TAD 5881 grading

I've got a bunch of TAD selected 5881 tubes, that I was gonna put inside my Ceriatone OTS. Some of them have a sticker saying "1" on them, and some are marked "4". What does these classes signify?
I'm assuming it means that 1s are matched and should go with other 1s, and 4s should be paired with 4s, but I thought I should ask first before putting them in.

 

Ok, no immediate answers, so I meassured them myself.

Out of five tubes marked 4, three matched well, one ran about 3mv colder (32mv while the others were set to 35), and one ran 6mv colder.
Out of the tubes marked 1, one tube ran 10mv colder than the matching ones, two were microphonic, and one didn't work at all.

I bought these second hand several years ago, although the seller assured they were new. TAD doesn't use these classifications anymore, so I guess they might be kinda old, or maybe some sort of b-stock.

A shame about the unusable tubes. I had hoped to be able to sell the ones that got left over, but left with only two unmatched tubes, I guess it no use bothering with that.

 

Really? This is the first time I have ever heard anyone say this. From what I've been told, you should only use new tubes, that are as closely matched as possible (I'm actually a bit worried about the one tube that is running cooler than the others, but I'm hoping it will only result in that it will age slightly slower, and cause any problems). But I'm definitively no expert, just another forum person.

 

Sigh... and when I pluged in, it started humming, blew a fuse and died. Times like this that makes me thinking about getting a kemper.

 

TAD 5881 aw well, probably from the same batch I had. I thought my tech told me he had switched tubes last time he looked it over, but I might have misheard, because they look awfully familiar.
There's only one way to insert the tubes, so that's probably not it. I didn't measure the current the old ones were running at, I just put the new ones in. I actually didn't have to adjust the bias, as ceriatone recommends a voltage of 35-40 mV, and as mentioned, they were all at 35 except the one runing at 32.

I tried switching tubes because the amp has a tendency to start making sizzing and popping noises from time to time. Two techs have been over it, without succeeding in eliminating the problem completely. After watching some videos on Youtube, I had the idea that it might be to microphonic tubes. Since I had these lying around, I thought I might as well give it a go and see if it would improve anything. What's the worst that could happen, right?

This amp has been giving me so much trouble over the years. Always acting up, totally unreliable. Don't dare to bring it to gigs, don't want to sell a broken amp at a considerable loss. And for what it's worth, it is my favourite amp when it decides to work. Really love the tones I'm getting from it.

 

Thanks! Both techs are locally reknowned amp builders, but that doesn't mean they are the right guys for this amp. I don't think I will risk Ceriatones list of techs. Seems like any hobbyist can get on there just by sending a mail. But I do have a friend who has a well made OTS, so I'm gonna ask him who built it for him.

One thing I noticed when swapping tubes was that when turning the amp off, while it was draining, putting my finger on the first power tube caused a hum. The other three was silent when touched. Might be some kind of grounding issue with that one?

 

Thanks! That's a good advice. Unfortunatly I can't test it as the fuse is blown, and I don't have a spare. Don't want to mess around with it anymore now anyway.
I'm a bit of a tinkerer, and tries to get the hang of electronics, but I guess that a 100w, 1500 dollars tube amp is not ideal to start practicing on.