Using a power conditioner in my rig- Juice Goose or Furman?

[Al Coda]

I quieted my system by removing all the grounds (except on the amplifier). Everything I use goes through the same power cord to the wall (which is also grounded) and now my system is very quiet. I also use a GFI at the wall for yet extra protection.

 

I have been told by some that I am stupid (or reckless) for doing this. I was given this advice by an audio/studio engineer.

 

Might be a solution to get rid of hum in the homestudio,- but for the road, I´d never remove all the grounds from my gear except the amp.

Hum eliminating isolation transformers are he better way to get rid of ground loops for me.

 

A.C.

[BillWelcome Home Studios]

 

I quieted my system by removing all the grounds (except on the amplifier). Everything I use goes through the same power cord to the wall (which is also grounded) and now my system is very quiet. I also use a GFI at the wall for yet extra protection.

 

I have been told by some that I am stupid (or reckless) for doing this. I was given this advice by an audio/studio engineer.

 

Depends upon what you mean by 'removed all the grounds.

 

In the 'old days' there used to be technical and chassis grounds. There aren't so much anymore.

 

In an audio signal cable, you have a send and a return, and usually a shield; which would be three wires.

 

With a guitar, the shield and return are bonded, making it into a 2 wire system.

 

Shields go to ground.

 

Now, there should be only one path to ground.

 

If, what you have created is a situation where there is a single clear path to ground, that could be okay.

 

But it is not only questionable to remove the ground pin from equipment (from a safety standpoint, as you have taken away the saftey ground), but it is also against the electrical code.

So, you run into the possibility of some hard-assed inspector shutting down your show. And if you think that it won't happen, I saw an inspector shut down a big show at Carnegie Mellon, because he had a hard-on for Carnegie Mellon. Why? Because the insulation on a hand-made AC cable had come out of the cable clamp. It only took a screwdriver and 30 seconds to fix it..... yeah, after a LOT of arguing, big wigs everywhere, puffed out chests and ugly discussions. I was glad that it was not my issue.

 

Sometimes the technical issues are outweighed by the legal ones.

 

 

Following your same description, if everything that you had plugged into the same power strip, you should still have one path to ground and you would maintain a legal safety ground... though you could have ground loops within such a setup. The difference in a studio is that they tend to pay a LOT more attention to the grounding in a studio, and that rig NEVER MOVES and is always attached to the same mains. Not true for your traveling rig, unless you do your own power distribution.

 

For what it is worth, in they typical home or small commercial establishment like a bar, power comes in as two hots of different phases and a ground/neutral. In the panel, each hot feeds every other breaker (becoming the black wire on the outlets) , and the ground/neutral is split into the two remaining wires, white and copper. So the ground and neutral are bonded at the panel anyway. The saftey ground provides a second, emergency path to ground in case something interrupts the neutral, allowing there to be some other path to ground besides through your body.

 

This means that you can derive 'balanced power' though the pains, by tapping the two hots. But it will be 208 volts. Most gear is made to run in the US and Europe, so most gear can be run on 208. My Cello amp has a 200 volt tap, and I ran it balanced in the studio for the studio monitors. Dead quiet. But this might not always work because within typical supplies, nothing guarantees that the two hots are exactly the same voltage and if they are not, you loose the advantages to CMR, which is what makes three wire systems quieter than two wire systems. Since each hot is on a different phase, any signal that is common between them would be out of phase one to another.... and two equal signals exactly out of phase with each other cancel each other out.

 

The real big problem with any balanced power solution that does not use an expensive box like the Equi=tec is that no electrical inspector can approve the usage, because the cords used on standard gear are not rated for balanced power. Also, no insurance company will cover any damage or electrical fire , for the same reason.

[Dave Horne]

Al, since all of my audio equipment in is one case, it just seemed easier to remove all the grounds (except the amp) since only one power cord leaves that case.

 

On a job I have all electrical connections first go through my rack to further eliminate any ground problem or electrical shock problems.

 

If and when I sell any of the equipment in my rack case, I'll rewire the plugs so the ground is present.

 

Incidentally, if I do a continuity check, everything in the case is grounded with each other. The difference is the noise floor level was noticeable to me.

 

 

[Dave Horne]

Bill,

If, what you have created is a situation where there is a single clear path to ground, that could be okay.

 

That's the case.

 

Also, I don't think I'll ever have an inspector checking my equipment that closely.

 

Also, at least one piece of equipment in my rack case did not have a three pin plug to begin with. (My CP300 only has a two pin electrical plug.) As I wrote earlier, I did a continuity check and everything is grounded - chassis and audio shields.

[BillWelcome Home Studios]

As I wrote earlier, I did a continuity check and everything is grounded - chassis and audio shields.

 

Right. That is why I bothered to explain about the two wire/three wire thing. Guitar jacks are often (but not always) metal, and attached directly to the chassis of the amp. So your guitar, through to the strings and your hands upon them, become a part of the electrical circuit attached directly to the ground/neutral bars of the AC panel. When you jack the gear together using guitar cords, you chain that connection one piece to the next. All of the grounds and neutrals are connected to the panel through that amp connection.

 

 

[Al Coda]

Al, since all of my audio equipment in is one case, it just seemed easier to remove all the grounds (except the amp) since only one power cord leaves that case.

 

Different here,- I have 3 racks, usable in any combination or alone plus 5 keys and a Oberheim Xpander.

