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External power supplies

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@@Karin @@andyr

A welcome in NMI has grown into a small thread about external power supplies. Too few ppl get the benefit of contributing so I've started a new thread here.

The original thread is a mix of greetings so I encourage ppl who have relevant comments from there to move them here

"My name is Karin Hoks. I am co-owner of the Dutch company Sbooster. We develop upgrade products to boost the sound quality of a wide variety of audio device with external power supplies. Our main focus is power supply related.

I am here on this forum to give insight on power issues and our products."

Edited by djb

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Welcome! The more the merrier working on supplying more stable and reliable power supplies. Wall warts are the most unreliable components in any system.

I did a large project that needed lots of wall warts, because that was the technology available at the time. In the eleven years the system has been running they were/are the main source of failure.

Sent from my GT-N8010 using Tapatalk

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@@Marc missed that thread thank you

Here is the

OP from @giesler to add to our education

Commercial Member

I had a good chat with Marc the other day & we both agreed that some good quality low noise 5v, 9v & 12v locally produced power supplies would go down well.

I have already done quite a bit work in this area & have built several 12v Intel NUC psu's which customers were most impressed with. I know there are lots of low priced units on EBay but they generally use low quality parts especially in the filter cap, diode area & the mains input voltage is often a bit low ie. 220v. There are some great units coming out of the US but with our plummeting dollar & high postal cost don't represent good value. What I am proposing is two models & both will be powered by external fully AUS approved 240v AC transformers. I love using external AC supplies as I then have full control over rectification filter cap choice etc.. OK so a 5v or 9v (pick voltage on order) at about 2A & a 12v unit at 2.5A. I am limited to these maximum currents by the external transformer choice, trying to keep everything legal & approved. I know you guys like to see massive current ratings but even a mini itx MB only draws about one amp after initial start up surge. I find diode & capacitor choice has a much bigger effect on sonic qualities than an outright current rating. Case style will be the same as the Klein DAC series as I have this well sorted now. Canadian manufactured Hammond extruded aluminium case with slide in PCB & zero internal wiring. I will be using high spec very low noise regulators. That give great protection & will make them short circuit proof. Noise levels from these are now the same as the boutique super regs that are so popular. Marc also suggested the possibility of a DIY version ie populated board only which could be fitted into a custom server case. Lots to think about & any feed back much appreciated.

R

Edited by djb

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Guest

Hi

Have been playing around a bit too with DC supplies.

Switchmode

Transformer based

battery

 

Will say there is audible differences between types of supplies, particularly phono pre amp just with different batteries.

 

Have been using Meanwell and find them to be the best of the switchmode.

 

Interested to hear others opinions.

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Hi djb, Matt and all other interested audiophiles,

 

Give us a couple of days and my partner and I will write something on batteries and DC-power supplies. When my partner, Wiebren (the brains behind our company), was still young, he used to maintain & repair batteries and later he was a sales rep. for batteries. So he knows batteries ... :)))

 

So "talk" to you soon!

 

Regards,

Karin

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Karin

Thanks for joining SNA

Looking forward to your contributions.

Johannes

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I recently received an Sbooster BOTW P&P ECO 12-volt linear supply for my DSPeaker Anti-mode 2.0 room correction unit. 

I was knocked out by the improvement in sound quality. What a marvelous upgrade to my system. Best decision I've made in a while.

Congrats, Karin.

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I recently received an Sbooster BOTW P&P ECO 12-volt linear supply for my DSPeaker Anti-mode 2.0 room correction unit. 

I was knocked out by the improvement in sound quality. What a marvelous upgrade to my system. Best decision I've made in a while.

Congrats, Karin.

 

Hi Goldiver,

 

Sorry for my late reply, but thank you very much for your compliment!

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Finally, I have found the time to write a little about power supplies. 

 

We were occupied with our new stock to arrive after the weekend and with postings on measurements on Whatsbestforum #1130/#1208 and ComputerAudiophile

 

I have only written a short note, because there are libraries full of books on power supplies. Hereunder I write how we came to the power supply we have built. It is just our point of view, nothing more.

 

Power supplies are a trending topic in audio. Many people, of course including us, say that “in the end you listen to the power supply†:)))

 

There are three ways of powering an audio device:

·         Linear power supply;

·         Battery supply;

·         Switch mode supply.

 

Building audio grade power supplies before the 80-es was “very†difficult, but after the introduction of the first integrated linear regulator – called “IC†- building a power supply became a piece of cake. This was revolutionary! See also the link above posted by 125dBmonster.

 

In the 90-es it appeared that this IC was not really suitable for audio applications. The power supply was easier to build, but it was not optimal. The power supply was slow and noisy.

High end audio brands started to use batteries to solve the issues. The benefit was that a battery was less noisy than a conventional power supply and that it was disconnected from the mains. Their idea was that the overall performance was better.

 

However in the late 90-es the battery became discarded due to the fact that a battery was expensive, large, was quickly empty and needed to be charged and also the batteries needed maintenance.

