The No.1 Website for Pro Audio
balanced power; necessary? advantages?
Old 7th February 2007
  #1
Lives for gear
 
dubrichie's Avatar
balanced power; necessary? advantages?

alrighty,

i'm finalizing the spec for my new studio and am wondering whether or not i should drop the $2.5K on 2 x Furman IT-20 II, or just go with 2 x PL-Pro II for $640.

do i really need balanced power?

what will the extra $1860 really buy me in terms of audio performance?

thanks,

regards,

richie.
Old 7th February 2007
  #2


Balanced power gets you a transformer that acts as a filter and insures that you have a dedicated, isolated power circuit for your audio gear.

You are better off having an electrician install a technical ground or isolated sub-panel.




-tINY

Old 7th February 2007
  #3
Lives for gear
 

I was struggling with dirty power issues with guitar amps etc and was pulling my hair out. I discovered the Equitech site, and was conned by all the BS about the benefits of 2 phase balanced power. It seemed too good to be true, all that **** about how it made tube amps totally silent. Bollocks. A noisy tube amp will still be noisy will balanced power, because it's a basic design issue. Balanced AC power is still AC power, so if you amps lack shielding and filtering, or run AC heaters, they are just going to hum.

Also, so many studio toys have ungrounded power packs that will never "see" balanced power as being balanced anyway.

I did observe that the EMI field around a coiled up extension cord got less with balanced power, instead of intensifying as normal. Interesting, but it didn't serve any practical purpose for me. I believe it might help if you actually have ground loops in your system. But I go for shortest path, with as much audio transformer isolation as I can get, so ground loops have been an issue for me.

The huge improvement I got out of the whole exercise was totally due to putting in a dedicated ground spike. Balanced power forces you to do this, and I'm sure most of the claimed benefits come from this clean earth alone.

A transformer (balanced or otherwise) filters out RFI, but it doesn't filter out audio frequency crap such as harmonics of 50/60 Hz. With all the switching PSU stuff out there now, you just can't get pure sine waves anymore.

My goal is to fit sinewave inverters on my audio AC outlets, with a bank of lead acid batteries on permanent charge. That would be the ultimate. Even UPS units don't deliver pure sinewaves, and tend to be connected to the dirty earth.

I tired of the clicks and pops that come down the AC line, and i'm not convinced any so-called power conditioning boxes really solve that. They might save your equipment from frying in an electrical storm, but the only way to get pure power is total isolation.
Old 7th February 2007
  #4
Lives for gear
Balaned power can be very dangerous, especially witha 230V supply. Also the benifits it brings are marginal or none at all.

If you think that you are having power supply problems, then find out. Do not just assume something to be true, actually find out. Look at the supply on an oscilloscope when such clicks occur and see if that is where it is coming from. Also measure the voltage. Very often supply companies allow the voltage to creep up or down from 230V. 10% is all they are allowed to vary and no more. Too much will cause things to fail and too little will cause performance problems and introduce additional noise into your various signals.

If the supply is uncertain (brown-outs, fails altogether etc.) then an in-line UPS is the only piece of kit that will really be able to do something about this. Power conditioners and other fancy boxes are not going to help and can only remedy very specific problems that hardly ever occur in real life.

99% of the time, pops and clicks have nothing to do with the power supply and are not entering your signal path via the mains cable, but are coming through the air as radio waves and entering the equipment AFTER the internal PSU.

All equipment has so-called taps at the beginning and end of longer signal paths to filter off RF interference and all PSU act as small power conditioners to a limited extent, but if someone near you has, say, a faulty light switch that sparks, then clicks and pops will be the result, no matter what you do and even an in-line UPS will not help.
Old 7th February 2007
  #5
Lives for gear
May I just add to the above, the one most important thing you can do to improve your power supply side of things is to make 100% sure that there is no diffenrence in potential between any of the earths in your house and that the earth is 100% connected to the outside earth - i.e. the brown stuff you are standing on.

If there is a difference, get an electrician to install a unified earth.

It never ceases to amaze me how many people waste money on power conditioners, when what they should have done is connect a piece of wire from the earth wire to the foundations of the house.

Remember that the water pipe that enters your house is made of plastic, so just connecting the copper pipes in the house is nowhere near enough.
Old 7th February 2007
  #6
Lives for gear
Quote:
Originally Posted by Kiwiburger View Post
My goal is to fit sinewave inverters on my audio AC outlets, with a bank of lead acid batteries on permanent charge. That would be the ultimate. Even UPS units don't deliver pure sinewaves, and tend to be connected to the dirty earth.
What you are describing is an in-line UPS.

The other sort is an off-line UPS that takes over if the power fails, but does not regulate the power in any way.

