A3, 300B, 12AX7 (3 variations known), EL34 (3 versions), 6CA7 fat, 5AR4, 5881, 6922, 6EU7, 6L6GB, 6V6GT, 6072A, 6973, 7199, 7591, 7868, EL84 (2 versions), KT66, KT88, KT90, 6P15P. "Sovtek" also markets 5U4G, 5Y3GT, 6SN7, 6SL7, three 12AX7s and a few other types made at other factories.

Note: there is no "Sovtek" factory. "Sovtek" is only an American brand name owned by New Sensor. New Sensor now owns the Svetlana brand name and is using on tubes manufactured by Reflector. The Electro Harmonix tube are also made by this plant. In 2005 New Sensor bought the names of Mullard and Tung-Sol and are placing these names on tubes of their New Sensor banner.

Ryazan Plant of Electronics, Ryazan
Makes power triodes for RF and audio applications. Some are sold outside Russia by Svetlana Electron Devices. Ryazan has also made large thyratrons and pulse tubes. Types in production: 811A (popular and sold all over the world), 812A, SV811-3, SV811-10, SV572-3, SV572-10, SV572-30, SV572-160, GM-100, others. SV types and 812A are made especially for Svetlana Electron Devices.

SED Winged C, St. Petersburg
A major Russian power-tube manufacturer. Formerly a part of the huge Svetlana collective factory, now independent. SED tubes are now distributed in North America and Europe by PM Components. Types in production: EL34, SV6L6GC, SV6550C, 300B, EL509, EF86, 6BM8, 6AS7, 3CX300A1, 6D22S, GP-5, and a long list of large power types for amateur radio, broadcast and industrial uses. KT88 and 12AX7 are have been recently introduced.

Ulyanov, Ulyanovsk
Large state-owned factory specializes in military equipment. Also makes tubes for use in military aircraft electronics. Types in production: GU-50, GU-13/813, 6S33S-V, 6S19P, 6S41P, others. 6S33 is becoming popular in high-end amplifiers in America and Japan.

Voskhod, Kaluga
Large collective factory, makes many ICs and other semiconductors as well as receiving tubes. Types in production: 6N1P-EV, 6AX7, 12AX7WA and WB, 6SN7, 6SL7 and a few other types sold by various firms outside Russia, such as New Sensor/"Sovtek" and Svetlana Electron Devices.


Shuguang Electrical Factory No. 1
Owned by Korean firm Samsung. Shuguang makes most of the popular audio and guitar types, which are frequently rebranded by importers and OEMs. Types believed in production: 6L6GC, EL34 (3 types), 6550, KT100, 5AR4, 2A3, 807. Possibly 211, 845--unconfirmed. Shuguang's low-cost tubes are often seen in guitar amps. (Thanks to Chris Beeching for info.)

Makes many types which are marketed abroad. PM Components, a British firm, has "Golden Dragon" types made by Liuzhou. (Thanks to Chris Beeching for info.)

O&J Enterprises/Valve Art
Makes the following: 6L6GC, EL34, 6550A, KT88, KT100, 300B, 300B-C60 (graphite plate 60w), 5300B (graphite plate 80w 150mA), and 6300B (graphite plate 80w 180mA), plus possibly other types, at a factory in Changsha, Hunan. (Thanks to Wilfred ter Borg for type list.)

"Sino" factory in Beijing recently stopped making 12AX7, 12AT7, 12AU7, 6GH8, 6AN8 and other small tubes, due to a poor market and tough competition from Sovtek/New Sensor. It is said that Sino made the popular, low-cost 211s and 845s often seen in SE amplifiers; this cannot be confirmed. Sino is apparently no longer making any tubes. There are other tube factories in China. Most keep a very low profile. Some of these lesser-known factories specialize in transmitting tubes such as the 811A, 812A, 813, 3-500Z,4-400, 100TH, 833 and others. Such transmitting types are often branded with old American/European brands and sold without notification that they are Chinese-made, as are the audio types.


