You don’t need more than 1 V coming out of any preamp, mixer, or FX box.

 

The NE5532 was introduced in 1979, the TL074 in 1978.
Modern opamps are better - 40 years of improvement.

New opamps have larger output and input ranges, you don't need 30 volts of supply to get 24 volts of output anymore.
The trend has been to reduce supply voltages, making everything simpler and cheaper.

What is the maximum output signal you really need? - this is what should drive the design choice.
A single supply 5V opamp can probably give you all you need.

 

Here's my spice model. Just looking at the Gain (first) and Volume (last) knobs and ignoring all the filtering, it can go from -22db to 43db. Passive guitar pickups can be as low as 25 mV, active can be a few volts. This amount of gain/volume adjustment gives the musician a lot of flexibility with pickups and sound systems and seems consistent with most preamps of this type.

I am a mechanical engineer, so I'm out of my depth in this arena but willing to learn. I adjusted the supply voltages from +-15 to +/-5 and it didn't change the output.

A different project I'm working on with an LM358. I know it has a common mode voltage of Vcc-2. At one point we were trying to power it with 3v3, but that only left 1.3v of signal due to the common mode voltage, we wanted a full range signal of 3v3 into an ESP32. So we had to raise it's supply voltage and will probably settle somewhere between 6 and 9v on a single sided supply. Anyway, I need to learn that type of thing for this situation (where the signal resides within the limits of the TL074) and I don't know how yet.

Changing this from a +-15 to single sided 9v would simplify things. As a reference, the bones of this circuit comes from a Fishman Mini acoustic amp that runs +/-14v, attached. My circuit has much better filtering.

 

I need a +/- 15v dc supply (100mA), powered from a +9vdc source. Application is guitar pedals. 90% of guitar pedals work off 9v, and the vast majority of 9v power supplies output 9.2-9.6vdc. My application has op amp rails at + and - 15v.

The easy answer is a Traco TEC 3-0923. Supply from 4.5-13.2v. But they cost $15.26 on Mouser.

Other options:
View attachment 342372

The mornsun used to be cheaper, not so much now with additional tariffs.

Two Questions:
1) Is it bad to run a 12v nominal supply at 9.2-9.6v, at the lower end of it's range?
2) Any suggestions at something that might be closer to $10 each instead of $15?

How about using mc34063 for boosting and same for inverting voltage?
Look at it's datasheet, it mention step up circuit and also inverting circuit

 

Looking at similar preamps available. Most acoustic guitar preamps are similar to each other. I'll list one popular one as a reference:
LR Baggs Venue
Input: 25 - 1.8 dBv
Preamp Gain: -12 - 26 dB

Looking just at that Preamp Gain, converting to volts, that's 0 - 15v roughly. So given the gain range involved, it doesn't seem that a 9v single sided supply would have enough voltage to cover that, right? So when @MisterBill2 talks about Headroom, maybe this is why?

 

"Headroom"can be the unfortunate reality that makes "great ideas" sometimes not quite so great. There are a few op-amps that are sold as "rail to rail", and some of them do very well in their intended applications. But there are always compromises of some sort..
And in many cases, especially in audio systems, the higher gains are not used to provide the greater output levels, but rather to amplify the much smaller signal levels.

 

The Input and/or Output "ranges" are very simply handled with their respective Control-Pots.

The maximum Output-Levels don't vary very much in realistic applications,
the same goes for the Input-Gain.

Only the maximum Output-Levels are constrained by the Power-Supply limitations.

The maximum Amplification, ( Gain ), is not limited by the Power-Supply-Voltage.

It's possible to have a ~1000X Gain, or even more, with only a ~5-Volt Power-Supply.

The Equipment that is being driven by the Pre-Amp will go into unusable Distortion-Levels
with as little as 1-Volt of Input.
.
.
.

 

To provide a "best possible one volt "line output level" from a low output "zero distortion" magnetic pickup that only delivers a few millivolts I need a lot of gain, not for a high output, but just to reach that 2 volt internal level to allow for the tone shaing circuit losses.