How to safeguard from voltage sags and I am having a chirp.

[Skiroy]

Okay I am having a ongoing problem with my equipment and it seems like I never know if I have a issue with my houses wiring or if these anomalies are normal. I wont get into the anomalies,but I feel like I have educated myself enough and have bought enough protection that I shouldnt still have to be worrying about this.

I have Furman power conditions on all my equipment,which I thought were good till someone told be they are glorified power strips and that a power strip from office max is actually quieter. BUt none the less they are supposed to protect my equipment from spikes and peaks. I also have a premium surge protector on my houses main electrical supply. I also checked all my rooms outlet terminals for loose connections,And I ran a second good ground rod for my house.

Finally I changed a couple breakers in my house as a I was told one was bad by an electrician. It was actually a different one I found later that was bad,but the problem was solved. The problem wasnt in my room anyway. But the electrician told me I had a unbalanced load on my rooms grid,that was present even without my equipment being on,but it was mild.


So my questions to you guys is these 4:

1. The other day my furman voltage meter when down to 85 voltage for a brief moment. I was told by the electrician that these are bad for my equipment and are cause by the Power company. But if my furman is not protecting my equipment,which I thought it is suppose to trip from peaks AND sags,then how do I protect my equipment from voltage sags?

2. This morning I realize Ileft some of my equipment on,2 500 series preamps and a dbx 160. When I turned it off it made a loud chirp sound though my monitors that lasted several secs. I also remember my tube mic PSU doing the same thing before.What is this and is it a bad indicater?

3. As far a having to use ground lifts. I have had to use lift switch on pretty much everything that has one. I was having issue with noise on my tube mic,when the manufacturer said to use a 3-2 prong converter and it worked.I have way less noise when I use a 3 to 2 prong power cord adapter also on my guitar amp,ect. ect. So what is this indicating? Do I have a ground problem and how do I fix this? And is using a 3 to 2 prong adapter putting my equipment at risk?


4. Finally I have a couple of pieces of equipment that have 2 prong electrical cables. Does that mean they are at risk,even if they are plugged into a Furman with a 3 prong? And should I rewired then with a 3 prong,but if I do I worry they will have more noise. And does a ground lift switch essentially take the 3rd prong off the wiring scheme,thus putting your equipment at risk again?

Sorry for all the questions but this is getting frustrating. Every time I turn around its some other weird noise I cant figure out where its coming from or something malfunctioning. Ijust want to have peice in mind with my investments.

Thankx

 

[JohnRoberts]

#1. get a decent VOM and measure your outlet voltage.. 85V is too low. That alone is enough to explain hum in most products.

#2 Don't automatically use ground lifts..  If you need them on everything there may be a better system based approach.

#3 products with two wire line cords are double insulated so "safe"...

Using ground lifts makes products unsafe by opening up a safety ground chassis connection to service ground.

If your outlets are miswired that could be a serious problem.

JR

 

[guavatone]

1. The other day my furman voltage meter when down to 85 voltage for a brief moment. I was told by the electrician that these are bad for my equipment and are cause by the Power company. But if my furman is not protecting my equipment,which I thought it is suppose to trip from peaks AND sags,then how do I protect my equipment from voltage sags?

You could call out the power co. Rule out their fault and keep on on their toes. 

 

[Speedskater]

My thoughts:
a] Most of the electrical load in a home is from the major appliances which being 240V won't unbalance the system.
b] Lost Neutral or other Neutral wire problems from your breaker boxes to the power company's pole pig transformer can cause voltage strangeness.
c] The new ground rod should only be connected to the same point as the original ground rod near the service entrance.
d] Power conditioners can only protect from under-voltage if they have a battery and then they are called a UPS.
e] Equipment turn-on order is mic-pres & mixers first then power amps last.
f] Equipment turn-off order is power amps first then mic-pres & mixers last.

 

[Speedskater]

I wrote:
d] Power conditioners can only protect from under-voltage if they have a battery and then they are called a UPS.

But on second thought, a power conditioner can have a multi-tapped transformer and select the correct tap for the voltage present.

 

[sodderboy]

Furman does make a multi-tapped stabilizer product that I have used with success.  I had an MCI console powered through three of them and they worked well through sags.  The house was at the end of a long causeway-lane-driveway-etc. and the power would get smacked every time it thundered.
I have a Monster 2000 for my tech power.  I have it because I have a long run from the transformer to my house, about 300 feet, and my power sags if any of my neighbors' appliances kick on.  I need stable power when working on toob stuff.  The Monster is a huge variac inside and is quite quick.

You should search here for power problems etc.  The usual rules are listed- plug everything into one circuit if possible, which is possible for most production studios.  Get a test plug to test all your house outlets for proper wiring.  You should also UPS your computer.  They are so cheap there is no excuse.  I would not worry about a chirp on power-down.  Furman also makes a stepped power rack that I like for ProTools rigs.
Mike

 

[Skiroy]

So I need UPS systems on everything to fully protect it. I had them but the damn things go dead and you have to buy them all over again. I now only have one on my PC.

Thankx guys,

So what causes the need for using a ground lift switch? In other words why does some equipment become very noisey with a 3 prong power cable?
And does what risk does the ground lift put your equipment at when its switched on?

 

[sodderboy]

The AC third pin creates a second or third connection between your chassis which creates a circuit generating noise.  Google or search "ground hum audio" for mucho info.
Lifting your power grounds is just unsafe practice- they are there to protect YOU.  You should be selectively lifting cable shields at the load sides instead of the power ground.  Build a mini mic cable with the shield disconnected at one side to test problem audio runs.

The way to get a system right is to have everything plugged into one circuit if possible.  All power grounds connected with no audio connected.
Then connect your monitoring switcher and monitors one at a time.  Lift shields at the load side if anything is humming.
Then add computer.
Then add audio interfaces.
Then add outboard.
Addressing any hum issues as you go along by lifting audio cable shields at the load.  You have to do it in stages just like building a solid house.

Mike
PS: or you can go with a balanced power situation like the Furman IT20.  Connect all shields, connect all power grounds, run whatever all over the place, and never worry about hum ever again.  I use these in studios with multiple computers/DAW's, USB/FW running everywhere to interfaces, more than 10 hardware synths, multiple programming pods etc.  Works like a charm, and is cheaper for the client than paying to de-buzz the whole mess.

 

[Speedskater]

The small gains from balanced AC power are not worth the cost and effort. Balanced AC power is often against the rules and regulations in many locations.

 

[sodderboy]

Small gains?  I absolutely disagree when you are looking at complex setups, as I described.  For console-less studios with two hundred or less patchpoints I might agree, but as you scale-up the gains are great.  Add a huge hunk of metal console to the room, it also becomes less necessary.  Connect 30 boxes of roughly the same weight in metal together with multiple paths, and you are going to need more than a shield clipper.

I build with and without balanced power depending on the job.  If you are talking 500 patchpoints and no console, a studio with balanced power and every shield tied will have a much lower noise floor than one without and shields lifted or lines transformer isolated all over the place.
I was hard-won over to this reality, having built rooms without balanced power for 20 years, but the equipment dynamic has changed and the integration has changed along with it.  The best "gain" is that I can design future expansion for a client where they can add or change anything and not have to call me to de-buzz it over the phone or in person.  Being married to every job is bad practice.
Mike