Transformer has no center taps?

[MikeH]

This is the power transformer I pulled from an old tube reel-to-reel unit:

https://ibb.co/NT5TjK7

Two wires for the primary, two wires for the HV secondary, two for the LV secondary. No center tap wires.

Here’s the schematic (printed inside the unit):

https://ibb.co/Kx5dNX0

The PT is at the bottom, just right of center; you’ll note that it shows both secondaries have grounded center taps. So what gives? Are the center taps internally grounded? Is that a thing?

[Enzo]

Is that a thing?

Got an ohm meter?


(Gotta bring along those Ann Arbor guys...)

[dmeek]

I've seen power transformers with internally grounded center taps. You have to hope the mounting bolts don't come loose.

[MikeH]

Got an ohm meter?


(Gotta bring along those Ann Arbor guys...)

Yeah I suppose I should have thought of that. It is indeed internally grounded. Seems like a lousy way to do it though. Makes the chassis connections really important.

Too bad there’s no 5v tap, would actually make a decent PT for a low wattage tweed style amp.

[g1]

It is indeed internally grounded. Seems like a lousy way to do it though. Makes the chassis connections really important.

I'm a bit surprised seeing those 'clip on' nuts like that for the mounting. There's no external wire to the casing?

[Chuck H]

And with enameled bell covers and base mount.?. I'd remove the covers and see what internally grounded means. If the internal ground contact is visible and it didn't satisfy me I'd add a lead that could be soldered.

[MikeH]

I'm a bit surprised seeing those 'clip on' nuts like that for the mounting. There's no external wire to the casing?

It may be under the bells, but yeah definitely seems like a sketchy ground connection. If I ever have the itch to use it I’ll take the bells off and see if there is a lead that is accessible.

[The Dude]

And with enameled bell covers and base mount.?. I'd remove the covers and see what internally grounded means. If the internal ground contact is visible and it didn't satisfy me I'd add a lead that could be soldered.

Amen!

[Enzo]

"tinnerman nuts"

[Chuck H]

"tinnerman nuts"

Show off.

But really, that's cool. I use to work with a carpenter that knew the names for every type of trim appointment ever installed on a house. Who knows what an astragal is!?! It was fun.

[Enzo]

I know what an ogee is. Ooh ooh, and a finial.



OK, how about apse, nave, and narthex?

[olddawg]

Too bad there’s no 5v tap, would actually make a decent PT for a low wattage tweed style amp.

Couple of diodes.. doubt if it would make a huge difference. If its out of a R to R it’s probably a single ended amp.

[g1]

OK, how about apse, nave, and narthex?

Just nave with a K.