[wushuliu]

Maybe I missed it but is it necessary to have a felix for each outlet of a duplex or can one be used for both?

[Occam]

The Felix is simply a mains low pass filter and can feed as many outlets as you wish to wire them to. Your decision should be guided by -

1. Outlets fed from the same filter are not isolated from each other.
2. The total current draw for those outlets fed by a single filter should be (usually substantially) less than the current rating of the choke used. If the choke's rating is less than 15/20 amps, depending on the circuit's breaker, the filter should be fused to reflect the chokes limitations.

[wushuliu]

The Felix is simply a mains low pass filter and can feed as many outlets as you wish to wire them to. Your decision should be guided by -

1. Outlets fed from the same filter are not isolated from each other.
2. The total current draw for those outlets fed by a single filter should be (usually substantially) less than the current rating of the choke used. If the choke's rating is less than 15/20 amps, depending on the circuit's breaker, the filter should be fused to reflect the chokes limitations.

Thanks. i think this project will be next on the docket. I know someone briefly mentioned using 2 Felix in series to greater effect. Are there any cons to this approach?

[Russtafarian]

I have a somewhat Felix related question.  About three or four years ago I built a 10 outlet power box with a Felix (3 or 6 amp chokes) or Corcom (10 amp) filter on each outlet. 

Last night I plugged my notebook computer's switching PS into the powerstrip and was shocked at all the noise it dumped into my system.  As an experiment, I plugged the PS directly into the wall and got even more noise.  Plugging into the Corcom, the noise would hit then quickly ramp down but was still very audible.  Same result with the Felix.  When I lifted the ground pin on the computer PS, the noise went away regardless of the outlet I plugged it into.

Why does the computer PS dump so much noise into the system when grounded?  Should all switching PS's connected to an audio system be ground lifted?  Is there a "rule of thumb" to follow that will keep switching PS noise out of the system without creating a shock hazard?  Thanks.

Russ

[Occam]

......
Why does the computer PS dump so much noise into the system when grounded?  Should all switching PS's connected to an audio system be ground lifted?  Is there a "rule of thumb" to follow that will keep switching PS noise out of the system without creating a shock hazard?

Russ,

Have you tried a different mains supply for your laptop to check if your particular ps brick isn't faulty? Is the problem eliminated when you power your laptop from its internal batteries and its not connected to the external supply?

-Paul

[wushuliu]

The Felix is simply a mains low pass filter and can feed as many outlets as you wish to wire them to. Your decision should be guided by -

1. Outlets fed from the same filter are not isolated from each other.
2. The total current draw for those outlets fed by a single filter should be (usually substantially) less than the current rating of the choke used. If the choke's rating is less than 15/20 amps, depending on the circuit's breaker, the filter should be fused to reflect the chokes limitations.

Hi Paul, don't know if you caught my other question above so I'll clarify: would it be just as effective or more so to use two in series, CLCLC, or even more?

[Russtafarian]

Thanks for the explanation Paul.  That's what I was looking for. 

I don't usually have a computer plugged into the system's power block.  I have it there for now to run Room EQ Wizard and set up MiniDSP.  I find it interesting that some notebook computer PS's are grounded and some aren't.  The grounded one's always dump noise into the system in my experience.  Lifting the power ground on the PS or using battery power removes the noise.

BTW, I've got two particular power cables on my tube amps and they are singing quite sweetly. 

Russ

[rajacat]

Hi Paul, don't know if you caught my other question above so I'll clarify: would it be just as effective or more so to use two in series, CLCLC, or even more?

Good question! I'm interested in this too.

-Roy

[Occam]

would it be just as effective or more so to use two in series, CLCLC, or even more?

Cascading a second LC adds 12db/octive of additional differential/normal mode attenuation to an existing Felix (CLC). WRT common mode noise, it lowers the -3db point. The impact is quite measurable and significant subjectively, though not as major a improvement as adding the initial Felix in a noisy mains environment. This has worked quite well cascading the 3amp Coilcraft chokes, on source components, specifically dacs and the Behringer digital doodads. I can't opine on this for preamps, as my CAT SL-1 Mk III preamp actually has the power conditioning where it belongs, within the component, specific to its needs, and no matter what I do, external conditioning efforts simply don't help.
I wouldn't recommend this for power amplifiers, as cascaded filters might well choke the performance, especially with linear supplies with large, low angle of conduction charging pulses.

FWIW,
Paul

Edit added in italics

[wushuliu]

Cascading a second LC adds 12db/octive of additional attenuation to an existing Felix (CLC). The impact is quite measurable and significant subjectively, though not as major a improvement as adding the initial Felix in a noisy mains environment. This has worked quite well cascading the 3amp Coilcraft chokes, on source components, specifically dacs and the Behringer digital doodads. I can't opine on this for preamps, as my CAT SL-1 Mk III preamp actually has the power conditioning where it belongs, within the component, specific to its needs, and no matter what I do, external conditioning efforts simply don't help.
I wouldn't recommend this for power amplifiers, as cascaded filters might well choke the performance, especially with linear supplies with large, low angle of conduction charging pulses.

