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Old 10-08-2016, 09:29 PM
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microstrip microstrip is offline
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Originally Posted by plurn View Post
Further to my earlier post I decided to stock up on the Philips PCC88 tubes while they are still relatively cheap at the place I buy them. These should last me a while:

For my current usage of about 2700 hours per year, I estimate these 30 tubes will last at least 16 years in my ET5. Could end up less than that or a lot more then that depending on various factors. Hopefully most of them are as good as the four that I originally purchased.

Does anyone know if these are the same as the one CJ supplies for the GAT? They have factory code DJER.

What follows is probably of no interest to anyone but you never know.

Researching these tubes I have the following information:

- from the factory code DJER, DJ = PCC88. Don't know what ER stands for.
- They are not from CJ or from Upscale Audio. Upscale says the following about their Philips PCC88 which looks the same "This tube has Philips Holland parts, and the associated sound. They were assembled in the Ei factory according to the small etched codes on the glass.". They don't say what the code is.
- Another site worthpoint had very similar looking Philips PCC88 for sale in the past and their ones had factory code "DJER @ 4I". Their description said "Philips PCC88 Produced in Sept. 1964 for Philips by EI (Electronska Industria, Jugoslavia)". My ones just have factory code DJER rather than "DJER @ 4I". Perhaps from the "4I", the 4 indicates 1964, and the "i" indicates september? If that is the case then I suspect something in the "ER" from DJER indicates that they were produced by EI.

So I don't know if that means mine were made by EI or somewhere else. I suspect they were made at EI with Philips Holland parts since all the others seem to be. If they were made in Holland I would think they would say "Made in Holland". That is just a guess.

I also bought a large stock of the same type PCC88 Philips with codes DJER 4F and 4G. I have measured about 10 and they are in general low noise and both triodes are matched in gain and DC - an important parameter as the sections work in parallel in my LP275s. From these 10 only one had one noisy triode in the low frequencies - it is now burning-in for a few days, as I have found that some tubes that are initially noisy become silent after 50-100 hours burn-in.

Measuring a few used noisy ECC88/6922 I have found that their triodes were significantly unbalanced. Probably tubes in these conditions will ear out much faster as the tube current does not split equally between the triodes.
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