Back in year 2010 I lost a few perfectly good NL-6844A tubes to some of those "killer sockets". That very painful lesson was what it took to show me how and why certain sockets are very bad! I had just built the smaller clock with the 6844 tubes. Had it running for a few days when one tube went dark. It had a cracked base. Changed it out and started testing again. Later same day it failed again. Then took clock all apart and closely examined the sockets. Turned out I had 2 different types of sockets. There were some good ones that have very thin and springy forks. Then there are others which I have since dubbed them "The Tube Killers". Those have very thick and very stiff forks. Later testing revealed that those killer sockets can be tamed by adjusting with the tapered probe to open up the fit. But I still do not like them because even loose, they still side-load the tube pins. Here is a link to a video of two of my clocks. The smaller one has the NL-6844A tubes and it is the one that had the broken tubes due to the bad sockets. https://youtu.be/gJ84ItTar-g
On Wednesday, December 17, 2025 at 11:42:27 AM UTC-5 Tom Katt wrote: On Wednesday, December 17, 2025 at 11:31:23 AM UTC-5 Leroy Jones wrote: I would advise being very cautious regarding the tightness of the fit of the tube pins into ANY socket! Certain sockets are so tight that they tend to put a side-loading spreading force on the tube pins enough that in extreme cases the glass tube base will crack. My standard procedure now for any such socket for tubes such as NL6844A and 8422 is to use a tapered aluminum soldering probe to wallow out each socket pin to a much looser fit on each tube pin. If you go too far and open the socket fork too much, you can reach in there using a pointed exacto blade and add back some tension. Sockets adjusted that way give the tube a very easy and buttery feel going in and coming out of the socket, yet they retain good contact. Those russian socket pin forks are some real doozers last time I checked. As I recall they are massive thick things with practically go give at all. My impression of them is they will destroy a tube in a New York minute! My advice is STAY AWAY from those russian sockets by all means. Get the good USA made green ones and carefully open them up for a nice fit. Your tubes will then not break. Thanks very much for the advice. Although I could *probably* manipulate the Russian sockets to work, I agree that you'd never know if mechanical stress will cause issues or breakage down the road - especially with thermal cycling. I have decided to not be stingy and just fork over the $ for US made sockets. My experience with other Russian hardware is that frequently costs are cut to bare minimums and the quality often suffers as a result. It's curious how the Russian designs are basically cloned by the American products... and yet modified to require their own pin layouts. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/97184178-86a9-483c-9624-21c07ccc665en%40googlegroups.com.
