Run 24V Preamp from +-16V supply

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drjay

New member
Joined
Apr 5, 2018
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2
Hello forum members,

first of all, I‘d like to  thank you all for the great info in this forum! Altough I gathered some electronics experience by tinkering with modular synth modules, I‘m pretty new to the audio electronics bussiness. So please bear with me  :)

Reading through a couple of schematics recently, I came across a circuit, which ran a 24V (Neve style?) preamp from a symmetrical 16V supply. As far as I can remember it was done by replacing the 0V connection by -8V thus giving 24 V differential voltage. Could be I‘m wrong with this assumption... Unfortunately I can‘t find the thread or schematic any longer. Can someone please point me in the right direction? Thanks for your help.
 
This is what I have done before
To get 24V of a bipolar 15VDC/16VDC like the API 500 series module use a 7824 regulator. where the in is the +16V, GND pin was referenced to the -16VDC  which  gives output of +24VDC.    well that's the basics of it.  there are a coupl of diods and caps in that part as well.
 
Thanks. I think I did not describe it precisely enough. I actually wanted to run a Neve amp design as make up gain stage in a passive eq to get some colouration. Unbalacing und balancing would be done by the standard 5534 stages on the input and output.
I thought it would be sufficient to AC couple the make up gain stage in order to get away with the different voltages (the 5532s are being powered by +-16V).
Is that correct?
@pucho812: sounds interesting. Are there any schematics out there? Otherwise  I would probably screw it up...

By the way I found the schematic. It was done like that in the EZ1081 from Audiomaintenance (-16/+8)
 
drjay said:
Reading through a couple of schematics recently, I came across a circuit, which ran a 24V (Neve style?) preamp from a symmetrical 16V supply. As far as I can remember it was done by replacing the 0V connection by -8V thus giving 24 V differential voltage. Could be I‘m wrong with this assumption... Unfortunately I can‘t find the thread or schematic any longer. Can someone please point me in the right direction? Thanks for your help.
You probably won't have to do that. Most circuits that work on single rail 24V can work on 32V a rail with minor mods. Indeed, AC coupling ins & outs is necessary, and some attention is required to decoupling. In particular, nodes that are decoupled to the single-rail's 0V, would benefit being decoupled to the "new" 0V (watch out for capacitors' orientation).
Some analysis of the circuit is required.
 

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