NEWBIE - quick question on multiple outs from one terminal

Back to my Generic 48v PSU for Phantom Power
I have eight - 4 pin XLR Female panel sockets to deliver 48v and 0V out (I know I have two spare pins but Neutrik don;t make 2 pin XLRs any more - and I am not using a three pin plug)

I have on my PCB one 48v and one 0v terminal.

How do I distribute the power - fo I:

Solder the 48v and )v to two pins of the 4 pin XLR and then from there - solder in the same XLR solder sockets to the next one - in effefct daisy chaining them
Or do I try and combine 8 wires from the XLRs into each of the PCB terminals
(it's going to be tight - I can only tend to fit one wire into each PCB terminal) - ideas (or RS part numbers...) please....

Hi uk,

Where are these connectors connecting to? Are they going to separate mic inputs located further away which will have their own local smoothing/decoupling filter? If it's a main "phantom distribution" panel feeding a rack of mic pres, I'd just buss all the +'s and 0V's together with thick-ish tinned copper wire and then run two good size wires to the main PSU. Then in each source unit, use a 100R/100uF (or something similar) filter before it hits the 6k8's.

Just a thought!

Mark

Thanks Mark
Just what I was after
It's a "phantom distribution panel" - for use with further projects

Stupid Question - how do I do the bussing?
Do I daisy chain each one in turn or do I do a "star" arrangement and solder nine wires together (8 from the XLRs into one to the PCB terminal)..
Then how do I manage to keep the 8 wires to one terminal wire solder conenction away from shorting the box?

Yep,

I'd just buss all the "+" pins and "0V" pins from the XLR's with a bit of tinned copper wire (available from Craplin :roll: ) and insulate it between connectors with a bit of plastic/PTFE sleeving. Then connect the PSU supply wires to these "bus bars". If you're stuck for space (which it sounds like you are!) then keep any filtering in the pre's you're feeding.

Using 18swg tinned copper wire keeps the resistance of the bus low, so you'll have no problems there.

EDIT>

Just a small tip when using tinned copper wire for this- solder one end into the first connector, then make a right angle in the wire, run it along the rear of the connectors, snip off a bit more than you need, and then bend the other end into the last terminal and solder in. Then you can cut small pieces of the wire, solder them into the other connectors, and bend each "stick" of wire over the main bus wire, and solder. This makes a nice neat job. Learnt this from many hours of patchbay ground bussing :shock:

This method also allows you to replace the "sticks" of wire with 100R resistors and run a 100uF cap from the +Ve pin of the XLR to the 0V bus. Handy when running directly to mic connectors. But don't bother with this because you're sending the +48V to other devices which will have a phantom filter anyway.

Mark

Aahhh... I get it now...
It is a proper 48v phanotm DC powr supply I have built with filtering and everything!! (I copied Bo Hansens design for a big 100mA output)

Dodgy Diagram alert...
Example of 3 XLR's (pins registered as 1,2,3,4)
1 = 48v
4 = 0v
X = cable

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 48V from PCB PSU
X...................X......................X
1..2................1..2..................1...2
3..4................3..4..................3...4
....X...................X.......................X
....XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 0V from PCB PSU

Bingo!

Mark

I don't see the phantom 6k81 resistors in your picture. Remember you need a pair for each XLR, not just one par altogether (sorry if you knew that already)

:thumb:

[quote author="zebra50"]I don't see the phantom 6k81 resistors in your picture. Remember you need a pair for each XLR, not just one par altogether (sorry if you knew that already)

:thumb:[/quote]
Not knowing much about this - just following this diagram
http://w1.316.telia.com/~u31617586/#48%20volts%20phantom%20power%20supply
(I have built the bottom one)

I was going to stick the 6k8 resistors on the preamps
I was planning to have a 4 pin XLR male on the preamps to feed the DC 48/0v into
Have a switch after this then the 68k resistors


Hopefully this is right....

I think get it now. So this is simply a power supply 'box' to feed some other preamp 'box'. But then why do you need 4 parallel supplies at this point. You could just send one 48V supply and then split it at the preamp inputs? Saves on cables and connectors. Or is it just to go out to several different preamp boxes - that'd make sense!

I was going to stick the 6k8 resistors on the preamps

Click to expand...

Sounds right. If in doubt check you're doing it as shown for the gyraf G9...

http://www.gyraf.dk/gy_pd/g9/g9_sch.gif

The 4-pin XLR is a good idea so you can't plug a mic in by mistake.

stewart

[quote author="zebra50"] Or is it just to go out to several different preamp boxes - that'd make sense!
[/quote]
Yep - that's it....

I was going to stick the 6k8 resistors on the preamps

Click to expand...

Sounds right. If in doubt check you're doing it as shown for the gyraf G9...

http://www.gyraf.dk/gy_pd/g9/g9_sch.gif

The 4-pin XLR is a good idea so you can't plug a mic in by mistake.

stewart

Click to expand...

Click to expand...

It wasn't my idea - I was going to use IEC inlets - but was quickly assuaged out of the idea by members of this forum...
http://www.groupdiy.com/index.php?topic=1695&highlight=


I am just about to build a +18/-18/0 box now for a multitude of possible preamps or calrecs that will use this....
I have got a 60vA Avel toroidal so I think I can drive 8 Calrecs of this

Stupid question
I was planning to solder the 48v and 0 v bus lines to pins 1 and 4 of the 4 pin Nuetrik XLRs
There is also an earth "lug" on the 4 pin XLRs
what do I do with that?