IC Voltages

[Karl]

Just a noob question here out of curiosity... What would setting the voltages for more than +/-18 Volts do, exactly? The instructions mention "If you need more headroom, the OPA2604s will withstand as much as +/-24V."

So, does this mean basically it has less gain the higher you set the voltages? I'm sorry if that's obvious. I'm just not sure I understand the headroom factor within the preamp... My mind wants to think "higher voltage would = MORE gain...?".

For example, I just used these on stereo drum overheads with a Røde NT4. I had the gain at 1 and the output all the way down and found I still had a few peaks here and there. I've got barrel pads, so it's no big deal for me, but if I should set the voltage higher to avoid this, that would be cool. Just want to understand and make sure before doing this.

thanx!

[tpryan]

Supply voltage doesn't have anything to do with gain. Higher supply voltages allow higher signal levels before the onset of clipping. If the rest of your signal chain can't handle those higher levels, however, you'll still need a pad.

[Karl]

I see... so this is essentially headroom within the preamp, not the output level? IOW, if I'm not clipping the pre, keep it at 18V and don't worry about it?

[tpryan]

"Headroom" is the difference between the nominal operating level (usually agreed to be +4dBu) and the maximum output level. The maximum output level is limited by the power supply voltage. The higher the voltage, the higher the maximum output level.