bipolar powersupply question

[nosamiam]

I'm going to be building a rackmount version of the Neutron envelope follower (http://www.generalguitargadgets.com/diagrams/neutron_filter.pdf).  Since it won't be using a battery, I'm wanting to include the power supply in the rack enclosure.

It requires 9v bipolar power and I found what looks to be the perfect thing, courtesy of GGG.

http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

My question is, is this PS sufficient for the Neutron?  Most of the power supplies I've been looking at have a bridge rectifier and this one doesn't.  And if I understand correctly, the rectifier converts AC to DC, right?  So can the Neutron handle AC power as-is?  Or do I need to rectify the voltage before it hits the circuit?

Help?

[gtrmac]

The GGG PS will supply DC output but since the AC is half wave rectified there will be more ripple in the output than a full wave rectified supply. Elliot Sound Products has a PSU that I've used which is full wave rectified.

http://sound.westhost.com/project05a.htm

[toneman]

The GGG PS will work fine....except.....
The Filter has minimal current needs.
Except,....  where will U get a 9V regulator???
U *can* bias any POSreg higher, & any NEGreg lower.
U will have to modify the GGG's pcb.
Look at the datasheets for an LM7805 & LM7905.
U have the technology.   
U have the need.   
U need no batts...   
Stay PwredUP!!
T

[Paul Perry (Frostwave)]

The GGG supply is perfectly OK for that application. I've made hundreds of dual supplies just like it. And, everyone has +9 and -9 regs in TO220 cases (Mouser, Jameco etc) about half a buck. Personally, for +- 9 regs, I'd use a 12v AC supply (but, even 10v AC would get you there, with  500uF input filter caps.

[R.G.]

A word of caution here.

I have used the half-wave rectified supply for decades and occasionally found that some opamps don't like to have one power supply come up before the other. They can latch up and not come up at all. So if you use it, experiment with your opamps and be sure they reliably come up to normal operation with the half wave supply bringing up one side then the other as it walks up to normal voltage one side at a time. Some will work fine. Some won't.

I ginned up a circuit to hold off power until both sides are over about 3V that seems to work OK in such situations, but it's about 5 transistors and a pain if you don't need it.

[Paul Perry (Frostwave)]

R.G., looking at that power-up problem from the perspective of a 0, +9,+18 supply (instead of -9, 0, +9), it appears that the system is equivalent to a single sided supply, that is increasing from zero, while the bias voltage is swinging around wildly. So, performing this "thought experiment", I suppose it is a matter of one of the chips locking up (or even reversing output) thru the usual out of range input latching. I've never had it happen myself, but I guess if chips that are normally prone to latch up were used, then it could happen. Thanks for the headsup! Wonder what else there is out there that can go wrong, and hasn't yet...