Etherwave vs Etherwave Plus Power supply, Conflicting info.

Hi all, new member here, after learning so much from these forums, I find I need to join you and post a question I could not find a definite answer for. 

I have read a number of posts saying an Etherwave and etherwave plus power supplies are interchangeable.
However, the supply I have on my EWS is 14.8v x 2, for positive and negative supply voltages, whereas the power supply shown with the Etherwave Plus I just found, has only a single 12v output. 

What gives? I'm not electronically illiterate, so I can't see either one working with the other and don't want to damage anything inadvertantly.

The EWS is s/n 10743 and the EW+ is s/n 1098, I found them both 2nd hand recently, so have no idea what years they are from.
I can only assume Moog must have changed something inside between one and the other?

I do realise the forums are all but deserted these days, but any info would be greatly appreciated.

Enjoy your Theremins in good health.

Stephen

(don't know what's going on with the font, I've seen it on other posts too)

My EW+ has serial no. 6892, bought in 2019 and it has a 230V ~ -> 14 V ~ power supply. The rectification to DC and the voltage regulation circuitry are inside the theremin. 

Thanks DV, so that's different again!

I'll open them both up when the + arrives and have a look at the regulators.

I think it's safe to say that "any EW power supply will do for any EW or EW+" as I have read here on the forums is wrong advice.

My EWS power supply is an Eversure, the EW+ is a Powermaster, but I have no idea if it is the original, it is only single 12v.

Cheers.

If the instrument uses LDO (Low-Dropout) voltage regulators (instead of first-generation types such as 7812, 7912), then 12 V AC from the power supply should suffice.

12 Volt * sqrt(2) = 17 Volt peak (amplitude) value.

This is approximately 16 V rectified value (since about less than a volt will drop across the rectifier diode).

If the electrolytic capacitors have lost capacitance over time, the ripple voltage may reach 2–3 V.

At 13 V, 12-volt LDO regulators still function quite well.

That's good info Illya, thank you.

You've got me really curious now, I'm looking forward to opening it up on the weekend if it arrives in good time.

Been playing and building instruments, fx, and Tube/valve amps for many years but theremin is relatively new to me.

Cheers, Stephen