Plexi6v6 internal channel jumper

[deiseldave]

Hello. I have built a Mark Huss-esque Plexi6v6 with V1 grid resistors mounted on the board. I am wanting to put the grid resistors at the V1 end of coax directly from input to tube socket.
I have (2) plastic switching input jacks, one with a 1M resistor to ground (Hi & Lo). My question is, where/how should I internally jumper the channels together?
This is part of an effort to reduce noise, a bit. I am in the process of improving the grounding scheme. But, had also read that coax grounded at the jack with grid resistor on the end helps, as well.
I sincerely appreciate the help you guys have given so far. Thanks in advance for advice on this. Dave.

[Stevem]

What type of noise are you dealing with,gain hiss/ white noise, or 60 hz or 120 hz hum, or some of all three?

[deiseldave]

Some of all 3. I elevated the heater supply 50V (which helped), readjusted some grounds (that I could reach without lifting out the board) based on Hoffman's grounding method. That also helped some.
Now I have un-soldered enough leads to lift the board enough to be able to re-ground everything.
I have looked at Randall Aiken's ground info, and Hoffman's info, and they seem to differ a bit.
My plan is to run the OT secondary ground directly to the speaker jack ground (plastic switched jacks), and take a ground lead from it to meet, 1st can cap (for 6V6 plates and screens) ground, HV CT, bleeder ground to closest PT lug. Then, bus ground for PI section, bias, elevation circuit, and presence to another close PT lug.
Input jacks, preamp ground bus, and pot grounds to a grounding terminal located near the input jacks. The earth in is run (by itself) to the closest PT lug to the AC in. Does that sound right?

[deiseldave]

Good Lord, these switching jacks confuse me. It seems like there should be a way to tie the coax down to the jacks to where I would have both hi and low inputs and channels jumped. But, I can't seem to figure it out. Help please.[/img]

[deiseldave]

It beat me. I just wired up one jack with a 1M load resistor and both V1a and V1b feeds. We don't need no stinking second jack.
If someone knows how to do the two jacks (hi & lo) and jumping both channels, please let me know, because it whoop'd me.

[deeder]

Dave, here is the schematic for jumpering the inputs I'll use in my 1987 build:

[deiseldave]

Thanks, Deeder.