Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: theundeadelvis on July 20, 2010, 08:31:57 pm

Title: Transformer heater leads - Continuity
Post by: theundeadelvis on July 20, 2010, 08:31:57 pm

If I use the continuity tester on the the two heater leads (not the center tap) should I get a beep? I sure hope the answer is yes.  :cry:

Title: Re: Transformer heater leads - Continuity
Post by: theundeadelvis on July 20, 2010, 08:34:24 pm

Momentary lapse due to being exhausted. I think it's ok. I tested the leads on the rectifier heaters and they show there is continuity too, so it must be alright. Brain isn't working at 100%. May be bed time.

Title: Re: Transformer heater leads - Continuity
Post by: Dave on July 20, 2010, 08:44:09 pm

There should be continuity. Not a direct short, but not k-ohms of resistance either.

Dave

Title: Re: Transformer heater leads - Continuity
Post by: PRR on July 21, 2010, 12:17:15 am

"Continuity" is undefined. Some peepers peep anything under 999 ohms, some not until it gets below 10 ohms.

In any case: a typical heater winding is 0.3 ohms or less. Most meters don't read this low. They either show the ~~1 ohm of their own leads, or they fool you by rounding-down to zero. I have a meter will read sub-ohm but it needs a battery. I have a unique peeper which gives different pitch for anything over 0.02 ohms.

But in general, without exotic tools, a heater winding measures as the next best thing to a dead short.