Baldwin 12AX7? Who Made These?

Hazy · Post by **Hazy** » Mon Aug 22, 2005 8:40 am

I got about 30 "Baldwin" 12AX7s last year and have been trying to figure out what they are. I was told that they are Westinghouse; but, I don't think that Westinghouse manufactured tubes. I picked up four 12AX7s independent of my 30 tube score and those 4 were marked as "Balwin" with the seller telling me that they were Sylvania.

Does anyone know that I have? Are they all Sylvania? I am using them in most of my V1 and V2 slots with great results, low noise and clean clear tone. It just bugs me not knowing what they are.

Thanks,

Rick

rjgtr · Post by **rjgtr** » Mon Aug 22, 2005 5:19 pm

Hazy,

There's really no way to totally know. A lot of manufacturers bought tubes from whoever was the cheapest when they needed them. Radio Shack sold a lot of tubes, none of which they made by all kinds of manufacturers.

If you bought the tubes from a reputable vender, then his best guess is probably the right one. You could post a couple of pics and the real experts could probably tell you from looking at the details of the innards of the tubes.

Gonzo · Post by **Gonzo** » Mon Aug 22, 2005 5:34 pm

I bought some Baldwin labled 12AX7 tubes (green lettering) last year from a guy on Ebay and He said they were made by Sylvania.

Whoever made them they are very nice tubes.

Tim

Dai H. · Post by **Dai H.** » Mon Aug 22, 2005 6:52 pm

could be sylvania but might be something else too. Any match w/the tubes on this site?

http://www.eecs.berkeley.edu/~loarie/12ax7.html

p.s. the best way in general to get a tube ID'ed is to supply a picture (if you can)

Hazy · Post by **Hazy** » Mon Aug 22, 2005 8:54 pm

Dai H. wrote:p.s. the best way in general to get a tube ID'ed is to supply a picture (if you can)

Here ya go...a pair of the tubes back and front. Thanks for your help.

Hazy

Dai H. · Post by **Dai H.** » Mon Aug 22, 2005 9:44 pm

if all of them look the same, then they are all Sylvania. 30 is a very nice stash and should last you a long time. They can sound pretty good in Marshalls IMO. Seem to be a bit higher gain and microphonic in general, but it seems in the Marshall bright ch. w/the 0.68uF bypass and 0.0022uF coupler cap microphonics from a tube doesn't matter as much since the freq. range is restricted (compared to the normal ch. which uses up to 330uF for cathode bypass--a much much bigger cap and 0.022uF for the coupler).

Hazy · Post by **Hazy** » Mon Aug 22, 2005 10:09 pm

Dai,

Thanks. What are the distinguishing Sylvania marks?

Dai H. · Post by **Dai H.** » Mon Aug 22, 2005 11:33 pm

I guess the most noticeable is the shape of the plates, which look kind of unique:

http://www.eecs.berkeley.edu/~loarie/12AX7/page10.html

then maybe the tube type markings (which didn't look like GE markings), and lastly the fact that I've seen some Baldwin labeled Sylvanias at some tube vendor before.

Hazy · Post by **Hazy** » Tue Aug 23, 2005 8:16 am

Thanks, Dai.

I also scored 10 GE 12AX7 black plates at the same time that i got the Baldwin 12AX7s. I got all 40 tubes for $50...my score of the year.

Rick

Dai H. · Post by **Dai H.** » Tue Aug 23, 2005 9:46 am

wow nice, that's an excellent deal