Power conditioners in series?

[camshash]

Hey guys, had a thought the other day.

I can predict there would probably be power limitations by running 2 power conditioners in series, but is there any added benefit?

I know some more expensive power conditioners have a filter on the initial input, and then a filter for each outlet.

For example, would I gain anything by running a furman power conditioner into another furman?

Thanks!

 

[JohnRoberts]

additive losses...?

JR

 

[john12ax7]

It depends on topology. A simple MOV that fails open would have redundancy.

In general I would say don't do it though. You can sometimes make things worse. Furman actually warns of this, with some of their products you actually compromise the overall protection when running things in series.

 

[Tubetec]

Probably a major financial loss with little gain from mains bourne interference.

Why not get a 3kw 1: .5+.5 isolation transformer and add your own filter blocks at input and output , drive down a ground spike and connect it to the secondary centre tap and run all your audio gear off it ?

I just found out recently that my mains connection to the pole comes via underground sheilded single core cable , (CORE LIVE, NEUTRAL SCREEN) neutral and ground connect in the fuse box and the ground wire runs to the outside utillity box , where the meter is located and onto the ground rod nearby . If you get your power overground you get twisted pair from the local step down transformer . As far as I remember in the studio I worked the console had its own ground and was on a seperate phase to all the other domestic appliances in the building .
Mains systems differ depending on territory , If theres any shaddow of doubt consult a qualified electrician , but to be honest your average 'Sparky the clown' doesnt know shit about it and will need to refer to the manual anyway .

 

[scott2000]

drive down a ground spike

Wasn't sure this was a recommended thing? I know my buddy electrician talked about doing it at one point in time...

 

[Ricardus]

The power conditioner I own explicitly says not to do this on a sticker on the unit.

 

[ccaudle]

drive down a ground spike and connect it to the secondary

That is explicitly against electrical code unless the secondary ground rod is bonded to the primary ground rod (at which point why bother).
2002 NEC section covering balanced power

You are also required to use GFCI outlets at the balanced side.

 

[MisterCMRR]

Since "power conditioning" is so widely misunderstood, a significant part of my seminars on system noise is devoted to explaining facts and de-bunking the myths surrounding earth grounds, so-called "balanced power" and the actual sources and coupling mechanisms that create system noise problems. The slides from a typical seminar are posted at:

https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

Bear in mind that nearly all of the benefits attributed to "power conditioning" arise from simply plugging in all the system components to a closely-spaced strip of outlets ... and have little to do with what's inside the box. In most cases, a cheap outlet strip will have the same results. I once was hired to reverse-engineer a $3,000 "power conditioner" that contained a lot of impressive-looking circuit boards and fancy components - but after tracing its schematic, the only functional parts were two garden-variety MOVs across the AC line and a small "wall-wart" power supply to light the blue LED on the front panel.

 

[Tubetec]

Site style iso transformers transformers here have a circuit breaker on the secondary .
It may well be the console ground spike was bonded back at the fuse board , I suspect the codes vary from place to place as there are some technical differences in the implementations . In that particular case there wasnt an isolation transformer .

Thanks again Bill ,
Funny story about the $3000 box of trickery , all people are paying for is the Placebo effect .

The typical studio effects rack is where lots of electrical noise creeps into the system from my experience , there all kinds of ground loops formed between the chassis of the gear ,the frame its attached to and the electrical ground connection . I made a sloped 19 inch rack mount unit from timber , The gear is stacked insulated from each other with the addition of stick on rubber feet , this allows some space between units for better cooling also . Gravity does a good job of holding the units in place , otherwise I just use woodscrews and washers into the wooden frame to secure the boxes .

 

[Newmarket]

The typical studio effects rack is where lots of electrical noise creeps into the system from my experience , there all kinds of ground loops formed between the chassis of the gear ,the frame its attached to and the electrical ground connection . I made a sloped 19 inch rack mount unit from timber , The gear is stacked insulated from each other with the addition of stick on rubber feet , this allows some space between units for better cooling also

If needed for metal racks:

Adam Hall Humfrees Mounting Kit (4-Pack including Screws)

 

[camshash]

Site style iso transformers transformers here have a circuit breaker on the secondary .
It may well be the console ground spike was bonded back at the fuse board , I suspect the codes vary from place to place as there are some technical differences in the implementations . In that particular case there wasnt an isolation transformer .

