Are you kidding you cannot do that!😱 Thats like plugging your speaker into the wall socket - if you like the 50Hz bass note I guess its okay.
Please read #59 where I suggest cleaning up the 50Hz from your transformer, of course I am assuming the transformer secondary is impedance is 4 ohms.... Paying attention is not an attribute of this forum I guess.
I am not promoting this type of thing obviously and I don't make them either. My one comment was to convert DC into 230VAC pure sine wave and rid yourself not only of all conducted noise but also from some nebulous debate.
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To get the elliptical filter to work, do the component values need to be very accurate?
eg.
1.235mF = 1mF+-1%, + 220u +-2%, + 15uF+-10%?
Do we need the 940nF?
eg.
1.235mF = 1mF+-1%, + 220u +-2%, + 15uF+-10%?
Do we need the 940nF?
Has anyone posting here had experience with Isotek products? I'm running their GII Titan which I picked up used and a Polaris block off the back of that.
Then why did you post it at all?
Like 4 ohm resistive is the same as 4 ohm impedance? Sure.
Also good luck getting 1.2mF fom X1 caps...
You sad many times what not to do and what to do, but how is a myth.
I would like to hear about actual experience not sim...
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some remarks to audible noise induced by mobile phones.
It is true, they transmit GHz-frequencies, and if you put them close to sensible analog circuitry, you notice noise of some 100Hz. The reason for this is, that your fone sends bursts of Ghz-radiation, chopped with frequencies of some 100Hz.
This is like a 100% amplitude modulated radio frequency carrier, and thus any nonliniear circuit can detect it like a diode does.
And meanwhile the FM-radio keeps quiet.
I did some tests on my audio pre-amps with a mobile close to them and found that tiny ferrite-beads on base-connections of transistors helped a great deal - i.e. audible noise was significantly reduced. And there is no magic in that - just simple physics.
This is an example of high-frequency filtering that can really stop audible noise...
It is true, they transmit GHz-frequencies, and if you put them close to sensible analog circuitry, you notice noise of some 100Hz. The reason for this is, that your fone sends bursts of Ghz-radiation, chopped with frequencies of some 100Hz.
This is like a 100% amplitude modulated radio frequency carrier, and thus any nonliniear circuit can detect it like a diode does.
And meanwhile the FM-radio keeps quiet.
I did some tests on my audio pre-amps with a mobile close to them and found that tiny ferrite-beads on base-connections of transistors helped a great deal - i.e. audible noise was significantly reduced. And there is no magic in that - just simple physics.
This is an example of high-frequency filtering that can really stop audible noise...
No Andrew I took the exact values calculated in MathCAD I am certain 10% either way would be fine.
The in/output impedance was chosen 4 ohms which could be applicable to that of a transformer and of an amp driving a 4 ohm speaker although impedance is complex and would vary with the load characteristics.
Read #48 a few times until you understand what I am saying. You assumed that the filter is 230VAC why, this is impractical! It would have better effect on the secondary of the transformer because already your transformer will block a lot of high frequency rubbish, but as I say then inductors have to be for high current - I don't know Hungarian else I would say it in such a way that you can follow.
I show a typical filter because you asked me to show you. I can show some other things too if you ask, I try and be helpful.
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I suspect that a filter here would be best suited to a class A amplifier which looks like a constant current load and probably more like a constant impedance to the power supply.
DestroyerOS I have never tried filtering between transformer and rectifiers but it could make a significant difference since you are reducing the harmonics content related to 50/60Hz that could make an audible difference being inside the audio band.
I do have a JLH class A amplifier that I can easily convert by adding a LP filter, because the more I think of it the more appealing the idea becomes.
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Filter is Butterworth set for 70 Hz (not to have -3dB at 50Hz) and symmetrical. This should reduce the Line harmonics significantly coming from the line. Is it measurable? Most definitely. Will it be audible? - I don't know, will have to wait and see.
First I have to make some inductors that will have low losses not to drop the transformer voltage too much, otherwise make a transformer with slightly higher voltage and drop some over the inductors.
First I have to make some inductors that will have low losses not to drop the transformer voltage too much, otherwise make a transformer with slightly higher voltage and drop some over the inductors.
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Because we have 230VAC mains and for example my dac has 5 secondaries. Also if you want to add conditioner to an existing device, you probably will not put a filter in it. So simply real life reason, nothing serious. Again, I'm trying to think of ways that are actually used and not theoretically.
Why do you not try using a low distortion pure sine wave inverter run from batteries, there would be zero interference from the outside world - this is very audible. Maybe it could be a nice project designing such a device for the DIY community.
