DAC's Hi-Fi AV Power Line Filter

This is new for me.


Can any one tell what is a HiFi Line Filter ????

Dear Raftug.

While going in for a line filter always ask for approval at your site. If it makes an audible difference for the better, purchase it. If not, return it.

Behram.

Behram schrieb:

Dear Raftug. While going in for a line filter always ask for approval at your site. If it makes an audible difference for the better, purchase it. If not, return it.

BehramBhai,

Do these also provide a safer supply? Am I barking up the wrong tree?

Because actually that's what is my main consideration now. With the power fluctuations so prevalent in Bangalore, I'm hoping that this will protect my equipment - or would you recommend better alternatives? Voltage swings heavily sometimes and stays that way occassionally, hence am looking for both brown and blackout protection apart from spikes.

As for the sound part - Should I expect a dramatic or barely perceptible difference? Not sure whether the vendor would agree for a on-site approval though, since they say this is not readily available and they'll need to place an order....

hi Raftuq,

Line filters are not a solution to protect your equips from brownouts, blackouts and wild voltage swings, they are supposed to clean the power by removing RFI, spikes and other spurious signals, giving you pure sinewave.

To protect gear from wide voltage fluctuation you need some sort of voltage stabilisation, such as servo voltage stabiliser or CVT (not recomended for audio by most).

I have read inthis forum that someone in Bangalore makes excellent servo stabiliser for audio applications.

Thx Ani.

Does that mean I'll need to buy both: servo as well as the line filter? Hmmmm..

CVT not recommended for hi-fi protection? - very intriguing! I always thought it to be superior to servos and line interactives when it comes to protecting computers at least!

BTW, would you recommend a line interactive over servo or vice versa?

As for the sound part - Should I expect a dramatic or barely perceptible difference? Not sure whether the vendor would agree for a on-site approval though, since they say this is not readily available and they'll need to place an order

The difference is not phenomenol. It is somewhat like changing interconnects or speaker cables. If you do not get on site approval, forget it , its not worth taking the risk. If your only criteria is stabilization, use a servo voltage stabilizer.

ani schrieb:

hi Raftuq, Line filters are not a solution to protect your equips from brownouts, blackouts and wild voltage swings, they are supposed to clean the power by removing RFI, spikes and other spurious signals, giving you pure sinewave.

now, now, now, who told you this???
"pure sinewave" from a line filter?

a line filter usually works like a shunt filter, which will shunt the noise/spikes on the AC power line to ground. A line filter WILL NOT reconstruct the AC sine wave! That is the job of a signal regenerator like the PS Audio PS300 unit which is designed to take in the wall outlet AC signal & reconstruct a new sinewave with user specified frequency.
Another thing a line filter can do, if designed properly, is to be a reservoir of AC signal energy when the wall outlet AC signal gets near its crest & trough. When the wall outlet AC signal gets near its crest & trough, the AC power signal is increasin in amplitude but with a decreasing slope i.e. the rate of change of the AC signal is decreasing. This severely reduces (or stops) the delivery of current to the circuit it is feeding. For non audio applications its not a big deal. However, for audio, it manifests itself as "constricted sound" - the listener tends to say "the sound wants to break free but is unable to". So, if the line filter has a H-U-G-E inductor (in the shape of a toroidal xformer, then this inductor stores energy when the AC signal is ramping up/down. When this signal reaches its crest or trough, the inductor takes over & dumps charge into the circuit it is feeding. So, as far as the electronics is concerned, it is getting current all 360 degrees of the sine wave & it is never starved.

I've always found that AC line filters affect the sound, even the very best! I think that just the nature of the beast.
If you ARE going to use an AC line filter make sure that it is in shunt/parallel. Also, try to put only your front-end components on the AC line filter. I've found that running a power amp thru an AC line filter constipates them!

ani schrieb:

hi Raftuq, Line filters are not a solution to protect your equips from brownouts, blackouts and wild voltage swings, they are supposed to clean the power by removing RFI, spikes and other spurious signals, giving you pure sinewave.

now, now, now, who told you this???
"pure sinewave" from a line filter?

a line filter usually works like a shunt filter, which will shunt the noise/spikes on the AC power line to ground. A line filter WILL NOT reconstruct the AC sine wave! That is the job of a signal regenerator like the PS Audio PS300 unit which is designed to take in the wall outlet AC signal & reconstruct a new sinewave with user specified frequency.
Another thing a line filter can do, if designed properly, is to be a reservoir of AC signal energy when the wall outlet AC signal gets near its crest & trough. When the wall outlet AC signal gets near its crest & trough, the AC power signal is increasin in amplitude but with a decreasing slope i.e. the rate of change of the AC signal is decreasing. This severely reduces (or stops) the delivery of current to the circuit it is feeding. For non audio applications its not a big deal. However, for audio, it manifests itself as "constricted sound" - the listener tends to say "the sound wants to break free but is unable to". So, if the line filter has a H-U-G-E inductor (in the shape of a toroidal xformer, then this inductor stores energy when the AC signal is ramping up/down. When this signal reaches its crest or trough, the inductor takes over & dumps charge into the circuit it is feeding. So, as far as the electronics is concerned, it is getting current all 360 degrees of the sine wave & it is never starved.

