[pjchappy]

SO, let's throw some ideas on a DIY power conditioner.

I have minimal skills and I want to spend minimal money (of course!). . .


SO, where do we begin?  I know almost nothing about them, but I hear they do good.  

p

[byteme]

When I was looking to do this and not spend a ton of money I took some advice from around here and looked up OneAc and Powervar units.  They can be had pretty cheap on ebay, etc.  They're pretty good on their own, and with a couple tweaks they can be really really good.

Things I've done to them include:

Disable (bypass) the power switch and any LEDs
Dynamat Extreme the heck out of the case and interior
ERS the heck out of everything I could stick it to (using some BPT pictures as a guide)
Replace the internal wiring with cryo'd wire
Replace the outlets with higher end cryo'd outlets
Clean and progold connections
Mapleshade silver goop the connections
Replaced power cords with higher ga. cryo'd wire (didn't help at all and actually hurt things - made the transformers noisy - go figure)

I've currently got two OneAC 1102 2Amp, a Powervar ABC600 and ABC1200 6 and 12 Amp respectively in my system separating digital from analog stuff and a separate 1102 after the digital Powervar to separate the DAC and Transport.

I've been contemplating adding a Auricap to each outlet as well.  I've also heard there is something you can do to turn them into balanced units.  These won't be done because Chris at BPT had a killer sale on a 3.5 Signature that I couldn't pass up.  Pending a comparison all 4 of my Iso transformers may be up for sale.

Brian.

[JoshK]

First lets start with some very basic outlines.

A power conditioner is a marketing term and really all they are is filters of some sort or another. Sure there are some isolators, balancing transformers, yada, yada but when it comes down to it you are trying to clean up all the garbage on the AC line and from what I gather there is a LOT of garbage to clean.  If you'd like to read more about this subject, email DVV and ask him about his white paper on AC filtering and noise, it is an excellent paper.  

If you really want to make things simple start by asking yourself how many outlets do you need, factoring room for upgrades, changes in system.  This is really an important part, so don't overlook appropriate planning here.    

What type of devices are you going to connect to your filter/power center?  How many digital sources/devices, how many analog front end components, preamp, etc?  Do you also need to allow for HT components, you may also consider making a seperate power center for the HT stuff.  

Another very worthwhile preplanning stage, if possible, is to track down the maximum watts your components can draw.  This can be very useful in planning the appropriate filters to use.  

The casework always seems to be the most time consuming part of the DIY projects I have done to date, so a little planning can go a long way to help out.  Also if you want to spend a little more $$ you can use online services of frontpanelexpress.com to do all the drilling and hole making so the assembly is really simple.  

Building it

I chose to buy a Par-metal case that was intended for an amp chassis.  It is reasonably big because I wanted to leave enough room for big isolation transformers but I am really glad I did because it allows me to do a number of things more easily.  I cut all the holes in the back for the outlets I wanted which was a royal PITA.  This took 70% of the time I spent on the project so if time is a factor consider something like front panel express.  

Basically start really simple, make it just a big fancy power strip at first.  Put in your outlets first, an IEC inlet if you like, and leave some slack in the wiring for future use.   You might also use fast connect termination so that it is easy to test out and change if need be, you can find these types of connectors at your local Ratshack or other electronics shop.  

It is highly advised that you use a Fuse on the input of the AC power.  It is even better than you buy the fuse you intend to use once things are running well (15 amp slow blow for instance) and also a 'testing fuse', something like a 3-5amp slow blow.   This will tell you very quickly if you goofed your wiring up without finding out the hard way.  Once you know that it is working correctly (test out by plugging in a lamp in each outlet) then you can replace the fuse with a full rated fuse.  

Once you basically have the case made, the outlets and IEC installed and the wiring is done as it should be you can then start adding in your filters that you will choose.  It can also give you a reference for testing whether the filter is any good and you can take it out and put another filter in for comparison purposes as well.  

