I think its you that need to do some reading before answering in such a derogatory way. He is definately trying to block dc bias on the mains input something discussed on DIY as many time as I can remember. Peranders did a nice project on it.
Hi !
yesterday I tested a 1st regulator I did not remember I had with a Cambridge Audio transformer outputting about 14VAC.
It works but the regulator really needs an heatsink.
However I am thinking about a strange solution.
To use a 15-20VDC smps "genuine kind" brick followed by a regulator to step the voltage down to 12V
and place the regulator close to the circuit (their size usually fits perfectly inside the dac).
However I have a problem.
Do i understand correctly that a smps cannot stand big uF at its output ?
If so i need to change the cap before the regulator.
Usually it is around 4700uF.
Could 1000 uF be sustainable for the smps ?
which brand and model is the best around ?
As it will be supplied with 15-20VDC I guess a 25V part should be perfect.
In this way I could use almost any high quality smps for laptop around.
Is this idea insane ?
Thanks as always for all the kind and extremely valuable advice.
Have a nice day, gino
yesterday I tested a 1st regulator I did not remember I had with a Cambridge Audio transformer outputting about 14VAC.
It works but the regulator really needs an heatsink.
However I am thinking about a strange solution.
To use a 15-20VDC smps "genuine kind" brick followed by a regulator to step the voltage down to 12V
and place the regulator close to the circuit (their size usually fits perfectly inside the dac).
However I have a problem.
Do i understand correctly that a smps cannot stand big uF at its output ?
If so i need to change the cap before the regulator.
Usually it is around 4700uF.
Could 1000 uF be sustainable for the smps ?
which brand and model is the best around ?
As it will be supplied with 15-20VDC I guess a 25V part should be perfect.
In this way I could use almost any high quality smps for laptop around.
Is this idea insane ?
Thanks as always for all the kind and extremely valuable advice.
Have a nice day, gino
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There is quite usually the use of a linear regulator to improve the power quality of a SMPS. Actually to improve/lower the residual noise on a SMPS output.
This trick it works in some cases. However, if the SMPS it "see" a high capacity on its output (as the filtering on your regulator), while it start up, it may "think" there is about a somehow shorting (high inrush current at start up). So, it may stop delivering the power, and you should recycle it (power off/on). It may not start again before removing that big capacity connected... If the SMPS is a high current capable one, then it may work well enough.
In my opinion this solution it is far from a good one, especially when about a hifi device...
I do not understand why you are tempted to use the most complicated and low quality approach to solve your task. If you have already the transformer to connect that regulator to, then that is the most rational/appropriate solution, with the best results so far...
If a SMPS is made for a computer, then it is not necessary to be the best quality one either... A good SMPS, with lowest possible residual HF noise, is quite expensive, and an enough special device. Consumer SMPS are only cheep b** sh** types... One should never use such in audio, at least when one may have expectations for some quality results...
Connecting a transformer to that kit you got, it will allow you to increase its filtering cap quite much, improving so very much the performances of your power system. Place the regulator inside your device enclosure, then find some 50 cm length (reasonable section) wires to connect the secondary of your (out of the box) transformer to the regulator. That`s it. Done! Simple, easy, cheap, efficient, best results...
This trick it works in some cases. However, if the SMPS it "see" a high capacity on its output (as the filtering on your regulator), while it start up, it may "think" there is about a somehow shorting (high inrush current at start up). So, it may stop delivering the power, and you should recycle it (power off/on). It may not start again before removing that big capacity connected... If the SMPS is a high current capable one, then it may work well enough.
In my opinion this solution it is far from a good one, especially when about a hifi device...
I do not understand why you are tempted to use the most complicated and low quality approach to solve your task. If you have already the transformer to connect that regulator to, then that is the most rational/appropriate solution, with the best results so far...
If a SMPS is made for a computer, then it is not necessary to be the best quality one either... A good SMPS, with lowest possible residual HF noise, is quite expensive, and an enough special device. Consumer SMPS are only cheep b** sh** types... One should never use such in audio, at least when one may have expectations for some quality results...
