Gain Switching Problem

[glp]

I am using a front panel Push/Pull to deactivate the first gain stage of 12AX7. When pulled it passes the input on to the 2nd gain stage, nulling the 1st. It is very effective and useful.

I have tried Webers relay to make this footswitchable and while it switches just fine (I love that 6.3v power supply idea) it generates too much hum when engaged.

I emailed Ted and his simple reply was that I should use shielded wire. Which I tried to the input.... all to no change.

I can't help but think I am missing something really stupid...... or this is just the wrong relay to use in this application.

Could use some help on shutting down the 1st gain stage and passing along to the second with a footswitch.

Appreciate you guys!

[mhuss]

Make sure none of the relay power wiring is connected to circuit ground or the chassis, e.g., the push-pull switch, particularly if the heater winding is center-tapped and connected to ground..

--mark h

[glp]

So if I am pulling the 6.3v off of the same tube (V1) I am trying to switch -that could be a part of the problem? This PT is artificially center tapped thru 2 - 100 ohm resistors.

and now that you mention it - I am wondering how well I can make this work as I want to leave the front panel Push/Pull in place - in case no footswitch is available. So this relay would be in addition to it. I am having nightmares about alot of extra wiring going back and forth, signal and otherwise.

Boy could I use a layout of the idea.............