Re: U1 fried

Michael Hagen

Pilot Lamp Bulbs.

Here is a chart from the past.  Guys that build tube guitar amps still buy them.

#47 was the most popular when I was a kid, #44 to get more Light.

There would be a lot of experimenting to see if they would work to protect the amp.

What impedance speaker you are using would be a big factor too.


Mike, WA6ISP


On 2/28/2018 7:29 PM, Jerry Gaffke via Groups.Io wrote:
Now that we have a bunch of sources for the part,
I might be more inclined to experiment.

Resistance of a small incandescent bulb can go up a factor of 10 when it gets hot: 
That or a fuse would be easier to replace than an 8 pin dip.

On Wed, Feb 28, 2018 at 07:10 pm, Michael Hagen wrote:

I wonder if a small light bulb. like the old standby #47 could protect a speaker short.

Maybe some type fast lo-mass fast Thermistor?   Something that has small resistance, but goes up quickly with a short.

Just thinking crazy.

Mike, WA6ISP


Mike Hagen, WA6ISP
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