Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: worth on March 16, 2012, 11:59:23 am

Title: thermistor question
Post by: worth on March 16, 2012, 11:59:23 am

Looking at this schematic, there is a thermistor , (Thm1) in the upper left corner between the power receptical and the power switch. Someone has jumpered this thermistor with a wire. Could that cause a problem ? There is quite a hum in the amp.

Title: Re: thermistor question
Post by: phsyconoodler on March 16, 2012, 01:05:27 pm

That won't cause a hum.You have other issues.Find those first and then get a new thermistor.

Title: Re: thermistor question
Post by: worth on March 16, 2012, 03:27:47 pm

Turns out R11 , (4.7 ohm at bottom of schem ) was burned , breaking a signal ground.