JJ Electronic, Cadca, Slovakia
A spinoff from now-defunct state factory Tesla factory. Outside of Slovakia, JJ tubes are often sold under the Teslovak or Tesla brandname. Groove tubes is a major distributor. Types in production: GZ34, KT88S, EL34, E34L, ECC803S, ECC83/12AX7, EL84, 2A3, 6L6GC, 6V6GTS, 300B, 7027A, 7591S. Some of the power pentode types are available in red or blue glass.

AVVT, Prague, Czech Republic
Run by former Vaic Valve Co. founder Alesa Vaic. Manufatures audio power triodes for high-end hi-fi amplifiers. Types in production: AV300B SL, AV32B SL, AV62B SL, and others.

KR Enterprise, Prague, Czech Republic
Formerly Vaic Valve Co, now operated by Riccardo and Eunice Kron. Manufactures power triodes for high-end audio amplifiers. Types in production: VV30B, VV300B, VV52B, KR1, a single-plate 2A3 and other types.


EI Electronic Industries, Nis, Serbia
Former state-owned factory, makes all types of electrical products, still making tubes using some old Philips production tooling and equipment. Marketed outside of Serbia by Edicron Electronic Components Ltd, UK. Types in production: 6CA7, 6CG7, 12AT7, 12AX7, 12BH7, 12DW7, EL34, EL519, PL519, KT90, KT99, EL84, EL86, possibly a few others. Latest reports indicate that the EI factory was not destroyed in the 1999 Kosovo conflict by NATO missles. (as early 2011 I still do not know if this factory is back in operation.  Myles)


Poljaron, Lvov
Makes 833A and some Russian power types, plus related products such as vacuum capacitors.


Richardson Electronics, LaFox, IL
Makes a 300B, 845 and 50 sold under the Cetron brand for high-end audio, as well as a KT88 sold under the National brand.

Richardson has large quantities of tooling obtained from old American tube factories when they shut down. Also makes some larger transmitting and high-voltage types. Richardson markets many tubes, obtained from other factories worldwide, under their own brandnames; such as Cetron, National and Amperex.

Westrex Corporation, Kansas City, MO
Makes the reissued Western Electric 300B for high-end audio. Claims to be developing a KT88, WE308, WE274A and other old WE types for future manufacture. Corporate and sales offices are located in Atlanta and Chattanooga. Also has sales office in UK. Tube manufacturing facility was relocated from Kansas City to Huntsville, AL. This firm is independent of AT&T Corporation and has licensed the brandnames from AT&T.

MU, Oceanside, CA
Small contract factory, makes occasional runs of unusual glass and metal-ceramic tubes for military use. Still makes some of the old "Bendix Red Bank" tubes, such as the 6094 and 6384, in occasional lots.

Triton Services ETD, Gaithersburg, MD
Makes some Eimac and Litton glass power types, using equipment from the original manufacturers. Recently discontinued some glass types, such as 4-65A, 4-125A, 250TH, 304TH/TL, etc. (these types are now only available from China).

Great Tube Makers of the past - This information is from Vintage Tube Services. They have a great website at http://www.vintagetubeservices.com/

Located at 79 Washington Street in Brooklyn, New York, Amperex was a long established manufacturer of transmitting tubes when they were acquired by the giant Dutch firm, Phillips in 1955 or so. Phillips continued to improve and enlarge the transmitting plant in New York, but also used the Amperex name to distribute their fine new line of Dutch made minis, (12AX7, 12AU7, 12AT7) to feed the booming U.S. Hi-Fi market. These sweet & airy, but still full and solid sounding tubes have been the favorite of music lovers for 45 years! Classic Hi-fi brands such as Marantz, Fisher, Scott, etc... owe a large part of their great sound to these tubes. In the line up of the three sisters, the three European sisters that is, the Amperex is like the fair-haired Dutch blond. The Telefunken is the tall, well built, sandy haired blond in the family, and the Mullard is the ravishing black haired, British brunette. These are of course just slight "hues" in the perspective that these tubes present, as they are really all extremely transparent units. And of course we can't forget the 6DJ8, 6922 & 7308 frame grid tubes. Developed by Amperex in 1958 when transistors were already starting to take over the electronics industry & originally developed for video & radar use, the 6DJ8 has come into heavy use in audio over the last 15 years. And Amperex definitely made some great ones like the
Original "Bugle Boy" series with it's seemingly, magical ability to filter out noise like the Mullards do, and the later, map versions with their full, balanced sound, black background, and great sound staging.