Well that is for starters....I will answer any questions I can if you guys ask.  I can also fill in details on how to wire, etc, or point you to a tutorial.  This really isnt' very complicated though, the only caveat is that you are dealing with the power source so you must take caution to be safe.  Common sense goes a long way!

[JoshK]

I agree, I am currently using OneAC isolation transformer as my 'filter' in my above discussion. I am also evaluating some other methods of filtering.  However, if you have the case you want to use and things set up then you can try whatever you like.   Some prefer to leave the OneAC unit in its existing case and just modify it.  This can also teach you a lot as you can examine how it is wired and what it is doing as it is already done.  This is how I learned.   I wrote things down like white wire goes here, black there, ground does this and that, cap goes from here to there so when I took it apart I remembered how it went back together.   Basically you are writing down a crude schematic!

[Lost81]

Does your OneAC hum, JoshK?

Mine seems to do that.

It also boosts the voltage from 117V AC to 122V AC, which is why I stopped using it.


-Lost81

[JoshK]

You can see the insides of mine as I was working on it...



look at my gallery for more pictures.

[JoshK]

My wall AC runs around 119V and the output of my OneACs seem to give me about 120V.  They don't hum at all for me.  I have heard that too much DC on the AC line will make them hum and I saw a DC trap online that was said to make transformers stop humming if you have DC problems.  I can send you the link if you are interested, I think it was on the diyparadise.com site under simple projects.

[randytsuch]

One thing you could try is adding a zsleeve to it.
If you look at pics of a BPT CPC, there is one zsleeve in there.

They are not cheap though.

Randy

[JoshK]

A zsleeve is basically an RF Choke right?  In which case it gets rid of a lot of high frequency crap, i.e. 100Khz on up but it AFAIK it is the stuff in the audio band that is really detremental and an RF Choke and many other filters are pretty ineffective on the crap in the audio band.

[Occam]

PJ,

The simplest, most cost effective power conditioning addition you can make is the addition of capacitor(s) accross the line, Live to Neutral (with appropriate specifications for the task). A single capacitor serves to powercondition the whole line, regarless of the fact that that capacitor may be residing in a component. This is the "Sarah Lee" approach to powerconditioning.... Its cost starts at about $2.

'Eveybody doesn't like something,
But, nobody doesn't like Sarah Lee...."

I'll be starting a 'sticky' thread on the Lab board soon, titled "Q&D Power Cords and Conditioning, the Sarah Lee approach"

But this does not isolate the noise that may be originating in one component from other components that are also on that same mains line. For that one needs an inductive element (or resistive, whish isn't generally practical) between the power source and each load, an inductor, common mode choke, or transformer. And inevitably one faces the constraint that inductive elements can saturate, whiich is why many prefer non inductive power conditioning for components with substantial current draws...
[And in reality this is not that much of a constraint, for we can make the transformer in a component part of the power conditioning by simply adding a properly specified capacitor accross that components  transformer's sencondaries. But this does imply a willingness to rip into the guts of a product that may be under warrantee.]

[JoshK]

Occam (may I call you by your first name on AC, I like to but some people don't like their name said in a public forum),
I am a bit fuzzy as to what exactly the cap filters to ground.  How does one calculate the frequency at which the cap starts shunting to ground?  I am sure this is written somewhere in a text I have or online but I think it is useful for this thread if you don't mind.   Basically we only want the 50hz or 60hz sinusoid, but from the output of some oscilliscopes that I have seen the 60hz sinusiod is hardly recognizable from all the crap on the line.   What parts get through and what parts get stripped?  

Here is a good general question that relates to power filtering.   Say you have all this crap on the AC line that enivitably get through the inductance, the recitification and hits the power source of your active components.  Ultimately if that crap that hits the active fan comes out the audio signal we have troubles, but how much of that crap and what frequency of crap gets into the audio signal?  

That may be vague and totally obvious to some but it isn't obvious to me. I think like a mathematician still, 1 to 1 mappings and all, but real world doesn't work like that and I have no measured experience in the real world as it pertains to power.

