How safe is it to run an amp without a power condtioner

[rbonner]

So what's the answer?

I had some issues with a building automation system out in California back in 1980. I went out there with a tape recorder type power monitor. It monitored voltage on the power line and then recorded to a tape like a cash register tape.

What would happen is the system would "LOCK" it was just an industrial computer inside controlling through a communications system remote modules all over the building...

These were WICK's furniture stores. You Cali guys know how big those buildings were.

Well I had the store manager send me the tapes weekly from the thing and I reviewed every anomaly above and below the set points I had programmed into the unit.

I saw regularly single cycles or multiple cycles of up to 330V across the 120 circuit this computer was placed on. The store had monster power service and step down transformers... The office ran on a standard 3 Phase 208 Y.

Every minute it seemed there would be a hit of over 150V on those lines. The surges however NEVER exceeded maybe 3 cycles. Anything more than 20 cycles would have probably taken out the power supply in the unit.

I was amazed how dirty power from the power company really is.

So what did I determine? Since most hits from the power company usually never exceeded 3 cycles basic MOV protection which usually is 140V in most power strips, will probably handle your needs. It obviously doesn't short on one cycle, it take JOULES of energy to short an MOV, they will clip the small stuff however.

The MOV self destructs when it gets hit.. It conducts and shorts, this short blows the breaker on the power strip... You better have a breaker YOU CONTROL next to your MOV, don't rely on a smoke and fuzz clogged bar breaker that you probably couldn't flip off if you tried.....

The chance of the bar getting hit by lightning while you are playing is pretty slim, if it does take the hit, you'll probably be blown up anyway so who cares?

BOB

 

[Red Planet]

I'm happy for you........

Let the line go up 30% or so for a short while, and many of even the best "suppressors" will be toast. If 500kVA of 480V 3 phase wants to go up a bit, not much stops it.....for long, anyway. Thankfully, that is fairly rare.

OTOH, the "suppressors" talked about here are generally some dime-sized MOVs in a fancy box...... with no series impedance before them. Expensive sugar pills, that start failing with the first "hit", and have a very liberal interpretation of "limiting".

There ARE suppressors which DO work, and cost like it, too. But my point was that like seatbelts etc, they only work so far. Every unit has an energy limit, above which it will generally just quit.

A neighbor down the street "needed" suppressors...... The 4160V feeder line behind the house got crossed onto his 'drop" in a storm. Blew out every single electrical thing in his house, blew half the breaker panel literally out of it's box. Every wire in the place had to be replaced. I am astounded there was no fire.

It would have been nice if a suppressor of some kind could have protected against that, but the few he had basically went off like grenades. When you REALLY need one, it won't do the job!

Well Jerold I think you need to look a little more.

Have you not seen the picture of the roasted 208 transformer I posted?

Lightning, switch spikes, or something roasts my transformer. At this location I have a bunch of these little 120 volt protectors. There specs are they will take 32,000 Joules to ground before they sacrifice their self then they still protect by totally interrupting the circuit.

Everything I had the protectors on was spared but everything I did not was fried. Imagine that. There is absolutely nothing that comes factory in any audio equipment that will do what these do.

 

[levis76]

I gig in the Detroit area, which has some of the worst power in the entire country. Surges, sags, and spikes run rampant. I haven't had a problem yet. I always bring a socket tester and plug it in to check that the club has a decent ground. So long as the ground return is good, you are going to be just fine. If it makes you feel better to buy a rackmount conditioner, then do it and to hell with what everybody else says, it's your equipment.

The only thing that will completely isolate dirty power from wasting your equipment is an online UPS unit, which is going to weigh more than your rig. ANYTHING else is a gamble. Only an online UPS takes the utility and converts it to DC and then coverts it back to 120VAC 60HZ regardless of what the incoming power. Of course the club owners may not let you bring this in and your bandmates will hate you, but hey, you now have peace of mind that you have filtered reliable power to the tune of about $10K.

 

[jastacey]

As an electrician ... I always use a multi-meter to check the power, it just takes a few seconds to do and you know exactly what your dealing with, for those who are afraid of probing a outlet, there's those little outlet testers that have the 3 lights, those are O.K., but they don't test for voltage ..... no matter what you do, you can't really fix the power coming into the place, if it is out of spec .... those pole mounted transformers that utility uses, can be drifiting voltage wise, 2%-3% , and I've seen as much as 8%, due to heat & age, on another note ...... never, ever be talked into pluging your stuff into small generator power ( 3000-8000 watt gasoline generators ) , the voltage control is primitive at best, and no power conditionor will clean up that type of power, to many spikes, voltage wise and the Hz is always never correct, " when in doubt-check it out"

 

[rbonner]

Sometimes I don't even know why I waste my time posting here.

Time for a vacation.

 

[billfitzmaurice]

So what's the answer?
BOB

Jerrold's credentials give his opinion more weight on this issue than anyone else's. Bob Lee (QSC) would back him up, he's probably so tired of seeing this chestnut on such a regular basis that he's tired of wasting his time posting the same answer ad infinitum.

