Before match tube, It is better to make tube stable

[kldguitar]

Let us discuss the pair of tube in Class AB again. It is better to match tube after they worked in stable situation .Before tube worked in stable situation , it need be lighted about long time.It is too long to afford to tube manufacturer even some brand company. When you buy tube from retailer shop, It is impossible that tube worked in stable situation, so even they matched , they did not worked in better statement. Many people don't pay attention to this problem. But t is important detail.

[Regis]

I had a tube in a stable situation once. At least, I thought so. She and I got lit for a long time, and she didn't like the tube I inserted. I thought it was plenty long, but I she didn't think so, I guess we weren't matched. Seems I wasn't paying attention to the problem.

What was that? Guitar tubes?

Oh. Never mind.

[Chuck H]

Regis!!! Sir KLD is trying to contribute. This is a good thing.

On the subject of the post...

Here in the states most small manufacturers, home brewers and retail buyers get their tubes from a supplier that does:

1) burn them in
2) match them to some criteria that usually involves current during operation. Sometimes more involved depending on the supplier.
sometimes 3) shock test
and as an added criteria, occasionally 4) test in a circuit for microphonic sensitivity.

There is a substantial added cost for all this. Most of us pay it. There are some here that, like mid sized and large manufacturers, buy their tubes direct from the factory. The cost per tube is much lower but any stability, matching, durability and microphonic testing is left to the buyer. Not all tubes need to perform to the same criteria. Preamp tubes that are too microphonic for the first gain stage may still be acceptible for the next, etc. Power tubes are matched up and any durability issues or bad tubes in a batch are considered acceptible losses, or sometimes you may get replacements from the factory by returning grossley bad tubes.

Thank you for sharing. It's always good to make such observances known. Most of us here have some experience with this.