As for "tend to be connected to the dirty earth", this is gobbeldy-gook. They don't 'tend' anything, they are connected to whatever you have connected them to. Even the very best in-line UPS can do nothing about a faulty earth.
Old 7th February 2007
  #7
Lives for gear
 

Ha ha - you told me I meant "B" when I said "A", and then proceeded to tell me off for a problem that exists with "B" and not "A" ... nice logic.

I said what I meant for a reason. Let me explain.

IF you buy an in-line UPS, and plug it into your standard AC wall receptacle, I can guarantee that the device will be grounded to electrical earth for legal reasons.

In my personal circumstances, my legal house wiring has a very contaminated electrical earth. I can drive a speaker with a racous buzz by connecting it between electrical earth and a spike in the ground. Ain't nothing I can do about it - it's all legal and safe, but totally fekks up my audio. A shielded cable is not much fun if the shield itself has 1.5VAC present all the time.

IF you buy a sine-wave inverter, it is designed to run off batteries. It has a ground connection which you can connect to a dedicated ground spike. Safe, legal, pure silent earth. Result: happiness.

Balanced power units, because of there very nature, do not connect to your electrical earth, and force you to put in a dedicated ground spike. This, imo, is where the massive dB reductions in noise floor take place.

Never assume that your electrical earth is zero volts or safe.

The Byre - while I agree with you that the problem is in the earth, I disagree that connecting an earth spike to electrical earth solves the problem. In my cause, it very clearly made it a helluva lot worse.

In NZ, we have an earthing system that might be different. All house have only two wires, phase and neutral from the street. Electrical earth is simply a third wire connected to neutral, and to a ground spike, at each house (but not continued out to the street).

In theory, every house has a ground, and they are all connected together via neutral, so it's is fairly failsafe as far as major accidents are concerned.

But - what I believe happens - is that the individual house grounds dry up and fail, so you can end up with small but annoying voltage drops.

If you connect up a good new earth spike - this can attract noise currents from all the other houses in the neighborhood that have less than ideal earths.

This is exactly what happend to me: I was devestated. I spent a tonn of money on professional wiring that I had to rip out and replace. I had to learn a lot about how AC really works, and in the process I played around with a two-phase (centre-tap earth) transformer and also sine wave inverters, and finally found out what works for me.

Old 7th February 2007
  #8
Lives for gear
 
nosebleedaudio's Avatar
 

I will say most of what I just read is incorrect and not based on real technical info.
I have seen balanced power reduce noise. It is NOT a cure all for as one stated guitar amps. Some hum from older amps simply comes from the heater being powered from AC instead of DC.
Others is poor design ect.
See if you can demo one and see if it corrects any hum ect.
Old 7th February 2007
  #9
Lives for gear
Quote:
Originally Posted by Kiwiburger View Post
In my personal circumstances, my legal house wiring has a very contaminated electrical earth. I can drive a speaker with a racous buzz by connecting it between electrical earth and a spike in the ground. Ain't nothing I can do about it - it's all legal and safe, but totally fekks up my audio. A shielded cable is not much fun if the shield itself has 1.5VAC present all the time.
Then your earth is neither legal, nor safe.

Sorry if I misunderstood you on the UPS, but the electrical earth MUST AT ALL TIMES be connected to Mother Earth. I cannot comment on the law in your part of the World, but throughout Europe, all new installations have to be connected to the foundations of the house and to the water supply and all other major metal parts of a building.

To have a volt or two of AC on your shield (relative to what?) could be any one of a number of faults, but if the earth is 100% connected to the structure of the building and the problem persists, then there is something else going on.
Old 7th February 2007
  #10
Lives for gear
 
nosebleedaudio's Avatar
 

Quote:
Sorry if I misunderstood you on the UPS, but the electrical earth MUST AT ALL TIMES be connected to Mother Earth. I cannot comment on the law in your part of the World, but throughout Europe, all new installations have to be connected to the foundations of the house and to the water supply and all other major metal parts of a building.

In the USA the NEC requires that ALL metal parts of the building structure, water pipes, ground rod ect. is required to be bonded to the main grounded conductor.
Article 250.xx

So there can not be a difference of potential between them.
Old 7th February 2007
  #11
Gear Guru
 
drBill's Avatar
Quote:
Originally Posted by nosebleedaudio View Post
I will say most of what I just read is incorrect and not based on real technical info.
I have seen balanced power reduce noise. It is NOT a cure all for as one stated guitar amps. Some hum from older amps simply comes from the heater being powered from AC instead of DC.
Others is poor design ect.
See if you can demo one and see if it corrects any hum ect.
This is the best advice I've seen on this thread. The reason for balanced power is to lower the noise floor. If you have no prob lem - you don't need it. Before you start though, I'd suggest a thouroughly worked out AC wiring and audio wiring plan. ie: Star ground system, telescoping shields, transformer isolated AC, etc. Without a plan, you're shooting in the dark and will probably need balanced power to fix the problems you created by not having a plan. IMO, balanced power is a band aid for not haviing proper wiring. Remember - you should only have one path to ground for each piece of gear. In a non-thought out studio, you can have up to 4 (or more)! The 3rd (ground) pin of the AC, Audio wires, metal rack rails, chassis's, computer cabling (Network, SCSI, Video monitor, USB, FW, etc).