Telefunken of West Germany, founded in 1903 is the standard bearer of tonal neutrality in the 12AX7, 12AU7, 12AT7 series of tubes. These tubes are (along with the other European four) THE "Start of The Art" in miniature tubes, long prized, and now rare and expensive, dropping a couple of these under the hood of your pre-amp or power-amp can show just how bad today's 9 pin minis really are! They also made a good 6DJ8, 6922 & 7308 though the real ones are quite rare. Note; This does not apply to East German E88CC & other 6 volt mini's that were made behind the Iron curtain during the cold war years and many are sold by others, as the real thing, at top dollar. These tubes sound dark and hard, and are very sub-standard. They have been flooding the market ever since the Berlin wall came down. V.T.S. I has identified these tubes and you will never have to worry about ending up with these. There is more on these makers with photos and old artwork at http://www.vintagetubeservices.com/  which is where this vintage tube information came from.

Mullard was founded by Captain S.R. Mullard in 1920 and was from the beginning one of the finest tube manufacturers in the world. Mullard tubes have a rich, warm, presentation that still supplies all of the detail and information that any "state of the art" tube does but with a suave European flavor that is perfect for many of today's more forward systems. The EL34, EL37, & Mini tubes 6DJ8, 12AX7, 12AU7, etc are some of the longest - lasting, toughest, finest sounding tubes ever made! Mullard is one of the few tubes that have the almost magical ability to separate the noise from the music, and the ability to present the two in different places on the soundstage. This is something that transistors never do! Mullard did go into a gradual slide, correlating to general "efficiency & modernizing" starting on the late 60s and got pretty bad by the late 70s. It was all over by 1981. There also seems to be a good number of tubes coming to the surface that seem to be made by someone else, but on the same machinery that are completely sub-standard. They seem to be from the early 80s. The "other guys" sell these as the real stuff and YOU suffer.

Myles:  in 2008-2009 a group of folks tried to bring the old Mullard plant back into operation.  They had a few new design tube offerings that looked very promising but could not get the funding to continue.

M & O
Marconi - Osram later known as M&O Valve was founded in 1919 by the joining of the Marconi Wireless Telegraph Co., and The Edison General Electric Co. (Osram). This formed, what was at the time one of the largest pools of electron tube making experience in Great Britain. They continued making fine radio tubes, mostly for use in Europe until the Post WW-2 Hi-Fi boom hit in the 1950s and audio began to be big business. Big beam-power & pentode business like the 6L6 by R.C.A. and Tung-Sol's 6550 in the U.S. and the EL-34 in Europe. Well M&O was not one to be left behind, so they sat down and carefully designed three, direct drop-in competitors for all three of the new high-power audio outputs. These were of course the KT-66 for the R.C.A. 6L6, the KT-77 for the EL-34, and the KT-88 to compete with Tung-Sols 6550. These tubes are some of the most suave, rich, classy pentodes ever made period. They have the real-thing greatness that is so rare these days. It has offended me for 14 years that the Chinese, Russians and their American distributors have had the audacity to put the designation KT-66, 77, & 88 on any and all of the JUNK that came down the pike! And, by how many members of the U.S. audiophile press were and still are to this day, standing in line to glorify the emperor's new clothes. For the entire first half of this century, the very finest minds in the world were applied to making these tubes, starting with Thomas Edison. To give you an example of what goes onto the making of these tubes let me relate an event that happened a couple of years ago. I had a visitor from Germany who is a super sharp chemist and hangs out with the aristocrat types in Europe. He is a member of the Royal Academy of Science but doesn't know, or care much, about tubes or audio. So, he is sitting in my living room having coffee and he looks down at some tubes lying around and launches off about how one of his elderly friends at the Royal Academy used to be one of the chief chemists at M & O. They used to talk about corporate culture, trade secrets and how closely guarded many of the chemical & metallurgical processes were, as they had been worked out over the proceeding half-century. He mentioned that the old guard, Edison & Marconi, (and the next generation after) set the example of guarding important formulas & processes because of the patent wars they had fought all their lives. Even at that, he said with all of the equipment in front of you and everything running well, that the ticklish nature of making the finest tubes (inconsistencies in raw materials etc.) is more like cooking than anything else and they knew that someone without their experience could never make tubes quite the same.

