Fender Blackface Grounding

[Bombacaototal]

I am working on a Deluxe Reverb type build and have a couple questions regarding the grounding.

I am using a Ground Buss bar across the pots which is connected to an earth ground point at the chassis, all input jacks (for both channels) are isolated via washers and the jacks are connected to the Buss bar too. All ground points of the layout are connected to the buss bar except for the Phase Inverter (47K) the 1ohm resistos of each power tube, bias tap,heaters, etc which are using the power transformer ground lug. My amp has an FX loops which also has the isolation washers and is connected to the main Buss bar chassis ground point.

Here is where the doubt arises:
1) I am not using the washers on the footswitch jack and also on the speaker jacks which are "self grounded" via contact with the chassis. Should I use washers for those too and use the power transformer ground lug for the speakers jack and the ground buss earth for the f'switch, or are they fine like this?
2) For the reverb rca jack send/return I am using the washer on the return only and grounding it on the Buss bar earth ground point, while the rca send I am using the same approach of the f'switch and speakers jack and having it in direct contact with the chassis without washers and hence "self ground".
3) I am using the rca jack send ground for the reverb transformer ground, and assume this is fine

[pdf64]

...I am not using the washers on the footswitch jack and also on the speaker jacks which are "self grounded" via contact with the chassis. Should I use washers for those too and use the power transformer ground lug for the speakers jack and the ground buss earth for the f'switch, or are they fine like this? ...

Washers for the sockets etc come in 'flat' and serrated' types; usually flat dress washers on the outside, serrated inside. It may be useful to clarify exactly how you've arranged this.

[Bombacaototal]

...I am not using the washers on the footswitch jack and also on the speaker jacks which are "self grounded" via contact with the chassis. Should I use washers for those too and use the power transformer ground lug for the speakers jack and the ground buss earth for the f'switch, or are they fine like this? ...

Washers for the sockets etc come in 'flat' and serrated' types; usually flat dress washers on the outside, serrated inside. It may be useful to clarify exactly how you've arranged this.

Thanks for the note, the isolation washers I am using on the Input Jack, etc are a hard plastic and flat.

I will check how I did the non-isolation washwers on the pedal jack, thanks for the tip!

[Roe]

FEnder's grounding scheme leaves a lot to be desired. The input and output jacks and reverb rca phone plugs are not isolated. And many preamp stages share the same filter cap and the same filtering.

[TUBEDUDE]

I would connect the signal ground buss to the chassis as far away from the transformer ground as possible.

[Bombacaototal]

I would connect the signal ground buss to the chassis as far away from the transformer ground as possible.

Thanks! That is exactly what I have in mind, one close to the Normla channel volume pot and the other after the PT

[JazzGuitarGimp]

Are you using flat pladtic washers on both sides of the panel, or does one of the washers have a lip, or shoulder, that fits inside the panel hole?

[Bombacaototal]

Are you using flat pladtic washers on both sides of the panel, or does one of the washers have a lip, or shoulder, that fits inside the panel hole?

Indeed those plastic washers where one side has the elevated lip and the other is flat. I must confess that I haven't dirlled all holes large enough to fit the lip inside. Would it make any difference?

[sluckey]

The shoulders on the washers ensure the threaded barrel of the jack does not contact the chassis... BUT ONLY IF YOU USE A PROPER SIZE HOLE. Best to use a pair of these insulating shoulder washers for each jack.

[Bombacaototal]

The shoulders on the washers ensure the threaded barrel of the jack does not contact the chassis... BUT ONLY IF YOU USE A PROPER SIZE HOLE. Best to use a pair of these insulating shoulder washers for each jack.

Many thanks sluckey, it indeed makes sense and total oversight from my side. I will have to either drill larger holes or just ground to the chassis then...I appreciate the help

[sluckey]

Here's a pic of the shoulder washers that Hoffman sells. Chassis hole must be 1/2". Also, you may need jacks with the long barrel, ie, Switchcraft L12A. FWIW, Fender never used isolated jacks on the old amps we love.

[Bombacaototal]

Attached is what I am using. I didn’t realise but I had actually drilled it wide enough for the shoulder washers..only saw once I removed the jacks....this is what happens when you let a build sit in for too long ...

[Bombacaototal]

Is it an overkill to add the star washers on the bias testing points like I did?

I am also struggling to secure the RCA connector given the additional lug I cannot add the star washers. Any advice on how to go about it?

The larger holes are from a much bigger RCA connector which came with the donor amp..I will close those with grommets

[EDIT] not sure why the pics are uploading upside down

[pompeiisneaks]

It's a bug in the shrinking feature, see it randomly, but when you click on the actual picture they turn back up the right way

~Phil

[Bombacaototal]

It's a bug in the shrinking feature, see it randomly, but when you click on the actual picture they turn back up the right way

~Phil

Ah ok, thanks Phil!