If you don't want to spend the $$$, implement a well thought out star ground plan and see how it all works out. If you need a lower noise floor, test one of the balanced power units and see if it makes a difference. I've seen it go both ways. Either amazing - or next to no difference. Every situation is different. Plan ahead - and good luck.
Old 7th February 2007
  #12


Since the OP was in Dublin, he should probably talk to a local electrician. I know that some high tech manufacturing has been built in the last few years (so there are guys that know how to make low-noise electrical environments).

I don't know about Scottland - or Kiwiland, but in the states, the "ground" wire is a safety return where the "neutral" is grounded at the service pannel and the "hot" is 110v AC. In the states, most hum and buzz problems relate to currents on the ground connector that cause voltage drops. Proper balanced wiring cures the problem everytime (now if we can just get gear makers to use proper wiring internally....).

Guitars are a problem with EM fields no matter what and old tube amps without power filtering will pass noise on the mains right to the speaker. I donno what to suggest for that......




-tINY

Old 7th February 2007
  #13
Lives for gear
 
dubrichie's Avatar
thanks very much to you all.

interesting reading and probably going to help me get my ac sorted and save a few quid at the same time!

regards,

richie.
Old 8th February 2007
  #14
Lives for gear
 
numrologst's Avatar
I have an equitech 3q i think is what it is and a furman it20 ii.... I can definately tell you it makes a serious difference for me.

I have no hum, virtually no noise in my system at all... I even got my 24 track 2" machine plugged into it, and it doesn't take away hiss or anything, but it definately makes a difference as far as noise goes... I can't ever hear noise on my mixes from the tape machine.

Digital also sounds so much better, not a lick of noise going their either... And equitech states that it will lower jitter of the clock... I don't know if that is 100% true, but it definately think it helps.

In addition to clean power, you also know your gear is safe from high and low voltage.


I definately have noticed too that amps sound better... I have tried a/bing my amps with regular power, then the balanced... It sure does make a pretty big difference.



In addition to the balanced power though, I did make some changes to the power coming in.. It only cost me $400 too...

I had an electrician come out and make sure we had a good ground... Then he isolated 60 amps to come into the control room. He isolated it at the breaker and ran it's own line into the control room. The balanced power plugs into this, then i run lines of 12g extension cords into the live room for amps, mic power supplies etc...

I definately think it's worth the price... I can't remember the last time i had to try to isolate and destroy noise... It's definately a nice feeling
Old 8th February 2007
  #15
Gear Guru
 
drBill's Avatar
Quote:
Originally Posted by numrologst View Post
I can't remember the last time i had to try to isolate and destroy noise... It's definately a nice feeling
For those unsure, what numrologist is defining as "noise" is not tape noise, not IC noise from electronics - it's 60 cycle ground noise and possibly the upper harmonics of same. (120 & 240 cycle hash) Just wanted to clarify before we start getting "I bought balanced power and I still have tape noise" threads. heh
Old 8th February 2007
  #16
Lives for gear
 
numrologst's Avatar
Quote:
Originally Posted by drBill View Post
For those unsure, what numrologist is defining as "noise" is not tape noise, not IC noise from electronics - it's 60 cycle ground noise and possibly the upper harmonics of same. (120 & 240 cycle hash) Just wanted to clarify before we start getting "I bought balanced power and I still have tape noise" threads. heh
yeah sorry if i was unclear... No 60 cycle ground hum.
Old 8th February 2007
  #17
Lives for gear
 
nosebleedaudio's Avatar
 

I consider balanced power the NEXT step in better, cleaner audio.
Not a fix all, wiring still has to be done correctly and the same scheme maintained.
It depends, depends, depends on what and who is on the same service drop.

My last .02 cents, probably.
Old 13th October 2009
  #18
Here for the gear
 

Balanced AC grounding question

Hi all, I just signed up for this forum after finding this thread on Google. I know it's an old thread but obviously a good place to ask this one question:

With balanced AC, should the transformer secondary ground (that is, secondary center tap, wired to the green screw on an iso ground NEMA 5-15 or 5-20 outlet), be bonded to anything like a copper pipe or grounding rod, or building steel - or just connected to the secondary center tap and left at that?