I've always found that AC line filters affect the sound, even the very best! I think that just the nature of the beast.
If you ARE going to use an AC line filter make sure that it is in shunt/parallel. Also, try to put only your front-end components on the AC line filter. I've found that running a power amp thru an AC line filter constipates them!

Raftuq, it depends on how bad the power is, personally I will never go in for a servostab, an autotransformer turning up and down the input voltage is not my idea of clean power supply.

Bombaywalla, please note that I had written "they are supposed to clean the power by removing RFI, spikes and other spurious signals, giving you pure sinewave"

In theory you feed in sine wave you may get sinewave out from a properly designed filter, but as you said in practice they seldom work in that manner.
Bombaywalla wrote:

So, if the line filter has a H-U-G-E inductor (in the shape of a toroidal xformer, then this inductor stores energy when the AC signal is ramping up/down. When this signal reaches its crest or trough, the inductor takes over & dumps charge into the circuit it is feeding. So, as far as the electronics is concerned, it is getting current all 360 degrees of the sine wave & it is never starved.

What do you mean by
1. toroidal Transformer in filter ?
2. inductor dumping charge ?
3. electronice getting current all 360 degrees of sine wave?
4. What is the conclusion, good or bad for electronics ?

ani schrieb:

Raftuq, it depends on how bad the power is, personally I will never go in for a servostab, an autotransformer turning up and down the input voltage is not my idea of clean power supply. Bombaywalla, please note that I had written "they are supposed to clean the power by removing RFI, spikes and other spurious signals, giving you pure sinewave" In theory you feed in sine wave you may get sinewave out from a properly designed filter, but as you said in practice they seldom work in that manner. ?

i did read the words you had written. AC line filters are only supposed to filter the noise & not reconstruct the waveform. if the incoming sine wave has, say a flattened crest, the output waveform will retain the flattened crest. The only thing(s) removed will be the noise spikes & EMI (if designed in).
So, the filters work as intended 99% of the time w.r.t. to cleaning up the noise on the AC line. They do not ever yield perfect sine waves - passive components are incapable of re-generating a signal.
So, to put the words "giving you pure sinewave" in your sentence is plain wrong!

ani schrieb:

Bombaywalla wrote: So, if the line filter has a H-U-G-E inductor (in the shape of a toroidal xformer, then this inductor stores energy when the AC signal is ramping up/down. When this signal reaches its crest or trough, the inductor takes over & dumps charge into the circuit it is feeding. So, as far as the electronics is concerned, it is getting current all 360 degrees of the sine wave & it is never starved. What do you mean by 1. toroidal Transformer in filter ? 2. inductor dumping charge ? 3. electronice getting current all 360 degrees of sine wave? 4. What is the conclusion, good or bad for electronics ?

i don't have the exact schematic of this particular AC line filter but its a fairly small box but weighs 20-25 lbs. The reason is that there is a huge inductor in there that acts like a charge reservoir - storing the charge in its magnetic field & then releasing it at the top & bottom of the AC signal.

if you draw a sine wave, you can describe its crest & trough phase angle i.e. starting point = 0 degrees, then it crests at 90 degrees, the wave goes back to zero amplitude at 180 degrees, then goes negative & negative max/trough is at 270 degrees & finally the waveform comes back to zero amplitude at 360 degrees. The whole cycle repeats. So, you have 360 degrees in any sinusoidal waveform.

Conclusion of being good or bad for electronics: now, what are you asking here?
I already stated my opinion on AC line filters in my orig post. So, you must not be asking 'bout that.
Having the inductor in the AC line filter? good for electronics. However, I use it only for the front-end components. Nothing else. It helps to isolate (to some degree) the noise between components & the AC line noise.

Hope that this clarifies.

As for the sound part - Should I expect a dramatic or barely perceptible difference? Not sure whether the vendor would agree for a on-site approval though, since they say this is not readily available and they'll need to place an order....

A LOT depends on the actual Hi Fi component that is fed thru the device.

I agree with Bombaywalla - the source components seem to respond with the largest difference.

Also, I have personally observed ( in a limited way, I may add ) that Solid State Amps respond more significantly, than Valve amps, which usually hardly respond to line filters. Ditto for Mains cords.

Also, I suspect that Amps with SMPS power supplies will respond less to line filters, than those ( solid state ) amps with conventional Power supplies. This last point is my Speculation - Not based on actual experience.

So buy only after you try ! ( as suggested by 'Behrambhai' )