Switchable Rectifier

[Reeltarded]

my catthode!

[hans-jörg]

ok, I put it there. A Apem witch on/on, same way like the picture, next to the Recti tube. B+ is now 30VDC higher, dissipation is on the edge but still ok (166 Ohm at cathode, 12,8 V over the R, 355 V Anode, 335 V Screens. Minus the screen dissipation I´m under 100% )
But what´s important - the sound is def. better than with tube rectifying (I feel it so). More direct and the strings are very (more) sensible to attack. I can pick a arpeggio - clean, beautiful and next moment I can dig the shi... out of the guitar (without vol. rolling back and forth).
With tube recti. the sound gets (more) brown. Its not a different which moves the world but very noticable
So I will leave this switch in for more versatility.

Thanks for the help to all.

Hans-Jörg

[martin manning]

Which way did you wire the switch? Like the kitty cat or one of the others?

[hans-jörg]

Hi Martin,
like this one:
I think, this system works better with the EZ81 (Pin 3 is B+, 4+5 is filament)

but with an 250VAC/10A Apem switch
same I use for ON/OFF and STB.

[martin manning]

With a DPDT switch (my scheme) you can kill the rectifier filament current when you're in SS mode. The only thing less "green" than a tube amp with a vacuum rectifier is a tube amp with a hot vacuum rectifier that isn't being used ;^)

[hans-jörg]

I see.

Thank you for warning. Will pull the tube when in SS.

But work your switch with a EZ81 too? With this tube is one pin more in the game.
Could you show (or write) me how this tube will work with your switch?

I tried it on weekend but played both sides only a few minutes on pice. To find out what I really prefer to put it in a fixed mode, but both sides have their beauty

Hans-Jörg

[martin manning]

Is your 6.3VAC EZ81 filament powered by the same transformer winding as the other filaments?

[tictac]

I would be very nervous about using a Mini-Switch for anything Hi Voltage and or Hi-Current

Also, I would think that with any kind of Rectifier switching, to be on the safe side you'd want to do the actual switching with the AC power off...

my .02

TT

[hans-jörg]

Hi,
@Martin, no its an independent winding.

@tictac,
I have the STB switch in front of the rectifier and switch AC of both sides including a fuse at each side . So before switching the rectifier - I switch the STB off, that means, the rectifier too. Also I don't use this small switch you see at the picture above, but a Apem switch witch can handle up to 10A. Same as I use at power on/off and STB.

Best R.

Hans-Jörg

[martin manning]

Hi,
@Martin, no its an independent winding.

In that case you should be able to wire it as drawn using a DPDT, and connecting one filament pin to the cathode. Note that this will float the rectifier filament winding at B+ voltage (same as any vacuum rectifier with a common h-k pin), and you must be sure that there is no other connection to it.

P.S. You might edit the thread title in the first post to say "Switchable Rectifier" so it can more easily be found by search later.

[hans-jörg]

Hi Martin,
I see. I was not sure if I can run it this way with that common pin. But as the filament is independent and only for rectifier, there should be nothing against it.
And: its definitely healthier for the tube!
Thank you.
@your PS: its done

Best regards

Hans-Jörg