12AU7 Genuine or remarked

[yajnaS]

Could be coming from one of the many plants based in India as well.

As far as I know the only tubes made in India were made by Bharat Electronics (BEL) using Mullard machines/technology.

Were there any others ?

 

[fdegrove]

Hi,

No, not that I can think of. No idea if it was a single plant or several ones spread across the country (it is a big country after all)....

Odd that the GE tube in your pic has a painted on code and not an etched one...

Either way, if the tubes measure well and sound fine that's all that really matters.

Cheers, 😉

 

[kevinkr]

From the plate structure, I'm 99.998% sure it's a Sylvania/ECG Philips. I've held, touched, fondled untold quantities in my days as a TV tech.

I'll second that, and I worked for GTE in the days when they still made tubes and before / during the sale of ECG to Philips in the early 1980s.

 

[DaveG]

Hi, A couple questions.

@yajnaS-
There appears to be some green marking showing in 2 of your photos. Any on the others tubes you have?

@Tom Bavis
"I have Mullard, RCA, Sylvania tubes relabeled GE - they all have the 188-5 code (GE, Kentucky)."

Did GE acid etch when relabeling, with the dots and all?

Thanks, Dave

 

[yajnaS]

DaveG,
One other tube has a small green spot on it.
I wiped the tube in the photo with an acetone swab, and the white ink came off immediately but the line of green ink is still there.

I guess the original marking on the tube was in green ink ?

 

[DaveG]

Hi yajnaS,

I looked on ebay and there are several philips 5814a's (with a green ink) that look like they have a similar plate structure, so maybe as mentioned in previous posts they are late production Philips.

Rather than being remarked, possibly the green ink on your examples could be slopped ink from the previous production printing run just slightly transfering to the next batch being printed. Maybe the printing unit was not completely cleaned.

Dave

 

[AudioFreak88]

The first pics posted and a few others here, do not look like GE's.....those plates look/are like Sylvania's/Phillip's.....

get rid of them, sylvania/Phillips grey plate 12xx types are pretty boring imo nothing special....early black-plate types are what you want the bent/d getter 50s black plate 12au7 sylvania's are waaay better

I got some early Raytheon Black-plate's I think sound pretty killer too, like blow the GE's away...up there more with RCA like really.

 

[ericj]

The first pics posted and a few others here, do not look like GE's.....those plates look/are like Sylvania's/Phillip's.....

get rid of them, sylvania/Phillips grey plate 12xx types are pretty boring imo nothing special....early black-plate types are what you want the bent/d getter 50s black plate 12au7 sylvania's are waaay better

I got some early Raytheon Black-plate's I think sound pretty killer too, like blow the GE's away...up there more with RCA like really.

This kind of generalization is not really useful and is really just a driver of fad and fashion.

In different circuits the same tube will sound different.

If it sounds good, use it. It's just a 12au7. There are dozens of variations to try, and very few of them are expensive. There are mixed lots of tested used 12au7 types on ebay going for multiple tubes per dollar after shipping. there is no reason to apply any simplistic dogma as to what 'should' sound better based on hearsay and rumor.

My first 12au7 circuit, i was really excited to try out a NOS Telefunken ecc82 in. I didn't like it. I ended up settling on an RCA 5963 in that one.

 

[AudioFreak88]

Not exactly simplistic/generalizing man.....GE/Sylvania has always been more into the "run of the mill" area/category with a few good/better ones here and there.....On a whole I would say GE is like a notch higher....still though that was the common/every day/run of the mill sounding stuff pretty much.....just no comparion at all to some actually a lot of the RCA stuff....hell a lot of the Raytheon/Westinghouse/Tung-sol/CBS stuff made em look bad too in comparison.....

 

[optimationman]

other types

I got to digging in my stash to see what I had in terms of 12au7's. I don't have any equipment at this time that uses them so I had to dig deep. I got these in my many years of scrounging around.

The first picture is mostly Mullard made types from Blackburn. The Brimar is also made in England. The Siemens is a D getter type. There is also a "foreign made" mullard with the delta Holland etch.

Down further in the stash I found a sleeve of RCA 16-17mm large plates. I guess I might even have more of them somewhere.

Any trades???