[massappeal85]

I'd like to build an entirely integrated unit with amp, pre amp (with tone controls), headphone amp, and phono pre all hopefully in a single box, all out of proven and pre made pcbs (ESP pcbs and such). If not, I'll build the amp in a seperate box, but I'm looking to avoid using up alot of wall sockets and space.

Obviously this is not something a begginer like myself should attempt. I have a cheap sony mini system and that is all, so what I thought I'd do is build some monitors (from a kit, not sure which one) that could be powerd by the mini system, then build the phono pre so I can finally listen to my vinyl (still through the mini system), then the pre amp, the amp, and the headphone amp somewhere between all those and hopefully I'll have enough experience by the time I've completed each one to make an attempt at putting all the pre amp "goodies" in an integrated fashion.

My understanding is that I could have all these components (minus the amp) run by a single power supply, or at least a couple could share one. I know VERY little about power supplys, but my understanding tells me each component requires a certain amount of voltage, and power supplys are regulated to supply that certain amount of voltage. Is this correct? For instance a 16 volt (purely fictional number) component would need a 16 volt power supply? Two 16 volt components would then require a 32 volt power supply for the two to share?

If this is correct, then my question is... how are these power supplys configured to supply that certain amount of voltage? Will all power supplys (as far as audio oriented power supplys go) work with all components as long as the component is given the correct amount of voltage?

Thanks in advance, for any help you can give this newbie.

Tris

[JohnR]

Assuming this is all solid state, you typically would want separate power supplies for the power amp and all the preamp parts (even if it's in the same box). Power amps have a supply voltage of between +/-35 V and +/- 50V for typical (50-100W) amps. Most of the time, this supply is not regulated.

Preamp circuits that use op-amps typically use +/-12 to +/-15 V. This is always regulated, from a slightly higher voltage supply. This can be obtained by tapping of the power amp supply but I would suggest making a separate supply. Preamps using discrete circuitry (individual transistors) might have different supply voltages, often higher and sometimes just one rail.

The +/- means that there are actually two power supply "rails", one is +40 (say) V and one is -40V.

I believe the ESP site has a preamp power supply schematics and board.

When you add more circuitry (that requires the same power supply voltages) you don't change the voltages. You just need to be sure that the sum of the *current* used by the circuits is within the capacity of the supply. For example, if two circuits each use 50mA at +/-15V then together they use 100mA at +/- 15V. Preamp circuits don't use much current (typically).

HTH

[massappeal85]

I think I got it. So if I had 2 components that were 16V each, all I would need is a 16V power supply as long as it could handle the current of the two components?

Should/Are the + and - rails of a component always equal?

If I had a 12V component, and a 15V component, I would need two seperete power supplys?

And now, how does the transformer come into play? I know nothing of these either.

[JohnR]

I think I got it. So if I had 2 components that were 16V each, all I would need is a 16V power supply as long as it could handle the current of the two components?

Yep.

Should/Are the + and - rails of a component always equal?

Not necessarily, but usually.

If I had a 12V component, and a 15V component, I would need two seperete power supplys?

Yes, but... circuits using opamps anyway are not usually likely to be that critical, they'll probably operate fine on either.

And now, how does the transformer come into play? I know nothing of these either.

The transformer converts your 120V wall voltage into some lower voltage. This is then converted from AC to DC by rectifier diodes and smoothing capacitors.

JohnR

[Vinnie R.]

Tris,

Take a look at www.zero-distortion.com

There is a good article with schematics on the basics of a power
supply (unregulated) and it progresses with improvements
to that supply, with explanations.  

 As John R. mentioned, you need a transformer to bring down the
120Vac (alternating current) from your wall to a lower volage ac
waveform.  

Next, the power supply needs to make this a dc (direct
current) waveform, which is one that is either entirely positive or
negative, but doesn't alternate between the two (like a battery).  
The signal is then passed into a rectifier circuit that uses diodes (rectifiers)
that remove one of the polarities (+ or -) of the waveform.  What
remains is a waveform of one polarity, but there is still ripple in that wave-
form, meaning that it isn't a constant voltage like a battery would supply.

Then  that signal is passed into one or more capacitors that smooth
the waveform by charging and discharging to reduce voltage variations.
The trick is to make sure that there is enough total capacitance in the
capacitor bank to provide the amplifier with power on demand.  If there
isn't enough energy stored when needed, then the voltage will sag and the music will become distorted.  

   Also, the quality of the power supply output is very important because
it is that voltage which is used to make the amplified signal.  An
amplifier doesn't actually take an input signal and make it bigger.  What
it really does is use the input signal as a blueprint for making a new signal (using the power supply voltage + and - rails) that is proportionately larger to the input.  Transistors (or vacuum tubes) accomplish this.  
Distortion is the deviation of the amplified signal to the original signal.

Is this making sense?  Let me know if I can provide a better explanation
because I think it is important to understand the basics before you
get into a project, plus free knowledge is great assuming that it is
correct
 

[massappeal85]

"Yes, but... circuits using opamps anyway are not usually likely to be that critical, they'll probably operate fine on either."

If solid state equates to using opamps, most of the things I build will probably be solid state.

If I had a signifigantly higher or lower voltage power supply then what the component needed, what would happen? Kaboom?

And, If the current of both 15V components was too much for a power supply, would it be because the smoothing capacitors are rated too small to handle the current? Would using larger capacitors cure this?

"As John R. mentioned, you need a transformer to bring down the
120Vac (alternating current) from your wall to a lower volage ac
waveform."

So the 15V powersupply would require a transformer that brought the 120V wall outlet to a 15V?

Rod Elliots suggested pre amp layout has the pre amp and phono pre amp fed by the same power supply. I imagine this may be because both have a + and - rail voltage of 15. If the two had differing rail voltages from eachother, my understanding then is that they would need their own power supply. Does each power supply require its own transformer?

And most everything is making sense to me guys. I'll read that website and see if it answers any other questions I have.

Thanks!