Generally class D drivers could be used in portable equipments which has a battery or, on big audio systems powered through mains. In any case, these types of systems would have a power management section which does supply regulation using buck converters.
Even if there was not much supply regulation, the class D could be made to sound great using negative feedback around the driver stage.
Even if there was not much supply regulation, the class D could be made to sound great using negative feedback around the driver stage.
Hi Tinitus
Class-D has inherently a lower PSRR (Powre Supply Rejection Ratio), than class-AB, meaning that they are more sensitive to both hum (100Hz/120Hz) and other noise from the supply. The noise part can eaasily be the switching noise from one chanel to the other, resulting in beating. The noise will also be modulated and will show as distortion.
These problems are most visible in pure digital systems with no feedback.
See this on PurePath:
http://focus.ti.com/lit/an/slea049/slea049.pdf
But, with most designs today, there are enough feedback so this is not a problem, giving the amp a reasonably good PSRR
So to you question, it depends on the amp.
Using modules from e.g. Hypex will not have any problems with a non regulated supply.
Another thing is also that analog regulated PSUs only have good regulation at lower frequencies, and will probably not help anything for e.g. beating or switching introduced noise.
If you want regulation with Class-D, go for switch more power supplies.
These are inherently regulated, and well suited for class-d, and then you also get rid of the transformer
/Baldin
Class-D has inherently a lower PSRR (Powre Supply Rejection Ratio), than class-AB, meaning that they are more sensitive to both hum (100Hz/120Hz) and other noise from the supply. The noise part can eaasily be the switching noise from one chanel to the other, resulting in beating. The noise will also be modulated and will show as distortion.
These problems are most visible in pure digital systems with no feedback.
See this on PurePath:
http://focus.ti.com/lit/an/slea049/slea049.pdf
But, with most designs today, there are enough feedback so this is not a problem, giving the amp a reasonably good PSRR
So to you question, it depends on the amp.
Using modules from e.g. Hypex will not have any problems with a non regulated supply.
Another thing is also that analog regulated PSUs only have good regulation at lower frequencies, and will probably not help anything for e.g. beating or switching introduced noise.
If you want regulation with Class-D, go for switch more power supplies.
These are inherently regulated, and well suited for class-d, and then you also get rid of the transformer
/Baldin
Hi, all
I agree that some amps have a good PSRR, I know two (Hypex and AudioPower DXA series) just because I've tested. there will be others on the market.
Apart from PSRR, psu switch is regulated and want high performance, there remains the problem of the current response time, this affects the sound amplifier.
(With traditional transformer, add a lot of capacitors and the tone is much rock).
Another problem is the introduction of THD and IMD at low frequency. apart from good PSRR.
MDI-Laboratories two years ago advanced research in this area (apart RIPS) is now testing a new PSU, based on two-channel analog modulator with independent sensing on the outputs.
This system emulates the stage of class AB fully featured digital amplifiers with poor PSRR also ensures 10.000uF per side (real 1500uF).
Certainly the research costs are too high but this is justified by the assignment of patents to other companies operating in different sectors from Audio.
Regards
I agree that some amps have a good PSRR, I know two (Hypex and AudioPower DXA series) just because I've tested. there will be others on the market.
Apart from PSRR, psu switch is regulated and want high performance, there remains the problem of the current response time, this affects the sound amplifier.
(With traditional transformer, add a lot of capacitors and the tone is much rock).
Another problem is the introduction of THD and IMD at low frequency. apart from good PSRR.
MDI-Laboratories two years ago advanced research in this area (apart RIPS) is now testing a new PSU, based on two-channel analog modulator with independent sensing on the outputs.
This system emulates the stage of class AB fully featured digital amplifiers with poor PSRR also ensures 10.000uF per side (real 1500uF).
Certainly the research costs are too high but this is justified by the assignment of patents to other companies operating in different sectors from Audio.
Regards
Hi,
This is a simplified diagram of the concept that I presented before.
This new technique allows the use of small capacitors on the high voltage cell with the benefits of PFC
It also has the advantage of not introducing IMD / Noise on the device (fundamental reason is because when charge on transformer, it is disconnected from AC-line).
The core of the magic is the time base.
unfortunately can not be achieved with traditional chips and then this increased development costs, but ... this is a problem now passed.
This concept was derived from the RIPS, very similar, and was replaced with the second channel analog to better adapt to digital amplifiers, the result on amplifier is incredible ...
Regards
This is a simplified diagram of the concept that I presented before.