Connecting a transformer to that kit you got, it will allow you to increase its filtering cap quite much, improving so very much the performances of your power system. Place the regulator inside your device enclosure, then find some 50 cm length (reasonable section) wires to connect the secondary of your (out of the box) transformer to the regulator. That`s it. Done! Simple, easy, cheap, efficient, best results...
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Hi and thanks again for the always helpful advice.
It sounds to me as a matter of try and see. I was thinking to start with 1000uF and see. Nice to hear that usually smps have a current sensing circuit.
let's be honest ... the more I look at these transformers the more I do not like them.
And also I saw on internet some "devices" to be used after a smps in order to suppress the noise.
Maybe I am getting it completely wrong but on principle any noise can be filtered.
So given the excellent convenience of these smps bricks the idea of filtering the residual noise is very very intriguing.
From what I understand the current draw of these units like dacs and interfaces must be very very constant. Also a good point for using smps.
I see. So you are definitely against the idea ...
Actually I found a very interesting graph showing the unbelievably low noise that can be achieved with linear power supplies.
http://www.cliftonlaboratories.com/userimages/Bench supply noise.gif
An externally hosted image should be here but it was not working when we last tested it.
😱😱😱
Some of the filters for smps above mentioned promise to be very effective by the way.
But when the very top performance are requested it seems that linear is the way to go.
Now I have to buy some heatsinks for TO3P regulators.
Thanks a lot again, gino
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Gino,
Make a simple traditional linear PSU with 10.000uF in an external box. Use a 1A input filter (Schaffner). Use just about any transformer that gives you about the voltage you need. Run the unregulated DC up to your DAC. Put a LM317 regulator in the DAC with 10uF filter on the input and 1000uF on the output. Use a 47uF filter on the adjust pin on the LM317.
That simple solution is all you need and nothing else will improve things further.
I assume there are more regulators on the DAC board that in the end will be the limiting factor.
And please. Forget about the PC power supply for you audio equipment. Why send 100kHz noise to your DAC??
Make a simple traditional linear PSU with 10.000uF in an external box. Use a 1A input filter (Schaffner). Use just about any transformer that gives you about the voltage you need. Run the unregulated DC up to your DAC. Put a LM317 regulator in the DAC with 10uF filter on the input and 1000uF on the output. Use a 47uF filter on the adjust pin on the LM317.
That simple solution is all you need and nothing else will improve things further.
I assume there are more regulators on the DAC board that in the end will be the limiting factor.
And please. Forget about the PC power supply for you audio equipment. Why send 100kHz noise to your DAC??
He appears not to understand that a DC blocker works by acting as a high pass filter with a low corner frequency, thus ensuring that the AC voltage across the caps remains low under normal circumstances. I didn't think it necessary to explain this.Nico Ras said:
There is nothing more to discuss regarding DC on the mains. Some have it. Some not. And it makes our ( big) transformers hum. For a small DAC power supply it is almost certainly not required.
Everything that needs to be understood before attempting to make a DC blocking circuit is here:
Mains DC and Transformers
Every power regulator device (either linear or switching) on marked today it provide current protection. As a SMPS concept is to eliminate large filtering capacities, their current protection is also designed accordingly, and it may act when an inrush current is detected at its output.
Why do you want to struggle with HF filtering approaches, which it involve good measurement devices, good knowledge, lot of experience and expertise in the field, when you have already the best solution in your hands?
Well, at least everybody is free to chose their ways... So, good luck further!
Why do you want to struggle with HF filtering approaches, which it involve good measurement devices, good knowledge, lot of experience and expertise in the field, when you have already the best solution in your hands?
Well, at least everybody is free to chose their ways... So, good luck further!
Hi ! thanks a lot for the helpful advice.
It seems very easily doable for me.
Just to understand better the unregulated DC power supply will be just
Shaffner filter > mains transformer > generic single chip diodes bridge > 10mF capacitor ?
