DIYHiFi.org

Hi TD.

I put them immediately upstream of the power strip feeding the analogue or digital components.



They are L/C RFI fitlers with common/differential mode inline chokes, shunt filter caps, bleeding caps, & bleeding resistors, with or without VDR (voltage dependent resistors).
They are available from electrical/electronic parts stores. Make sure whatever powerline filters or brandname power conditioners to be used, they don't affect the sound. Not all powerline filters are made equal sonically.

I don't believe in spending big bucks to finance those brandname conditioners vendors, I am using one made in English, comprising inline chokes, shunt caps, bleeding cap & resistor but without VDR as all power strips already get VDR built-in. RFI insertion loss up to 52dB at 32MHz. Small size & cheap to buy. But they don't affect the music which is my bottomline of choosing any powerline filters.



As I know electricity as much as I know music & diy electronics, I DIY installed the dedicated powerlines myself. So it is not "expensive" to me at all.

It is not a "placebo", bud. It is a scientific methodology to BYPASS the digitally & analogically polluted house powerlines via the wall outlets!! You know why those expensive brandname powerline conditioners are selling so well? Their loyal customers are those who don't know how to kill noises from the wall outlets which feed their audio/video stuffs.

The most effective way is to use dedicated powerlines hooked up direct to the house breaker panel, better than any wal loutlet type conditioners, IMO.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

I don't think so.

When I play CD-audio & DVD-audio music, there is not hum at all. I can't even hear my tube phonostage/linestage & tube power amp are already powered on considering my audio den in my basement is so dead quiet - being 9ft underground, with basement door tightly closed.

I can detect very lowly hum with my ears up against the loudspeaker when I switch my phonostage to play LP, with volume pot fully cranked up. Maybe I ask for too much.

FYI, all components use 2-pin power cords except my tube power amp which I've upgraded it to 3-wire powering with its green ground wire bolted to the chassis & signal reference ground of the power amp star-grounded to the ground bolt via bi-polar R/C RFI blocking device.

There is only one ground wire for my whole rig via the power amp only. So multi-grounding loop should not exist.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

"FYI, all components use 2-pin power cords except my tube power amp which I've upgraded it to 3-wire powering with its green ground wire bolted to the chassis & signal reference ground of the power amp star-grounded to the ground bolt via bi-polar R/C RFI blocking device."

Aaaaaaaahhhhhhhhhhh....... I mean, Hhmmmmmmmmm..


Not all loops are made of wire, you know.

_________________
'I am... everything is... changed... they're calling... your face... interwoven... who is...

Hi.

I think we are talking about equipment ground looping via multi grounding wires, which causes hum.

Yes, hum noises can be caused otherwise. One most common source is 120Hz hum noise induced as AC rippling due to inadequate DC power supply filtering. Also, 60Hz hum noise
can be induced by interaction of magnetic fields of transformers seated too close on the same chassis.

Inadequate shielding of audio signal carrying conductors is anther source of hum.

That said, ALL the 4N purity silver interconnects I build are WITHOUT shielding. Guess how I build them with no RFI & hum problem.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

It only causes hum if you do it wrong. Again, see AES48.

What do you suppose the intention of star grounding is. Is it to keep all "common" points of reference at the same potential? Why in the hell then, do you employ a ground lift. Hmmmmm.

You know what, my class d amps run at full noise gain, there is no volume, and there is no hum. There isn't even an enclosure yet. There are balanced lines, the shields are connected at both ends, ground loop current does flow via PEC, it is all DC coupled, there is no common mode modulation nor noise rectification, but thems some big guns you don't need. Oh and my interconnects are some cheap radio scrap junk, maybe it takes 4N silver wire to hear the hum better?

Guess how you build them with no RFI and hum problem? I suspect you don't because it seems you haven't.

I am not advocating commercial line conditioners either, and I never heard of a bleeding cap as a good thing. Not all power bars have surge protection!

Placing the filters outside of the enclosure makes them fairly useless.

Whitlock made the statement his belief to improvements seen by "balanced power" type of mains conditioning is simply that of having all components plugged into the same outlet or at least branch, something you should consider. You know like the "star" thing, maybe then you won't have to go around with power bars switching everything off.

Masking the hum in your system by playing music louder ("can't hear it when it's playing") or turning the volume down is not resolving the issue.... it is just another placebo and that noise on a system that hums is going to modulate your input and if you truly had a trained ear you would probably hear the effect it had, but placebo is a potent drug.

