Tube Rectifier talk

[lowell]

Hi could someone shed some light on such tube rectifier wiring as the 5y3, 5ar4 etc? I've looked at some schematics and am confused about the heater connections. I see that the cathode is directly heated w/ 5vac on the heater. However the confusing part is that the heater is directly connected to the cathode... so my question is: How can the heater be 5vac if it's connected to the cathode which is also the high voltage DC supply?? Secondly why can't the 5vac be tapped off the normal 6.3vac heater supply?

[Bruce / Mission Amps]

Hi could someone shed some light on such tube rectifier wiring as the 5y3, 5ar4 etc? I've looked at some schematics and am confused about the heater connections. I see that the cathode is directly heated w/ 5vac on the heater. However the confusing part is that the heater is directly connected to the cathode... so my question is: How can the heater be 5vac if it's connected to the cathode which is also the high voltage DC supply?? Secondly why can't the 5vac be tapped off the normal 6.3vac heater supply?

The 5VAC is never referenced to ground so there will be no current flowing anywhere with respect to the B+ supply rail.
The only way to use a 6.3v heater for a rectifier is to use a rectifier that needs 6.3v and has a separate cathode element that does not connect to the heater elements.
Check out a 6CA4 EZ81 rectifier.

[lowell]

ok thanks Bruce... yeah I also found this thread titled "5Y3GT data sheet" that was rather informative.

[lowell]

Oh yeah, is there some mounting hardware to allow an EZ81 socket in a 5y3 chassis hole?

[stokes]

Oh yeah, is there some mounting hardware to allow an EZ81 socket in a 5y3 chassis hole?

Years ago I used a large fender washer that had a hole that fit a 9 pin socket,just drilled a couple of holes in the washer/chassis.I remember seeing someone,I think it might be AES,advertising an adapter for just that purpose.It was basically a step down washer type thing.

[Rocketrob]

Weber sells pre-cut adapter plates. check this link. Scroll down to AP1.
Rob

https://taweber.powweb.com/store/chassis/chord2.html

[lowell]

ok thanks!

[6267]

6x5 is a 6v cathode-filament heater with an octal base, but there is always the heater-cathode short danger with these tubes (not sure why, just keep hearing it). There may be some later variants that are better in that respect. You could use an 0z4 which has no heater, too although they apparently have their own issues.

[Bruce / Mission Amps]

Oh yeah, is there some mounting hardware to allow an EZ81 socket in a 5y3 chassis hole?

Yes. About five or six years ago I had a large number of them made out of stainless steel for my tweed chassis.
I was using the 5C5 chassis for my 5E3X2 amps and those were made with all octal sockets, 5U4, 6L6s and 6SC7s.... so I needed to mod the chassis for two 9 pin sockets.
Not surprisingly, I haven't used very many of them since Weber started selling the 5E3X2.