In this period audiophiles started to revert to the old IC. To eliminate the bad characteristics of the IC, people started to build electronic designs behind these ICs. This became a project of more than 10 years, but the super regulator was born.

 

The downside of using such super regulator for manufacturers is that it is practically not possible to get safety certifications for power supplies build with such a super regulator. That doesn’t mean that we say that they are unsafe, but it will not be possible to pass all the safety standard tests. Furthermore, technology has moved on. Today’s IC regulators can have the same or even better specs than the “old school†super regulators of the past. Also these new IC regulators are equipped with additional safety circuits as well.

 

In our memory the switch mode power supply was introduced somewhere after the millennium. In mid/high end audio, the Squeeze-box was the first serious mass produced audio device with an external switch mode power supply. Hereafter more audio devices with external switch mode power supplies entered the mid/high end audio market.

 

Hereunder we give a summary of the main advantages and disadvantages three types of power supplies:

 

Switch mode power supply – SMPS
The advantage of a SMPSs for manufacturers is that they are cheap, safety-approved and that they can be used worldwide. For this a audio manufacturer can bring less expensive audio devices on the market.

The main disadvantages of SMPSs in audio are

  1. They are switching, which causes high frequency noise;
  2. They do not have head room to “catch†a peak load;
  3. A SMPS pollutes the mains;
  4. A SMPS powered audio device can cause damage, when this unit is connected to an audio device that is grounded.

Batteries
The advantages of batteries are:

  1. No connection to the mains;
  2. Low noise, but only when at rest (when there is no chemical process going on).

The disadvantages are:

  1. A battery gets empty;
  2. Loading of the battery: to make the load-process less inconvenient “float charges†are developed. Float charges are always on. As batteries are high inductive they pass on the pollution of the charger directly to the audio device;
  3. Slow (reaction time on delivering current, when requested by the audio device), a battery is slow due to the chemical process.
  4. Difficult with peak loads due the ESR (Electrical Series Resistance). The exception to this peak load issue is probably the battery set of 125dBmonster  ;)  

Conventional linear power supplies

The advantages of conventional linear power supplies are:

  1. Less noisy than SMPSs;
  2. Having some headroom to handle peak loads.

The disadvantages are:

  1. Connected to the mains;
  2. Slow (reaction time to the demand of current).

If we look at the above, we see that every type of external power supply has advantages, but at the same time a lot of disadvantages. In the development of our new power supply we have set our goal to eliminate the disadvantages. We have looked for specific characteristics and features that are necessary to make an audio device perform at its best. The key characteristics and features in our opinion are:

  1. Ultra-low noise;
  2. Stable output;
  3. Fast reaction time;
  4. Powerful: sufficient head room to handle peak loads;
  5. Filtered mains and transformer shielding to block mains pollution.

To fulfill these characteristics and features we came to the conclusion that batteries and SMPSs are not suitable. Also it became clear that we needed more than a transformer and an IC regulator: we needed something more than “just†another power supply. So we came up with a power supply that has the following parts (see also the picture in my new member post):

  1. High performance dual stage mains filter with earth line choke;
  2. Audio grade transformer with static shielding;
  3. Anti-oscillation circuit for the audio grade transformer;
  4. Power schottky rectifiers;
  5. High quality polypropylene film capacitors;
  6. Efficient electronic design;

Also we invented a system to make the power supply practically a uninterrupted power source: the so called “Sbooster split-current†system. And with our Sbooster-technique at the end of the DC-cable, we guarantee that the performance of the power supply is close as possible to the audio device. The result is that this power supply is suitable for high current demanding equipment, but also for noise sensitive devices. It is fast, low noise and powerful. 

 

Should you have questions on power supplies, please let me know.

 

Regards,

Karin

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Hello Karin

Great post pointing out the good and the bad of our power supplies, same as yourself am a big believer in a quiet power supply as you are very correct we do actually listen to the supply. Elimination of the supply noise to the device and the injected noise back to the mains supply, crucial for subjective listening.

 

I am sure there are plenty of folk included myself interested in a quieter more dynamic stereo, using better well thought out Mains driven DC Linear Power. The section I find most interesting is the dual stage mains filter with earth line choke, "fast, low noise and powerful" sounds like a recipe common to almost all audio equipment. 

 

Well Done  :)

 

Cheers 

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Hi Guys, 

I thought I better have a bit of input here. Design, testing & fabrication work is all completed on my new low noise linear supply. I will definitely be doing a detailed Stereonet post this weekend so keep an eye here. 

http://www.stereo.net.au/forums/index.php/topic/88704-low-noise-power-supplies-5v-9v-12v/

Karin is spot on with all the technical requirments & my new supply should comfortably qualifi. It also has a few additional features like user adjustable output voltages & a high quality removable 10 A DC cable connected via a 16A Neutrix XLR plug. All components are in stock so I will be able to supply units from mid next week.

 

Regards

Clay

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