Help with 9v regulator

[StephanAR]

Helo guys! New member here!
Not really that deep into electronics, but as forums tend to be a good placed to learn, made my subscription today looking for some help.
I'm a musician and have some knowledge about guitar circuits, pedals, and stuff. Effects usually run on 9v, and as an option for a clean power I've made a battery pack with 8x 1.2v AA 2000ma NiMH batteries. The issue I'm having is that when fully charged they deliver around 10v, then they have a long stable 9.6v run, then they drop to around 8v when near diacharged.
As dedicated power supplies are really expensive (specially here in brazil), I think a regulator might help with my battery pack. Am I thinking right?
What I'd like to do is avoid the voltage changes during the battery discharge and set it on 9v instead of 9.6v. Is that possible? Too complicated? Will it add noise?
To start, I don't know where to start. Did a good google search, but only found regulators with transformers and stuff.
Can anyone point me a circuit I could use?
Thanks for any input!

 

[shaiko]

How much current do you expect to draw?

As dedicated power supplies are really expensive

What do you mean?
A simple AC/DC supply is really inexpensive.
https://www.amazon.com/Planet-Waves-9V-Power-Adapter/dp/B00191WVF6

 

[D.A.(Tony)Stewart]

how sensitive to voltage are your applications?
how sensitive to ripple even if above 20kHz?
How important to cost is efficiency?
How important to complexity is cost?
How good are your board design skills?
What can you afford to make or buy?
What average /peak current do you need?

These are all variables in choosing any regulator which can raise or lower the voltage?

The typical solution to boost or lower voltages in SMPS lingo is a "Boost-Buck" regulator

TI ant Linear both have free online design tools.
Be prepared to sink your teeth deeply into electronics.

https://www.linear.com/parametric/S..._10!vout_9!iout_1!vout2_!iout2_!vout3_!iout3_

 

[StephanAR]

Oh god, looks more complicated than I thought... I've found some 12v to 9v regulator schematics that looked kind of simple, thought maybe it could be easy...
- effects are tuned to run on 9v, but works fine with some variation that causes slight tone change
- don't know what ripple is
- cost is an issue
- can't design a board, hoping for something I could do by PtP
- max current draw with all applications connected and running is 130mah, but that isn't a real situation because I don't have all of them on at the same time

I'm looking for this solution because audio applications tend to be sensitive to interference. Using a cheap ac-dc adapter will put a lot of noise on my sound, so I decided to go with batteries. But now I'd like to stabilize the voltage I have so I can always have the same tone coming out of my effects.
A good power supply for guitar effects can cost some money...

 

[Audioguru]

Each Ni-MH cell is 1.4V to 1.5V when fresh off the charger. Then eight of them produce as much as 12.0V that is probably fine for your pedal circuits.
But yours is charged to only 10V (no where near a full charge). Your charger is wrong. Is it a real charger or is it a 10V power supply? A power supply is not a charger.

Most simple 9V regulators need a minimum input of 11V so they will not work when powered from eight Ni-MH cells.
A low dropout 9V regulator (if you can find one) needs as minimum input of 9.5V so that is also no good.

I have powered many audio circuits from rechargeable batteries without a voltage regulator and they worked perfectly. I added a simple low battery voltage indicator (1.0V per cell) so that the battery is not damaged from discharging too low.