PSU for multiple amps/effects

[werfi]

I am building some equipment (HP amp, mic pre, monitor controller) to my home studio. From now, I call those effects. Since all of them require same voltages ( +/- 15 v, +5v ) I thought of building one PSU unit (seperate box) which supplies power to all effects. This way I would need only one transformer, saving money, space and weight.

PSU would be something like trafo -> rectifier -> caps1 -> regulators -> caps2

What parts can be common to all effects, and which should be located inside effect unit, not inside PSU unit?

I thought that trafo, rectifier and first caps could be shared by all effects. Each one should have their own regulators (inside PSU unit) and own caps inside effect unit.

Well, what does this sound like? Is there any sense even to try do this?

[AndrewT]

Yes, I agree.
Transformer & Rectifier & first stage smoothing in the common PSU chassis.

Second stage smoothing and regulators near the current clients.

[werfi]

Ok, thanks for reply.

Now it's still unclear to me how I should add 5 volt lines. It will drive relays, so current draw may be quite high ( I might be using something like "relay pot" ( Mikkel Corydon Simonsens hjemmeside ) ) , so using 7805 or similar regulator probably won't be a good alternative. Would someone mind to point me to the right direction how to get 5v lines which can supply several amperes current. I'll be propably using 15-0-15 transformer.

[DF96]

Two options: separate secondary for 5V supply, 5V regulator (gets hot).

In either case, best to keep relay supply separate from main supply to keep clicks away.

[werfi]

I was planning to use some circuitry to mute outputs on powering off. Something like described here: Project 104 - Preamp/ crossover muting circuit . If using these schematics, I should use that relay marked on schematics to switch on and off 5 volt line going to effect's muting relays. That is because I don't know number of relays attached to circuit, thus I would not be able to size resistor R7 correctly if muting relays were directly connected to this. Then it's probably best to have another 5 volt line for other relay circuitry which is always on.

I think it'd be best idea to add separate secondary . That means, winding extra coil to existing transformer, coil own transformer or use two transformer, both connected to mains.

[AndrewT]

if you have not yet bought your relays then I suggest you buy 12V. They use less current and for different duty there are more options available.

12Vac to 15Vac would do for the relay regulator supply.

[werfi]

Thanks, why didn't I think of using 12v relays...

If anyone has good tips regarding to grounding I'd be glad to hear them. I thought of using non-isolated TRS plugs. Would it be better to use TRS plugs isolated from chassis? All the devices are in rack, and it is likely that their chassis' will touch each other. Would it be good idea to carry 0v potential and earth in separate cable leads to effects from PSU, and connect chassis to ground at first filtering caps?