Modded 53 Deluxe

[galtjunk]

I have a 53 Deluxe with a replacement OT and modded to use 9 pin preamp tubes.
It has a three prong plug but it looks like they left the death cap in.
Why?
It also looks like there is a bias adjustment.
Again why?

http://imgbox.com/g/4yE8Rw79qD

[sluckey]

It has a three prong plug but it looks like they left the death cap in.
Why?

Once a three prong power cord is PROPERLY installed the death cap is no longer a danger.

Can't really say about the "bias" pot without a schematic.

[galtjunk]

It's good to know that the cap doesn't matter.
I don't have a schematic but the gut shot in the 7th photo shows the mod.

Thanks

[Phil_S]

I can't see the value of the so-called bias pot. The 5E3 is cathode biased. The is a self-limiting design. Changing the value of the cathode resistor may shift the operating point a bit, but I can't imagine it has any meaningful effect on tone. The 5E3 has a good deal of distortion to begin with. Dialing Rk up or down in a limited range really does very little. That is the nature of cathode bias. If you caused a large swing in Rk, I suppose you could make it hot enough to make it really blatty sounding or cool it off enough to neuter it. What for? IMHO, the 5E3 is a one trick pony. Buy another pony if you don't like the one you have. I'd set it to the proper Rk value and forget it.

BTW, clip that death cap and sell on ebait. Those black ones with red stripes are considered desirable. You'll might get $10-$20 if it's not leaky.

[didit]

I've built a few cathode biased amps with adjustment simply using a higher resistance reostat in parallel with the fixed power resistor. No claim that this is what was installed here, but it's definitely possible -- and when used carefully it does work; note it's best to have a limiting resistor in series with that reostat to avoid smoke.

Best .. Ian

[Mac Dillard]

I've built a few cathode biased amps with adjustment simply using a higher resistance reostat in parallel with the fixed power resistor. No claim that this is what was installed here, but it's definitely possible -- and can when used carefully it does work; note it's best to have a limiting resistor in series with that reostat to avoid smoke.

Best .. Ian

I have done the same in order to use different power tubes, assuming the PT and OT are ok, you can do this and swap 6v6, 6l6 all the way up to a KT88.