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Hi Myles I have a general question about a `cooldown` period for tube gear. Often there`s a situation where you finish playing, you have to move your gear and the tubes are still hot. A bandmate of mine told me that they are easily damaged then because the filaments are still pliable. Is this so, and if so what`s a reasonable time to wait, assuming one has the option, before moving things around?

I`ll second that vote, dogg...

Skip .... GREAT post by the way. This has not come up before, but it's super that you brought it up. On pots .... Back in the earlier days of stereo, Japanese companies like Sansui and Pioneer, thought that it felt "rich" if a pot was damped, and felt sort of smooth and stiff. This was done by friction means, sometime by oil filled pots, and voila ... it was soon thought that stiff pots were better. This is NOT the case at all. Go what was a six figure Neve console and try the pots and faders. Flick a fader lightly, and it will bounce off the end of its travel. Look at a Rivera amp, which use some of the most expensive pots you can buy, and how free they turn. If your pots don't make noise, leave them alone. If they do make noise, try a little tuner cleaner and lube (not just cleaner, as it will dry them out). Chances are, your pots are just fine. Myles Ya, that slight resistance seems to have the psychological effect of, `this is ever so slightly better than you deserve, peasant` I wonder how much cost that little favor adds to the cost of production?

Hi Myles Back to the `dangers of unattended amps` topic-I went back to N.Y. recently and, sure enough, some of the control pots on both my amp channels have a `dry` feel, like they turn too easily. I take it these pots must now be replaced?

Skip, I saw James Peters below answer this a bit, and his answer is pretty spot on. I'd like to add a touch though. Class A amps that are single ended with one tube do not need a matched phase inverter. There is nothing to match, and there would be no benefit. In class A amps that use an output pair, such as Dr. Z amps and Vox, Matchless, etc ... these Class A amps, when driven at mid to high levels, operate in push-pull, or class A/B. A matched phase inverter, which in this case is really an output driver, really helps these amps. In Dr Z. amps it makes them even nicer. In Vox AC-30 amps is seems to make the output tubes last longer as they seem to be under less stress from imbalances. I am still trying to study this and figure out why from a scientific standpoint If you want to forget all this "amp tuning" and amp "blueprinting" trouble, and just have a geat amp, then go to the guy that I listen to and learn from .... James Peters His amp is a super product, and if you need to play a gigantic venue, use a open back 1x12 cabinet and mic it ... throw it into the house system with a few mega watts of amps, and now you will have terrific tone and sound that you can control, rather than the 100+ watt amp that is trying to control you (and that sounds it's best at only very high drive levels). Regards, Myles- Many thanks for thi info, as always. I am looking for a 1x12-is Mr. Peters online? I`d like to see what`s available.

thanks, mon. That basically answers my question.

Myles, sorry if this is a dumb question- you stress the importance of output matching in class A/B amplifiers. I`ve been looking at several `boutique`, low-wattage amps for several months now and all of them seem to be class A amps. Does this mean it`s less of an issue?