Cut-Throat Posted March 9, 2011 Share Posted March 9, 2011 I have a lot of Tube Amps. Some of them may not get used for 6 months at a time. I was wondering what the longest periodof time of inactivity would be before you should use a variac to power up the amps? Quote Link to comment Share on other sites More sharing options...
fini Posted March 9, 2011 Share Posted March 9, 2011 Good question, but I think you meant to say the shortest period of time. I'd be only guessing, but for a piece of gear that was "to spec" at retirement, you could probably go several years. I'm also guessing you'd like someone more knowlegeable to reply. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 9, 2011 Share Posted March 9, 2011 I read somewhere that anything 10 years old or older, that has not been used in 30 days, should be brought up initially on a variac. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted March 9, 2011 Author Share Posted March 9, 2011 Good question, but I think you meant to say the shortest period of time. I'd be only guessing, but for a piece of gear that was "to spec" at retirement, you could probably go several years. I'm also guessing you'd like someone more knowlegeable to reply. I think I meant the Longest period of time. --- IOW - If the tube amp sat idle for 6 months would it be OK to just fire it up,. Or if it sat idle for 1 year would it would be OK to just fire it up. ---- IOW what would be the longest period of time of sitting idle before a Variac would be the recommended procedure. Quote Link to comment Share on other sites More sharing options...
fini Posted March 9, 2011 Share Posted March 9, 2011 Now I'm confused. Maybe "longest" is correct. Sorry for my brain farts. I was just taking it to the extreme, thinking, "OK, a million years is the longest time you could let an amp sit idle." Good God, I know what you mean. I need to get therapy from a cunning linguist.[] I will now shut up. [:S][:#] Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 9, 2011 Share Posted March 9, 2011 If one has doubt, just use the Variac. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted March 9, 2011 Author Share Posted March 9, 2011 If one has doubt, just use the Variac. When are you in doubt? Quote Link to comment Share on other sites More sharing options...
HudsonValleyNoah Posted March 9, 2011 Share Posted March 9, 2011 When are you in doubt? at some point, every day... Quote Link to comment Share on other sites More sharing options...
bluesboy Posted March 9, 2011 Share Posted March 9, 2011 This is an interesting topic because recently a friend of mine drug out a couple of old Eico hp-50s that hadn't been fired up in 50 years. We put some new tubes in them and took a chance and plugged them in. We let them warm up and checked the voltage on power supply and everything seemed fine. We hooked a cd player direct to the amps into pair of Fortes and WOW ! It's amazing how good these amps sound after sitting dorment for so long. Quote Link to comment Share on other sites More sharing options...
Davecv41 Posted March 10, 2011 Share Posted March 10, 2011 Gents, what happens is that the capacitors in tube gear eventually dry out. The largest capacitors are in the power supply, and they're usually electrolytic. If they open up and lose their filtering capacity, you get hum. But if they short, you get an overcurrent in the high voltage section. This could fry the rectifier tube, or damage the power transformer. Tubes are replaceable, but transformers can be expensive or worse depending on the rarity of the equipment. If you think your amp needs to be brought up on a variac, it needs to be serviced. Healthy electronics don't need to babied that way. I've used plastic capacitors in lieu of electrolytics in some of my antique radios hoping they'll last longer, but it may be a long time until I find out if it worked. The only piece I own that I regularly bring up with a variac is a 4 tube Japanese AM radio kit with a 100vac primary. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 10, 2011 Share Posted March 10, 2011 If one has doubt, just use the Variac. When are you in doubt? All the time? All I'm mentioning is if you think the unit has been sitting long enough to warrant being ramped-up on a Variac, then just do it. It ain't gonna hurt anything. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted March 10, 2011 Author Share Posted March 10, 2011 All the time? All I'm mentioning is if you think the unit has been sitting long enough to warrant being ramped-up on a Variac, then just do it. It ain't gonna hurt anything. I have no clue and do not own a Variac. - That is why I am asking for a ballpark figure. Then I'll figure out if I should get a Variac or not. I have no idea if the time frame is 30 days, 6 months, 1 year, 5 years, 10 years etc................. All I need is a guess. Quote Link to comment Share on other sites More sharing options...
CIGARBUM Posted March 10, 2011 Share Posted March 10, 2011 Afew months ago I had the same question. I have several older amps sitting on shelves, I just got my SC 433 back from Craig, so I asked him what his opinion was on how long between when you used it and you want to use it again. About 6 months. Every 6 months plug it in and bring it up to operating temp, unplug, put back on shelf. Every 6 months. Anything longer I would hook it up to the varjig and bring it up to proper voltage. Cigarbum Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 10, 2011 Share Posted March 10, 2011 All the time? All I'm mentioning is if you think the unit has been sitting long enough to warrant being ramped-up on a Variac, then just do it. It ain't gonna hurt anything. I have no clue and do not own a Variac. - That is why I am asking for a ballpark figure. Then I'll figure out if I should get a Variac or not. I have no idea if the time frame is 30 days, 6 months, 1 year, 5 years, 10 years etc................. All I need is a guess. You have enough tube gear to justify buying one. Just do it...you'll be glad you did and so will those precious triodes of yours. Quote Link to comment Share on other sites More sharing options...
Audible Nectar Posted March 10, 2011 Share Posted March 10, 2011 I'm no expert on the subject, but on my MC30's, I have them hooked up to a variac as a permanent deal. Reason being that those amps are used occasionally - maybe every other weekend - and I'm not a big fan of allowing all that juice to thwack these vintage amps all at once. ESPECIALLY the replacement CE cans, which aren't as thoroughly/well manufactured as the older originals.... Now my VRD/Peach setup I use about 5 times a week. No variac necessary here: VRDs have 5AR4 slow start rectifiers (easy on the output tubes at start) and regular use has me less worried about variac-ing. So for me, it's mostly about frequency of use, and the added desire to take special care of my vintage gears. I might not even have to do this on my Macs....but again, it's more a "special care to be sure" kind of thing as much as anything else. If I went months between power ups I would definitely use a variac. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted March 10, 2011 Author Share Posted March 10, 2011 Afew months ago I had the same question. I have several older amps sitting on shelves, I just got my SC 433 back from Craig, so I asked him what his opinion was on how long between when you used it and you want to use it again. About 6 months. Every 6 months plug it in and bring it up to operating temp, unplug, put back on shelf. Every 6 months. Anything longer I would hook it up to the varjig and bring it up to proper voltage. Cigarbum Thanks for answering my question!!!! Good enough for me! - Craig knows his stuff. -- I don't need a Variac then. --- They always get some play inside of 6 months! Quote Link to comment Share on other sites More sharing options...
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