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I purchased this "matched" pair of Voskhod 6n23p's from a guy in Ukraine and this is what I got. Notice anything odd? I've bought a lot of tubes in my day but this is a first. :)
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This is a twin-triode tube, so if you rotate one of them 180° around its axis, they should look identical. Even if they are not strictly identical, what matters is that the internal connections give the same pinout.
The right hand tube shows a connection on pin 9, but this is normal if the connection is to the center shield. If pin 9 is connects to anything else, then certainly the tube is miswired and should not be used as a normal 6n23p/6922/6DJ8/ECC88 etc.
It is hard to trace all the connections in the photographs, but maybe viewing from a different angle could sort it out definitively.
Thanks everyone for the comments. The connections seem to be identical...but the getters are in different places (rotated 180 degrees from each other). I don't know enough about the internals of the triode components/connections to be certain about any of this but...
Pin 9 on both tubes is connected to a similar point directly above the pin. All the other pins are connected similarly to similar looking locations. The difference is that the getters aren't in the same place on both tubes. As shown in the photos.
I can post more picture if anyone is interested in trying to feret this out further but I now suspect that for whatever reason the getter was installed on the wrong side of the triode assembly. If this is the case, then BC is probably correct and the tube should work fine.
Perhaps I am being a little paranoid. I can't imagine this is a correct situation and suspect that one of these tubes was a factory reject. My real concern is/was that it's not a 6n23p at all...it just looks like one (not necessarily a fake). At this point I still don't believe I will use the tubes however. :)
Best
mt
I've tested them on my Hickock TV3b/u using the settings for a 6922. They test very strong. In fact that was what first got my attention. The mutual-conductance is waaaay higher than any 6922 (or 6h23p-ev etc.)I've ever tested. I thought wow!... maybe these are 6n1p's or something. Started looking at them and then noticed the physical difference.
You are indeed being overly paranoid. The dish that holds the getter material (it's not actually the getter) serves no function outside of manufacturing.
What's your take on the extremely high mutual conductance readings?
That they are likely unused tubes...
Having tested a great many 6DJ8/6922's on a TV-10, the trans-conductance of a very fresh tube can be off the scale listed as the appropriate range for the tube.
Really? Not my experience at all...until these.
This is really, really, really unimportant. I would not recommend bothering the seller about this, I'm sure if you looked at enough American dual triodes, you'd find the same thing.
What you say may very well may be true and these tubes might be fine (the seller insists this to be the case). It would be interesting to know if anyone else around here has ever encountered such a thing...with the Voskhod tubes (or any other brand). This is a first for me and I'm chalking it up to experience.
Because of the physical disparity there is also the question of authenticity (one of them seems to look like most of the Voskhod 6n23p examples posted on the internet...the other is it's mirror image). I'm not "vacuum tube" expert enough to say for certain. In any case, caution is advised so I wouldn't put them in my preamp for all the horilka in Ukraine. :)
In the sellers defense, the tubes were delivered from Ukraine blazingly fast.
When you question the "authenticity", you are making the claim that someone faked a relatively inexpensive tube (they did not).
I would put either of those tubes in any of my gear that uses 6922's, there's no issue here beyond mild paranoia.
Agreed. It shouldn't make any difference in operation of the tube in circuit, but it is a little disconcerting. Made by the millions and every one of them assembled by hand you're bound to get a boo boo once in a while.
Took me a while, but yeah, one of them is bassackward.
I guess there's a first time for everything. Glad i noticed before sticking it in my preamp!
Pinouts to opposite halves of the duo-triode?
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