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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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In Reply to: Re: Help this pathetic newbie to tubes : ) posted by Mechans on August 7, 2006 at 02:07:17:
Hi Mechans,Let me share a few more thoughts...
"You can't say a tube is really unused if it has been "burned" in or gone through an extensive battery of tests."
You know, this reminds me of what you see occasionally with new cars (my consulting business deals with auto makers and dealers). Occasionally you find a customer who insists the car they buy must have zero miles on the odometer. This is an impossible request, and not even a good idea. The cars are driven from the assembly plant to the staging area where they are loaded on transports for shipment. That puts a few miles on them. Then when the dealer does a pre-delivery service he is required by the manufacturer to road test the car (some even specify a minimum length of the test drive). So that means the vehicles for sale will have a few miles on them. Are they "new"? I think so, and I think that's a good analogy for the tube situation.
"is virtually impossible to know if they used for a brief test drive or they were used for somewhat longer or greater periods of time."
That is correct, sometimes you just can't tell!
" If you can't tell thermal discoloration means having current sent through them? What can you use?"
There is no 100% sure method. And there is no single parameter that will tell you either. I've tested thousands and thousands of tubes - I still can't be 100% sure if a tube is new or not in some cases. But at that point it really doesn't matter IMHO. I'll post the tube for sale and say I don't know if it's brand new, but it could be.
"How is that different than a used tube that tests strong?"
In practical terms it isn't any different (if test strong means identical to typical new testing). Both tubes can provide long and satisfying service to their owners.
"I stand by my question about untested modern tubes. Before you do your QC and start selecting tubes do most modern production tubes share any of those characteristics. All I'm trying to say with some dramatic emphasis that NOS is a tough call unless you absolutely know."
I'm not sure exactly what question you meant here. But my suggestion is whether a tube is NOS or has a couple hours on it is really not a big deal. If you trust the seller and find the price and other sale terms satisfactory then I wouldn't drive myself nuts worrying about if it has a couple hours use on it from sometime in 1968 and the seller didn't know about it. Besides, most people say it takes some hours for a tube to sound its best - if the tube did have a few hours on it then it might be a blessing!
Personally, I'd rather purchase a properly tested tube with a few hours on it than a new untested "pig in a poke". Most unexpected tube failures occur in the first few hours of operation!
I hope this was some help anyway.
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Follow Ups
- Re: Help this pathetic newbie to tubes : ) - Jim McShane 07:22:40 08/07/06 (2)
- NOS Indication........kind of - Jimmy 10:48:57 08/07/06 (0)
- Re: Help this pathetic newbie to tubes : ) - Mechans 10:25:46 08/07/06 (0)
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