Please check the following schema with two antiparallel diodes for both power line conductors
http://www.degenonline.de/hifi/index.html#dcfilter
The purpose is to create a power line audio conditioner.
I tryed by myself and it change dramatically the soundstage (not better, not worse, just change...)
But I don't understand:
1) how they works
2) do capacitor in parallell useful. Which value ?
3) the wave spectrogram of 50 Hz power line doen't change, nor the THD nor the SNR so I relly don't understand how the work.
Probably, I think they should not coduct in the crossover part (+- 0,7 volt)?? So in that time period the trasformer doesn't work??
Can you please clarify?
http://www.degenonline.de/hifi/index.html#dcfilter
The purpose is to create a power line audio conditioner.
I tryed by myself and it change dramatically the soundstage (not better, not worse, just change...)
But I don't understand:
1) how they works
2) do capacitor in parallell useful. Which value ?
3) the wave spectrogram of 50 Hz power line doen't change, nor the THD nor the SNR so I relly don't understand how the work.
Probably, I think they should not coduct in the crossover part (+- 0,7 volt)?? So in that time period the trasformer doesn't work??
Can you please clarify?
The capacitors C1 and C4 are to block any DC that may be present in the mains AC. The diodes D1 to D4 are to ensure that the caps don't get anywhere near their ratings. Once more than about 0.7v DC is present, the diodes will conduct, bypassing the capacitors and preventing a dangerous condition. I would want to use some caps with very good ripple ratings here.
In principle, this should be a good idea. DC causes vibration and heating in a transformer. Not sure how well it would work in practice however.
In principle, this should be a good idea. DC causes vibration and heating in a transformer. Not sure how well it would work in practice however.
ygg-it said:
Really? I'm sure you did a comprehensive duoble-blind test to find that out? Can you give details.
Jan Didden
ygg-it said:
Initially i really liked the effect of DC blocking on sound. Nice, liquid midrange but a bit softer bass. Then it turned out that those electrolytics are (as usually) quite audible. There was no real dc problem (mV) and the transformer was not toroidal so there wasn't much to be gained by the blocker anyway. Of course if one can't hear a difference between power cords, amplifiers, cd players, etc this will also be inaudible. If, otoh, one hears power cables, it's quite obvious that the introdiction of additional non linear reactance along the power lines will be audible.
There is also a pi-filter shown in the link. It can also be responsible for the change in soundstage.
As far as I know, this is more for physical noise, not for reducing electrical noise in the power supply. DC across a transformer can make it vibrate audibly, which can be damn annoying! I would be surprised if it made a difference to the actual output of the amplifier.
re
You wrote:
Once more than about 0.7v DC is present, the diodes will conduct, bypassing the capacitors and preventing a dangerous condition.
For me :
Once more than about 0.7v DC is present, the diodes will conduct and this can be dangerous for the trafo. In my opinion the filter just block less 0.7 DC. I'm right?
How do you calculate the capacitors? I saw also the same circuit without the cap, what does it happen to the trafo in this case??
PS: To people who asked: the soundstage became harsher
You wrote:
Once more than about 0.7v DC is present, the diodes will conduct, bypassing the capacitors and preventing a dangerous condition.
For me :
Once more than about 0.7v DC is present, the diodes will conduct and this can be dangerous for the trafo. In my opinion the filter just block less 0.7 DC. I'm right?
How do you calculate the capacitors? I saw also the same circuit without the cap, what does it happen to the trafo in this case??
PS: To people who asked: the soundstage became harsher
If there is more than 0.7v DC on the mains, then you have a seriously poor electricity supplier. This will probably heat the transformer and blow its thermal fuse. The diodes prevent the caps from blowing, covering the discussed circuit from a safety viewpoint.
In essence, this circuit guards against small DC voltages, but does not increase the susceptibility of the protected device to large (>0.7v) DC voltages.
In essence, this circuit guards against small DC voltages, but does not increase the susceptibility of the protected device to large (>0.7v) DC voltages.
As for calculating the size of the caps, C1 (and C4) and the resistance of the primary forms a high pass filter. The frequency of the filter, which needs to be well lower than 50Hz, is given by:
Since R (resistance of primary) is likely pretty small, it is important to make C (value of C1 and C4) big. The linked circuit diagram says anything larger than 2500uF is allowable, which sounds about right.
Since R (resistance of primary) is likely pretty small, it is important to make C (value of C1 and C4) big. The linked circuit diagram says anything larger than 2500uF is allowable, which sounds about right.
re
But the author just put 10 nF (10000 pF...
And here there are no cap at all....:
http://www.patentstorm.us/patents/5739732/description.html
Can you check why?
But the author just put 10 nF (10000 pF...
And here there are no cap at all....:
http://www.patentstorm.us/patents/5739732/description.html
Can you check why?
