About Transformer Grounding

When looking at schematics and builds of vacuum tube amplifiers employing output transformers some people notice a curious inconsistency. On some amplifiers, the output (i.e. secondary) side of the transformer is grounded, on others, it is not. This can lead to a dilemma for amplifier builders: To ground, or not to ground? Luckily, there are some simple guidelines which will almost always yield the correct answer.

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807 Triode Investigations

In my last post, I talked about the changes I’ve made to my 807 prototype jig so that I could investigate the 400v, triode strapped, plate voltage limit. Now I’ve managed to spend some time playing with the high voltage prototype power supply and my newly modified jig. As a result, I’ve learned a surprising amount about the 807 operating as a triode.

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Yup. More Testing

A comment by “Dave K” a few days ago got me thinking about how I intend to run my 807 power stage and the limitations listed on the data sheet. So it shouldn’t be a shock to anyone that I’ve decided that a little more testing is required. And that required an update of my 807 test jig.

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There is No Shelf

In the modern western world there is this pervasive, and slightly bizarre, idea that the advance of all things (e.g. technological, medical, political, personal comfort, success, etc.) is a monotonic increasing trend from awful to awesome. And that just because something was once done or existed, then that thing is now “in the books” and there is no reason to ever revisit that thing, whatever it was. It’s a belief that once it’s been done, it’s easy to do again. But the universe is ruled by entropy. And if you stop fighting to reduce it, it just keeps growing.

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