240 Power Pumping to Bass

[mark rachelle]

I have put 3 ART 4 X 4 power distributers into my studio
they have cleaned up the power whereby i can hear a difference

however when i crank up the volume the meter indicates a large draw on the power
ie 240 goes down to 225 momentarily
the focal twins are drawing quite a bit of power

should i run the powered speakers from another powerpoint and risk more hum?
or is this ok?
had i not seen the meter do this i would have never been aware of what was going on

[Alastair Reynolds]

Mark, the voltage dip you describe would point to some significant shortcomings in your mains power supply, about 5% and that's only with power speakers with a maximum power of 400W each (flat out). That suggests a significant resistance in any number of areas power point, IEC cord to the power distribution system or even the wiring to the room , Meter board, old circuit breakers or fuse wedges. Does the voltage variation show up when you switch on a heater /toaster/kettle.(1200-2400W) The other alternative is the ART system is limiting the current and showing this on its meter as a voltage drop . Try measuring the supply voltage direct from a power point with a multimeter.
These sort of drops also suggest "hot spots" in wiring/switchboards that could be a fire hazard.Good to get checked out before a disaster.We use thermal imaging to detect faults in switchboards and have identified potential points of failure on 200 Amp circuits.
This type of "Power Conditioner" like others at this price point sold as Surge protection etc are fairly rudimentary in their operation, usually using Metal Oxide Varistors (MOV) for surge protection with a balanced Choke and polycarbonate bypass capacitors forming a low pass filter to reduce RFI and EMR passing onto equipment. Any pro equipment with a well designed power supply should include these components anyway. Most of this sort of noise and interferance comes from switch mode power supplies with poor filtering , common in many computers/TVs/DVD players/Computer monitors and other domestic equipment, also energy saving lighting put out a massive amount of hash.
Switching to different power points for the speakers may introduce earth loops.
How old are the power points and wiring. Rectifing deteriorated wiring and ensuring a good earth will go along way to solving noise /hum problems .
Also don't bother with esoteric $50 or $100 IEC cables. It's a con. These exotic forms of super crystaline copper they spruik are fictional. I asked my father, a 3rd generation Metalurgist , specializing in copper refining if he knew of anything like this and it was news to him, and that's with 50 years of experience.

[rick]

ok Alastair
an answer like that gets you promoted to the turtlerock "techguy ' hall of fame
we probably should have done it ages ago anyway

mark if i cannot figure it out can you TRM tech endorse mr reynolds

[rick]

btw i might have to bring a " $10,000" ac power cord somebody gave me to try out once along to integrate

the cool thing about it is the cord has a 100 volt american plug and the sales rep has NEVER called me back to reclaim it

how much bigger con is a 10,000 dollar power cable then a $100 power cable ...?

err a lot me thinks

[mark rachelle]

Thanks Alastair

St Andrews Beach where i live is a well known brown out area
just ask my televisions all 8 of them in 20 years

and the wiring is getting on to be 20 years old with a couple of renovations added on
it is not ideal for pro audio

I have the feeling that once i go down this rabbit hole, i could be driven nuts!

there are a few week links still in the p/s chain
So I will do some tests and first eliminate the weakest link (mainly my knowledge!)

so if you have to use an extention cord and a 4 way power board is there a favoured type?

[Alastair Reynolds]

Hi Mark, maybe try some new powerpoints to start with ($7.50 at your local Bunnings ) and reterminate the points where your equipment is plugged in.A licenced electrician should do this work.Old pwerpoints with corroded screws and weak contact tension will also cause voltage drops and hot spots, particularly if the point has previously been used for high current devices like electric heating. For extension cords, use good quality 10amp cords, nice thick ones (Bunnings again) and only as long as you need them to be, Don't coil them up. Powerboards:- get some new ones, they don't have to be fancy with filters, surge protectors and costing a small fortune. They need to have good contact tension. avoid cascading them and no double adaptors. Higher quality power strips are available from Radio Parts or Jaycar.

For more advanced filtering and power regulation, consider a double conversion UPS. This will remove the hash, give a nice clean sinusoidal regulated supply and save your power supplies. They aren't cheap around $1500 for 2200KVA unit, (new) , but the protection they offer to expensive equipment is worth it.
I run an 80KVA double conversion redundant UPS system for our Studios and Master control. We have very clean power, stable 240V and equipment failure has reduced dramatically (more than 90%)Here's an example, but there are plenty of good models. Just make sure it's an inline system that is constanly regenerating the 240V , not one that does a quick switch.
http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SUA2200I&total_watts=50

Plus you have the advantage of not crashing your PC when a big brownout or surge occurs

Hope that helps
Cheers

[mark rachelle]

thanks Alastair