The linked circuit has a completely different purpose, AC noise spike suppression in mains, so of course the values are different.
about formula
If you take as R the total trafo impedance you have (as black box):
Load: 350 VA
Vin: 230 V
Iin: 350 VA / 230 V = 1.52 A
F= 50 Hz
Rin: 230 V / 1.52 A = 151 ohm
C= 1/ (3,14*2*151*50)= 21 uF !!
If you take as R the total trafo impedance you have (as black box):
Load: 350 VA
Vin: 230 V
Iin: 350 VA / 230 V = 1.52 A
F= 50 Hz
Rin: 230 V / 1.52 A = 151 ohm
C= 1/ (3,14*2*151*50)= 21 uF !!
Re: about formula
(This is basic knowledge, especially for a person that is able to design his own amps
)
1.52 A through the cap must not generate more voltage drop than 0.7 volts => R = 0.5 ohms in the formulaygg-it said:
(This is basic knowledge, especially for a person that is able to design his own amps
)
..right
I preffer the DA blocker... two diodes in series on the L line.. the diodes in oposite orientation (so two cathodes or two anodes meet) each paralleled with nice big cap from an old PC power supply, following the polarity orientation of the diode...
I believe the can of the cap is at mains potential.. so be carefull...
useing this method you can block higher DC values by adding more diodes in series...
I used this on my valve buffer...
It had a 2x24V pcb transformer doubled with a greinacher to provide in excess of 100V... so I was expecting noise... nada nothing zilch.. dead quiet. Tge transformer did run warm though, until I added the blocker.
I believe the can of the cap is at mains potential.. so be carefull...
useing this method you can block higher DC values by adding more diodes in series...
I used this on my valve buffer...
It had a 2x24V pcb transformer doubled with a greinacher to provide in excess of 100V... so I was expecting noise... nada nothing zilch.. dead quiet. Tge transformer did run warm though, until I added the blocker.
thank
Thank you, now is everything clear.
Thank you also for the web article. It was very exhaustive.
By the way this weekend I have tryied a lot of configurations, but at the end i finally give up the antiparallel circuit.
As told before the sounstage became too much hursh and less clean even if the dynamic improved a lot.
But at the end I prefer to have a much cleaner chain even if smoother...
If you wish you can visit my site with the final schematic of my power line conditioner configuration:
Thank you, now is everything clear.
Thank you also for the web article. It was very exhaustive.
By the way this weekend I have tryied a lot of configurations, but at the end i finally give up the antiparallel circuit.
As told before the sounstage became too much hursh and less clean even if the dynamic improved a lot.
But at the end I prefer to have a much cleaner chain even if smoother...
If you wish you can visit my site with the final schematic of my power line conditioner configuration:
the capacitors provide the AC path and are the DC blocker.
They will have an AC voltage across them when passing AC current to the load.
The AC voltage will depend on the current flowing to the load and on the effective capacitance at the frequencies contained in the AC waveform. This current is very much NOT sinusoidal.
The diodes have nothing to do with the DC blocking.
The diodes are there to limit the AC voltage across the capacitors. That's why they are fitted in inverse parallel (antiparallel?).
The diodes act as bypasses when the AC voltage rises above a tolerable and predetermined limit.
This limiting function becomes necessary to avoid the need for very large capacitances to pass the high peak currents that can be required during some short term operational conditions.
These short term peak currents can come about at start up, and when passing very high currents to the speaker load.
Exceptional peaks would happen during amplifier abuse and during a failure mode.
In effect the diodes are there for a combination of economy and safety.
They allow smaller capacitors to be used for the majority of operational modes and provide a safety bypass during abuse and failure modes.
The series combination of diodes completely fails to meet the safety requirement normally provided by the inverse parallel diodes.
The series diodes is a dangerous circuit to adopt and I cannot recommend it.
They will have an AC voltage across them when passing AC current to the load.
The AC voltage will depend on the current flowing to the load and on the effective capacitance at the frequencies contained in the AC waveform. This current is very much NOT sinusoidal.
The diodes have nothing to do with the DC blocking.
The diodes are there to limit the AC voltage across the capacitors. That's why they are fitted in inverse parallel (antiparallel?).
The diodes act as bypasses when the AC voltage rises above a tolerable and predetermined limit.
This limiting function becomes necessary to avoid the need for very large capacitances to pass the high peak currents that can be required during some short term operational conditions.
These short term peak currents can come about at start up, and when passing very high currents to the speaker load.
Exceptional peaks would happen during amplifier abuse and during a failure mode.
In effect the diodes are there for a combination of economy and safety.
They allow smaller capacitors to be used for the majority of operational modes and provide a safety bypass during abuse and failure modes.
The series combination of diodes completely fails to meet the safety requirement normally provided by the inverse parallel diodes.
The series diodes is a dangerous circuit to adopt and I cannot recommend it.
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