Higher voltage power supply 9v vs 18 volt

[alfafalfa]

Does a higher voltage power supply always mean that your ( distortion) pedal has more headroom ?
I'm planning to try this out with a BSIAB  running on 18 volt.
Has any of you tried this before  ?

Alf

[GibsonGM]

Generally speaking, increasing the power supply to 18v lets you increase headroom, yup.  BUT, there are other considerations!! Component tolerances are 1st & foremost, LOL...watch your opamp/transistor max voltages/currents, and cap working voltages in the ps line.  Current thru resistors will double, could be critical.   Most of the stuff I've built is set up for its stated power supply.  Gain is a tough one...too much and things like transistors can act 'weird' (oscillate, etc).   I haven't built the BSIAB yet so can't tell you specifically...sometimes more power available = LESS clipping since it HAS more headroom.   Feel free to play a little, but remember, you might waste something - or everything - in your circuit!!     

[Sir H C]

Most distortion pedals use diode clipping (either one or two in series) and this limits the swing to about 1.4 to 2.8 volts peak-to-peak.  So going from 9 V to 18 V will do little if anything.  WHere it does come in handy is with effects that are clean.  You gain a good amount of headroom, more than you might first think since many op-amps have about 1.4 volts from the rails as their swing limit.  So with a 9V rail, you get about 6V max swing.  At 18V, you get about 15 volt swing.  that is almost a 3x improvement.  As stated by GibsonGM, you have to watch the voltages and currents going through things now.  Still this is why many old mixing consoles had +-24V or higher supplies.

[alfafalfa]

A BSIAB  doesn't use clipping diodes so this must be a  good  candidate  to try.
So I only have to take care that I use electrolytics of 25 volts.
If I would like to make the gain switchable , a nice crunch in the lower regions and a full lead sound with the gain turned up I would have to use two potmeters , wouldn't I ?
But how do I switch between them ?
By the way , did anybody try different  Hfe in the J201 's ?  Does it make a ( great) difference ?

Tia  , Alf

[Rutherberg]

I tested the BSIAB with 12V and that tears off! More gain and fatally more unwanted noise 
But that remains reasonable !
 
But with more than 12V, it starts to whistle.

Rutherberg