FWIW,
Paul

Very cool. Thanks Paul.

[mgalusha]

The impact is quite measurable and significant subjectively, though not as major a improvement as adding the initial Felix in a noisy mains environment. This has worked quite well cascading the 3amp Coilcraft chokes, on source components, specifically dacs and the Behringer digital doodads.

Totally agree with Paul on this. I'm using cascaded Felix's in front of my modified DCX which is driving the subs. Adding the second Felix did improve things and on only the bass. Don't forget that it filters both ways, it also keeps nasties from the power supply from getting back to your other gear.

[wushuliu]

Totally agree with Paul on this. I'm using cascaded Felix's in front of my modified DCX which is driving the subs. Adding the second Felix did improve things and on only the bass. Don't forget that it filters both ways, it also keeps nasties from the power supply from getting back to your other gear.

Good to know.

@Paul:
Now as far as the caps go, would there be anything to be gained by adding .001 (1nf), and .1nf?

[Occam]

...would there be anything to be gained by adding .001 (1nf), and .1nf?

One can generally find metalized film interference (X2,y2,etc...) down to 1nf, 0.001uf. The reason for using bypass capacitor(s) is that the larger the cap, in both physical size and capacitive value, the lower the frequency at which the capacitance is ineffective, because of the capacitor's parasitic series inductance. A capacitor's impedance reaches its minimum at the frequency where its capacitive reactance equals its inductive reactance, and beyond that frequency, looses efficacy.

FWIW

[wushuliu]

Thanks Paul.

FYI to all: Newark/Farnell has the 8111-RC JW Miller on sale for $7. I bought enough for a 12 outlet
w/ double felix (to inc. some of the 9A chokes).

[poseidonsvoice]

Cascading a second LC adds 12db/octive of additional differential/normal mode attenuation to an existing Felix (CLC). WRT common mode noise, it lowers the -3db point. The impact is quite measurable and significant subjectively, though not as major a improvement as adding the initial Felix in a noisy mains environment. This has worked quite well cascading the 3amp Coilcraft chokes, on source components, specifically dacs and the Behringer digital doodads. I can't opine on this for preamps, as my CAT SL-1 Mk III preamp actually has the power conditioning where it belongs, within the component, specific to its needs, and no matter what I do, external conditioning efforts simply don't help.
I wouldn't recommend this for power amplifiers, as cascaded filters might well choke the performance, especially with linear supplies with large, low angle of conduction charging pulses.

FWIW,
Paul

Edit added in italics

I agree with Paul on this but in addition, I have Paul Kaplan's 1.5 conditioner cord on my dac detailed here. The dac has its own integrated Felix filter. I removed the Felix filter last week and had only Paul's filtered cord connected to it. What was lost was a smidgen of bass and the soundstage had shrunk a little. Adding the Felix filter back in restored that balance. I heard this across several recordings.

The improvement of the Kaplan 1.5 conditioner cord itself was a monumental experience to say the least. The addition of the Felix was a nice tweak. I also tested the Felix Filter on its own using a standard Kaplan cord and the improvement provided was definitely great, in all frequencies, especially opening up the top end. The Kaplan 1.5 conditioner however was a more substantial improvement, more foundational so to speak. The Felix filter was icing on the cake, but not a detriment in any way.

I need to try these changes on my other components, but I surmise that the biggest improvements will be at the source level depending on the design of the component itself.

So just to clarify:

Felix filter alone: 
Felix filter + the Kaplan non filtered power cord: 
Kaplan filtered power cord alone: 
Felix filter + the Kaplan filtered power cord: 

I don't know if the Kaplan filtered power cord has a Felix in it or it doesn't. But what it does is beyond what the Felix can do alone and in no detriment to the dynamics of the component being tested. In fact, it enhances that component in every way. I was pretty surprised but that's the honest truth!

Oh...and just so that this thread isn't derailed, any pertinent questions regarding the Kaplan filtered cord should be directed at Paul Kaplan the designer (through a pm), since this isn't the 'Critics' circle. I've already asked him what is inside the filtered power cord...no answers there, it's his design, it's proprietary and that's the way it should be.

Anand.

[wushuliu]

So you found the Felix less beneficial than a smaller - and no doubt proprietary - rfi/emi filter?

Edit: this was asked before anand added the last 3 paragraphs above.

[sts9fan]

I would not be surprised if it was a felix in the cord.  Notice how there is a 3amp and 15amp version and a fuse.     

[wushuliu]

Ah. Got it. Little slow in the morning.

[nottaway]

Would something like this work in place of the fuse?

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=074-022&scqty=1

Also will someone point me towards a DIY DC blocker? LINK?

[jtwrace]

Would something like this work in place of the fuse?

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=074-022&scqty=1

Also will someone point me towards a DIY DC blocker? LINK?

http://www.audiocircle.com/index.php?topic=25757.msg494404#msg494404

http://sjostromaudio.com/pages/hifi-projects/36/109-dct02-the-dc-trap-high-end-style