This can be done quite easily I think. I like the idea a lot indeed.
I could even use a high grade capacitor and even bigger than 10mF.
I like the idea. I would go this way then.
Exactly ! this type of units have dc to dc converters on the same boards with circuits.
The better ones are of course more refined but still have this limit.
I have understood now that smps solution is driven by practical considerations and not by the search for high quality performance.
What a pity ... they are quite cute.
Thanks again, gino
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Hi and thanks again. I give up on the idea then and will focus on a linear solution with DC unregulated supply to the unit with local regulation inside the unit.
I like a lot the idea because a regulator board can fit quite easily inside the unit without big issue due to the quite small size.
I am convinced about this solution.
I can also using a big dc umbilical like one of those used for car batteries.
I hope to post some pictures soon. I have just to buy some pieces (diode bridge and reservoir capacitor. A very good one).
Thank you very much indeed for the very kind and precious advice.
Kind regards, gino
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Shaffner filter > mains transformer > generic single chip diodes bridge > 10mF capacitor
Yes. That simple.
A schaffner filter on the inlet will help get rid of the worst net noise. The 1A versions have better filtering. http://no.mouser.com/ProductDetail/...=sGAEpiMZZMslPglT/XeKq9NMW7ZtYKboxkrnXCkzI3s=
There are also improved versions with a two stage filter that will reduce net noise even more. http://no.mouser.com/ProductDetail/...=sGAEpiMZZMslPglT/XeKq58/XzXseUIqTtzquJatUiE=
These are much more important that the quality of the 10mF capacitor. Just a generic standard quality will do just fine. There are many who claim that bigger is better and use 500VA transformer and 100mF for a small circuit that uses 200mA and claim that the sonic improves. It doesn't.
Depending on the transformer it could be beneficial to use a snubber circuit if you see ringing when the diodes are switching. Use a scope or even better a spectrum analyser to check this when the circuit is up and running. Good luck. 🙂
Yes. That simple.
A schaffner filter on the inlet will help get rid of the worst net noise. The 1A versions have better filtering. http://no.mouser.com/ProductDetail/...=sGAEpiMZZMslPglT/XeKq9NMW7ZtYKboxkrnXCkzI3s=
There are also improved versions with a two stage filter that will reduce net noise even more. http://no.mouser.com/ProductDetail/...=sGAEpiMZZMslPglT/XeKq58/XzXseUIqTtzquJatUiE=
These are much more important that the quality of the 10mF capacitor. Just a generic standard quality will do just fine. There are many who claim that bigger is better and use 500VA transformer and 100mF for a small circuit that uses 200mA and claim that the sonic improves. It doesn't.
Depending on the transformer it could be beneficial to use a snubber circuit if you see ringing when the diodes are switching. Use a scope or even better a spectrum analyser to check this when the circuit is up and running. Good luck. 🙂
Hi again ! cap is no problem. I have already seen some nice one on ebay.
Also transformer is coming. Filter is also ok.
if only i could afford a spectrum analyzer 🙁 ... i guess they are extremely expensive when of good quality. But i love instruments.
I can only see the results indirectly looking at the noise floor of the soundcard powered with the psu with a software named Arta.
And only up to 96kHz. Beyond that the mistery ... 🙄
I love this software.
Thanks a lot again, gino
you do not need to invest into anything. you should only read up on the work done by knowledgeable people here. for example the Salas regulator (SSLV for low voltage; Tea Bag was selling BiB pcbs and kits). it has remote load sensing so it has been designed for the reg to compensate for the connecting wire/lead length in case it is in a separate housing. there are other low noise regulators on the forum as well.
Hi and thanks for the valuable advice.
Is this the relevant thead to the Salas regulator ?
http://www.diyaudio.com/forums/powe...listic-salas-low-voltage-shunt-regulator.html
when i see a thread with 755 pages i get a little scared 😱
I do not know at what point the actual kit is presented
Thanks again, gino
Hi All !
last crazy idea
genuine laptop smps (19-20 VDC) > LC filter > linear regulator (even LM317)
With the LC filter and regulator placed locally and the smps external.