BTW if dedicated mains lines alone could free your system from"digital" noise, what then do you need the RFI filters for. I would caution against what you consider as scientific, and quite honestly, re-evaluate your entire ground structure. Just in case you decide on playing around your mains again, it has been a true pleasure.

_________________
'I am... everything is... changed... they're calling... your face... interwoven... who is...

All "common points" are same potential. No ground lift at all. Why?

First off, we need to provide shortest & safe exit of RFI & dangerous HV/LV insulation leakage off the amp. This can be done effectively by installing a device btween the star-ground & the chassis ground bolt. I have used a simple device comprising 0.1uF//10R// 2xSS diodes ying-yang parallel connected. The 0.1uF//10R is to provide exit for RFI somehow exists inside the amp. The SS diodes are to provide safe exit for dangerous +/- HV/LV breakdown voltages & currents from the amp.

The P/N junction capacitance of the SS diodes also provides exit for the VHF RFI in the amp.



I don't think you know how those "cheap radio scrap junk" built. Let me tell you.

To save manufacture cost, hence save you a few bucks to buy, those cheapie ICs are built with only one not-so-pure copper conductor for the incoming signal & use the shield as the signal return path. This is to borrow the principle of a PERFECT coaxial cable for external field cancellation.

But the cheap way they are built is no way close to the construction of a coaxial cable, let alone being "perfect". This defeats the crucial noise cancellation effect. No free lunch, bud.
You get what you pay.

The 4N pure silver ICs I built is something else. Each cable get 2 conductors of same gauge, same temper & same purity, one for incoming signal & the other for signal return. Precisely built to provide effective noise cancellation up to 1 Mhz. For audio use it should be OK proven by my years application.



I don't think you know what "bleeding" means.

ALL powerline filters get bleeding caps & resistors installed across the live line & neutral line.

ALL power bars or strips get VDR across the live line & neutral line & claimed to have "surge protection". Effective or not depends on the design.



Are you sure?

RFI have to be installed inside an amp to kill the RFI somehow got into the amp. But we must not overlook tons of RFI ejected into the house powerlines via the wall outlets by those digital gadgets lying all over the place inside the house, e.g PC+wireless routers (5MHz), LCD/plasma TVs, cell & cordless phones, major electric appliances, etc etc etc.

Inline filters are therefore a must to stop those unwanted RFI going into our audio system via the wall outlets.



Balance power supply is a classic technology to isolate RFI/noise from the load. In fact, many
expensive brandname powerline conditioners emply such technology. BUT, but my question is -
would such double wound transformers & complex electronic filters affect the music or not ???????



Who told you I test hum "by playing music louder"?? I always test the hum audibility of any system with phono catridge input (no CD input!!) if available, with volume pot set to full but without playing any music. Only this way can tell how effective is an amp hum handling.



Dedicated powerlines are to BYPSS the digitally polluted powerlines inside the houe. But we must not overlook tons of RFI coming from external power grids invading our audio system via the houe main breaker panels where the dedicted powerlines hooked up to.

Dedicted inline filters are indispensable.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

cj,

The “safety loop breaker circuit,” a popular version shown at http://sound.westhost.com/earthing.htm , is an effective tool for combating a ground loop, however it is not a panacea. It should be used if the ground loop cannot be fixed, which means that the poorly chosen grounding scheme in the component that is injecting noise into the ground system cannot be modified.

The safety loop breaker circuit inserts impedance into the loop which inhibits noise current in the loop. However, it does not eliminate any noise, rather it moves the noise current elsewhere in the ground system. If the noise is moved to a place that causes less of a problem, then you are ahead of the game but there is no guarantee.

The best solution is to eliminate the problem rather than trying to fight it. Then you don’t need the band-aid.

Dave

Hi Dave.

Tell me how? I am listenng.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

Hi c-j

The article explaining this is at
http://www.raleighaudio.com/Audio%20Com ... ection.pdf

Sections 3.1 and 3.2 discuss the basic problem of ground loops. Section 3.6 talks a little about remedy for the Pin 1 Problem. Section 3.7 discusses grounding schemes from a system viewpoint, and Chapter 4 has a lot of information of ground structure in a component, particularly section 4.8 is a detailed discussion of using the safety loop breaker circuit.

