Members AlanG Posted June 14, 2004 Members Share Posted June 14, 2004 OK - I did a search...and this subject needs more discussion! I have just got me a new (well - new to me) rack to hold my stuff (A 100watt keyboard amp head, Lexicon MPX110, and a Korg Tuner) - and there's an extra space in the rack - WHOO HOO. So, instead of mounting a power strip in the back (my old solution) - why not pick up a Power Conditioner ..... Furman/Gemini/Powerwerks.... to fill the slot? Per the aformentioned search - I learn that the cheaper ones may be no better than a surge supression strip from Home Depot. So...what specs should I be looking for? Filtering? Actual Conditioning? What would you pro's recommend? I rather not spend $80 bucks for someth'n that'll work as well as a $10 strip. Thanks - this place is awesome. Link to comment Share on other sites More sharing options...
Members B. Adams Posted June 14, 2004 Members Share Posted June 14, 2004 Well, they're a little better than a cheap power strip. And an $80 one would have lights on it, which are nice. Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 14, 2004 Members Share Posted June 14, 2004 My opinion here, I'm sure contrary to some of the "experts"... Virtually all of the sub-$100 power strips utilize only shunt protection devices (MOV's) and rely on the power source's impedance to limit the spike fault current. From a functional point of view, the results are all similar in that they will attenuate short HF transient voltages (both common mode and differential mode) by somewhere around 20dB at best. The more professional units become more sophisticated in that they generally include series indusctors to improve the attenuation ratios AND to help dissipate the fault current in the MOV's. They also generally have higher dissipation MOV's which increase reliability. There are even better units that include both active protection devices and passive series-shunt devices, but these are even more expensive. All of these devices require a very low impedance ground path to work effectively. In my opinion, the vast majority of properly designed equipment will see zero benefit from the sub-$100 protection. The power supplies are robust enough to absorb common transients. The issue is the marginally designed products, but even these are more robust than the power strip protection. Power amps are even more inherently protected given the size of the power transformers (or input X-Y caps on switchers) and filter caps (HF bypass). If you have a severe enough (joule-seconds) transient to damage your gear, then the amount of energy present will most likely damage your power strip protection also. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted June 14, 2004 CMS Author Share Posted June 14, 2004 Originally posted by agedhorse All of these devices require a very low impedance ground path to work effectively. I think this statement should be emphasized. Many otherwise decently wired locations have sub-par grounding. It's something that is only checked once, if ever, when the service is first installed in a building. And though it may seem obvious, the use of the ubiquitous 3-to-2-prong "adapters" to either reverse polarity or bypass grounding of the supply will render these devices useless. Link to comment Share on other sites More sharing options...
Members AlanG Posted June 14, 2004 Author Members Share Posted June 14, 2004 Thanks! I didn't know that a proper ground was necessary for these devices to work - ya learn sumpt'n new every day... I'm an Aerospace Engineer - dealing with airframe structures..what does "MOV" mean? I was led to believe (wishfull thinking?) that power conditioners will help/eliminate line noise from florescent lights or other things plugged into the same circuit - that would seem to me the main advantage of a rack mountable Power Conditioner over the ubiquitous power strips. Would the sub $100 units be useless for this purpose as well? Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted June 14, 2004 CMS Author Share Posted June 14, 2004 Originally posted by AlanG Thanks! I didn't know that a proper ground was necessary for these devices to work - ya learn sumpt'n new every day... I'm an Aerospace Engineer - dealing with airframe structures..what does "MOV" mean? I was led to believe (wishfull thinking?) that power conditioners will help/eliminate line noise from florescent lights or other things plugged into the same circuit - that would seem to me the main advantage of a rack mountable Power Conditioner over the ubiquitous power strips. Would the sub $100 units be useless for this purpose as well? MOV - metal oxide varistor Inexpensive power conditioners will lessen EMI and RFI noise, but again, not as well as pricier units. No free lunches...... Link to comment Share on other sites More sharing options...
Members dboomer Posted June 14, 2004 Members Share Posted June 14, 2004 You have to ask yourself 'what do I expect this thing to do?' What does 'conditioning' really mean? I mean where are you where you are having power problems ... gennies ... lighting strikes ... navel ships? Your best (cheap) protection is to measure any/every socket you plug into. Those little $5 plug in checkers work fine. If you manage to plug into 220 (in N. America) they glow double bright. They also check for hot/neutral reverse and lack of ground. Most sensitive gear has emi/rf filtering built in already (at least as good as cheap power strips. If you aren't spending multi hundreds of bucks you are probably wasting your money ... of course if it helps you sleep at night, it is your money! btw ... MOVs usually burn out after a couple of trips so how would you know if yours was really working anyways Link to comment Share on other sites More sharing options...
