PSU question

[HeavyHand]

i have 7 RCA BA 72's that need a PSU. it need -30 volts and each unit draws 1/16 of an Amp. i was just gonna round up to 1 Amp for the PSU to be generous. but i just dont know what i need to actually buy. i hear Acopian makes good PSU's. so heres what i found...

http://www.acopian.com/power-supply-vol ... ?search=30

on the page there are ones that are dc-dc regulated, linear regulated and switching regulated. no idea what any of that is about and how it relates to my situation. any ideas??

my best guess was http://www.acopian.com/store/productdetail.aspx?q=i795 the 30WB100 which is dc-dc regulated.

thanks for any help.

[Andy Peters]

i have 7 RCA BA 72's that need a PSU. it need -30 volts and each unit draws 1/16 of an Amp. i was just gonna round up to 1 Amp for the PSU to be generous. but i just dont know what i need to actually buy. i hear Acopian makes good PSU's. so heres what i found...

http://www.acopian.com/power-supply-vol ... ?search=30

on the page there are ones that are dc-dc regulated, linear regulated and switching regulated. no idea what any of that is about and how it relates to my situation. any ideas??

my best guess was http://www.acopian.com/store/productdetail.aspx?q=i795 the 30WB100 which is dc-dc regulated.

thanks for any help.

In the Acopian case, a supply that's DC-DC regulated means it can accept either standard AC mains voltage on its input, or a high-voltage DC supply. If you do the math, you'll see that the DC voltage input is the same as the peak voltage of the AC mains (120 VAC is RMS, which is about 170 Vpk). Otherwise, it is the same as a switching supply (see below). You don't want this supply for a good reason: it is very expensive.

A linear-regulated supply is the standard sort, with a big 60 Hz transformer, a rectifier, smoothing caps and a voltage-regulator circuit. Linears are used when you want the absolute lowest noise. They are also somewhat inefficient, compared to a switcher. (They are also, in spite of the name, not linear.) The higher the power rating, the more expensive. The Acopian Gold Bricks are great supplies, as are similar Power One units. They might be expensive, and they are heavy. You will need to provide wiring for your AC mains input (meaning IEC cable entry or hardwired in cordage, fuse on the hot lead, power switch, maybe a power-on light) as well as your DC power output. You an enclosure for everything.

A switching supply uses a smaller mains transformer and some magic circuitry to reduce the size of the circuit while still providing the required output power. They are more efficient than linear regulators. The trade-off is that a switching supply can be noisier than a linear (although the newest high-quality supplies are excellent).

For a low-current low-noise circuit like your RCAs, a small linear supply will work well enough.

[HeavyHand]

awesome! thank you very much brother.