Trying a new board layout. Thoughts?

[hesamadman]

This is new to me it may not be new to you but I wanted to get opinions on the layout. This is the first stage of my preamp. It is sharing an 8uf filter capacitor. I kind of based some of my ideas off of Sluckeys AC 15 lay out. His first filter Had the power rail on the bottom of the board rather than on the top like in Hoffman's AC 30 lay out. I wanted to try to implement that. in my new build I am taking grounding very seriously. My goal is to ground all of the board components separate from the potentiometer bus bar. Which is something I'm not used to doing but I see it done a lot. A lay out like this new one will also help lead dress I won't have any wires crossing other wires.  Thanks for looking. I appreciate and comments.

[Willabe]

Now you have 2 buses, 1 for the pots and the 2nd on the board, you only need 1 buss there.

(That is if your going to use a buss.)

[hesamadman]

Isn't that what Sluckey did here? Bus on pots and board?

[DummyLoad]

the two busses should be ok as long as they are connected together at only one point.


--pete

[hesamadman]

If I connect tone stack bus to chassis termination point and board component bus at same point, it should be ok and create no ground loops correct?

[Willabe]

Isn't that what Sluckey did here? Bus on pots and board?

Yes.

Sluckey and Doug do the best work I've ever seen on there builds. (Without listing more guys, so as not to leave anyone out, (DL and HBP) others here do great work also, better than mine.) AND their builds and the builds of others who followed their layouts are very quite.

And I agree with DL as long as you only ground both buses as he described your fine, no ground loops.

But to me if you have a ground buss running the length of the eyelet/turret board close to the pots, why not just run each pot ground wire down to the eyelet/turret board ground buss?

Not to be any quieter but a little less work?

[John]

why not just run each pot ground wire down to the eyelet/turret board

It's not as purty. 


I've done it both ways, most recently the Sluckey way and I like his best. I use 22 gage wire and twist it like heater wire, and then make that the buss. Twisted for no other reason that it looks cool. 

[hesamadman]

It does look neat. I wonder if his method had anything to do with isolating the vibrato grounds or something?

[sluckey]

There's a ground scheme drawing in the pdf document for the AC-15. It should clear up any questions about the grounding in that amp.

[hesamadman]

I see that each channel is grounded separately and controls are grounded separately. Ultimately connected together but is there a reason for the control buss to be separate from components of each channel on board?

[sluckey]

Neat and orderly. The vib preamp has it's own  separate ground bus on the board and the nor preamp has it's own separate ground buss on the board. The control panel pots and input jacks have a ground buss bar. All three of these busses tie together on a chassis ground lug just below the input jacks.

[hesamadman]

That's awesome. Thanks a lot. I like that layout.

[hesamadman]

Where is the control buss bar physically connected. I can't seem to trace it down by photo. I know it connects with the others just trying to see how you did it.

[Willabe]

There's a ground scheme drawing in the pdf document for the AC-15.

I have a question, why is there 2 ground wires (one is solid black, the other dotted black/yellow) coming from the OT secondary to the power amp chassis ground?

   

[sluckey]

It's a funky Hammond OT that has two separate secondary windings that have to be strapped together for various impedance schemes. I'm strapped for 4Ω and 8Ω outputs. Look at the transformer data page to see what I mean.

The newer Hammond OTs have a more straightforward single tapped secondary winding that's much easier to use.

[DummyLoad]

There's a ground scheme drawing in the pdf document for the AC-15.

I have a question, why is there 2 ground wires (one is solid black, the other dotted black/yellow) coming from the OT secondary to the power amp chassis ground?

old parts:


http://www.hammondmfg.com/1608.htm


new parts:


http://www.hammondmfg.com/1608A.htm


--pete