Chassis layout & placement of parts & Trannys HELP!!

[Greg]

Also, make sure the regulators are isolated when mounting to the case.

 

[khstudio]

OK... I just went ahead and built an external supply
(JLM ACDC board & Toroidal)

Now, what should I do inside the Pre-Amp Chassis :?:

I'm going to have 4 wires coming into the chassis from the external supply. (but NO earth ground... I've seen other pre do it)

0v (I know it goes to audio GND but ?= Pin 1 ? = Chassis ?)
48v (I know where it goes)
-24v (I know where it goes)
+24v (I know where it goes)

I NEED to know with to do with Pin 1 INPUT XLR?
I normally connect it immediatly to the chassis... one way or the other it has to connect for phantom to work.

Can or should I connect the chassis & audio ground (star point) to the 0v coming in from the supply :?:

- or -

Should I NOT connect the chassis & connect ALL pin 1 XLR's & run them over to join the Audio GND & 0v going to the external supply :?:


Please help... I'm so close & don't want to ruin all that hard work now by skimpin out :green:

I did not run the main wires yet so IF I need to run 5 wires (1 extra for the chassis) I will... I just have the 4 pin plugs & jacks already.

BTW, I could not find any info on how to deal with this issue in the META's.
I think it would be helpful. If it is there, please post a link if it matches my scenario... if not, I'll read it anyway :thumb:


Thanks,
Kevin

 

[CJ]

Great on the external supply!
Only prob is that when you find out how much quitier
it is, you will want to run everything off of it.

Then theres the tube stuff that I bet you have hanging round there somewhere...

Yes, keep noisy pin 1 leads off the main chassis.
Wire it to 0, just like you said.

You can alwas add a lift sw if you need minus 140 db noise, but
you never know what is quietest til you fire it up.

 

[khstudio]

Damn CJ, Your QUICK :green:

So I can just let the PRE-AMP chassis float... although it will be in a rack with other gear that is "EARTH-ed"

I am going to try NYD's 1 or 2 bottle pre & would like to do the same but that's another whole thread :wink:
(AC or DC heaters, 48v supply... probably separate) :?

Thanks again for your input

Kevin

 

[CJ]

I solder the ground wire from the ext pw supply directly to the chassis via a big solder lug. Then everthing ground, electrical, audio, shields, go to that lug.

You need a big bertha iron to do this, but it guarentees a solid ground that will not erode with time.

Sand the chassis, get a big puddle of solder going, drop the lug down with needle nose, let it set up, then put the iron on top of the lug to hold it whilde you add the finishing tiuches of solderon top, get it looking good, then grab it with the pliers again, try not to move for 30 seconds, and your set for life.

I know you don't want to hassle an iron right now, so save that thought for later.