Switched Mode Power Supplies (SMPS) - Page 11

col · 28th August 2010, 12:49 PM

Quote:

Originally Posted by Cristi

Add one 1KR at min 5W resistor on the negative rail, and use the voltage from the positive rail. the voltage can be adjusted from the small pot. from 25 to 32V.

thanks, will give it a try.

col.

atterbud · 30th August 2010, 02:55 PM

Hi Cristi
I have a question regarding your SMPS modules. I would like to use your A1000SMPS modules to power a pair of ClassDAudio.com SDS-254 stereo amp boards that will be used in bridged mode (500w @ 8ohm or 4ohm) - one SMPS per amp board.

Is the A1000SMPS overkill for these modules or will it offer benefits over your SMPS500R model? The price difference between your 2 modules is so small that I'd rather go with the larger supply A1000SMPS if it offers any benefits at all.

The information on the required power supply from classdaudio is as follows...

Power supply
A dual (bipolar) DC power supply of +/-45 to +/-60 Volt should be connected to the terminals V- GND V+ of the 3-position terminal block (shown in photo on following page). The minimum supply voltage is +/- 45V, and the maximum value is +/- 60V. Any value below or above the stated value, and the amplifier will not turn on due to the un-der voltage and over voltage protection that is built into this amplifier. The current ca-pability of the power supply depends on the load and the voltage. The amplifier has a good power supply rejection ratio of -65 dB at 1kHz, and accepts any power supply topology as long as the supply voltages fit in the min and max range.

Any help or advise that you can offer would be much appreciated.
Regards,
Dave.

Cristi · 1st September 2010, 07:50 AM

To power two amplifier modules, each delivering 500W i strongly recommend to use a bigger smps than 500w. so, the A1000SMPS is the choice. to get 500W at 8Ohms in BTL mode the supply voltage should be +-50 to +-55V. the A1000SMPS can be set for this ouptut voltage.

back · 1st September 2010, 09:29 PM

hi cristi.

the resonant smps perform worst than regulated ones in sound quality?

Cristi · 3rd September 2010, 07:30 AM

As I know, the resonant smps perform better than a normal, hard-switched smps for audio applications. the quasi-resonant smps's which have unregulated output might not be as good as regulated ones when they are used for class D amps with lower PSRR, such as open loop or pre-filter amps.

andpol · 4th September 2010, 01:16 PM

Dear Cristi

The yellow trimmer close the 10.000uf caps is for changing the 10% output's voltage of smps500r?

If no how can i change the output voltage?

back · 4th September 2010, 04:35 PM

Quote:

Originally Posted by Cristi

As I know, the resonant smps perform better than a normal, hard-switched smps for audio applications. the quasi-resonant smps's which have unregulated output might not be as good as regulated ones when they are used for class D amps with lower PSRR, such as open loop or pre-filter amps.

so for class D regulated smps are better than resonant ones?

Cristi · 6th September 2010, 06:05 AM

The Output Voltage of the SMPS500R can be adjusted within 10% limits from the small potentiometer which is between the transformer and the output filter caps. Anyway the output is already adjusted to required value and i do not recommend to change this.

There are plenty of SMPS topologies, the resonant ones can be regulated or not, depending on the topology. my advice is that for a class D amp is better to use a regulated smps, either resonant or a regulated hard switched smps.

avionic · 6th September 2010, 09:00 PM

Received the SMPS500R and hooked it up to my ClassD Audio amplifier, (125x2 8ohms,250x2 4ohms), sounds great. More than enough power and the power supply board is smaller than the amp board.
Thanks Cristi for a great item. I have been looking for an SMPS for this amp for quite a while and the 500R seems to be exactly what I have been looking for.

alkasar · 17th September 2010, 04:36 PM

Quote:

Originally Posted by Cristi

Add one 1KR at min 5W resistor on the negative rail, and use the voltage from the positive rail. the voltage can be adjusted from the small pot. from 25 to 32V.

Hello Cristi, i consider recycle my smps250 in a project where i need single +30V voltage.
With the above mod, will the full power (minus about 1w lost in the resistor) be available on the positive rail ? will the smps suffer from working in this "unbalanced" mode ?
thanks

1st September 2010, 09:29 PM	#104
back diyAudio Member Join Date: Nov 2005 Location: crete	resonant smps. hi cristi. the resonant smps perform worst than regulated ones in sound quality?

6th September 2010, 09:00 PM	#109
avionic diyAudio Member Join Date: Nov 2009	Smps500r Received the SMPS500R and hooked it up to my ClassD Audio amplifier, (125x2 8ohms,250x2 4ohms), sounds great. More than enough power and the power supply board is smaller than the amp board. Thanks Cristi for a great item. I have been looking for an SMPS for this amp for quite a while and the 500R seems to be exactly what I have been looking for.

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30th August 2010, 02:55 PM	#102
atterbud diyAudio Member Join Date: Jul 2009	Hi Cristi I have a question regarding your SMPS modules. I would like to use your A1000SMPS modules to power a pair of ClassDAudio.com SDS-254 stereo amp boards that will be used in bridged mode (500w @ 8ohm or 4ohm) - one SMPS per amp board. Is the A1000SMPS overkill for these modules or will it offer benefits over your SMPS500R model? The price difference between your 2 modules is so small that I'd rather go with the larger supply A1000SMPS if it offers any benefits at all. The information on the required power supply from classdaudio is as follows... Power supply A dual (bipolar) DC power supply of +/-45 to +/-60 Volt should be connected to the terminals V- GND V+ of the 3-position terminal block (shown in photo on following page). The minimum supply voltage is +/- 45V, and the maximum value is +/- 60V. Any value below or above the stated value, and the amplifier will not turn on due to the un-der voltage and over voltage protection that is built into this amplifier. The current ca-pability of the power supply depends on the load and the voltage. The amplifier has a good power supply rejection ratio of -65 dB at 1kHz, and accepts any power supply topology as long as the supply voltages fit in the min and max range. Any help or advise that you can offer would be much appreciated. Regards, Dave.

1st September 2010, 07:50 AM	#103
Cristi Banned Join Date: Dec 2008 Location: Hong Kong or Europe	To power two amplifier modules, each delivering 500W i strongly recommend to use a bigger smps than 500w. so, the A1000SMPS is the choice. to get 500W at 8Ohms in BTL mode the supply voltage should be +-50 to +-55V. the A1000SMPS can be set for this ouptut voltage.

3rd September 2010, 07:30 AM	#105
Cristi Banned Join Date: Dec 2008 Location: Hong Kong or Europe	As I know, the resonant smps perform better than a normal, hard-switched smps for audio applications. the quasi-resonant smps's which have unregulated output might not be as good as regulated ones when they are used for class D amps with lower PSRR, such as open loop or pre-filter amps.

4th September 2010, 01:16 PM	#106
andpol diyAudio Member Join Date: Apr 2008	Dear Cristi The yellow trimmer close the 10.000uf caps is for changing the 10% output's voltage of smps500r? If no how can i change the output voltage?

6th September 2010, 06:05 AM	#108
Cristi Banned Join Date: Dec 2008 Location: Hong Kong or Europe	The Output Voltage of the SMPS500R can be adjusted within 10% limits from the small potentiometer which is between the transformer and the output filter caps. Anyway the output is already adjusted to required value and i do not recommend to change this. There are plenty of SMPS topologies, the resonant ones can be regulated or not, depending on the topology. my advice is that for a class D amp is better to use a regulated smps, either resonant or a regulated hard switched smps.