Can you guess what this is for vintage audio gear?

[Michaels HiFi]

My guess is most people won't know what it is or what it does and WHY it's so important to use on new vintage or newly repaired gear.

I bet Ralph will know what it is...

 

[MikeCh]

I know what this is. DBT/crude ICL.

 

[Speedskater]

It's a dim bulb starter. It limits turn-on AC current. It allows old power supply capacitors to re-form slowly.
Also in components that have a serious problem, it prevents blowing the power supply fuses.

 

[Michaels HiFi]

It's a dim bulb starter. It limits turn-on AC current. It allows old power supply capacitors to re-form slowly.
Also in components that have a serious problem, it prevents blowing the power supply fuses.

Exactly!

It's something I use when I receive new vintage tube testers / complete internal restoration when turning them on.

Rather than spending the money on a Variac, an EE friend made this for me.

 

[Bones13]

Used one of those whilst I was DIYing Nelson Pass amps. (With a Variac)

 

[Barry]

I used something like this when I had a Phase Linear 400 with a 200,000 uF power supply. That bulb was blindingly bright when I turned the amp on

 

[atmasphere]

My guess is most people won't know what it is or what it does and WHY it's so important to use on new vintage or newly repaired gear.

I bet Ralph will know what it is...

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If you are restoring old tube equipment these are really handy sorting out the condition of the power supply. But at the same time on any old tube gear the power supply is always suspect until its been renovated.

I've seen a few cases where this sort of thing would be handy servicing solid state equipment too. A shorted power transistor will light that right up.