The LC filter should cut out the high frequency noise coming from the smps ? 🙄
Problem is to select the parts for the LC filter.
Could something like this work for instance ?
High Quality Power Supply Filter with Switch FPV LC Filter for RC Quadcopter | eBay
But if you recommend me any L and C parts I could assemble one myself.
The higher voltage smps to compensate for any voltage drop across the filter.
I have already many many 19-20V units and some 15V units (to use in case the voltage drops very little).
Could this work ?
I love the convenience of using a very common smps for laptops.
They are compact, light, cheap, powerful, reliable, completely encapsulated.
Genuine of course.
I have open a generic one and a Dell one ... even to these eyes the difference in quality is staggering.
The Dell one is very very nice indeed.
I would keep it as a ornament on my desk 🙂
last crazy idea
genuine laptop smps (19-20 VDC) > LC filter > linear regulator (even LM317)
With the LC filter and regulator placed locally and the smps external.
The LC filter should cut out the high frequency noise coming from the smps ? 🙄
Problem is to select the parts for the LC filter.
Could something like this work for instance ?
High Quality Power Supply Filter with Switch FPV LC Filter for RC Quadcopter | eBay
But if you recommend me any L and C parts I could assemble one myself.
The higher voltage smps to compensate for any voltage drop across the filter.
I have already many many 19-20V units and some 15V units (to use in case the voltage drops very little).
Could this work ?
I love the convenience of using a very common smps for laptops.
They are compact, light, cheap, powerful, reliable, completely encapsulated.
Genuine of course.
I have open a generic one and a Dell one ... even to these eyes the difference in quality is staggering.
The Dell one is very very nice indeed.
I would keep it as a ornament on my desk 🙂
Attachments
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Hi, sorry to take them back to the inlet 3.
For some years I have been assembling audio kits ago. Lately I've assembled some kits phono preamps.
And recently reading this topic I understood that the transformer box must be the rectifier. I did not understand properly if they must be also the filter capacitors or may be in the preamplifier box.
I always put the transformer, rectifier with capacitors and voltage regulator in a box, and another box preamplifier connected by a three-wire cable protected by shield.
But the last kit I've built, is to place the plate and the plate preamplifier rectifier-filter-regulator in one box, powered by AC wall wart 18v.
Because I could not remove a slight rrrrrrr, I chose to give energy to the pre with another PSU already had and delivering 15+ 0 15- regulated.
I ask for all those who have put together this kit with wall wart mentioned they have had no problems with noise and I do.
It is simply to get me curious, and I will continue with the PSU I mentioned them.
Greetings.
For some years I have been assembling audio kits ago. Lately I've assembled some kits phono preamps.
And recently reading this topic I understood that the transformer box must be the rectifier. I did not understand properly if they must be also the filter capacitors or may be in the preamplifier box.
I always put the transformer, rectifier with capacitors and voltage regulator in a box, and another box preamplifier connected by a three-wire cable protected by shield.
But the last kit I've built, is to place the plate and the plate preamplifier rectifier-filter-regulator in one box, powered by AC wall wart 18v.
Because I could not remove a slight rrrrrrr, I chose to give energy to the pre with another PSU already had and delivering 15+ 0 15- regulated.
I ask for all those who have put together this kit with wall wart mentioned they have had no problems with noise and I do.
It is simply to get me curious, and I will continue with the PSU I mentioned them.
Greetings.
Ginetto 61, I'll show you photos and the circuit of the PSU.
Greetings.
The circuit is known (TNT Solidphono).
Greetings.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The circuit is known (TNT Solidphono).
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Hi ! thanks a lot indeed.
Great units indeed and with great looking parts.
i am sorry to be of no help for your specific issue.
Good luck !
Great units indeed and with great looking parts.
i am sorry to be of no help for your specific issue.
Good luck !
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