Preamp Tubes? - Who, What, When, Where, Why, and How?

[MartyStrat54]

Hello!!! Are you new to the thread? Here is a primo four pack of 12AX7's. These would make any tube amp sing.

V1-Amperex
V2-Raytheon Black Plate
V3-Sylvania Gray Plate
V4-Sylvania Gray Plate

Super picture by RACKO!

 

[solarburn]

I like that you guys are posting pics now. Helps getting to know them for everyone.

 

[solarburn]

Here you go Alan. Another country of manufacture. These are copies of the Sylvania Fat Boys. Made in South Korea for the U.S. Military. Era approximately 1982.

South Korean 6CA7's The Sylvania's have three round holes on the plate.

I shed a tear...

Cause they're real.

Now that's a fatty!

 

[MartyStrat54]

I'd like to have about eight of them. I'll bet they were very well made. They had to be...they were MIL SPEC tubes.

 

[racko7566]

Sorry for the jumbo pic, I have to figure out how to size them right. Guess I got a little exited.

 

[solarburn]

Sorry for the jumbo pic, I have to figure out how to size them right. Guess I got a little exited.

That's a good pic. Can see everything...

Off to work now. Have a good one guyz!

 

[racko7566]

Don't work too hard solarburnDSL50.

 

[RiverRatt]

What tubes had pinched or seamed tops other than Mullards?

 

[MartyStrat54]

What tubes had pinched or seamed tops other than Mullards?

Well as I said in other areas of this thread, you have to look at Philips. Philips was the giant towering over everyone else...European or US. Philips had financial interests in just about every tube company. Philips actually bought Amperex in 1955 so they could sell their new line of small signal tubes such as the ECC81, 82 and 83 in the US market. Philips also had a huge share in Mullard. Remember, Philips bought Sylvania in 1984 and the company became Philips ECG. It produced tubes until 1988. The last giant standing.

Amperex and all of the tubes produced under Philips has a pinched top. Now the pinch isn't as coarse as what is on a Mullard, but it is still there. Apparently their technique was a little better than Mullard.

Here is a Canadian Philips/Amperex relabeled as Electrohome. This was a very popular brand in Canada and if you come across any, buy them. Make sure that they have the pinched top.

In the first shot, I tried to get the "pinch" in focus. The pinch is located at a 2 and 8 o'clock position. You can see a white reflection near the 8 o'clock position. Anyway, all Philips, Amperex, MiniWatt, Valvo, POPE, etc. are all made the same.

In the top picture, you can see the pinch at about 2 o'colock. The yellow tip denotes the tube underwent special testing for medical equipment use.

 

[MartyStrat54]

Here is a page I stumbled across. I love finding stuff like this, because I am a knowledge buff in regards to tubes. What I liked was the Sylvania story. They actually made the best tubes until the early 60's. Their equipment lasted until the 70's, but they had lost the "magic" to make the best tubes. Basically, they say the later stuff (Philips era of ECG tubes) were junk. I'll take that to heart. I have told you that some of the ECG military tubes sound just awful. They are rugged and last forever, but they have no soul.

History of Tube Companies

 

[MartyStrat54]

Here is my latest acquisition from EBAY. A real pair of high test, double getter Philips 6CA7's. I got them for about one third of what the online stores want for tubes like this. $104.

Pair of Philips 6CA7/EL34 Vacuum Tubes - NR - eBay (item 140351951821 end time Oct-19-09 11:35:48 PDT)

Click on the "Enlarge" under the picture to see them in all of their glory.

 

[solarburn]

Here is my latest acquisition from EBAY. A real pair of high test, double getter Philips 6CA7's. I got them for about one third of what the online stores want for tubes like this. $104.

Pair of Philips 6CA7/EL34 Vacuum Tubes - NR - eBay (item 140351951821 end time Oct-19-09 11:35:48 PDT)

Click on the "Enlarge" under the picture to see them in all of their glory.

Well you know I'm chomp'n on the bits to hear how these sound.

Much better price than those stores...

Oh shit those 6CA7EH's are loud! They make lead 2 sound pretty damn good. Usually I don't play on lead 2 but these tubes make it sound raw and fat in a good way. In a naughty way. This is the second day of cranking them and I just got done. I like it without a boost too. Just a slight boost is ok. Any more and it diminishes the great lows coming through. Actually after this last session I'm liking them more. I haven't spent any time on lead 1 yet so I can't comment there. The Clean & Crunch is very warm and fat. So for blues and rock they are delivering some fat raw tones. The women tones are pure sex.

Alright I gotta hit the hay now.

 

[solarburn]

Here is a page I stumbled across. I love finding stuff like this, because I am a knowledge buff in regards to tubes. What I liked was the Sylvania story. They actually made the best tubes until the early 60's. Their equipment lasted until the 70's, but they had lost the "magic" to make the best tubes. Basically, they say the later stuff (Philips era of ECG tubes) were junk. I'll take that to heart. I have told you that some of the ECG military tubes sound just awful. They are rugged and last forever, but they have no soul.

History of Tube Companies

This is cool.

 

[MartyStrat54]

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.

Just doing a lot of reading and it blows my mind that solid state devices had overwhelmed the tube companies since the early 50's. They knew well in advance that tubes would be history. Based on what I have said before, RCA crumbled well before several other giants. When RCA folded, it destroyed the foundation of the remaining tube companies. Like Philips/Sylvania, a few made it to 1988. That seems to be the final year of production for USA tube companies. 1989 was a dead year and that's when everyone was looking at RFT and Tesla. Damn good tubes, maybe not as good as some, but still above average. Solid state amps were not going to hit this part of the world for some time and tube production flourished. I was sad to see RFT, Tesla, Tungsram and Ei fail. If these four companies could have remained, they would be blowing the Russian and Chinese tubes out of the water. We would have decent, good working tubes. One's that would be safe to use in the power section. These were some of the last giants to fall. Some made it as far as 2003.

