JW

Multiple outs questions 1272>LO1166 Neve
« on: February 21, 2021, 12:28:56 PM »
Hi,

I have a simple 1272 summing bus in my console and I'm trying to find info on how to wire a mult for the main outs. Can someone direct me to the schematic or just mention how Neve would have done this . .
Do I just add another LO1166 with the primary connected to the 1272 unbalanced output? So, each out would be driving 2 Xformers with 2 loads?

And to answer an obvious question. The two outs would be 1. Main outs with the ability to drive 600 ohms 2. Might be feeding an unbalanced -10dB, high impedance input (monitor amp)

Are both transformers necessary or can I possibly just tap the Neve unbalanced output at the same time that it's driving a 600 ohm load in parallel? Or would this be bad?



boji

Re: Multiple outs questions 1272>LO1166 Neve
« Reply #1 on: February 21, 2021, 03:53:22 PM »
Quote
Can I possibly just tap the Neve unbalanced output at the same time that it's driving a 600 ohm load in parallel? Or would this be bad?

If splitting off the 1272's output into a high impedance input (balanced or not), the single 1166 should not be affected significantly. An example would be tapping a line driver's output to add a vu buffer.

Tx primaries will see a reflected impedance of whatever the secondaries are connected to, so perhaps someone else can explain what would happen if a 2nd tx was added (probably not advisable).
« Last Edit: February 21, 2021, 04:10:01 PM by boji »

Re: Multiple outs questions 1272>LO1166 Neve
« Reply #2 on: February 21, 2021, 04:15:43 PM »
If your secondary load will always only be that -10dBv high impedance monitor amp then I would use the 1272's unbalanced output.  That 1272 unbalanced output is 4dB lower in level than the main out too which is closer to what -10dBv expects. 
 

Without adding another high current buffer, the 1272 can't drive 2 low impedance loads.   The output transistor on the 1272 amp has enough current to drive the 200 ohms that's reflected to the LO1166's primary when there's a 600 ohm secondary load, but not much more. 

Adding the equivalent of a 1271 would allow a second low z loaded outputl, which is how Neve did it on the big desks. 

Edit: I'm assuming we're keeping this all Neve so, alternatively, a 31267 10K:600 on the input of your monitor amp would drop the +4dBu to -10dBv and then you can just strap that across your main 1272 outputs as well as your other 600 ohm load. 
 
« Last Edit: February 21, 2021, 04:27:29 PM by Winston O'Boogie »
D. J. H.

The standard way to reduce much of the noise and distortion in audio gear in 1955 was to have a couple of beers.
 Anything else was too fiddlesome and too expensive.


 

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