I was very interested two years ago in designing a small 600VA sinewave inverter but had too many problems with transformer losses. I designed it as a bridged amplifier stepping 24VDC to 230VAC.
The 50Hz was derived from a PIC followed by an 8th order filter changing the square wave to a pure sine wave. The signal was fed into two amplifiers in bridge mode driving the power transformer for up conversion.
600VA would be enough for someone with lesser demands, say a 2 x 100 watt amp and not too many ancillary stuff added. B.T.W. this heat sink is fan cooled else it has to be much larger.
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Could we use a higher frequency than the usual 50/60Hz?
What are the benefits?
I suspect a smaller transformer, and less ripple after conversion to DC.
Any others?
Should we aim for 100Hz or 200Hz or 400Hz?
What are the benefits?
I suspect a smaller transformer, and less ripple after conversion to DC.
Any others?
Should we aim for 100Hz or 200Hz or 400Hz?
Implementing an automatic gain control to stabilize the output voltage was the next step, but I lost interest in it since I could buy a commercial unit of 2.4KVA rating with all these nice things included for a lost less than the development cost me to that point.
Doing it yourself is not always cost effective, but it was an interesting excercise. To get this far took five PCB iterations alone and close to more than 80 blown IRF1010 mosfets. I also wound and scrapped seven 600VA transformers some e-core and some toroid.
Doing it yourself is not always cost effective, but it was an interesting excercise. To get this far took five PCB iterations alone and close to more than 80 blown IRF1010 mosfets. I also wound and scrapped seven 600VA transformers some e-core and some toroid.
Andrew, I guess one could because a mains transformer is quite capable of much higher frequency - who chose 50/60Hz in the first place. Maybe it is not practical to run Megawatt turbines higher than 3000 RPM they will disintegrate.
British Westinghouse decided on 50 Hz, I just googled so there we have it -as always the Brits set the standards.
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Nico,
the PS audio shouldn't be to hard to make, it's still high on my to do list.
If you look for US patent 7259705B2, you can find some schematics.
http://www.google.com.mx/patents/US7259705
It is made of a floating +30/-30 V power supply with the center connected to the mains, i.e. tracking power supply. This powers a power amp which gets it's reference from a synchronized 50 or 60Hz generator.
It basically adds the top of the sine wave to the mains, because this part is usually flatted out and polluted.
the PS audio shouldn't be to hard to make, it's still high on my to do list.
If you look for US patent 7259705B2, you can find some schematics.
http://www.google.com.mx/patents/US7259705
It is made of a floating +30/-30 V power supply with the center connected to the mains, i.e. tracking power supply. This powers a power amp which gets it's reference from a synchronized 50 or 60Hz generator.
It basically adds the top of the sine wave to the mains, because this part is usually flatted out and polluted.
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Hi Andrew, this I found on Wikipedia and the reason for 50/60 Hz was due to transmission line limitations. 400 Hz may be well suited to a local power grid - say that of your entertainment area.
400 Hz
Power frequencies as high as 400 Hz are used in aircraft, spacecraft, submarines, server rooms for computer power,[17] military equipment, and hand-held machine tools. Such high frequencies cannot be economically transmitted long distances; the increased frequency greatly increases series impedance due to the inductance of transmission lines, making power transmission difficult. Consequently, 400 Hz power systems are usually confined to a building or vehicle.
Transformers, for example, can be made smaller because the magnetic core can be much smaller for the same voltage level. Induction motors turn at a speed proportional to frequency, so a high freqeuncy power supply allows more power to be obtained for the same motor volume and mass. Transformers and motors for 400 Hz are much smaller and lighter than at 50 or 60 Hz, which is an advantage in aircraft and ships. A United States military standard MIL-STD-704 exists for aircraft use of 400 Hz power.
400 Hz
Power frequencies as high as 400 Hz are used in aircraft, spacecraft, submarines, server rooms for computer power,[17] military equipment, and hand-held machine tools. Such high frequencies cannot be economically transmitted long distances; the increased frequency greatly increases series impedance due to the inductance of transmission lines, making power transmission difficult. Consequently, 400 Hz power systems are usually confined to a building or vehicle.
Transformers, for example, can be made smaller because the magnetic core can be much smaller for the same voltage level. Induction motors turn at a speed proportional to frequency, so a high freqeuncy power supply allows more power to be obtained for the same motor volume and mass. Transformers and motors for 400 Hz are much smaller and lighter than at 50 or 60 Hz, which is an advantage in aircraft and ships. A United States military standard MIL-STD-704 exists for aircraft use of 400 Hz power.
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