Hey Peter,
Some quick thoughts about power conditioners - they do several things:
1. Provide some protection from lightening;
2. Provide some protection from spikes and other transients on the power line; and
3. Provide some protection from surges.
I say “some” because lightening in particular is impossible to truly, fully protect from if you get a direct strike from the main bolt, unless we get into a discussion of sophisticated grounding systems, Farady cages, and the such which cost significant dollars.
Also importantly, if you mean a true power conditioner (as opposed to a surge suppressor - people often confuse the terms), a true power conditioner will do still more, such as smooth out the voltage provided to the load, filter out RF energy from nearby transmitters (from broadcast services, ham and CB operators, police or fire vehicles nearby, induced by microwave ovens and other appliances in your home or nearby homes and businesses on the same side of the transformer feeding your house/apartment, etc.), reduce or eliminate power line noise, etc.
There’s another category that I prefer to a power conditioner, and that’s an Uninterruptable Power Supply (UPS). Like a power conditioner, a UPS will act as a buffer between your power line and the load. And like a surge suppressor, it will also reduce and quench most transients and spikes so they don’t get to sensitive electronics. I have a UPS powering the most sensitive parts of my studio (DAW, DM, pre-amps, etc.) It even powers my monitors and subwoofer – I don’t generally listen at high volumes, normally around 74dB and short spurts in the low to mid 80s, but try to keep it sparingly to save my hearing which I did damage some in my teens and 20s as a rock musician.
UPS also have several types. The two mentioned above are a form of “standby UPS” – they kick in immediately when the power fails. If you go this route, look at something at least in the 1,500VA to 2,000VA range and expect to pay from $500 – $1,000 U.S. Make sure it provides a true sine wave output, not a somewhat rounded square wave that’ll surely contaminate your recordings.
I originally had the thought that, as with using a UPS on an office computer, that it will kick in instantly when the power fails and let me continue recording that take. HOWEVER, the few times a power did fail while recording, the surprise of having the main lights go out and my guitar or bass amp fail (if one of those was the instrument I was playing) still made me pause or stop, thus ruining the take. As a result, I’ve realized that the primary value of the UPS is protecting my equipment from damage.
Another and still better type of UPS is the double conversion type - this one is ALWAYS on line. AC power coming in is rectified to DC and used to charge the batteries. The batteries provide power to an inverter that regenerates and filters the outgoing AC power that then feeds the load. This provides true isolation from the power line in that all incoming problems get eliminated when the incoming power avec spikes and noise is changed to DC to feed the batteries. This is the best and most expensive UPS. While I say that, I didn’t want to spend that much money of protection. If I was a commercial studio with a thriving business, I would have gone this route and also included a standby generator. But alas, I am merely a simple project studio with simple means…
So, a surge protector does just that, and only that, to the limits of what it can absorb. A power conditioner performs most of the surge protection functions as well as smoothing out the peaks and dips in power. A UPS does all those things, plus instantly kicks in to continue providing power to the load from its internal battery(s) for as long as the batteries can provide energy. And among UPS types, a true sine wave output is better than a sine wave approximation, and a double conversion unit is the very best.
I hope this helps and that my attempts to be complete and clarify doesn’t instead further confuse the issue.
Jerry