My latest project involves either 2 or 4 SET amps, each driving separate drive units.
My question is this: Is it possible for me to spec a more powerful power supply so that I can have the transformer and other components on a separate board and that this board then powers the individual SET boards?
And, if not, why not?
Thanks in advance
Steve
My question is this: Is it possible for me to spec a more powerful power supply so that I can have the transformer and other components on a separate board and that this board then powers the individual SET boards?
And, if not, why not?
Thanks in advance
Steve
In principle, it should work the same, power wise, but now you have 4 different amplifiers sharing grounds through the power supply common ground, which besides lies outside any of them.
This *might* complicate grounding at the signal level, *might* introduce a little instability, crosstalk, buzz or hum, return paths are not closed inside each amp but to an external, shared supply.
Or it might not, just answering your question
I guess you will have no problems if you give some extra thought to grounding.
I for one, always try to return speaker ground terminal straight to power supply main filter cap(s) with its own separate ground wire ...maybe that´s not so easy with 4 power amps fed from an external supply.
The basic idea, in general, is to have "clean" ground paths, not contaminated by high currents, specially audio current (hint: speaker return wiring) .
Cathode returns also mean important audio currents, although way smaller than those involved with speakers.
If your layout and wiring is clean, you will have no problem.
This *might* complicate grounding at the signal level, *might* introduce a little instability, crosstalk, buzz or hum, return paths are not closed inside each amp but to an external, shared supply.
Or it might not, just answering your question
I guess you will have no problems if you give some extra thought to grounding.
I for one, always try to return speaker ground terminal straight to power supply main filter cap(s) with its own separate ground wire ...maybe that´s not so easy with 4 power amps fed from an external supply.
The basic idea, in general, is to have "clean" ground paths, not contaminated by high currents, specially audio current (hint: speaker return wiring) .
Cathode returns also mean important audio currents, although way smaller than those involved with speakers.
If your layout and wiring is clean, you will have no problem.
SE amps put the whole signal current through the last PSU capacitor. They also apply much of any signal on the supply rail straight into the OPT. That is a good combination of characteristics for interchannel crosstalk (i.e. bad if you want to avoid crosstalk!). It may explain why SE fans often prefer monoblocs rather than stereo amps.
You could give each amp its own local cap, but then you may have problems of grounding as the finite impedance of the ground connections mean that each amp will have its own idea of what the signal reference is.
All these issues are easier with push-pull, as that pushes less signal current through the PSU and has much better PSRR. The downside with PP is that the PSU current contains lots of second-order components - so smaller but more distorted.
You could give each amp its own local cap, but then you may have problems of grounding as the finite impedance of the ground connections mean that each amp will have its own idea of what the signal reference is.
All these issues are easier with push-pull, as that pushes less signal current through the PSU and has much better PSRR. The downside with PP is that the PSU current contains lots of second-order components - so smaller but more distorted.
I usually use one single power supply for my amp and preamp. I don't want to build this twice since it has two enormous chokes, all polypropylene caps and two AZ1 mesh rectifiers. I have more polypropylene caps on the input of the separate amp and preamp chassis. I don't have a problem with this setup.
You then have to think about connectors. Since my PSU is under 300v I use 4 pole Speakon connectors which are shrouded and cheap.
You then have to think about connectors. Since my PSU is under 300v I use 4 pole Speakon connectors which are shrouded and cheap.
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