In my studio, this is all running and combined w/ my console, the studio-outboard gear racks, the DAW computers and the monitors.

No chance to power everything from only one AC-wall outlet in the house.

 

For touring, I prefer to go w/ a smaller rig of 2 racks and 3 keys, one large rack housing all the midi-modules, mixers etc., capable runing off-stage and a small one housing a power-amp, tuner, MIDI-matrix/processor, midi-patchbay, a 5-way stereo audio-signal splitter and a racked power distributor for the keys and the devices in this small rack.

 

So, in both cases, more than one line of power distribution from different outlets are neccessary.

 

In addition, for me, it would be hard to decide which ground to lift and which not.

There are devices in the racks which have 3-prong AC plugs, otheres have 2-prong ones, some have wall-warts strapped to the power strips inside the racks and there are unbalaced audio connections inside the racks to the mixers,- all stereo-outs from the mixers are balanced, but even MIDI cables can cause groundloop hum (which is rarely the case, but happens).

 

Some devices have chassis ground, some technical ground, some both,- and there are the rackrails ...

 

My opinion,- I better keep the ground for saftey reasons and invest for better solutions which in addition saves time.

Can´t imagine the time investment to look in each box separately just only to remove the right ground which eventually cancels the hum but doesn´t protect/condition the line at all.

 

A.C.

 

 

[jarrell]

Another point to make is about wall circuits: try to stick to one plug and daisy-chain if necessary, but don't exceed the total (usually 1200-1500 watts if that's the measurement that is most readily available across all of your equipment).

Hmmm... As an example, the new QSC K series speaker people have been talking about are 1000 watts each, so if you have 2 of them, plus a bunch of keyboard gear, you really are going to need 3 different circuits on a gig, right? In other words, this is different than using that 100 or 200 watt keyboard amp. Or am I missing something here?

[Maze Sound]

Jerrell Just because it has 1000 watts doesn't mean its drawing it all the time. You'll never get that speaker to pull that under normal operating conditions. A 20 amp circuit is 2400 watts (volts times amps is watts) and can normally handle more than that. You should be able to run a pretty large keyboard rig plus the two speakers off a 20 amp circuit as long as thats all that is on that circuit. If you kick the breaker you are probably exceeding what you should expect out of the speakers.

[BillWelcome Home Studios]

"A 20 amp circuit is 2400 watts (volts times amps is watts) and can normally handle more than that. "

 

I don't agree with this because it dose not consider age, number of times the breaker has been tripped, wire size/distance, or any other facts of life/use/abuse. Indeed on paper 2400 watts equals a 20 amp circuit. The standard wall jack is rated for 15 amps, as is the wiring, but nearly everyone has upped their panels to 20 amp breakers. I still would not assume that 20 amps was available. You also do not know how many other wall jacks are on that same circuit.

 

If I was running -my- system, I would not want to be even close to max draw. I'd want to have a lot of headroom, mostly because the amps are going to draw much larger amounts of voltage on the transients (like kick drum strikes, snare strikes)and I would not want to starve the amp of the voltage that it needs to properly reproduce those tones. But also because you just don't know that the entire circuit is entirely dedicated to your use.

 

Plus, in that 1000 watts, are we talking about the AC draw, or some of those mythical output watts that manufacturers try to use to describe possible volume levels? If it IS the AC draw of roughly 10 amps per cabinet, I would feel okay splitting the load across two circuits. Most gear outside of amplifiers and lighting equipment have pretty modest power requirements.

 

Both circuits, if they are in reasonably close proximity to each other, are likely running close to the same distance to the panel and likely to the same panel (we hope..) so I would feel okay about plugging into the two of them and not worrying about trying to be on a single circuit.

 

There is a lot of stuff to know about power, and a lot of the quoted rules are indeed accurate in some circumstances but do not apply in others. Real knowledge is better, because it will make you safer. But in most small clubs these days, you can plug in and go to work. And in most cases, if they have done something unfortunate, likely they have also hidden it well.

[Mark Schmieder]

And, in fact, Bill's point about headroom and transients is precisely the reason why a ZeroSurge or SurgeX (or similar unit) is much better for your audio quality and overall safety of operation than the filtration-oriented devices from Monster, Furman, et al. They designed their units specifically to avoid starving anything connected to the circuit.

[Mark Schmieder]

And as for UPS devices, there are several issues. One has to do with the rather coarse criteria most of them use for switching (that is, for when to kick in the backup power vs. using the mains). With computers it doesn't matter so much, but it sure matters for audio equipment, which even if not affected in terms of integrity of the signal, will get lots of wear and tear rapidly.

 

There's also the sine-wave-vs.square-wave-vs.emulating-wave controversy regarding how the power is even delivered. There are some UPS devices (a tiny tiny number) that are supposedly optimised for audio, but the price of entry for those is around $1200, so you have to ask yourself if it is really worth it, just to have zero downtime, given the repercussions during normal operating use. But some people indeed do need them.

[Mark Schmieder]

Actually, Bill's point about how wattage is measured and published is also why the current rating is more reliable for summing up your total needs per rack or per unit, when published and available, as it is generally more consistently determined.

[BillWelcome Home Studios]

"And as for UPS devices, there are several issues. ..."

 

for me the most important is that most guys reach for (cheap) computer UPSes, which are not designed to supply a reactive load.