[Occam]

Josh,

Here comes the pedantic part....
A capacitor is a frequency dependant resistor who's reactance (capacitive resistance) is defined by -

Rc = 1/(2pi x F x C)
where Rc is the capacitive reatance in ohms, F is the frequency in Hertz, and C is the capacitance in farads.

Lets examine what happens when we wire a 1.0uf X2 cap accross the line from Live to Neutral (Neutral for the sake of this discussion can be viewed as Ground). At 60hz this capacitor will give a reactance of 2,653 Ohms. At 10,000 Hz we have that same capacitor showing a reactive component of 15.9 Ohms, i.e. high frequencies, noise, has a much easier path accross the capacitor; it is that frequency dependant 'resistance' that make a shunt capacitor function as a noise filter. Its simply not a very good shunt at low frequencies, and become more effective as the frequency increases This shunt variable resitance along with the load impedance of the transformer (which we assume is constant for the typical toroid over a rather large bandwidth) forms a 6db/octave low pass filer, e.g. a power conditioner. This is why you hear reports that the "Auricap Tweek', is more effective with low power source components. As they have smaller transformers with higher input impedances, they make the filter action more effective by shifting its cutoff frequency downwards.


Well, "Why don't we increase the size of this shunt capacitor and increase its effectiveness?", you ask.

You could, but there is a cost. Lets say you increase that capacitor to 20uf (a big mutha oil filled ac motor run cap). At 60hz it will have a reactance of  133 Ohms, and at 10KHz (noise), 0.8 Ohms.  And when I say cost, I mean cost. That 133 Ohms being fed 120v RMS AC, assuming electricty costs $0.20/kwh, for 24hrs/day, 365days a year, is going to cost $190/yr.
That 1uf cap costs $9.51/yr in electricity,

Power =( V^2)/Rc
But, if you're not in North America, and your mains voltage is 240V, that cost would quaduple!! (ignoring the change in mains frequency).

[EDIT] {I just realized my comments on power consumption caused by shunt capacitors is inaccurate. A capacitor is a reactive, not resistive component and therefore my comments on power consumption were inaccurate. As a cap causes a 90o phase shift between voltage and phase, there is going to be reactive power consumption (VAR), when the sign of voltage and current are different, and it simply won't register on the typical residential Kwh Meter.}

I'll try and address the rest in a followup, unless someone else wants to step in...
_______________
Paul aka Occam, but you can call me anything as long as its not late for dinner.

[JoshK]

Thanks Occam.

[Lost81]

My wall AC runs around 119V and the output of my OneACs seem to give me about 120V.  They don't hum at all for me.  I have heard that too much DC on the AC line will make them hum and I saw a DC trap online that was said to make transformers stop humming if you have DC problems.  I can send you the link if you are interested, I think it was on the diyparadise.com site under simple projects.

Hmm, that's interesting.
Yes, that link will be great.
Thanks, Josh!


-Lost81

[Occam]

Does your OneAC hum, JoshK?
Mine seems to do that.
It also boosts the voltage from 117V AC to 122V AC, which is why I stopped using it.
-Lost81

Lost,

I'm unsure as to the specific reason you've given up on this isolation transformer/conditioner.

Hum can originate from a number of sources. Mechanically, it could be loosely attached to the chassis, or more seriously its laminations could be loose. Sadly, this sometimes requires the vacuum impregnation of varnish whithin the laminations which requires cutsom work by a transformer specialist. If the hum is caused by dc on your ac line, there are DC blockers that are discussed on this thread -
http://www.audiocircle.com/index.php?topic=12706
What is said about buzzing toroids applies equally well to EI lamination transformers. The thread contains links to diy solutions, as well as mention of the products offered by Diycable and Peranders.