This new technique allows the use of small capacitors on the high voltage cell with the benefits of PFC
It also has the advantage of not introducing IMD / Noise on the device (fundamental reason is because when charge on transformer, it is disconnected from AC-line).
The core of the magic is the time base.
unfortunately can not be achieved with traditional chips and then this increased development costs, but ... this is a problem now passed.
This concept was derived from the RIPS, very similar, and was replaced with the second channel analog to better adapt to digital amplifiers, the result on amplifier is incredible ...
Regards
Attachments
Hi,
this is in production for audiopower.it ,I think is ready
in mid-May.
dimension (156x90x30mm) version 750w max.
Regards
I do not know, but I think the price will be competitive for the product launch.
All models of this new technology can accept 100-130/200-260VAC.
Regards
Hi All,
I am starting to explore this fascinating world of class D amps and I am not sure if I understand one thing correctly. So I would much appreciate if you could help me to understand...
I plan to order either Meanwell switching PSU or something like A500SMPS (switching PS module) from Connexelectronic. Some of the amp boards I consider to order for my experiments are designed for DC voltage so there is no problem in this case to connect them to one of the switching PSU's, I think. But some of the amp boards include linear power supply and need 3-wire AC input from transformer.
I wonder if I can connect the DC output of switching PSU to the 3-wire AC input of these boards, and if yes then how? Or is it better to bypass the onboard linear PS and connect the DC voltage after it?
I think that the big capacitors which are included in the onboard linear PS would help to make the power suply stronger but maybe I miss some disadvantage of it. Also I do not know if it is good or bad if the DC voltage passes through another rectifier - if it helps to make the DC voltage more stable and cleaner or not.
Even a brief answers to my questions how help me much. Thank you!
I am starting to explore this fascinating world of class D amps and I am not sure if I understand one thing correctly. So I would much appreciate if you could help me to understand...
I plan to order either Meanwell switching PSU or something like A500SMPS (switching PS module) from Connexelectronic. Some of the amp boards I consider to order for my experiments are designed for DC voltage so there is no problem in this case to connect them to one of the switching PSU's, I think. But some of the amp boards include linear power supply and need 3-wire AC input from transformer.
I wonder if I can connect the DC output of switching PSU to the 3-wire AC input of these boards, and if yes then how? Or is it better to bypass the onboard linear PS and connect the DC voltage after it?
I think that the big capacitors which are included in the onboard linear PS would help to make the power suply stronger but maybe I miss some disadvantage of it. Also I do not know if it is good or bad if the DC voltage passes through another rectifier - if it helps to make the DC voltage more stable and cleaner or not.
Even a brief answers to my questions how help me much. Thank you!
yes, up to car battery you can connect and sound is good.
Jokes aside, the main SMPS in the audio industry are used for high power, make use of (pfc, sync) and other devices created by chip manufacturers.
for esoteric amplifiers remains issue, PFCs and other devices solve only the efficiency but they are very dirty.
In other special fields is the same problem (medical, aeronautics).
is much better not to produce EMI instead of putting so many filters, I think.
these new psu are the result of pure research.was necessary to create chips and after , the psu.
for the current instead of using large capacitors, it generated energy when it is requested. only to solve this particular (Because current is a transient from amplifier) do not be surprised if the control circuit has 300MHz BW
in short, psu is ultra compact, does not create noise and responds to current irrespective of the duration of the sound. (Capacitors decreases if the period is long).
This is identical at RIPS (modified analog stage to fit the digital amplifier stages).
I do not want to force the purchase, I have no interest in this. I just want to tell you that now is possible to feed an esoteric class AB elegantly and without 5 kg of weight of the old transformer.
this is technology.
Regards
Last edited:
Thank you for your replies...
Actually I am looking for a high quality universal PS for audio apps. Universal in terms of output voltage - some of the amp modules I want to play with need about 30V while others 50 to 70V. So for my purposes it would be ideal if the PS allowed to adjust output voltage in wide range continuously by a pot or something like that or at least in several steps within the specified range by a switch.
The short description of DPS-400 and DPS-500 at audiopower.it mentions some output voltage adjustability but I do not understand if they are user adjustable or if I have to specify the voltage I need when I order the PS.
Anyway, if I will have a switching PS (with 2-wire DC output) and an amp module with 3-wire AC input from transformer, how should I connect them?
Thanks!
Actually I am looking for a high quality universal PS for audio apps. Universal in terms of output voltage - some of the amp modules I want to play with need about 30V while others 50 to 70V. So for my purposes it would be ideal if the PS allowed to adjust output voltage in wide range continuously by a pot or something like that or at least in several steps within the specified range by a switch.
