Dual supplies in stomp boxes

[tackleberry]

Im working on my valve jr adding a SS FX loop. I have a book with the design for this loop using a dual supply for power versus single supply and ground. As Im ordering parts for the amp would this be good to use in stomp boxes also? A 9v+ supply from my wall wart and a regulator at the power jack giving 9v-? Or since Im building this supply into the amp add a jack to the amp to run power to my pedals. I built a voltage doubler for one of my pedals and like how it sounded this way but didnt like all the noise the doubler created. Building the cascading voltage regulator for my SS FX loop would be easy to give it 18v +/-, 12v +/-, and/or 9v +/- taps for pedals.

[Paul Perry (Frostwave)]

I make pedals based on the old analog synth circuits that are +15 and -15.
To get the + and - 15 easily, I use a 15V AC output plugpack, tie one end to ground, the other end goes to a + and a - half wave rectifiers, and the raw + and - 15V is smoothed by 7815 and 7915 regulator chips.
Works well for me! maybe a variation of this will work for you.

[tackleberry]

The dual supply schematic calls for a 24v center tap transformer then diodes then 7815/7815 to 7812/7912 regulators to get the supply for the FX loop. Mouser had plenty of regulators to get just about any voltage. So this would be worth doing then.

[Andi]

On a related note, if one had bipolar supplies in a TS style pedal, would one still want to decouple the input and output and have bleed resistors to ground from the outsides of the decoupling caps? I would think that the answer would be "yes" to both from a good-practice point of view...

[Paul Perry (Frostwave)]

The dual supply schematic calls for a 24v center tap transformer then diodes then 7815/7815 to 7812/7912 regulators to get the supply for the FX loop.

yes, this works.. but you don't gain anything, in my opinion. At least, considering that you need a 24V centre tap tranny, instead of a cheaper and more available AC output plugpack. And if you need to change the mains voltage, it's easier to change the wart, than the transformer

[tackleberry]

Im building it into the amp to power the SS FX loop. So was going to build it this way anyways. And Im gonna make a stand alone spring reverb unit thats SS and it will need power to. A few extra parts and I can have 18v, 12v, and 9v taps. I know the 18v to my DoubleD pedal made a huge difference in its tone. My store bought stuff I dont feel like modding to run on 18v. I have read that the 1spot I am currently using can add hiss so this would eliminate that issue.

[PerroGrande]

On a related note, if one had bipolar supplies in a TS style pedal, would one still want to decouple the input and output and have bleed resistors to ground from the outsides of the decoupling caps? I would think that the answer would be "yes" to both from a good-practice point of view...

Yes, both are good ideas. 

An "ideal" op amp might not require it, but the real world ones that we're "stuck" using are imperfect devices (as are the devices producing our power supply voltages, etc).  We also don't know what the behavior of the following stage will be, so depending on the connected device and our circuit, DC coupling may change the operating parameters of our circuit...  We know all these parameters internally, so DC coupling inside a circuit is cool.  However, for most stuff on here, AC coupling is the way to go, even if you're running split supplies.