Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: goldstache on May 29, 2026, 07:32:13 am

Title: Heathkit T3 signal tracer
Post by: goldstache on May 29, 2026, 07:32:13 am

I got one of these going. Been great.


But I have a question.


The unit is a kit build, no mains fuse, 2 prong similar blade power cable.


When I plug the unit into mains, the optical magic eye indicator only responds with the heathkit T3 is antiphase plugged in.
(Dmm in AC, across the T3 and a grounded device, shows mains potential across units)


So with mains polarity aligned, T3 doesn’t illustrate readings optically, and even sig trace responds differently.


What’s up here. I mean the magic eye is an AC driven stage, so I wouldn’t think mains ac polarity would matter.


Should I just swap PT primary for the DC supply transformer? And how do I observe the wattage series setup when trying to iron out.


Schemo attached

Title: Re: Heathkit T3 signal tracer
Post by: goldstache on May 29, 2026, 07:52:44 am

https://youtu.be/-zH3Rsig2Cw?feature=shared (https://youtu.be/-zH3Rsig2Cw?feature=shared)