The short description of DPS-400 and DPS-500 at audiopower.it mentions some output voltage adjustability but I do not understand if they are user adjustable or if I have to specify the voltage I need when I order the PS.
Anyway, if I will have a switching PS (with 2-wire DC output) and an amp module with 3-wire AC input from transformer, how should I connect them?
Thanks!
Hi,
DPS-400 if see datasheet is fixed voltage (at order decide vout) at 230VAC.
DPS-500 and DPS-600 decide at order but it includes trim for ADJ 10% vout
es. order +/-68V (can up to +/-74V).
Sorry,last you question not understand.
If you have other question,please direct it to audiopower.
Regards
Last edited:
Thank you for your reply, AP2.
Regarding my second question, I will try to explain what I mean in other words. I want to use a switching PS to power various amp modules I am going to experiment with.
Some of the amp modules / boards are designed to be powered by DC so then there is no problem to power them by the switching PS as I understand.
But some boards have a rectifier and big capacitors on their power input and they typically expect AC voltage from dual secondary circuit of thoroidal transformer to be connected to their 3- or 4-wire input (which is typically marked like "AC24V GND AC24V").
My understanding is that in such case I can connect +34V output of the SPS to both inputs marked AC24V (on the amp board) and -34V output of the SPS to the GND marked input (on the amp board). Is that correct?
If not, what is correct way to power an amp board with AC input by SPS with DC output?
Thanks!
Hi,
It possible that "24gnd24" ref to dual voltage but is also possible is double wave rectifier (single voltage).
I not have sufficient parameters for help you. You have photo or scheme of this?
In both modes,NOT possible connect -38V at gnd.
If you amp is dual voltage,then can connect +38v and -38v at AC and gnd to gnd .
Regards
Thank you as always, AP2.
It seems I start to understand it.
Some amp boards, like this one, for example:
4*100 watt @ 4ohm, TK2050 D-class Audio Amplifier Board -
have single voltage DC input (2-wire) and are ready for laptop like SPSU's. If I want to power this amp board by Meanwell SPSU (36V DC 9.7A 349.2W Regulated Switching Power Supply -http://www.sureelectronics.net/goods.php?id=460) I have to use the "+V" and "Gnd" terminals of the SPSU, right?
And I if I had for example this amp board:
http://cgi.ebay.com/TRIPATH-digital...tem&pt=LH_DefaultDomain_0&hash=item483a46d473
and wanted to power it by the above mentioned Meanwell SPSU then I would have to connect "+V" terminal of the SPSU to one of the "AC24V" market voltage inputs of the amp board, "Gnd" to "Gnd" and "-V" to the second "AC24V" input of the amp board, right?
What about the voltages in the second case - if the amp board requires dual 24V AC power, do I have to recalculate the voltages somehow if I put dual DC voltage there?
Thank you for your patience with my lack of knowledge in this area.
Thank you as always, AP2.
It seems I start to understand it.
Some amp boards, like this one, for example:
4*100 watt @ 4ohm, TK2050 D-class Audio Amplifier Board -
have single voltage DC input (2-wire) and are ready for laptop like SPSU's. If I want to power this amp board by Meanwell SPSU (36V DC 9.7A 349.2W Regulated Switching Power Supply -http://www.sureelectronics.net/goods.php?id=460) I have to use the "+V" and "Gnd" terminals of the SPSU, right?
And I if I had for example this amp board:
http://cgi.ebay.com/TRIPATH-digital...tem&pt=LH_DefaultDomain_0&hash=item483a46d473
and wanted to power it by the above mentioned Meanwell SPSU then I would have to connect "+V" terminal of the SPSU to one of the "AC24V" market voltage inputs of the amp board, "Gnd" to "Gnd" and "-V" to the second "AC24V" input of the amp board, right?
What about the voltages in the second case - if the amp board requires dual 24V AC power, do I have to recalculate the voltages somehow if I put dual DC voltage there?
Thank you for your patience with my lack of knowledge in this area.
ok,np for patience,I...relaxed
first example is correct because Amp is single voltage.
2st example NOT correct because PSU "Meanwell SPSU" is a single out DC ref to gnd.
TRIPATH-digital-power-amplifier-TA2022-2x90W, necessity of dual voltage ref to gnd (+36V and -36V) (36VDC if you entry a DC instead of 24AC).
DC=(AC*1.41)
Regards
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