astouffer said:
GEC was a British company. Their chairman insisted on keeping £1bn in ready assets to tide the company over in the event of untoward events, but the financial boys in the City engineered his replacement by people more disposed towards gambling that money on the stock market (and coincidentally earning the City boys a nice commission). The gamble failed, the untoward events arrived, and GEC collapsed. Still, look on the bright side, the City boys were able to buy themselves Porsches.
USA made GE and Philips ECG Jan types all had bar codes right from the factory from the early 1980's onwards - I have had scads of these over the years.
IMHO These late production Jan tubes are nothing special (at best) in most cases, and in the case of more common tubes including 12AX7A/12AU7A/6DJ8 or their industrial # equivalents you might just be better off with current production JJ - usually somewhat cheaper too. Late Jan types are usually reliable, but whether or not they sound good is another question.
IMHO These late production Jan tubes are nothing special (at best) in most cases, and in the case of more common tubes including 12AX7A/12AU7A/6DJ8 or their industrial # equivalents you might just be better off with current production JJ - usually somewhat cheaper too. Late Jan types are usually reliable, but whether or not they sound good is another question.
In many cases the manufacturer packed Jan tubes in individual boxes for the US military - those that weren't are usually very clearly marked as packed by another entity.
I have bought tubes that were in bulk packing as well.
The US government in most cases purchased tubes direct from the factory - no distributor involved due to the huge volumes. (I used to work for Sylvania and this is what I was told.)
At the very end of the era a lot of rather expensive JAN tubes appeared at outfits like Newark which sold single GE6550JANTX for $150 U.S. in the mid 1980's.
I managed to get a bunch of these free from the place I was working for at the time, they were literally going to throw them out.. I put them in MKIII's I was refurbing for sale.
For $7 AU I guess these surplus tubes are worth the risk, again though they often sound quite mediocre.. IMO most US made 12AT7 sound lousy. European made ones were often very much better.
I have bought tubes that were in bulk packing as well.
The US government in most cases purchased tubes direct from the factory - no distributor involved due to the huge volumes. (I used to work for Sylvania and this is what I was told.)
At the very end of the era a lot of rather expensive JAN tubes appeared at outfits like Newark which sold single GE6550JANTX for $150 U.S. in the mid 1980's.
I managed to get a bunch of these free from the place I was working for at the time, they were literally going to throw them out.. I put them in MKIII's I was refurbing for sale.For $7 AU I guess these surplus tubes are worth the risk, again though they often sound quite mediocre.. IMO most US made 12AT7 sound lousy. European made ones were often very much better.
My measurements correlate with that observation. I did a series of 1kHz distortion measurements with 1.7V bias and CCS plate load, 2mA. From the standpoint of distortion magnitude and harmonic distribution, far and away the worst tubes I tried were some branded Sylvania and some premium GE 6201. Far and away the best were JJ. Try those out at lower currents than people usually use and see what the fuss is about.
Wow, a lot of people are dissing the 12AT7. I tested a bunch of different tubes for the driver tube in my SimpleSE. I needed a tube that could drive a 6L6, EL34, or KT88 to clipping from a CD player. I wanted a single stage, and preferably a triode, or triode wired pentode. A CCS load would be used if it offered an advantage. Of course I selected tubes based on low distortion, but I also wanted the predominant distortion to be 2H. I also wanted a tube that would be available world wide, and preferably still in production. It should not cost a lot either. When I designed the TubelabSE, 5842's were $5 USD each, now some can cost over $50 USD.
I found a few tubes that worked good, but selected the 12AT7 because they are everywhere, and still in production. I have about a zillion 12AT7's of several flavors. I listened to several different types, and made a list. Then I took the amp to an audition session where a few people listened to it. We tried some 12AT7's and they liked one of my top choices...... The GE 6201.
Why the big differences of opinion. I think it has to do with the fact that I feed them a lot more current than most people do. I found that these tubes sound best at 10 to 12 mA, with a CCS load. I find that many triodes sound best with much higher current than the usually accepted value. The limiting factor is often the plate dissipation rating. The 12AT7 can dissipate 2.5 watts and the 6201 can handle 2.75 watts (per section).
The 12AT7 will not replace the 5842, and I don't think that I would use a 12AT7 to drive a 45 or other high end DHT. In that use the amp costs enough to justify the expense of a 5842. However for a lower cost amp using a 6L6, EL34 or KT88, the 12AT7 (at 12 mA) works quite good. Since a few million were made, they should never get super expensive.
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