Dave

Hi Dave.

Sorry to reply so late. Just too busy lately.

Without borrowing ideas from any textbooks or papers, just basing on electrical principles, I install my amps in line with the article as per fig 3.3-1 page 20 therein, e.g. one point star grounding for power supply, for EACH audio channel, etc etc. The three grounding points are then star grounded to the safety ground bolt on the metal chassis of the amp.

Exceptions:-

(1) Safety ground is installed ONLY in the power amp for draining away dangerous HV/LV insulation breakdown currents & RFI. All comsumer electronic devices, e.g. CD-audio,/DVD-audio players, TT, tape decks, tuners, premaps, power amps, receivers, etc nowadays are built to comply Class 2 insulation level (double insulation), withOUT the need of any safety ground external connections. I will not install such safety grounding for other 'minor' devices.

I installed safety ground for my 50-year young tube power amp (orginally 2-wire power cord)
is simply to play save against any potential insulation failures in its old O/P & power transformers.

This also eliminates any loop grounding via the safety grounding connections among the components.

(2) No shielding for all the silver interconnects I diy built used in my audio rigs & my audiophile friends' with single-ended interphased systems.

Shielding adds conductor-shielding capacitance to the load, causing audio RF roll-off. Worst is such shielding affect the music, making it sound suppressed & much less airy.

My ICs are all built with 2 conductors of same metal, i.e. silver, same gauge size, purity & temper, one for incoming signal & one for return path. Precisely built so that the noises generated on the cable are cancelled. No shielding at all to screw up the music! The way I look at it - it is a quasi balanced audio signal transfer with single ended interface.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

The way I look at it, it is purely single ended.

Quasi-balanced or pseudo-balanced needs another ("drain") wire or shield, connected only at the sending (source) side.

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein

Hi Dave.

As posted above, all my phonstages, tube & SS & tube power amp are built/upgraded with star grounding scheme connected to the safety ground bolt of their respective chassis.

Yet I still install similar "safety loop breaker circuit" to each amp to ensure direct transfer of RFI & insulation breakdown currents out of the amps. IMO, this is indispensable even with tbe best grounding schemes.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

For home audio use, technically speaking NO need any balanced audio signal transmission as signal cable run is too short to worry about noises & crossptalks which is a huge issue to resolve in recording/broadcasting/P.A applications where miles of multi cable runs are involved.

Besides, balanced transmssion needs balanced O/P & I/P interfacing devices, i.e. transformer or phase inverting active stages, which makes the amp buildng much much more complex to build right & costly.

My question is: does all such complex balanced interphasing really make music sound better at home??????



Why "only" at the sending side, not receiving end???

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.

I just said your cable is single ended. Period.



It will work either way, but in theory you should drain the RFI to ground of the component that was left behind.

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein

Yes, the cable shield forms a helical RF antenna picking up RFI which MUST be grounded away.



Yes & no.

Yes, which end the shield grounded will kill the RFI picked up by the shield.

No, for audio ICs, it should be grounded at the driver end only (I asked you why in my post above is to see if you know the theroy behind it.)

The O/P impedance of the driver device plus the IC conductor-shield capactance will form a low-pass filter for EACH conductor of the IC. Given no realworld conductor/insulation is extruded identical, the low-end filter of each conductor will not be exactly matching. This will change ground noise to differential signal on the conductor. Such noise conversion will be worse for high O/P impedance of driver device & large capacitance of long run cable.

Now it all depends on which side of the cable shielded is grounded. If the shield is grounded at the receiver side, the low pass filters will formed at the I/P of the receiver, allowing the noise voltage go amplified by the receiver device. NO good!

But if the cable shield is grounded at rhe driver side, the low-pass filters will be formed at the O/P end of the driver device, no noise signal will be form across the I/P circuit of the receiver end. Good!

That is why for audo use, shield should always be grounded at the driver end.

That said, for high speed digital applications, where the near-field energy surrounding the shield is mostly magnetic field mode (vs electrical field mode in slow speed audio application), the shield should be grounded at BOTH end to ensure minimum shield/ground transfer impedance. Shield grounded at only one end will get too high ground transfer impedance up to 100R which will render the shielding no effect.

c-J

_________________
"If the facts don't fit the theory, change the facts" quoted Hans Albert
Einstein.