[izquierdaste]

Hello,

I just bought some supposedly "new in box" gold aero 6922 tubes that supposedly "test at 100% on sencore checker" off ebay. quotes are seller's exact words. When I plug these into a morgan jones amp, they sound distorted and have no gain (volume is very low to other tubes at same setting). I have cheap chinese 6n11 tubes that sound 100x times better. I have heard that NOS tubes may need to time to burn in, but I have run them for about 10 hours with no change in sound. I also notice that the tubes do not get very warm compared to others. Did I just get used up tubes? I don't have a tube tester of my own and I guess I have never had a tube go bad on me. I replaced some tubes on a guitar amp that lost some of their sizzle, but they didn't sound like this. I only spent about $12 on the tubes, but this is still annoying and about the 4th time in the last month that I got a misrepresented item from a seller on ebay.

Anyways, is this what happens to tubes when they die?

Thanks for any help

 

[BushGuy]

Tube usage goes back to "ancient times" for me..........but what I remember from the late 50''s onward was a) we always had a "kit" tubetester at home and it got fairly regular use b) tubes simply died and several others got replaced because spurious noises would develop.......sometimes after only a week or two of use......many lasted considerably longer. Even then the 12AX7 was a very common number that I replaced many times....but oddly enough never had to replace a tube in guitar amplifier (God, how I wish I never sold my orig. Les Paul). So, buy or build thee a tubetester or don't get into tubed amps. Secondly, while there are likely a few reliable vendors selling in this area on ebay - I'd only go with a "store (or could be a Head-fier of well-known reputation)" that you are SURE will back up their product. Like all other gambling - you will eventually lose playing against house odds.

 

[928GTS]

Atleast from my experience with tube powered guitar amplifiers usually dying tubes cause a decrease in output volume when pushed and also distort a lot. Selling bum NOS tubes is a very common occurance on eBay and can be a real crapshoot. Just for fun if you know anyone near you(perhaps try looking up an antique electronic repairman?)who has a tube tester you can try to test the tubes there and see what happens.

 

[Glod]

The art of dying for a tube (6SN7GT) knows several different expressions.

I haven't had many, perhaps 3 or so, but all started to distort heavily and emitting high pitch whistling noises. I never had the heart to let them wither away completely to the bitter end: One reason being fear of shorting the network in the amplifier.

 

[kramer5150]

Ive had tubes whistle, whine... swirling kinds of sounds. Crackle, distorted, buzzy output. Little or low output at all.

Ive had tubes glow bright too.

 

[Jbucla2005]

At very high volumes on headphones I could sometimes detect a slight ring. Could this be tube microphony? Is this natural and to be expected with good tubes?

 

[izquierdaste]

Thanks for the replies. I guess you what you pay for. I have gotten some good deals from ebay, but it seems like none of my audio purchases work out. Usually, I end up getting my money back, but it is a hassle. What is the point of selling obviously bad tubes in the first place?

oh well

 

[echo1]

They go *cough* *gasp**groan*