[Rclark]

 Hello sir, I'm afraid I'm a relative newb when it comes to understanding power supplies and such. I'm building my first system and have landed on the ClassD SuperD amplifier (I even cancelled an order on another amp to try this diy out), but have come to understand that while the amp itself is superlative there can be great gains made on the power supply itself.

You'll have to pardon me but reading your site it might as well be Turkish. Do you offer a high performance power supply that can be used in my application and how much would it cost?

[Paul Hynes]

Hello Rclark,

Can you give me a link to the power amplifier details so I can advise you correctly.

Regards
Paul

[HT cOz]

Hello Rclark,

Can you give me a link to the power amplifier details so I can advise you correctly.

Regards
Paul

Hi Paul,

I would like to help out a little in this post. Here is a brief table of the 3 models available.




There are 3 basic models with a variation betwees the CDA and SDS.  The SDS adds balanced input, line buffer, and volume pot.

Of the three modules, I think it is best to focus on the 254 module because the 258 becomes current limited due to circuit protection in bridged mode.

Using the 254 module the manufacturer states that the required supply is (required Power Supply: +/- 40 Volts DC to +/- 55 Volts DC) and optimal is (+ /- 50V at about 2.5 to 5 amps is optimal).

Here is a link to the manuals for all modules:
http://classdaudio.com/index.php/manual/?___store=default

and the 254 module specifically http://classdaudio.com/documents/50V_manual.pdf 

I am by no means an expert on these amps but thought I could get you started.

Kind Regards,
Robert

[HT cOz]

And the rest of the info...

There are 3 basic models with a variation betwees the CDA and SDS.  The SDS adds balanced input, line buffer, and volume pot.

Of the three modules, I think it is best to focus on the 254 module because the 258 becomes current limited due to circuit protection in bridged mode.

Using the 254 module the manufacturer states that the required supply is (required Power Supply: +/- 40 Volts DC to +/- 55 Volts DC) and optimal is (+ /- 50V at about 2.5 to 5 amps is optimal).

Here is a link to the manuals for all modules:
...www.classdaudio.com/index.php/manual/?___store=default

and the 254 module specifically ...www.classdaudio.com/documents/50V_manual.pdf   

I am by no means an expert on these amps but thought I could get you started.

Kind Regards,
Robert

[Paul Hynes]

Thanks Robert,

That will be a great help.

Rclark,

I still will need to know which module you are going to use.

Regards
Paul

[HT cOz]

I'm interested in both the 254 and 258.  I don't know where RClark went?

[Paul Hynes]

Hello Robert,

As long as you do not want to operate these amplifiers at disco levels the PR3HD positive voltage regulator and NR3HD negative voltage regulator modules can be set up to work well with the 254 and 258 at any working output DC voltage of between 30v and 50v. To run the 258 on a 70v supply would require higher voltage regulator output stage devices, as I do not like running semiconductors too close to their ratings, which in this case is 100v. Unfortunately I have not seen P channel mosfets with suitable ratings for use with the NR3HD at elevated voltages and currents.

There is a work-around for this. The regulator modules are fully floating in operation and derive their ground reference from the load ground. This means that you can connect a PR3 module positive output terminal to ground and use the 0v output terminal as a negative supply rail. The regulator does not care which terminal is grounded as it still regulates the voltage between the two output terminals. This allows the use of a beefy IXYS N-channel mosfet with more than adequate specifications to run at higher voltage and current levels. This module is called the PR3EHD (extra heavy duty). You can use this module for disco levels if you wish.

I would suggest using the DC input versions of these regulator modules as this allows the use of large can energy storage capacitors and heavy duty rectifiers enabling plenty of energy storage for this application.

The modules will require a good size heat-sink and I can advise you regarding this should you wish to proceed with setting up a power supply for the amplifiers.

To allow you to assess costs, the PR3HD and NR3HD DC versions cost £80 each and the PR3EHD costs £100.

If you have any further questions I will be pleased to help.

Regards
Paul

[Rclark]

Yes Mr. Hynes, sorry. I'll be running the 254 amp and want a power supply that is high quality and will provide ample and large headroom for the amp.

[Paul Hynes]

Hello Rclark,

Both of the regulators I recommended can deliver large transient currents to the amplifier. I am happy to recomend the PR3HD/NR3HD to you unless you are going to operate the system into a low efficiency loudspeaker at disco levels. If this is the case go for the PR3EHD. The IXYS output device is a seriously rugged part.