 

[Jazzdogg]

With no disrespect intended to anyone who's contributed to this thread, isn't there a sticky that effectively addresses these kinds of chestnuts?

Perhaps TalkBass would benefit from the addition of a Mythbuster forum in which we can isolate the kinds of threads in which people attempt to argue that their opinions are superior to science and engineering facts.

 

[newbold]

You'd probably get more value over the lifetime of your gear to spend the money on better cables, cable wraps, and regular professional maintenance of your gear.

That being said, at least the one time in your life that your head gets fried, you'd be able to spend all potential insurance money (if you insure your gear) on a new head instead of being tempted to get better cables and such.

 

[BartmanPDX]

With no disrespect intended to anyone who's contributed to this thread, isn't there a sticky that effectively addresses these kinds of chestnuts?

Perhaps TalkBass would benefit from the addition of a Mythbuster forum in which we can isolate the kinds of threads in which people attempt to argue that their opinions are superior to science and engineering facts.

If there isn't a sticky about this, there should be. It comes up often enough.

At the risk of jumping into a flame war, I'll take a stab at it. Engineering folks, feel free to correct me where I'm wrong, but it seems to me to break down like this:

1) Surges come in a variety of degrees. For most low-level surges, the transformer in any reasonably well-designed amp/unit is capable of handling them, and does on a regular basis.

2) For slightly larger surges, a surge suppressor may provide some protection by sacrificing itself. These surge suppressors largely work the same whether they come in a $20 surge strip or a $300 power conditioner, so there's not much reason to get one of the expensive ones unless you like pretty lights.

3) For much larger surges, there are some units that might provide protection, but they are not typically used in rackmount power conditioners either because they are expensive or heavy. I think these are what Red Planet is referring to.

4) For catastrophic surges like the one in Jerrold's story, not much is going to help. If it's plugged in, it's fried, regardless of what you've got it plugged in to. The only real way to protect against these is not to have anything plugged in at all.

Does that about sum it up? Have I got any of this wrong? Feel free to correct me. I think it would be nice to get something together that we could refer people to. There's just too much misinformation about power conditioners out there and it would be nice if the experts could get something together to help us all out.

 

[RickenBoogie]

That's what I read from this discussion, which, btw, got interesting fast, huh.

 

[greenboy]

It's around the umpteenth one I've seen this year alone. I no longer bother to type up anything of substance because I implicitly trust that once the facts make the FAQ there will no longer be a need. This has been proven many times over on the subject of OHMS ; }

 

[MrRiff]

IMO
A decent amp should not need EMI filtering as it should have been done at the factory
can't wait to see how the digital amps do

GOOD POINT! I have a Markbass F1 which has a digital power and and I swear it sounds different at various venues depending on how much clean power is a available for the band. My band has a ton of gear and power consuming PA so at times I might not be getting enough clean power. I also do a lot of outdoor festivals off generators. I hope this amp can hold up and take some punishment. Would love to hear from anyone who knows about this.

 

[randallmartinez]

Sometimes I don't even know why I waste my time posting here.

Time for a vacation.

cuz you got a friggin sweet rig that i wanna see pictures of!!!! Make it happin capt'n!
~diz~

 

[randallmartinez]

If there isn't a sticky about this, there should be. It comes up often enough.

At the risk of jumping into a flame war, I'll take a stab at it. Engineering folks, feel free to correct me where I'm wrong, but it seems to me to break down like this:

1) Surges come in a variety of degrees. For most low-level surges, the transformer in any reasonably well-designed amp/unit is capable of handling them, and does on a regular basis.

2) For slightly larger surges, a surge suppressor may provide some protection by sacrificing itself. These surge suppressors largely work the same whether they come in a $20 surge strip or a $300 power conditioner, so there's not much reason to get one of the expensive ones unless you like pretty lights.

3) For much larger surges, there are some units that might provide protection, but they are not typically used in rackmount power conditioners either because they are expensive or heavy. I think these are what Red Planet is referring to.

4) For catastrophic surges like the one in Jerrold's story, not much is going to help. If it's plugged in, it's fried, regardless of what you've got it plugged in to. The only real way to protect against these is not to have anything plugged in at all.

Does that about sum it up? Have I got any of this wrong? Feel free to correct me. I think it would be nice to get something together that we could refer people to. There's just too much misinformation about power conditioners out there and it would be nice if the experts could get something together to help us all out.

\
thats good enough of an explanation for me. Moderator can shut this one down whenever. Thanx guys
Diz

 

[Red Planet]

OK I'll have some fun with it.

Sure fire way not to have any problems with your amp = don't plug it in.

 

[JonathanD]

I like to tape down something like the furman $27 thigg in the back of a rack. Lets say that 1 in 10000 times I play out I am going to lose my amp to a power surge. Say my amp costs $1250. It is worth the $.13 every time I go out not to have the extra rack space and weight. That is unless I have multiple things plugged into the rack. and can leave it all connected if I have a rack mount. then it may be worth it.

