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Old 2nd December 2007, 03:25 PM   #51
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Did anybody here try Russian tube 6sh52p? This special tube is better than 7788, I suppose
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Old 2nd December 2007, 03:45 PM   #52
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Quote:
Originally posted by minorchange
Did anybody here try Russian tube 6sh52p? This special tube is better than 7788, I suppose
Do you have data sheets for this type?

7N7
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Old 2nd December 2007, 03:50 PM   #53
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I think this is the tube he's referring to. How's your Russian?

6J52P data sheet
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Old 2nd December 2007, 04:00 PM   #54
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Quote:
Originally posted by Brian Beck
I think this is the tube he's referring to. How's your Russian?

6J52P data sheet

Thanks Brian,

My Russian is effectively non-existent. However this looks to be an impressive valve: only 330mA for the heater, yet 7.5W Pa max. I note with interest that there are the usual rather wide tolerances for emission and gm, with which we are familiar from our experiences with 6C45P! Best to bet on them generally making the lower end...

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Old 2nd December 2007, 04:59 PM   #55
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Quote:
Originally posted by 7N7
Best to bet on them generally making the lower end...

7N7
Probably true. A cursory look suggests that the 6J52P is similar to the 7788 in the key specs. The 6J52P is specified to have a gm value of 55mA/V at 42mA, while the 7788 is spec'd at 50mA/V at 35mA. These values are within the tolerance range of each other, especially if both tubes were run at the same plate current. Given the occasionally optimistic nature of Russian tube data sheets, it's hard to make the conclusion that on is "better" than the other, whatever "better" means.

I've never touched a 6J52P, but I think it would be worthwhile looking into it.
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Old 2nd December 2007, 05:09 PM   #56
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Quote:
Originally posted by Brian Beck


Probably true. A cursory look suggests that the 6J52P is similar to the 7788 in the key specs. The 6J52P is specified to have a gm value of 55mA/V at 42mA, while the 7788 is spec'd at 50mA/V at 35mA. These values are within the tolerance range of each other, especially if both tubes were run at the same plate current. Given the occasionally optimistic nature of Russian tube data sheets, it's hard to make the conclusion that on is "better" than the other, whatever "better" means.

I've never touched a 6J52P, but I think it would be worthwhile looking into it.
Absolutely.

Every E810F (7788) I ever tested made its specified gm, whereas the 6C45Ps were all over the place.

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Old 2nd December 2007, 10:09 PM   #57
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Default Another thing

I just remembered something about 6C45Ps.

After they arrived I used to put them on the valve tester of course. The ones that read low on emission or gm, I would leave on the valve tester overnight, running more or less flat out.

Quite often by the next day, things had improved considerably.

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Old 3rd December 2007, 12:53 AM   #58
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Seeing the Russian tubes going cheap on ePay I bought and tested some ‘standard’ ones as the 6P15P-ev and the 6N6P in existing circuits. As experience was positive I went chasing the high GM ones. It was not hard to find the E180F, the E280F, 437, 417 ‘clones’, all selling for very modest prices: the Russian sellers are kind enough to state the western equivalents in their listings, once in a while they rather mention E180F in the title instead of 6J9P. Anyway, I never found any offering a E810F or a D3A, so I went looking for their ‘clones’ on google, and found references towards the already mentioned 6J52P (also called 6sh52P or 6zh52p – in Cyrillic it is a kind of X) and the 6P38P, this one reaching (on datasheet) values above the 60ma/V. Still I have not found any ePay seller with these tubes.
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Old 3rd December 2007, 01:51 AM   #59
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There seems to be a rather extensive Russian tubes list at Klausmobile (apologies if everyone already knows about this). Datasheets aren't available for all of them, but quite a few, are.
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Old 5th December 2007, 09:11 AM   #60
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Default D3A Datasheet question

The D3a datasheets that I can find
http://www.mif.pg.gda.pl/homepages/f.../009/d/D3a.pdf
http://www.mif.pg.gda.pl/homepages/f.../128/d/D3a.pdf
both suggest (when triode strapped) a plate voltage of 160V, Rk of 470R and an anode current of 24mA. Now, 24mA through Rk of 470R is going to bias the grid up over 11V, which is not possible according to the curves ... so what am I missing?
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