Regards
Paul

[Rclark]

http://speakerdesignworks.com/Statements_Monitor.html


These are the speakers I'm building. There are graphs right there that demonstrate sensitivity and the like.

I would like to have the ability to drive them hard if desired.

[TRADERXFAN]

Go "heavy duty" with those specs...

[Rclark]

Ok, I'm confused, all I see is an "SR1". I don't see these other units you're talking about.

[Paul Hynes]

Hello Rclark,

I would normally suggest the Heavy Duty version too with your chosen combination, however as you wish to be able to drive these speakers hard, I would be more comfortable to recommend the Extra Heavy Duty option with a decent size heat--sink of at least 1 degree C per watt rating on each regulator module. I can work all the heat-sink details out for you if you decide to continue the project. The speakers you will be using are low impedance and relatively inefficient, which will require more drive current than a higher impedance more efficient speaker. I like to ensure a safety margin.

If you are referring to my website, this is well out of date. I have been too busy with consultancy business and making power supplies/regulator modules, as well as a few family issues to deal with this last year, to be able to find the time to rewrite the website. There are now many more products available that few know about yet. These heavy-duty PR3 modules are just one part of the new product list.

As I like to discuss each application individually with my customers to make sure I provide good advice regarding power supply/module choice, specifying all the available products on the website has not been high on my priority list. I was hoping to have completed this task, during what is normally a quiet period in the early Summer months, but it has been busier than ever, with no signs of slowing down. My priorities at present are keeping up with orders whilst maintaining a sensible lead-time. 

Regards
Paul

[Rclark]

Could you please somehow describe this heavy duty unit for me, maybe I can see what it looks like, etc. Capacitance, wattage, qualities vs a stock power supply, etc. And how much in dollars, I suppose.

[Paul Hynes]

Hello Rclark,

I will be building PR3HD modules this week and will take some photos for you. More detail to follow when I have more time.

Regards
Paul

[Rclark]

Ok thank you sir.

[poseidonsvoice]

Hello Robert,

As long as you do not want to operate these amplifiers at disco levels the PR3HD positive voltage regulator and NR3HD negative voltage regulator modules can be set up to work well with the 254 and 258 at any working output DC voltage of between 30v and 50v. To run the 258 on a 70v supply would require higher voltage regulator output stage devices, as I do not like running semiconductors too close to their ratings, which in this case is 100v. Unfortunately I have not seen P channel mosfets with suitable ratings for use with the NR3HD at elevated voltages and currents.

There is a work-around for this. The regulator modules are fully floating in operation and derive their ground reference from the load ground. This means that you can connect a PR3 module positive output terminal to ground and use the 0v output terminal as a negative supply rail. The regulator does not care which terminal is grounded as it still regulates the voltage between the two output terminals. This allows the use of a beefy IXYS N-channel mosfet with more than adequate specifications to run at higher voltage and current levels. This module is called the PR3EHD (extra heavy duty). You can use this module for disco levels if you wish.

I would suggest using the DC input versions of these regulator modules as this allows the use of large can energy storage capacitors and heavy duty rectifiers enabling plenty of energy storage for this application.

The modules will require a good size heat-sink and I can advise you regarding this should you wish to proceed with setting up a power supply for the amplifiers.

To allow you to assess costs, the PR3HD and NR3HD DC versions cost £80 each and the PR3EHD costs £100.

If you have any further questions I will be pleased to help.

Regards
Paul

Given the SDS254 model which requires at least a minimum of a 40V DC supply, what are the headroom requirements for your PR3HD and NR3HD regulators? The amplifier itself is recommended to be used with a 400VAC transformer and dual 32V AC secondaries to provide a DC voltage of a minimum ~ 40V DC (assuming full wave bridge rectification). I figure your regulators will require at least 10-15V DC headroom right? So perhaps a 500VA transformer with dual 40V secondaries? That will provide (assuming again full wave bridge rectification) a DC voltage of 56 volts before your regulators come into play.

My speakers are 95dB (2.83V into 8ohms) sensitive, and given the amplifier's power output of 125 watts into 8 ohms, I have plenty of reserve.

Thanks again Paul!
Anand.

[Paul Hynes]

Sorry Anand, I missed this,

The DC version of the PR3HD requires a headroom of 6 volts and the NR3HD  requires 9 volts so aim for 10 volts and you will be fine.

Regards
Paul