Variac 101 (please) ???

[OldSchoolDave]

Hoping some experts here will help provide background and guidance on the use of a variac to "condition" vintage equipment that's been sitting unused for awhile.

Of particular interest would be things like:

What to look for in a used variac?

Best places to find one?

Recommended procedure (time at each setting) for warming up a vintage amp?

And, anything else I missed?

thanks in advance,
Dave

[mhuss]

I use an old STACO unit that's I've had for decades (so I can't offer much advice with current shopping). It's very useful to have a dedicated voltmeter attached. I'd get a 10A unit minimum (for testing DR201s ).

As far as 'conditioning' use goes, I just turn it up part way, wait a few seconds, turn it up further, wait a few seconds... (lather. rinse. repeat.) Total of maybe 4 "part ways" to full mains, total time of about 30 seconds.

--mark

[OldSchoolDave]

Total of maybe 4 "part ways" to full mains, total time of about 30 seconds.

Thanks, Mark. For some reason, I got the impression it was more involved (and time-consuming) than that. Good to know!

Dave

[mhuss]

For some reason, I got the impression it was more involved (and time-consuming) than that.

Heck with it, just plug 'er in and flip the switch! That will eliminate the weak and wimpy.

--mark

[Dr.HI-TONE]

Break it in or break it down has always been my philosophy!

I have never bought into the "reforming" concept.

[OldSchoolDave]

Break it in or break it down has always been my philosophy!

Easy to say when you've got a storeroom full of spare capacitors .

Dave

[mhuss]

All kidding aside, I never "form" new/recent vintage caps, and I have never had a problem. The only time I do the slow dance is if I'm firing up something that hasn't been switched on for decades.

A cheap and easy solution to soft starting is the "light bulb limiter." Make up a box using LowesDepot hardware: Connect a (real incandescent) light bulb -- 60w or so -- in *series* with an outlet in a box, and add a plug to it. Plug into this rig first, and it will limit that initial jolt. This rig is also great for testing amps that blow fuses -- if the light glows brightly and stays bright, you haven't fixed it yet.

--mark

[OldSchoolDave]

A cheap and easy solution to soft starting is the "light bulb limiter.

Now there's the tip of the day !

Glad I asked .

Dave

[GigawattCustom121]

.

[GigawattCustom121]

.

[OldSchoolDave]

Actually, I just checked, we have both Powerstat models 3PN116B and 3PN116C at work. I'll vouch for both.

Great info, THANKS! I am still variac-less, but your detailed post may lead to a change in status .

Dave