Well all I can say is that these guys had it because it is now 1999 and damn near of all of the hundreds of real KT-88s, 77s & 66s I have distributed over the last 6 years are still making sweet music for their purchasers! This includes 20 KT-88s that run in a pair of Jadis JA-200s that were tubed up in 1995. Not only have they not missed a single beat but they still all measure and look almost NEW! I have had my own personal set of 4 for 16 years and they are still perfect. M & O made these tubes from 1957 until 1976 or so and then re-introduced them in 1982. Unfortunately these later ones were, of course, not up to the previous production quality, and it was all over for good in 1988.

Siemens & Halske was a quality German tube manufacturer from way back. They made an excellent 12 volt series of tubes (12AX7, etc.) but nothing that special. However those of us that go back 20 or 30 years with the 6DJ8 know that when it comes to frame grid tubes (6DJ8, 6922, 7308), Siemens really shines and has always been one of the very best. This is not surprising, as that part of the world (Germany & Holland) produces some of the world's finest machinists. And that is what you need because the 6DJ8 tube uses a very tightly strung tungsten grid wire that is 0.00029 inches in diameter! This is the smallest tungsten wire that can be drawn consistently and is not even visible to the eye without a close look! But this was not new to Siemens as they had been experimenting and producing a tube, which was a predecessor to the frame grid back in 1926, it was the OCK tube, developed for undersea cable amplifiers. Well, what does all this experience and intrinsic skill give your music? A very quiet, smooth and neutral tube that has as much or more mid and high end detail as anything else ever made. The Siemens are particularly good at being free from noise & mic. and staying that way for a good long time. (I am talking about early production, not the mid- and late- 70s stuff) The only problem I have ever heard voiced about a Siemens 6-volt tubes would be in a system that was already too far on the light side and really needed a richer tube.

Centered in Harrison New Jersey on the sight of Thomas Edison's original lamp works and not too far from Menlo Park where his "invention factory" started it all, R.C.A was the backbone of the receiving tube industry in the U.S. R.C.A. was a very well run corporation from the beginning, and was in many ways the cornerstone for tube manufacturing worldwide. I say this because they developed and (if by no other means than sheer volume), standardized most of the basing system worldwide.

Consistency is an R.C.A. herald and this consistency showed in their tubes all the way from the 1920s to the 1970s! R.C.A. tubes have an accuracy that is never hard, just accurate! Tonally the mini's, 12AX7, etc. seem to be just a hair on the softer side of a Telefunken if you could give them any kind of label at all. The power tubes from the 6L6 to the 845 also have this broad balance from top to bottom with all the natural detail and sweetness of the real thing. R.C.A. never tooled up for the 6DJ8 so any such tube labeled as such was made by someone else. Unfortunately the entire R.C.A. receiving tube division was liquidated in a 12 day auction during the fall of 1976, this basically broke the back of the tube manufacturing industry (and the supporting industries) in the U.S.A.