Members CME Posted June 14, 2004 Members Share Posted June 14, 2004 I have a similar question. What do you guys think of the new Furman Power Factor pro. I'm thinking of getting on for my guitar rig. Are those worth it or not. thanks Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 15, 2004 Members Share Posted June 15, 2004 Originally posted by dboomer btw ... MOVs usually burn out after a couple of trips so how would you know if yours was really working anyways Very true, often they fail short circuit with breaker opening, but they can fail open circuit too, but usually there will be some "mess" associated with that kind of failure! Testing requires special equipment to limit conduction rnergy, but it generally involves discharging a HV cap through a current limiting resistor into the MOV at a known voltage. Link to comment Share on other sites More sharing options...
Members AlanG Posted June 15, 2004 Author Members Share Posted June 15, 2004 Originally posted by AlanG OK - I did a search...and this subject needs more discussion!. Originally posted by agedhorseTesting requires special equipment to limit conduction rnergy, but it generally involves discharging a HV cap through a current limiting resistor into the MOV at a known voltage.. errr - more'n what I needed to know... glad that I helped to start a bit o' conversation... Hmmm - what this does mean is .... If ya pick up a used Furman - ya might want it checked out - as there's no obvious way to know if the thing's been fried... Thanks! That is useful info! - I see used Furmans at the local GC all da time.. I now know that it's better to buy new. Also - stay away from cheap. Damn power strip is looking better ... Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 15, 2004 Members Share Posted June 15, 2004 Originally posted by AlanG Hmmm - what this does mean is .... If ya pick up a used Furman - ya might want it checked out - as there's no obvious way to know if the thing's been fried... Technically, probably a good idea! They don't really fail all THAT often though. Link to comment Share on other sites More sharing options...
Members dboomer Posted June 15, 2004 Members Share Posted June 15, 2004 MOVs are cheap and easily replaced if you're worried about it. btw ... anybody out there ever had anything blow from a power surge that you KNOW was actually a power surge. Repair guys will tell you that sometimes but they're just guessing. In 30 some years of doing this the only problem I've ever had was to lose some filter caps in a guitar amp when it was run off of a way too small generator. I mean I guess you're screwed if you took a lightning bolt but how often does it really happen? Link to comment Share on other sites More sharing options...
Members B. Adams Posted June 15, 2004 Members Share Posted June 15, 2004 Originally posted by dboomer I mean I guess you're screwed if you took a lightning bolt but how often does it really happen? Once, right? I mean, lightning doesn't strike twice. At least that's what I heard. Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 15, 2004 Members Share Posted June 15, 2004 Originally posted by dboomer MOVs are cheap and easily replaced if you're worried about it.btw ... anybody out there ever had anything blow from a power surge that you KNOW was actually a power surge. Repair guys will tell you that sometimes but they're just guessing. In 30 some years of doing this the only problem I've ever had was to lose some filter caps in a guitar amp when it was run off of a way too small generator. I mean I guess you're screwed if you took a lightning bolt but how often does it really happen? Very true, I've seen only a couple in over 25 years, and MOV's won't protect from the gennny problem OR a real lightning strike anyway. Link to comment Share on other sites More sharing options...
Members AlanG Posted June 15, 2004 Author Members Share Posted June 15, 2004 OK - So I'm dumber than I thought (you don't know what you don't know..). Wha cha mean by "genny" (dboomer also mentioned gennies..) Thanks for the lessons!!! Link to comment Share on other sites More sharing options...
Members NMR Posted June 15, 2004 Members Share Posted June 15, 2004 a genny is a generator. a petrol/diesel motor that generates electricity. and i think both agedhorse + dboomer were talking about the fact that they don't give out very clean power and may surge or not give out enough juice, please correct me if i am wrong. NMR Link to comment Share on other sites More sharing options...
Members thunderpaw Posted June 15, 2004 Members Share Posted June 15, 2004 I put a RackRider power 'condtioner' in my rack. Not for EMI/RFI. Not for protection from other than minor surges. Simply it was a clean and convenient way to power up all of my effects devices in my rack. No more. No less. Kim Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 16, 2004 Members Share Posted June 16, 2004 Originally posted by thunderpaw I put a RackRider power 'condtioner' in my rack. Not for EMI/RFI. Not for protection from other than minor surges. Simply it was a clean and convenient way to power up all of my effects devices in my rack. No more. No less.Kim And that's an excellent reason... you know exactly what you are getting, why and for what cost. With that data you can make an informed decision. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.