2. amps-preamps
  3. 1297216126

How to restart tube amp and pre in boxes for 2yrs

I want to start listening to music again i have Sonic Line 3 SFS 80 and i was told to be careful before i plug in listen anybody have any idea wether it is true i have to recharge the amp and pre before using Ill wait for some answers before doing anything tks for any advises
frencowboy

Showing 5 responses by larryi

larryi
4,273 posts
 
I'm too much of a chicken to be close by looking for warning signs. I lend my stuff to a friend who can power it up on a variac for me.
larryi
4,273 posts
 
Two years is not a long time to be sitting idle. The electrolytic caps should be okay (assuming they were okay going into storage).

You should not have a problem with speakers not attached if you don't put a signal into the amp.

Elizabeth's approach would be a not to difficult to implement safety measure. Be sure to have a reasonably long time between turning on the amp again. Some tubes hate being turned on again immediately after being turned off. If I do that with my power amps, I sometimes get a tiny flash from the rectifier.
larryi
4,273 posts
 
Hifigeel1,

Yes, the rectifier does act as soft start for other tubes and for the power supply caps.

Perhaps you can help with the issue of using a variac for tube gear that use solid state rectification. A friend had such an amp that had problems with diodes in the bridge rectifier blowing up. The manufacturer stated that both over-voltage and under-voltage could be responsible for that happening. Since the use of a variac would create such under-voltage situation, I am wondering if that claim is really correct.
larryi
4,273 posts
 
Hifigeek1,

You are far braver than anyone I know when charging up questionable caps. A friend had a cap blow up when he turned on an old amp and he said the explosion was unbelievably powerful. He is a gun person so he knows what loud is, and he said the cap going up was louder than any gun he has fired.
larryi
4,273 posts
 

Yes, a device to monitor voltage and current draw of the amp is the best approach.  I've seen situations where even at a low voltage setting when powering up, the current draw appears too high so one knows there is a problem somewhere when well below when full voltage is applied.  Measuring current and voltage together is the best approach.  Interestingly, a very young tech I know said that he actually prefers a dim bulb to relying on the ammeter.  He said that the bulb reacts faster than a readout of current.

More to discover