Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: stratavox on November 21, 2019, 06:19:02 am
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I have an amp that has sat unused for at least three years...any suggestions as to the best way to turn it on for the first time ? TIA...
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Was it working OK 3 years ago last time it was used?
You may get responses to use a variac or a light bulb current limiter to check the amp out. * See 2nd post on this thread:
http://el34world.com/Forum/index.php?topic=2376.0
IF it worked OK last time it was used & it were my own amp, I'd use the on/off switch.
with respect, Tubenit
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Morning Tubenit...sorry, I should have included a little more info. Yes, worked fine, just in dry storage. I thought of the bulb limiter, I just seemed to recall someone along the line saying you should turn a tube amp on at least once a year just to keep caps from drying out...I appreciate your time this morning- take care.
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I thought of the bulb limiter, I just seemed to recall someone along the line saying you should turn a tube amp on at least once a year just to keep caps from drying out...
Yes, because of the E-caps. They need to be reformed by having a dcv on them. They will leak current until they are reformed. But every time you apply dcv on an E-cap it reforms, and they all leak some current. The longer an E-cap sits with no dcv applied to it, the more it will leak until it is reformed. And the longer it has been sitting with no dcv applied to it, the longer it will take to 'completely' reform to the least amount of leakage it's capable of. Will they leak enough current to over heat the E-cap? Probably not after 3+ years sitting unused, if their good quality caps. Will it stress the E-caps by heating them up because of leaking current until they reform, shortening their overall life span? Depends on how much current they leak as they reform. So after (only) 3+ years, probably not.
If it were my amp, I'd probably use a light bulb limiter if it were handy. It can only help ease any stress on the E-cap using a light bulb limiter. But I wouldn't worry too much if I just turned it on either.
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Light Bulb and if you haven't a Variac but have a low voltage PT with enough current (say a 40-60V PT) use it as an improvised variac
supply the amp for .... 1/2 hour or a bit more, then apply the full line voltage
Franco
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plug it in and flip the switch.
--pete