Neve Direct Output Mod Complete!!!

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Sarcastic Sound

Well-known member
Joined
Dec 4, 2008
Messages
110
Location
San Diego
Hey all, just wanted to show off the latest project

Special thanks to:
Pete @ Grandmaster Audio for the Front Panel
Colin @ Audio Maintenance for the Transformers
Everyone at Prodigy Pro for forcing me to do cool projects like this.

So, here it is. This Neve didn't have direct outputs as it was a broadcast desk back in it's day. So we put some That Corp 1646's in with some Carnhill Iron and this is what we managed to come up with.

The desk had 3, 8 channel "line driver" boards inside of it that feed a 2U rack case with the transformers in it. The toggle switches let you switch between electronically balanced output from the desk or transformer isolated. The idea was "clean" and "balls" with the toggle switch. Sonically it really depends on what you put through the transformers to hear a justifiable difference, but the choice is there for those who choose to venture down that road.

Enough talk, here's some gear porn!

The line driver boards
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The Front Panel
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The Completed Switching Unit
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Console wired up
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Power
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It's been a month long war to design/build/test/change/test/install/test/change/test  ::)

But now that the war is won, time for a beer!  8)


 
I have a question, are these 1074-84 type BA283 based preamps? Because I didn't think they would work without a transformer in the circuit? Do you have a link to the type of preamp that is in the channels?  ???
Looks great though, prodigy posse are suckers for a bit of iron pr0n  ;D ;D ;D
 
I mean the following in a good way.

Why are the transformers aligned like that?  Is there a reason you did not mount them at 90 degrees to each other?

Did you test for coupling between transformers?  Drive one and look at the outputs of the ones around it with a scope.

Do you pick up signal from the other channels in the || bundled signal wires?

 
Woooooooooooooooow thats some beautiful neat wiring !
Thanks
I mean the following in a good way.
Oh good  ;)
Why are the transformers aligned like that?  Is there a reason you did not mount them at 90 degrees to each other?
I thought about this as I was building the switching box and after running a few tests (moving transformers around each other and checking for induction) I found it didn't make a difference in this case.
Did you test for coupling between transformers?  Drive one and look at the outputs of the ones around it with a scope.
Yup, tested. I used a Sencore SP495 to check for induction crosstalk. I don't remember the exact number but it was in the ballpark of -100dB crosstalk... meaning, when I send +18dbu into a channel, the amount of signal that bleeds onto the channel next to is reads around -100dB.
Do you pick up signal from the other channels in the || bundled signal wires?
I acutally found out while testing this box that the redco patchbay I was using to test actually brings the crosstalk level up 4 dB from where the box is on it's own. So the patchbay has more crosstalk than this modification does.  :eek:
As for the bundles of wire, I used Belden 24 channel cable with foil shield in the console for the unbalanced runs and elco cables, then mogami for the transformer box. And like I said, cross talk is at about -100dB for this box.
I know for a fact that Neve stacked their transformers much closer together in the console than I did, and they run unbalanced signals much further than I did. Actually the more I look at Neves the more amazed I am that they actually work... but that's another story entirely!
I have a question, are these 1074-84 type BA283 based preamps? Because I didn't think they would work without a transformer in the circuit? Do you have a link to the type of preamp that is in the channels?
The channel modules are 31114's... I don't recall off the top of my head the preamp cards it has. But for this mod I didn't actually get signal for the direct out from the 31114, not directly. (no pun intended). We wanted a post fader post cut feed for the direct out. So the signal actually comes off the 33752 routing module just after the fader return which is independently buffered of the 31114 output.





 
Gus said:
Is there a reason you did not mount them at 90 degrees to each other?

They are Neves!  Never done in 90 degrees.  It's not allowed.

Gus said:
Did you test for coupling between transformers?
Do you pick up signal from the other channels in the || bundled signal wires?

That's part of the Neve sound, man!   :D

Sarcastic, thanks for sharing and big congrats!  Yes, they are robust machines, aren't they?  Amazing how they survive through all kinds of electronic and signal conditions...
 
sarcastic, thanks for sharing and big congrats!  Yes, they are robust machines, aren't they?  Amazing how they survive through all kinds of electronic and signal conditions...

I know right!?! It really is amazing, especially after almost 30-35 years since being built this thing is still kicking!  Must have something to do with the fact that EVERYTHING going into and out of the desk hits a transformer to isolate it from the world... or maybe they just knew how to build a console back in the day?  ::)

Next up for this desk is 48V switches in banks of 8 Channels, originally this desk had 48V on all Mic inputs all the time. BAD for all those fancy ribbon mics everyone seems to have
 
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