Thanks again Bill ,
Funny story about the $3000 box of trickery , all people are paying for is the Placebo effect .

The typical studio effects rack is where lots of electrical noise creeps into the system from my experience , there all kinds of ground loops formed between the chassis of the gear ,the frame its attached to and the electrical ground connection . I made a sloped 19 inch rack mount unit from timber , The gear is stacked insulated from each other with the addition of stick on rubber feet , this allows some space between units for better cooling also . Gravity does a good job of holding the units in place , otherwise I just use woodscrews and washers into the wooden frame to secure the boxes .

Never thought about ground loops within the rackmount chassis. Do the plastic washers supplied with rackmount gear do a good job of isolating?

 

[scott2000]

Do the plastic washers supplied with rackmount gear do a good job of isolating?

I always thought they were just to prevent scarring up the front panels. Doh.. But maybe the shoulder washers are missing from the ones I've seen.

I never thought about the grounding through the rack either as many times as it's been brought up. Makes sense though. Thanks for the reminders.

The set Newmarket linked looks good. Spendy.

Saw maybe 1 of these on each side of the panel could work?

https://www.bhphotovideo.com/c/product/421040-REG/Middle_Atlantic_SW_SW_Shoulder_Washers.html

 

[JohnRoberts]

"Ground loops" are a catch-all term to describe multiple different ground related noise problems. Ground loops are a specific phenomenon involving a one turn magnetic winding that generates a voltage across that turn from intercepting a strong local magnetic field. I recall this being a design concern "inside" large power amps where ground wiring decisions could involve an unintended winding in the presence of strong magnetic fields.

Interfacing between multiple equipment chassis is generally a simpler issue of uncontrolled ground current flows. "Pin one problem" pretty well describes effective strategies for proper input design to reduce ground contamination problems.

JR

PS: regarding insulating rack screw washers, rack chassis should be happy to be securely ground bonded to other safety grounded chassis. However if the audio path is not properly differential, it can become contaminated by noise between the chassis safety grounds that should be ignored.

 

[john12ax7]

I use those plastic insulating washers. But mostly because it helps the rack gear line up better and not get scratched.

 

[abbey road d enfer]

Having to resort to separating chassis grounds is a sign of one or more units being faulty, poorly designed or simply unbalanced.
My typical solution was to use properly balanced interfaces. I have sold thousands of balance/debalancebuffers just for that.

 

[camshash]

Having to resort to separating chassis grounds is a sign of one or more units being faulty, poorly designed or simply unbalanced.
My typical solution was to use properly balanced interfaces. I have sold thousands of balance/debalancebuffers just for that.

Are balance/debalance buffers the same as baluns?

 

[JohnRoberts]

Are balance/debalance buffers the same as baluns?

no... warning I am not the transformer expert but AFAIK baluns are a type of transformer for bal/unbal interfacing.

Active balance/de-balance buffers (affectionately known as "bump boxes") were very popular for interfacing between unbalanced -10dBV (bedroom recording gear) and more professional +4 dBu balanced gear. These bump boxes involved the conversion between single ended and differential adding and /or scrubbing off gain as required.

These were more popular a few decades ago, when Abbey and I were younger...

JR

 

[abbey road d enfer]

Are balance/debalance buffers the same as baluns?

Baluns are RF devices.

 

[camshash]

Gotcha, I am still a bit confused though. Could you give me a real world example of where/why you would use a balance/debalance buffer? Is it only for setups that have a mix of balanced and unbalanced equipment?

 

[JohnRoberts]

Say you have a signal source that is single ended and puny (like a music player headphone jack), but want to feed it into balance +4 gear.

It is to fix problems, if you don't have a problem you don't need one.

JR