[izquierdaste]

Hello,

I just bought some 6dj8 tubes to try in my morgan jones amp. They are branded rca and amperex, but there seems to be a lot of variation in what I got, so I thought that I would see if anyone can help me identify these. The first set has the amperex orange globe label, but does not have the normal Dutch-plant identification label, like my other dutch-made 6dj8s that I have. It does have the seams on the top of the tube coming out from the nipple. Unlike most other Amperex 6dj8s, it does not have any shield over the second plate. Instead, it just has the halo getter. I also notice that silver top goes farther down the glass than most of my other amperexes with factory codes. Otherwise, the tubes seem to be about the same size as the dutch code amperex that I have. They also have the pointed top and bottom plates and a similar rather intricate grouping of ridges on the top plate. (Interestingly, I also received an RCA branded tube that looks almost identical to the non-factory-coded orange glodes. It also labeled as Made in Holland). Some pictures of these non-factory coded orange globes next to a coded bugel boy and a coded orange globe are shown here:

http://www.unc.edu/~bmaskery/amperex6dj8.htm

Next up, I have some rca 6dj8s that are labeled made in the UK. These also do not have any plant information, but are dated 8104. These tubes look much different than the amperex. They are shorter and fatter. They have round (not pointed) plates on top and bottom. Instead of a halo getter, there is some sort of disk getter. There is also no shield and the series of ridges on the top plate are less intricate relative to Dutch-coded Amperex. Finally, there are no ridges on top of the tube. I am guessing this might be a Russian tube? Here are some pictures next to the Holland tubes.


http://www.unc.edu/~bmaskery/rcauk6dj8.htm

Finally, I have some supposed Amperex 6922 that came with the amp. These tubes also have the orange globe logo and are labeled Made in W. Germany (white lettering). These tubes have chrome pins (not steel or gold) and the printing is much stonger than my NOS amperex. There is no factory code etched on the bottom. There are, however, 4 seems protruding from the nipple. In addition, the shield over the top plate is smooth (rather than the Bugel Boys which have two ridges on the shield. The getter is a halo over the shield. The top and bottom plates are rounded instead or pointy like the bugel boys. In addition, there is a number impressed into a piece of metal on the inside of the tube. I have heard this might be a Siemans code, which would match the W. Germany label, but I don't think Siemans made 6922s without gold pins. There is also a number (2) embossed in the glass on the bottom of the tube in the middle of the pins. In addition, this tube seems to be slightly taller than the bugel boys. Here are some pictures.

http://www.unc.edu/~bmaskery/amperex6922.htm


As for sound, I just got the non-factory code 6dj8s. They sound somewhat similar to bugel boys with a nice smooth tubey sound. I quite like them, even if they aren't from the Heerlen plant. Maybe they were builty with Heerlen machinery that was sold after closure? in Japan, E. Europe? Anyway they are pretty good. The W. Germany 6922s aren't as engaging or enjoyable to me as the Heerlen tubes. They are much better than some generic Chinese tubes that also came with the amp. I haven't tried the UK RCAs yet. Anyways, I was just curious if you know where some of these tubes were actually made. Thanks for looking.

 

[jamato8]

The short fatter 6DJ8's are made in Russia. I have a bunch of them and they are great, at least he ones I have. I bought all the company had as the price was right and frankly, since I have about all the different Amperex and so on, they are right up there at the top of the heap in all areas of sound. I like them better than most of the Bugle boys I have. They also hold up very well. I haven't looked at the other tubes as I don't have time right now though the shiny steel pins, that are normally slightly smaller in diameter are Russian.

 

[izquierdaste]

Thanks for taking a look. I am pretty sure the short, fat RCA tubess are 6n23p's, because they look just like pictures I've seen. What is funny is that I bought a quad of 6n23p (Vokshod plant) that haven't arrived yet and I think that the date codes are the same 4/81. It will be interesting to hear if the rca sound different than the 6n23p. Do you know which factory your russian tubes are from? My future 6n23p's will have the rocket logo.

