Thoughts regarding zener/transistor regulator vs. buck/boost type?

Thread Starter

superduper

Joined Dec 5, 2010
53
Hi folks.

I am in the planning stages of building an audio project, (radio, amplifier, etc.) using some pre-built modules which are very cheap online. The modules will require various voltages:

Amp: unregulated, up to 25vdc ok.
Tuner: 12vdc
CD: 12vdc and 5vdc
Preamp (tone/balance/volume, etc). some are 12vdc and some are +/-12v (dual supply).

So in considering the various requirements, I am thinking of using a 12.6v transformer, which after full-wave bridge rectifier and smoothing caps, should result in about 18vdc. I am planning to feed the unregulated voltage directly to the output amplifier. The other modules require lower voltages and I was wondering what the groups thoughts are with regards to using either (zener diode/NPN-transistor) vs the cheap buck/boost regulator modules that are only a few bucks on eBay? I am concerned whether using a combination of several buck modules to arrive at various sub rail voltages to power the different modules will result in some ground imbalance and perhaps introducing some noise as well into the circuits from the switching? Zener/Transistor regulators have been used for almost forever in old portable radios and seem to work well but these off the shelf pieces have somewhat significant current requirements (tuner = 1amp, CD = 1amp, etc). Also, I found a few tone board modules, and several work at 12vdc, but one I would particularly like to try requires a dual supply. I've not found a suitable converter that would convert, say 12vdc to +/- 12vdc and I know it's simple enough to get dual supply using a suitable transformer but I need this to be able to be powered on batteries as well which complicates things. a bit.

Anyhow, perhaps I'm making this question over-complicated so let's just start with the (zener diode with transistor type) regulator vs. buck regulator. Any comments and pro/cons? Reliability is a priority for me. Thanks in advance.
 

MrChips

Joined Oct 2, 2009
23,244
The rationale for use a buck/boost supply is to minimize wasted energy from a battery, i.e. aiming for highest efficiency.

For an audio amplifier you want to stay away from switching regulators because of switching noise generated by the power supply. Go with linear regulators instead.

±12VDC is commonly used for powering audio opamps. Linear three-terminal voltage regulators such as LM7812 and LM7912 are straight forward and easy to connect.
 
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