One way of many to put vibration isolating grommets on the Foreplay Preamp's Power Transformer:

To modify the 1/8" ID Grommet, cut one grommet flange off so that the side view changes from and "I" to a "T". Keep as much rubber as you can on the grommet.

Adjust the top #4 nut so that the bottom of the nut is flush with the bottom of the 1/4" ID Grommet before putting the transformer into the chassis holes. The bottom nut can be torqued down as hard as you want and the top will stay as loose as you desire.

I haven't figured out how to ground the chassis of the transformer with this technique, yet. Since the bottom nut holds the fuse holder, I wanted that nut to be tight more than I wanted the chassis of the transformer grounded.

I wonder if the transformer tab will take solder if it is sanded and RMA flux is used? I'll update this page when I figure it out.

The Foreplay Preamp

Grounded Transformer Tab with Some Vibration Isolation.

I have an idea on how to attach a ground to the Foreplay transformer and still have the transformer standing on grommets:

1. On one transformer mounting hole install the grommets as shown above.
2. On the other hole install the grommets as shown below.
NOTE: Solder a wire to the solder lug BEFORE you put the solder lug on the screw. The heat from soldering may melt the grommets.

The TO220 insulating bushing (optional) is used if you wish to keep the safety ground of the transformer from touching the chassis. This is useful if you are trying to precisely control where chassis attaches to safety ground. If you install a bushing on the hole used for grounding, you may want to install a bushing between the transformer tab and the modified 1/8" ID grommet on the un-grounded hole to keep the bottom of the transformer closer to parallel to the chassis surface.

I have not tried this yet. My guess is the screw will have to be 1 inch long to work.

First installment before 7/20/00. Last update 1/12/01.