One thing I forgot to mention in my previous message. My RCA "made in Holland" (no factory code) does have a date code of 7339. Also, the same paint seems to have been used for the amperex and the rca logos for all the "made in holland" tubes. However the RCA just says Holland in white letters, while the Amperex tubes say Made in Holland in orange letters. The Russian (or U.K. if you believe the label) rca's have a different font logo and different color paint. I don't think these are counterfit, because they look old and I can't imagine there is a lot of profit to be made from fake orange globe 6dj8s, but I wonder why they are labeled Made in Holland, but have no factory codes.

 

[izquierdaste]

Since I like to talk to myself in threads, I thought I'd let you all know that I am pretty sure that the mysterious made in holland orange globes without shields are actually made by matsu****a in Japan with old Mullard tooling. Apparently, they were commisioned by Philips to produce OEM tubes in the 70s, based on my reading over at audio asylum. I think these tubes are quite nice.

The W. Germany 6922s are still a bit of a mystery though.

 

[jamato8]

Yes when the older tooling from Mullard was purchased in Japan they made some fine tubes. With the ribbing on top it led to confusion for a while and it was made all the more confusing when Japan stamped made in Holland on the tubes. They went for very hard vaccuums and they often made very good tubes. I have some EL34's that are made by a company in Japan but not the typical type. I got them used with many hours of hard use and they are still the best 34 I have ever heard and I have many of the Mullards and others.

 

[jamato8]

Quote:

Originally Posted by izquierdaste Since I like to talk to myself in threads, I thought I'd let you all know that I am pretty sure that the mysterious made in holland orange globes without shields are actually made by matsu****a in Japan with old Mullard tooling. Apparently, they were commisioned by Philips to produce OEM tubes in the 70s, based on my reading over at audio asylum. I think these tubes are quite nice. The W. Germany 6922s are still a bit of a mystery though.

Towards the end of Amperex's life they sourced tubes from anywhere and put their label on the tube. The quality went way down because the country of orgin could have been anywhere and the quality control was gone. It is too bad but the Russian 6DJ8s are a very good tube.

 

[Aethelred]

Hope this will help - I had similar problem with my Valvo D-getter.
All credits to http://www.audiotubes.com
Normally should be first letter second row of the code.

 

[rodentmacbeastie]

I don't know if this will help, but Amperex had two plants in Holland... The one in Heerlen and another in Eindhoven. I heard that the one in Eindoven was were most of the research was done. For example, I had a pair of Amperex CCa tubes from Eindhoven and they sounded nothing like the rest of the Amperexs I had, and I had many. I also hade a pair of Valvo CCa in yellow labels which were identical to the Amperex CCas and that is how I found the history. Valvo were made by Amperex and the yellow lable meant Eindhoven. They could be made in Eindhoven, lots of crazy things went on there is what I understood.

As for the 6922's, I read a while back about this issue. The problem is I cannot remember exactly what the facts were. I remember it clearly being a certain fact that Siemens and Amperex had something going on. I had a pair of 6dj8, which I liked with their tight bass, and the 6922's I remember them being very dark and uninvolving. Both pairs made in West Germany, branded Amperex.

 

[izquierdaste]

Thanks for the help guys. One of the problems with identifying the tubes was that there were no acid-etched codes on the tubes. However, after reading up over at tube asylum, I am pretty sure that I got some matsu****a-made tubes that were relabeled as Amperex/RCA OEM.

The W. German Amperex 6922s might be relabeled Russian tubes, but I am leaning toward Siemans, because of the stamped number on the interior of the tube, the seams on top, and the number in the middle of the pins on the bottom. I am just surprised that they don't sound as good as the 6dj8s that I have. It also seems strange that the ink is such good shape and the pins are so clean.

Oh well, if you see some bargain japanese 6dj8s on ebay, i'd recommend snatching them up, because they are quite nice for the price.

 

[Aethelred]

On all my tubes ink is pretty weak and easy to remove. So I'm really surprise you reporting you experiance.
As for experiments with tubes also valvo Hamburg - same factory for Siemens was quite famous. I have a pair of 6dj8 Valvo - D-getter and normally they were not distributed as a final product but some kind of experiment. They maintain parameters range of 6299 or CCa except still having steel pins that was a bit strange.