AEG tubular rectifier . Where to find ? Or eplacing with silicon diodes ?

[Rob Flinn]

Looking for a black AEG tubular rectifier like you get in V72 & EMT plate amps ?  ANyone know where to get them ?

Or has anyone done a silicon diode sub in a mono EMT 140 amplifier ? 

 

[synthiaks]

Can't you exchange them to any full rectifier?

Is pinout an issue, or is this an exact original restoration?

 

[analogguru]

If you are talking about the component marked with B300C70 which looks like this:

then it is a selenium rectifier bridge with 300V and 70mA which can be replaced by 4 x 1N4007 or a silicon diode bridge with a voltage rating of 300V or above .

Currently you can buy an original one here:
http://www.ebay.de/itm/Gleichrichter-B300C70-Radio-Amateur-Funk-Sammler-Nostalgie-selten-/301817022266?hash=item4645b2473a:g:FNUAAOxy3HJTJI4z

 

[gridcurrent]

silicon diode sub in a mono EMT 140 amplifier ?

replaced many with 1A, 1000 PIV, silicon bridges.  no issues.

 

[CJ]

selenium cans?

B+ will come up as less fwd drop,  watch cap ratings,

 

[Rob Flinn]

It looks like the one to the right  in the attached pic but is longer.

Grid current.  Did you use a dropper resistor to get the V down to what it was with the selenium rectifier ?  If so do you know the resisitance & power of the resistor you used ?

 

[Michael Tibes]

You can replace it with a silicon rectifier / individual diodes and a serial resistor and it will give you the right voltage . I believe it won't sound different until the psu gets pushed hard. A V76 in full distortion does sound different with the silicon replacement, but I guess that you won't distort the reverb, so nothing to worry about 

If you want the original you might have to look on ebay, I've been looking occasionally and never found the right type. There were a lot of different types and sizes...

Michael

 

[gridcurrent]

Did you use a dropper resistor to get the V down to what it was with the selenium rectifier ?  If so do you know the resisitance & power of the resistor you used ?

Yes.  I have added series resistance in some units.  As the dual section filter capacitor usually needs replacement with new pieces @  450 VDC, the higher B+ did not appear to be a problem.  But your concern is well noted.
Attached is photo of a power supply revision.  Two 82 ohm, 1/ W  resistors in series with the bridge made up of 1N4007's.
A 6 VDC regulator powers the front end tube heaters, input derived from series connected transformer secondaries.

 

[Rob Flinn]

Thanks for the advice everyone.

 

[CJ]

there might be some toxic issues with those old stacks, not very tasty anyway so no big,

 

[ln76d]

Try on ebay.de and look for "seleniumgleichrichter", usual there were AEG cans