A few things I can't see on the Kelly '90 schematic

[Phil_S]

I see in various BOM made by others reference to these:

47pf poly blue cap (preamp)
metal oxide varistor 130v 50A (pots/swtiches)

I don't see them on the schematic at all. I know that sometimes you can stare at these things all day and things hide in plain sight. I would be grateful if someone could tell me where to look.

Also, in the tone stack, it is not clear how the Mid pot is wired. there is a .022 cap and it looks like that goes to the wiper. One outer leg of the Mid pot to the Bass pot and the other outer leg to ground. What is confusing me is that I can't tell if there is an erased line from that .022 cap to the outer leg of the bass pot. So, what exactly do I do with this cap and the Mid and Bass pots?

Thanks.

[Chris G]

Hi,
The 47pf goes between the plates in the output of the phase inverter.....reduces fizziness........the MOV goes across the power switch,there for protection against spikes in the ac...........

The other .022 goes to the outer lug of the bass pot.(where you thought it went)

Chris

[UR12]

I have re-drawn the schematic to include the proper power switch and added the varistor. The schematic shows a 50pf cap accross the PI plates. Either 47pf or 50pf is fine to use. The tone controls are wired correctly in the schematic. Look at the francesca pics in the files section to get a better idea of how it is connected.

[Phil_S]

Dana and Chris:
Thanks very much. I could not read what was between the plates on the PI and thought it might be a voltage reading. I see now it is the 50pf cap.

Also, now that I see the varistor on the primary side of the PT, what is this thing? I've never encountered one before. (Yes, I get the concept, variable resistor, but why, what's it's function?)

Is it important to have a double pole switch on the primary? I always build with a single pole that breaks the hot side of the connection. Is there a good reason to break the neutral as well? Does this have something to do with the varistor?

Thanks.

Regards,
Phil

[UR12]

Dana and Chris:
Thanks very much. Also, now that I see the varistor on the primary side of the PT, what is this thing? I've never encountered one before. (Yes, I get the concept, variable resistor, but why, what's it's function?)

A varistor basically filters noise or spikes on the ac line. It's not a variable resistor .

Is it important to have a double pole switch on the primary? I always build with a single pole that breaks the hot side of the connection. Is there a good reason to break the neutral as well? Does this have something to do with the varistor?
Thanks.

Regards,
Phil

It's just the way that Ken did it. There is no reason that you cant use a single pole switch and it has nothing to do with the varistor. I'd say Ken had a bunch of these switches on hand and decided to use them