SSE grounding question

[neonthecat]

Hello to all....
This is my first post as I have a SSE board on the way. In preparation, I've been studying the George's website and the SSE schematic and wiring diagrams.
I noted that the main power ground goes from the IEC socket, to the RCA input jack (non-signal side). The RCA jacks I'm going to use have insulating washers to isolate the entire RCA jack from the chassis ground. The last amp I built did not ground the jacks to the chassis.
So my question is if this grounding method will cause any hum problems? Would it be better to supply the board (and chassis) a ground directly from the IEC socket, and let the RCA's stay isolated?

Thanks!
"The Cat"

 

[rknize]

That is exactly what I did and it works fine. The key is just to make sure you have only one path between the PCB and the chassis.

 

[neonthecat]

Russ,

Thank you for the reply.
BTW....Your SSE build looks great. I hope to post some shots of my own in due time.

 

[motosapien]

I was just looking at RCA plugs and wondering the same thing. The hours I've spent sifting through and searching posts here has been very worth while. All my board parts have been ordered so I'm starting to look at sourcing chassis mounted parts.

 

[Sodacose]

Arise, forgotten thread!

Where did you all ground the board? Looks like the other half of the connector with the HV center tap is a good candidate?

 

[harry888]

Arise, forgotten thread!

Where did you all ground the board? Looks like the other half of the connector with the HV center tap is a good candidate?

Like many others here I used one of the transformer bolts as my star ground.
Use a long bolt. A wire from the IEC ground pin is connected to this bolt.
Then make all your ground connections to this bolt.

Following Tubelab's diagram for a basic triode config without CFB a wire from
one RCA ground is tied here, both speaker grounds must be connected here.
Your RCA and speaker jacks must be isolated from the chassis.

A good idea is to use tooth washers between connections on the grounded
bolt to ensure strong contact.

 

[harry888]

Some other things I didn't mention above.
Use ring connectors for connections to your star ground, do not rely on
simply wrapping wires around the bolt.
The chassis will be grounded through the bolt, and as a reminder, all
other objects bolted to the chassis must have good paint free contact.
Double check all your ground connections before powering up your
amp.

 

[Sodacose]

Is there any advantage or disadvantage of grounding the rca and speaker posts to the IEC directly instead of through the chassis bolt? It would actually be the cleaner and easier solution for my build. Seems to me that would also isolate the signal ground from the chassis?

 

[harry888]

Is there any advantage or disadvantage of grounding the rca and speaker posts to the IEC directly instead of through the chassis bolt? It would actually be the cleaner and easier solution for my build. Seems to me that would also isolate the signal ground from the chassis?

It is okay to make the ground connections directly to the IEC ground pin if
it is more convenient for your build.
However, you must be absolutely sure that the chassis and all metal objects
bolted to it are grounded, these groundings can only be done from the IEC
ground pin. That is why I suggested using a transformer bolt as your star
ground.
The main ground point is the IEC ground pin, that one point must be seen
by everything that should be grounded -
- the pcb which must be grounded only once which is through one RCA
ground connection.
- the speaker ground jacks if no CFB is used
- the chassis
- all metal objects bolted to the chassis, screws, switches etc.

 

[Sodacose]

Harry, I omitted the part about the transformer bolt, but that's certainly part of my plan (as chassis ground). My chassis is metal top/bottom/front/back with wood sides so grounding a transformer bolt should take care of all the chassis mount components.

I'm very close to the end of the build so I'm starting to obsess over the details (like the black art of grounding)!

 

[harry888]

Harry, I omitted the part about the transformer bolt, but that's certainly part of my plan (as chassis ground). My chassis is metal top/bottom/front/back with wood sides so grounding a transformer bolt should take care of all the chassis mount components.

I'm very close to the end of the build so I'm starting to obsess over the details (like the black art of grounding)!

You'll be okay if you just follow Tubelab's wiring diagrams. Which is
what I did.
I also was a bit unsure about grounding. I read all of what is on Tubelab's
site plus dozens of posts about grounding on the forum and on other sites
before I got confident about grounding, at least on the SSE. I followed
Tubelab's wiring diagrams and everything turned out okay.

Good luck on your build.