 

[thefyn]

I'm open for opinions on current production pres for the 3 pre slots on my 50 watt JCM800.

 

[racko7566]

Do you think with the rising demand for quality tubes that some small american companies might consider making tubes? Not super mass produced, but more like a specialty product.

 

[MartyStrat54]

Here's some codes for you tube hounds. They were talking about an FB code on a Mazda tube. I don't know what FB code is...perhaps it
could be related to the Mazda stuff such as date or lot codes.

KB = tube factory

D = Mullard

DA = Mullard but in different location

FE = STC (Standard Telephone and Cables)

Z = M.O.V

DA = Brimar

In the early 1960's STC spun off Brimar to "Thorn-AEI Radio Valves and
Tubes LTD." The history gets a bit complex.

This company made tubes under the Mazda and Brimar names, as well as
Ediswan. FYI, Mazda was a British company for those who don't know, and
in the 1920's Ediswan and Mazda were major makers of radio tubes.
Ediswan being the world's first radio tube maker (A joint effort started
in 1883 by Edison Eletric Light Co and Swan Electric Lighting Co.)

All of the tube makers, all of them, started out as light bulb companies.


Many of Mazda's later tubes were made in French factories and are
excellent. I have some of the 6V6GT's someone mentioned, and they are
very nice sounding, and extremely durable. They are early production
made for the war dept labeled "services plublic guerre". Guerre meaning
war in French.


In fact one of the earliest 12ax7's I've ever seen was a Mazda made in
France. It has the exact same plate as the first Amperex 12ax7 (I'm
talking before Bugle Boy). This Amperex tube is very rare and may not
have even been made in Holland, though the label says it was. The
getter ring of the Mazda is unmistakably Telefunken. It's very nice.

Mazda 6V6's are probably French, or at least I've heard of French
Mazda 6V6-GT. I did miss British maker, there were Cossor 6V6-G, too,
made in UK, and Cossor did use at least some US numbers, eg: I have
a Cossor 6J5-G here. BTW, the price was 7 bob & sixpence, plus
1 bob & 8d PT, for a total of 9s/2d. Out of a guinea you'd have
recieved 11/10 in change. Got that?

Don't quote me, but I believe Mazda is another head of the
Philips hydra, there was British Mazda, French Mazda, plus
another Belgian cousin, Adzam, which is Mazda spelled
backwards.


I'd bet FIVRE in Italy and Neotron in France made
6V6-G, too. Just to confuse matters further.
ADZAM did make 6SQ7-GT, so I'd bet they made
(or sold) 6V6-G or GT, also.

More INFO on the big headed HYDRA...Philips. Man, they owned everybody.

Tube Questions FAQ

 

[RiverRatt]

Here's some codes for you tube hounds. They were talking about an FB code on a Mazda tube. I don't know what FB code is...perhaps it
could be related to the Mazda stuff such as date or lot codes.

According to the Philips book I posted a few pages ago, it most likely stands for:
F = La Radiotechnique, Suresnes
B = February

If you don't have the book (you probably do), it's a great source for factory and type codes.

http://www.audiotubes.com/PhilipsCodeList.pdf

 

[MartyStrat54]

According to the Philips book I posted a few pages ago, it most likely stands for:
F = La Radiotechnique, Suresnes
B = February

If you don't have the book (you probably do), it's a great source for factory and type codes.

http://www.audiotubes.com/PhilipsCodeList.pdf

The one I have is an actual printed copy. I don't know where to look for it though. It was unrevised and didn't have the revision numbers crossed out. It's around here somewhere.

The thing that's blowing my mind is that Philips owned Mullard and Amperex and a whole lot of other tube companies. I did some reading and before Philips bailed out, they were getting a lot of their tubes from Japan. Also, when they sold the rights to Mullard, Tung-Sol and Amperex, they turned around and bought out Sylvania and part of GE. This was the Philips ECG brand. As I said, they were all toast by 1988. The Multi-Headed Hydra was slain. Like they said in one of those articles, most Amperex made in Holland were MiniWatt tubes. The one's made in German were Valvo. Then they had their hands in Mullard, Brimar, Mazda and many others. Where did you say that Amperex tube was made? It could say, Made In Holland," but it could have been made in Japan.

Rule of thumb. Always try to buy tubes prior to 1966. The hanky-panky all started after that. That's why I prefer White Label RCA's over Red Label. With the White Label, you can assure yourself that they were made in the USA. I like the Red Labels, but the country of origin can be misleading.

Even an Amperex Bugle Boy is still a Philips tube, that was probably made at the MiniWatt plant.

Oh I need to add this. Avoid ECG preamp tubes. They were made on worn out Sylvania equipment and they are a poor USA tube. The ECG power tubes, like 6550's, 6L6GC's and 6CA7's are okay, not as good as a 60's model, but could still take high plate voltage.

 

[RiverRatt]

I found a strange little tube in a box of TV tubes I left in the garage at some time. It's a 3HA5 labeled NEC (MIJ). It's got flat-sided mica like the RCA 12AU7A tubes. Here it is next to a 12AX7 for comparison. I told my wife that if I could find another one, they'd make a nice pair of earrings. She wasn't impressed.