How long is a 300B good for?

[AJSki2fly]

So this morning I switched on my trusty Allnic and Tuner and all was well as I listened to radio 4 through breakfast. I then started to tidy up and went into the lounge and realised things did not sound quite right, in fact I was missing the left channel completely. On inspection of the amp I immediately could see that there was no current on the left channel current gauge. So I dug out my spare 300B's and swapped over, powered up the amp and hey presto left channel reception was resumed.

So obviously the 300B valve has failed. I am a bit surprised and concerned about this. The valves are Psvanne 300B Black Bottles purchased new about 3 years ago. Originally I used them in my mono-blocks for about 18 months and I would estimate they did about 800 hours and then in the Allnic doing about another 700 hours. 1500 hours does not seem a great deal to me for a 300B, or maybe I have the wrong view.

I'd appreciate others views or experience on this.

Thanks

Adrian

[anthonyTD]

To be honest Adrian, i think you did quite well out of them, they are run very hard in some amps, especialy single ended, having to draw all the current needed all of the time, whether there is signal present, or not.

So this morning I switched on my trusty Allnic and Tuner and all was well as I listened to radio 4 through breakfast. I then started to tidy up and went into the lounge and realised things did not sound quite right, in fact I was missing the left channel completely. On inspection of the amp I immediately could see that there was no current on the left channel current gauge. So I dug out my spare 300B's and swapped over, powered up the amp and hey presto left channel reception was resumed.

So obviously the 300B valve has failed. I am a bit surprised and concerned about this. The valves are Psvanne 300B Black Bottles purchased new about 3 years ago. Originally I used them in my mono-blocks for about 18 months and I would estimate they did about 800 hours and then in the Allnic doing about another 700 hours. 1500 hours does not seem a great deal to me for a 300B, or maybe I have the wrong view.

I'd appreciate others views or experience on this.

Thanks

Adrian

[Ali Tait]

I haven’t tried any of the Chinese ones, but I’ve always had good service life from JJ’s. Used some in my WAD monoblocks for about five years and they still sounded fine.

[anthonyTD]

I wonder if its a base problem, ie; one of the pins has developed a bad solder connection ?
A

[Flo]

1500hrs ain’t that bad, I’ve had some pricey ones that didn’t make 1200. Best I had were EAT , I think I had good life for 6 years approx 2500hrs. Depends on amp, friend has shindo 300b, afaik he’s never changed valves, signal or power in over ten years of use. Amount of times switched on \off is as important as hours.

[Pigmy Pony]

Seven years ago I bought my Audion SET amp secondhand, complete with PS Vane black bottles (mileage unknown). Then earlier this year I bought a used low hours pair of Electro Harmonix ones. Three months later one valve decided to throw in the towel. So I'm back with my ancient PS Vanes and all's good.

To be fair I probably only average about 2-3 hours per week, but I don't know how much of it is luck of the draw, and whether some amps give them a harder time.

[Sixty2]

Interesting: In the first Transatlantic telephone cable, there were ‘repeater stations’ along the cable every 10 miles or so. These housed The Western Electric 175 HQ valve to boost the signal. Think The WE 175 HQ might have been a 300b variant, though not too sure.

The ‘expected’ life of these valves was 20 years. The 307 tubes along the cable actually operated for 22 years without a failure! Pretty amazing!

[anthonyTD]

Hi Mark,
The 300B, [and possibly the 300A] were used in telecomunications, indeed, i think this was the main reason for their development/production.
Where valves are concerned, the saying "They don't make em like they used to" is very apt, i suspect a good set of original Western Electric 300B would last much longer than any modern equivilent made today!

Interesting: In the first Transatlantic telephone cable, there were ‘repeater stations’ along the cable every mile or so. These housed The Western Electric 175 HQ valve to boost the signal. Think The WE 175 HQ might have been a 300b variant, though not too sure.

The ‘expected’ life of these valves was 20 years. The 307 tubes along the cable actually operated for 22 years without a failure! Pretty amazing!

[steveinspain]

Hmm, this may have swayed me away from valves - we have music playing for about 12-15 hours a day here every day.
My little solid state amp gets left on all the time !

[Sixty2]

Hi Anthony,

Yes, I agree. Like a lot of things these days, quality can be compromised for profit!
Western Electric do have a reputation for reliability. I did own a pair of WE 300B’s for many years, used them very lightly then sold them to a dealer. Wonder what they’d be worth now? Oh well!!