I ask b/c I a studio client of mine recently acquired a used Neve digital desk, and has been having problems (crashes) that may be ground related. His power system is balanced AC, but he also says he has two copper ground stakes as well - which with everything I know about balanced AC, don't seem necessary, but I haven't checked his power wiring to see if the ground stakes just ground the unbalanced portion of the system, or the balanced AC as well.

FWIW, I once heard a rumor of one manufacturer (Sonic Solutions) advising against balanced AC, but on this install I discussed it with the Neve tech before we started any work, and he said it would be fine...
Old 14th October 2009
  #19
Gear Guru
 
drBill's Avatar
Quote:
Originally Posted by spmaudio View Post
FWIW, I once heard a rumor of one manufacturer (Sonic Solutions) advising against balanced AC, but on this install I discussed it with the Neve tech before we started any work, and he said it would be fine...
I have seen installs where the manufacturer didn't advise AGAINST it, but suggested to not do it. That said, I think they knew the right way to do an install, so they said don't waste the money.

I've done installs where Balanced power did:

Not help for all intents and purposes,
Was a salvation
Created unusual situations in an install that was pretty good before the BP was initiated

So.....

It really is more about the particular install situation rather than a "general" set of rules.

BTW, welcome to GS!! thumbsup
Old 17th October 2009
  #20
Here for the gear
 

Where did BP do more harm than good?

Quote:
Originally Posted by drBill View Post
I've done installs where Balanced power did:

Not help for all intents and purposes,
Was a salvation
Created unusual situations in an install that was pretty good before the BP was initiated
What were the installs where the BP "created unusual situations"?

How about where it did "not help for all intents and purposes"?

This experience would be well worth sharing, since it would help others in deciding whether or not BP would be worth the extra $ for their particular situation.

Thanks drBill!
Old 20th October 2009
  #21
Here for the gear
 

My own 1sthand experiences with balanced AC power

Reflecting on my previous post reminded me of my own two real experiences with balanced AC power, both of them retrofits - and in my own home. My first install was my living room AV system (stereo, not 5.1/7.1 - hence my refraining from calling it a "home theater"), which is mostly high-end consumer components, except for my Crown D150A amp. I noticed HUGE difference right away: Much more clarity and dynamic range, and much clearer picture as well - even with lowly VHS.
(Incidentally, my VHS experience was really startling. I noticed the difference with one of the Wallace and Gromit cartoons, which I had seen a number of times pre-BAP. But post-BAP I noticed, for the first time, that the walls in Wallace's living room aren't painted - they're fabric-covered. With BAP I noticed the texture of the wall covering for the first time! I was truly stunned; I never expected such a big improvement with VHS!)

So, I did the same thing in my studio (essentially a MIDI and digital editing room, mainly for my own use - "project studio" if you will) and didn't notice much of a difference.

Now, my living room system is entirely unbalanced signals, but my studio is about 50/50 balanced and unbalanced, with some AES connections between DAW and a small digital mixer. Post-BAP most work in my studio involved mostly just the digital mixer and DAW, so all digital and balanced analog connections. It's been a long time since I fired up any of the synths & samplers, which are unbalanced, so I honestly have yet to notice if there's any improvement there.

But, I'm starting to wonder if the BAP does much more good for unbalanced signal connections, than for balanced or digital (which already have much better noise immunity than unbalanced). I recall something in some Equi-Tek literature about a video dupe facility reporting a 47 dB improvement in noise floor when they went to balanced AC! But, this was in a system running unbalanced signals. It would be interesting to see similar before/after measurements with systems running balanced signals - especially studios running Neve/SSL/Studer and similar top-line gear.

In conclusion, I think it would be great to see reports from others regarding balanced AC experiences - good or bad. Most valuable would be before/afters in retrofit situations. Again, it would be a great help for anyone trying to decide if they should spend the extra $ on BAP or not.
Old 20th October 2009
  #22
Here for the gear
 

PS - my BAP wiring scheme

One important detail, which references back to my first post on this topic: My BAP setup has the OSHA ground (ground prong) on the load side tied to the transformer secondary center tap ONLY - it's not bonded to anything else. Just FYI for anyone wondering...
Old 20th October 2009
  #23
Lives for gear
 
deuc647's Avatar
This is a good thread. I just bought a new house(new as just build) and when I move in, one room is going to be my personal music space. I was going to call the electrician the first day I moved in to install a spike for seperate grounding and do what he had to do to get me balanced power. Now I think imma see if I have any problems first with hum, then take the necessary steps.
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump
Forum Jump