they will protect your gear (mebbe), but they won't add much of anything beneficial to the sonics, imo. do *not* use them on amps - they *will* suck all the life & dynamics outta them, in spite of their 2400w rating.
ymmv,
doug s.
Is this statement from experience?
yes, i have two of these. i used one on my front-end gear, where it made absolutely no difference one way or the other, sonically. during a lightning storm, i lost one piece of equipment plugged into it. mebbe i'd have lost more, if it wasn't in place? the piece was known by mfr to be sensitive, & it fortunately was easily repaired be replacing two diodes.
the other was used to protect two amps - electrocompaniet aw60ftt's - which were used in a wertically biamped configuration. the sound was considerably improved when i plugged the amps straight into the wall...
if yure looking for power conditioning on the cheap, i'd strongly recommend searching ebay for isolation transformers. not sure how much protection of equipment they offer, but they will make your system sound better by lowering the noise floor. especially beneficial is separating digital sources from each other & the rest of your equipment.
i found that a vans evers "unlimiter" was beneficial in protecting my amps w/o degrading sonics. these are not what i'd consider cheap, but they are not too bad when ya find 'em used... they actually did improve the sound a hair, tightening the bass, but it was such a tiny amount, i wouldn't be buying them for this; i bought the "unlimiter" to protect my amps, so i dint hqave to plug 'em directly into the wall. no sonic degradation was all i was wanting...
doug s.