Replacing ST70 selenium diode

Okay, I've inspected this diode's connections.
I've inspected the rectifier tube connections.
I've read the yellow diode sheet.

I's got one question.

There are two lugs on the selenium diode.
The one closest to the chassis has a yellow/black
wire coming from the transformer and is very short.
The lug farthest from the chassis has a black hookup
wire going to the 7 lug terminal strip.

If I want to keep this amp looking closest to stock
and the designer's vision, what is the best way of dealing
with these connections and placing in the new diodes.

Bob himself in a post says to put in a 2 lug strip.
I like this and it would look like it belongs in the amp.

The yellow sheet says to connect the diodes at the
rectifier tube's red wires after changing the positions.

If I connect the diodes to the two red transformer wires
after changing their positions...

What do I do with the selenium diode and its two
wire connections.

I don't think I can just leave the yellow/black transformer
wire hanging and I really don't know what to do about
that other black hookup wire going from the selenium diode
to the 7 lug terminal strip.

Helpppp
Thanks for reading.

It sounds like you have combined two unrelated issues. The yellow sheet, as it is called, pertains to a modification to the rectifier tube socket and has nothing to do with the selenium rectifier, which supplies negative voltage to the bias supply. If you are attempting to replace the selenium rectifier, then remove the rectifier, put the 2 lug strip in its place, connect the red/black transformer wire and the banded end of a IN4007 to one lug and the black wire and the other end of the IN4007 to the other lug.

Actually a 3 lug terminal strip might be better, because terminal strips often have one lug that is attached to the mounting leg for the strip and will therefore be grounded. You definitely don't want any of your connections here to be grounded, so be aware of this when making your connections. The only other thing to consider is the possibility of having to tweak the resistor values in the bias supply. See Bob's comments below that I have copied from an older post:

The only minor thing that could happen is that in some amps after a change from the stock selenium rectifier to a diode the bias range will change somewhat. You won't get your "1.56 volts DC" bias voltage near the center of the bias control anymore. The standard thing to do if this does happen is to alter the values of the two 10K resistors on the 7 lug terminal strip. The usual cure is to add another 10K resistors in parallel with the 10K resistor between lugs 1 and 2 (to give a 5K effective resistance) and a larger 20K or so resistor in parallel with the 10K resistor that is now between lugs 3 and 4. A 20K resitor here will give you an effective 6.66K resistance between lugs 3 and 4. This should now give you the correct bias somewhere near the center of the bias control. The reason for the necessity of the resistor alterations is due to the greater forward flow of current by a diode as opposed to a selenium rectifier.

Yikes..

Now, after your explanation all this makes sense.
except for one thing.....

should the banded end go on the transformer side ( yellow/black wire )?

Wow, this makes a great bit of difference in my thinking.

thanks so much for your help !!!!!!!!!

So.....

the banded end goes hard right to the yellow/black transformer
wire and the other end goes to the smaller black hookup wire
that connects to the 7 lug terminal strip, right ???

Silly me.........

JackF999 wrote:So.....

the banded end goes hard right to the yellow/black transformer
wire and the other end goes to the smaller black hookup wire
that connects to the 7 lug terminal strip, right ???

Silly me.........

Yes, you are correct.

Bob is right: