cold start-up

Bill · « **on:** 3 Dec 2009, 03:00 pm »

I have a couple of pieces of equipment (tube phono stage and SS amp) that haven't been fired up for at least a year or more. Should I take any precautions when starting up? I've heard of thermistors but have no idea on how to implement them. Any ideas out there?

Thanks

sts9fan · « **Reply #1 on:** 3 Dec 2009, 03:51 pm »

not sure you would use those. I know "I" use then on line with the ac input. You would be better off with a variac.

ctviggen · « **Reply #2 on:** 3 Dec 2009, 04:59 pm »

I say just turn them on. What's the big deal?

rollo · « **Reply #3 on:** 3 Dec 2009, 05:02 pm »

No problem whatsoever, turn them on.

charles

Pez · « **Reply #4 on:** 3 Dec 2009, 05:20 pm »

I've turned on pieces of equipment that have been unused for way longer than that with no problem. The only time a variac is really necessary is if you are dealing with a really old piece of equipment you are not 100% sure works or you're firing up a DIY project for the first time or after mods. Now depending on who you ask the tubes may have a few days or so before it sounds good because the tubes need a little time to come back to their full potential after a long period of no use.

*Scotty* · « **Reply #5 on:** 3 Dec 2009, 05:27 pm »

Depending on the age of the storage caps in the power supply and the rail voltage you might be better off bringing it up to voltage slowly with a variac. In the case of the high voltage supplies in an analogue oscilloscope that does not see constant usage on the bench it is a good idea to exercise the power supply by turning the scope on for 24hrs once a month. This increases the life of the storage caps as they are partially formed up and not being hit with high voltage in a completely unformed condition.
Scotty