Partly to save my Mullard EL34s, also just to try stuff out... The concern was that by swapping the Mullards in and out to save them a little, I was actually shortening their lives...
It is a "Damned if you do; damned if you don't" situation. You can take out the Mullards, hang them on the wall in a frame, and look at them, it won't do them any harm, but then what is the use to having them? They won't sound good.
I kept telling my father this. He has a good wristwatch, he's retired, and he likes it but is worried about scratching said watch or knocking it about. I told him that he won't enjoy it if it is in his sock drawer because when will he want to wear it? It won't tell him what time it is nor will it do him any good in his grave. Sure he can save it for me, but use it. Make it practical and use it. If it gets damaged, it can always be repaired or replaced.
If he can't bring himself to wearing it, then get another watch and wear that one.
Granted Mullards are rare and expensive, but only you can decide how to enjoy them. Tubes are pretty strong and most times don't burn out like a filament lightbulb.
Me? I'd use them and listen to the sound they produce.
In all honesty I think your more likely to damage them changing about tubes..
I have had tubes last for years just left alone and run as normal.
I have broken more tubes swapping and changing or moving tube amps about than through normal wear and tear.
That’s the problem with tubes on show..you keep messing with them. If they are inside an enclosure you tend to leave them alone and they last for ages.
However I like to see them as most people do…that’s the problem we like them and can’t keep our hand s off…such is the likes of us J
Mechanical damage is the problem..how many things have you dropped by accident? Don't hold them and your fine..
I would even say I tend to do more damage when I am over cautious with tubes and then get mad when one rolls off the table..
Regards
M. gregg
I have had tubes last for years just left alone and run as normal.
I have broken more tubes swapping and changing or moving tube amps about than through normal wear and tear.
That’s the problem with tubes on show..you keep messing with them. If they are inside an enclosure you tend to leave them alone and they last for ages.
However I like to see them as most people do…that’s the problem we like them and can’t keep our hand s off…such is the likes of us J
Mechanical damage is the problem..how many things have you dropped by accident? Don't hold them and your fine..
I would even say I tend to do more damage when I am over cautious with tubes and then get mad when one rolls off the table..
Regards
M. gregg
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A socket saver sounds like an interesting idea, no impact on sound?
I do take "the leave them in and listen" arg, in my case I have some EH KT88's that I like to listen to too... Also I play the TV through the amp and I just can't bare to watch the Mulls burning away to TV Burp...
The amp is old (Croft S2) so I guess the sockets should be old skool robust. Not too fussed about having to change them anyways....
or just sell the dam tubes and dont worry bout it buy a parametrical EQ and 2 sets of new EL34 for the money they fetched .
hadn't thought of that, would save an awful lot of bother....
In the high gain stages the capacitance of a socket saver may cause a little high-frequency rolloff depending on the design. The wider bandwidth designs with lower impedances (smaller values for the plate resistors) are less affected. Some tube testers can actually damage tubes. Its generally low current preamp types suffering some cathode damge in emission-type testers from too much grid current. Most of what thoses testers flows through the grid since it is closer to the cathode. Often Pentodes with plate caps read nearly the same with the plate disconnected on the lower grade testers. As for prized tubes, enjoy them but don't let them bake needlessly. Consider using a variac or bucking transformer coil to bring filament voltage down to the lower limit (usually about 5.7 Volts) and run the bias current as low as your ears are happy with. Avoid circuits that overheat the screen grids (worst at high bias, when clipping, and with light loads). If you made your own screen supply, set it to current limit at the rated screen input power. Use of a small PC fan, run from rectified filament voltage, to quietly blow some air across the tubes will also greatly extend their life and that of nearby filter caps. I read the failure data from one cap manufacturer showing that a particular 85C cap good for about 6 months at 85C, over 20 years at 25C. Rated for heat doesn't mean lasts as long when hot. Those concerned about minimizing tube use and energy conservation might consider using tube amps in the cooler months when the heat is useful, and lower power for summer. If it is tubes all the time, Class A and SET in winter, lower bias push pull when its warmer.
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Elaborating on the above comment the extra set of contacts theoretically reduce reliability (by virtue of doubling the number of contacts), definitely increase stray capacitance, and may result in [VHF] oscillation with some high transconductance triodes and pentodes. Fine in a tube tester IMHO, but not such a good idea in an amp.
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