Bottlehead Forum

Bottlehead Kits => Mainline => Topic started by: Phippers on October 29, 2021, 02:43:54 AM

Title: Mainline temperature
Post by: Phippers on October 29, 2021, 02:43:54 AM

Hi,

How warm should the Mainline be running?

I'm reading about 50 deg centigrade on the power transformer bell.

It is consuming around 36 watts.

thanks

Paul.

Title: Re: Mainline temperature
Post by: Paul Joppa on October 29, 2021, 05:10:09 AM

It should be under 60C/140F.That's a widely accepted maximum for surfaces that can be touched.

The power transformer is designed to generate a low magnetic field, for minimum hum and vibration; consequently it gets warm. (The internal materials are rated for 155C.) Tubes get hotter, but they were not originally designed to be accessible. At least they glow as a warning  :^)

Title: Re: Mainline temperature
Post by: Phippers on October 29, 2021, 01:09:47 PM

Thanks Paul,

Yep I was reading around 70C on the 12AU7.