I would suggest a 4 space with a rack tuner. If you play outside on a hot day in the sun, put a fan on your amp if you must. I had an SVT4 for a long time and it always handled being racked with no 1 space vent.

 

[Jerrold Tiers]

Red Planet is talking about a very large and heavy-duty protective system..... Apparently specifically intended for a particular situation. Just not at all comparable to a "surge protector" that you can buy anywhere reasonably.

R Bonner is also referring to the lowest end of that sort of situation. I'd be seriously shocked if the general run of larger amps couldn't deal with a cycle or three of overvoltage, particularly when it comes down a 120V circuit, which is normally (in "our" sort of situation) not exactly a straight pipe to the power company.......

Without being tediously rigorous about this, it's hard to really give any information. But suffice it to say that the surge protector is INTENDED to act to 'clip" the power line, and prevent an overvoltage from getting to the unit, whatever it is.

So the idea is that the surge protector takes the hit and protects the amp...... Simple, right? But is it really?

How well do these things really WORK? What would a "designer" do to make a surge protector?

Probably the designer would first decide that 'MOVs" were the most cost effective units, and go to select a type.

The voltage rating on these devices is not particularly accurate, although they can be "selected". And, the 'withstand" voltage (what it will take as far as mains voltage) comes down a little bit every time an MOV gets "hit".

As a result, you have to compromise a bit. There is a rating for AC voltage that it will take. Digikey shows 8 or 10 units at voltages between 115 volts and 165 volts AC. Since US voltage is anywhere up to 132VAC normally, a lot of them drop out. The next rating is 140V, which is a little low, in case the unit gets degraded by bad bar power quickly. So figure 150V.

Right there, you KNOW it will not do a THING at 150VAC..... which could be enough to potentially toast your amp. A 50 volt power supply would be 62.5V, which is 125% of normal.

Actually, the transformer would be likely be well saturated at 150V, meaning that there would NOT be much if any additional voltage coming out, so a transformer supply is fairly well protected anyway, but never mind that. Suppose you had an SMPS instead, a lightweight amp power supply..

Now you need to pick a current capability...... they start at 5A (or 4 joules), and go up to anything you like.... probably 400A is enough for a 20A circuit, that's a 20x overload, but let's pick 1200A instead. Total energy rating? we have several choices, let's pick the highest one, like 20 Joules (watt-seconds) it only costs a few cents.

So, how have we done? This is actually a serious unit, better than in many surge protectors of the standard type......

Not really very well!

According to the spec sheet, this wonderful little unit will NOT protect until the peak voltage reaches about 240V (equal to 170V mains)! And despite being a 1200amp unit, if the transient puts as little as 10 amps into the protector, the actual voltage it holds is only limited to 400V!

So we have a "surge protector" that won't do ANYTHING until the mains voltage reaches 170V (140% of normal).

And this "essential piece of equipment", if it gets any actual current flow through itself, will only hold the voltage 'down" to 400V peak, which is equivalent to a mains voltage of 280V, or 230% of normal.......

And, to top THAT off, if it DOES hold the voltage to 400V peak, it will only do that for 5/1000 of a second..... any more than that and it will be over-loaded, and over-heated, possibly failing.. As a point of reference, R Bonner's 3 cycles of surge voltage are, at 60 hz, about 50/1000 of a second, or 10 times longer than it takes to give the MOV as much as it can take.

Remember what i said above? About transformer-based power supplies?

The transformer will typically saturate pretty hard at a mains voltage of around 140 to 150V maximum (US mains) and will do a dandy job of preventing longer-term mains voltage surges from getting through. It might pop the fuse or breaker, but that is all to the good. You don't want to fry the transformer if the mains volts go up.

Most any fast transient type surge just won't even get through the transformer, it isn't made to respond to them, especially if the secondary is grounded somewhere, as most are.

That is why I don't believe much in surge protectors......... because the typical surge protector just does NOT DO much to hold down surges to where a non-transformer power supply can deal with them.

Basically, if the designer has not already handled that problem, there isn't going to be much YOU can do externally to make it better. The absolute best place for the MOV etc is INSIDE the unit, AFTER any mains voltage EMI filtering, etc.

And the typical transformer-based supply DOES hold down transients and surges to voltages that are meaningfully close to reality.

 

[cabrego]

Furman strip is the way to go.

 

[Jerrold Tiers]

To be fair, there are versions, and Furman at least USED to make some, which regulate voltage, and are well filtered. Furman and Tripp-lite are virtually the only companies who pretty much stay away from snake oil.

The problem is that you could almost have a whole spare amp, or two, for the cost of a really good unit........

 

[Billnc]

To be fair, there are versions, and Furman at least USED to make some, which regulate voltage, and are well filtered. Furman and Tripp-lite are virtually the only companies who pretty much stay away from snake oil.

The problem is that you could almost have a whole spare amp, or two, for the cost of a really good unit........

I do some extra work for a backline company (actually a good one) we keep a heavy duty, non snake oil model, that does what you say. It's rare (not worth buying for most of us?)that I need to pull it out of the truck, but it can save the day.