Western Electric
The mother of all Electronics Companies. Western Electric always did a pretty good job of documenting it's activities, & here we see the setting of the stage upon which some of the finest electron tubes ever to be made would appear. By it's 50th anniversary (1919), Western Electric had already been making telephone repeater tubes for 5 years. 1919 was also the year the first large-scale public address system utilizing tube amplification was demonstrated. (Peter Jensen was also doing systems but at a much smaller scale.) The event was New York's "Victory Day" celebration after WW-1. This system used 113 loudspeakers and approximately 66 tubes! Eighty-five years later thousands of Western Electric tubes & speakers still make beautiful music.

Tung-Sol was an old hand at electron tubes and such. Starting in 1907 they developed the first successful electric headlamp for cars, they followed that in 1913 with the two filament high and low beam headlight in a single bulb. They also developed the flashing turn signal, and made that little thing that goes click, click under the dashboard for almost every American car until the 1970's, yes, we all grew up listening to Tung-Sol. In the 1920's they entered the electronics field and applied their basic company policy "make the best that can be made." They were leaders along with R.C.A. in the development of sophisticated, statistical quality control systems and one of the greatest qualities of Tung-Sol tubes to this day is consistancy!

Tung-Sol's greatest contribution to the world of audio was the 6550, conceived and developed for Hi-Fi and introduced in 1955 this tube is still powering many of the world's greatest sound systems 45 years later! Tung-Sol was a privately held company and was run like a laboratory this gave T-S tubes some of the best metallurgy and chemistry that has ever been pulled off in actual production. Tough as nails and as sweet as tupelo honey, all Tung-Sol tubes are as accurate, neutral and dynamic as you could ask for, very much like a Telefunken which is what they remind me of.

Sylvania electronics of Emporium, Pennsylvania was the second largest receiving tube manufacturer and R.C.A's arch rival. As with most of the "New Jersey" bunch, Sylvania got its start in the light bulb business. Yes it was the light bulb manufacturers who had the skills and experience in glasswork, metallurgy & high vacuum that are needed to make a fine tube. Like the rest of the NJ bunch, Sylvania sought out and retained the most skilled men and women available, including former Edison employees. They also lured away R.C.A.'s chief tube engineer of seven years, Roger T. Wise in 1927. This was a real jewel in Sylvania's crown, and was reportedly announced with much fanfare. It's hard to say why he did it for sure, but he moved out to Emporium and built a beautiful house 5 months before he took up his post at Sylvania which makes me think that part of the reason for the change was he just wanted to get out of the smoke and clatter of NJ to start his new family. He was having his first child and Sylvania's tube plant was nestled in the beautiful, wooded, rolling hills outside Emporium, PA, a point they stressed in their recruiting efforts. Another one of Sylvania's main philosophies was to start with the highest quality materials possible, and they were very good at it. They were so good that by 1948, they were the largest supplier of getters, wire and other internal tube components in the industry. Their getters were so good that most major tube manufacturers in America used them and their wire was good enough to be used extensively in Western Electric tubes! This emphasis on material and employees showed in the final product to. Even to the casual observer, Sylvania tubes manufactured during the golden years (1920's-1950's) simply exude an intrinsic beauty with their large, sweeping, mirror-finish getters and often, optical-quality micas. In certain tube types, the early Sylvania simply blows away everything else. Unfortunately, good things often don't last and Sylvania was one of those. The tooling held out pretty good up until the late 70's maybe even the 80's but the chemistry and intrinsic quality of the entire package went to hell in the late 50's. Of course, some 96 percent or so of what is out there for sale today is the horrid sounding mil. spec. Phillips branded stuff from the 70's and 80's but you won't have to worry about that here.

Myles:  Unfortunately there is no information in this piece on Raytheon who made my favorite 12AX7.  This information on the vintage companies cane from Vintage Tube Services. There is MUCH more information, great photos, old advertisements and lots of great things at http://www.vintagetubeservices.com/

- the end-

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