That high voltage doesn't strike me as particularly high. Hereabouts in Noo Yawk, my wall voltage runs about 126V ac.... But if you measured that output voltage with your conditioner not powering a current draw, one would expect a higher voltage. This is intrinsic to all transformers and is characterized by 'transformer requlation', the % change in voltage between the unloaded voltage and voltage produced at rated load.


Assuming the buzz can be fixed, the actual performance of these isolation transformers/conditioners might be substantially improved by replacing its filtering capacitors( and other components) with higher performance ones. This is not a criticism of the OneAC or Powervar product, they are typically intended for computer use and not audio. Replacing the existing caps with Wima MP3 caps might do wonders....

Would you and/or Josh tell us what specific caps are in your OneAC?

[ludavico]

I am about to embark on a "poboy" AC conditioner using some imput for byteme (thanks brah).

I have a 4.6a ONEAC and I plan to:

- replace receptacles with cryo'd P&S 5262-A! outlets
- place ers(cloth)+dynamat around the inside of the enclosure ala BPT
- install a single Auricap 0.47uF 600V cap around each receptacle
- bypass on/off switch

I was also thinking of doing the Auricap mod  (using 2x 0.47uF 600V caps) but where is the best place to put them?  Across the AC inlet inside the ONEAC unit, or can I put them across the AC receptacle in the wall?  I have read up on this mod, but no one mentioned putting these buggers in the wall outlet.    

I would really prefer to go upstream (i.e. in the wall outlet) with the 2 Auricaps since I am only going to plug digital components into the ONEAC.

TIA,
John

[JoshK]

Would you and/or Josh tell us what specific caps are in your OneAC?

I'll take a look when I get home and let you know.  I had intended to replace those caps, just haven't gotten a round tuit yet.

[ludavico]

Then, if any of the above actually does anything , I would like to check out spicing the poboy up by converting the tranny to balanced mode.  

Do you gentlemen know how to do this?

I heard the conversion is relatively inexpensive, and produces tangible results.  


John

[JoshK]

I am about to embark on a "poboy" AC conditioner using some imput for byteme (thanks brah).

I have a 4.6a ONEAC and I plan to:

- replace receptacles with cryo'd P&S 5262-A! outlets
- place ers(cloth)+dynamat around the inside of the enclosure ala BPT
- install a single Auricap 0.47uF 600V cap around each receptacle
- bypass on/off switch

I was also thinking of doing the Auricap mod  (using 2x 0.47uF 600V caps) but where is the best place to put them?  Across the AC inlet inside the ONEAC unit,  ...

If you are a 'poboy' and want more bang for the buck, skip the cryo treatment of the P&S outlets and just get the 5362 outlets or 8300 series outlets.   I am going to break audiophile norm but I have compared cryo to uncryo'd outlets of the same make and I can't tell much of a difference, if any.   Proponents of cryo treatment say it changes the metal by lining it all up making it conduct better, others say this is horse poo and that cryo treatment doesn't permanently change the structure and normal use will do what should be the same affect.  Most likely the difference is more of a change to the plastic (dielectric).  I say save your money for better things.

Auricaps can be replaced with Wima's as Occam mentioned.  Probably save a few $'s and may get better performance too, who knows. I wouldn't put the caps on the wall outlet, sounds like a safety hazard and a code violation.  

ERS/Dampening is a good idea, but don't forget to put some rubber grommets or feet under the unit as the OneACs are made to rest on dimples in the chassis bottom.  Not a very good mechanical coupler/decoupler, which will cause vibration, rubber feet under will go a long way to help out.  

Remember if you bypass the switch, you are bypassing more than just a switch.  Those switches are breakers, which is a safety feature.  You might want to do this last after you know you did all your wiring correctly otherwise you could fry something or hurt yourself.

[JoshK]

Then, if any of the above actually does anything , I would like to check out spicing the poboy up by converting the tranny to balanced mode.  

Do you gentlemen know how to do this?

I heard the conversion is relatively inexpensive, and produces tangible results.  


John

I didn't know you could convert them to balanced mode.  IIRC there is only one secondary.  Would be interested to know more.