NEW OLD STOCK...Should I worry?

Just a question, not a confident suggestion. A dimmer won't work as a jury rigged variac for the reasons cited. But could one use the secondary from a spare amp/receiver that would provide say 60 or 80 VAC? It wouldn't work for careful dialing up. But could it allow some soaking time to reform capacitors?
 
Got these preamps in my hands and I have been running them on a 25w bulb for a while now.

Date of manufacture is a bit older than I thought. They are from 2002.

Anyhow, bulb stays dim on all of them.

So, I ran them on the bulb for about 12 hours then wall power for about 12 hours. I took the tops off and looked around inside. Nothing odd. No swollen caps or anything. Heatsink mounted transistors get warm as they should.

Should I call them good?

I have not yet run audio through them.
 
Got these preamps in my hands and I have been running them on a 25w bulb for a while now.

Date of manufacture is a bit older than I thought. They are from 2002.

Anyhow, bulb stays dim on all of them.

So, I ran them on the bulb for about 12 hours then wall power for about 12 hours. I took the tops off and looked around inside. Nothing odd. No swollen caps or anything. Heatsink mounted transistors get warm as they should.

Should I call them good?

I have not yet run audio through them.

I'd have no concerns about using them after running for that length of time. Sounds like they're ready for a proper test in your system.
 
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