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5V 3A PSU

Printed From: Graham Slee at Hifi System Components
Category: And the rest
Forum Name: Power Sources
Forum Description: Where the power comes from has always been a hot topic - even more so now with new World legislation
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=4221
Printed Date: 11 Jul 2020 at 5:25am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: 5V 3A PSU
Posted By: Graham Slee
Subject: 5V 3A PSU
Date Posted: 17 May 2017 at 6:22am
Currently in development in my workshop is a new power supply. It is a 5 volt 3 amp unit and because it is single voltage and uses a proper transformer, it is not legal to sell it in the European single market or in some states in the US (and maybe Australia?).

Actually that just spoiled my intro, realising that you could only benefit by it by buying it on the sly. But anyway, if you look up my surname (Slee) you should find it's a derivation of sly... Wink

How could you benefit by it? Good question: one of our senior members reckons he will benefit by it because he instigated the process - namely msphil (hi Phil!). He wants it for his Squeezebox Touch, and on hearing about this another senior member (Fatmangolf) became interested (there, I spilled the beans... Wink)

I must admit that this has been on my pile of things to do since 2015, and poor old Phil must be losing patience by now (Wink) and so to restore his faith I decided to write about its progress here.

Yesterday I did all the workings out and ordered up the remaining parts required. What took longer than I thought was working out a little extra feature I consider essential for a 5V supply...

Logic/digital chips run on 5V (and some on 3.3V), and it would seem like many devices, this might not use any intermediate regulation (other than if 3.3V is required) and relies on the 5V from its supply being a good stable 5V.

If you were to try supplying a 5V circuit from say a 12V supply what would happen? Well, if the device has no overvoltage detection built-in, it would break!

One good thing about the EU, is it thought about things like this, and legislated on it, but in an abstract way. Now, in Yorkshire we have a reputation of calling a ***** a ***** (political correctness prevents me from using the actual word here).

Because of the abstract way the legislation is formed, manufacturers of such devices may not have understood what it means, and so I have to assume they didn't, and put into the power supply what they may not have done at their end.

And that is overvoltage protection such that if part of the power supply failed and decided to output more than 5V, it will shut down and prevent catastrophic destruction of the device it is powering.

When making power supplies for ones own products this is not an issue, but making an aftermarket power supply one needs to think about such things.

Anyway, after much frustration (the world seems to be getting that way these days) I was able to find/decipher what I was looking for in the form of a chip and external MOSFET required to perform the action.

So, it should comply in that respect, but it is still against legislation to actually sell it. However, by providing another output voltage, it becomes legal. And because nobody actually wants another output voltage - they just want the 5V - we can make that voltage anything we want, and it makes sense to use a voltage which appears somewhere in the circuit. And so I will designate a pin on the output connector as one of those. Hey presto! It then complies!

More on its progress shortly.



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Replies:
Posted By: Ash
Date Posted: 17 May 2017 at 7:19am
Bitzie users can also rejoice then? I could use this together with the Lautus powerwire product to provide a lift in performance.


Posted By: BackinBlack
Date Posted: 17 May 2017 at 10:26am
This PSU could be an upgrade for Raspberry Pi users as well. The Digi + Pro and DAC+ Pro convertor boards for the RPi need 5V and 3.3V supplies. If this is within the scope, then would you please add me to the list for a unit.
I have previously LM723N based regulators with BD140 as "output" device for (higher) current capability. These sounded quite good, but didn't have the benefit of professional design and measurement, which I'm sure your PSU will benefit from and therefore be a significant improvement.

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Just listen, if it sounds good to you, enjoy it.


Posted By: Graham Slee
Date Posted: 17 May 2017 at 11:34am
A regulator is a regulator is a regulator...

Will my choice sound better? I would doubt that. They're all much of a muchness, and all seem to have very similar specifications. I know great claims are made by little firms who make power supplies, especially when using adjustable types. I read somewhere where Mr Ahem of Such and Such Co made a big meal of his discovery that using a 10uF capacitor between the adjust pin and ground made a huge improvement, and his fanbase loved him for it. I had to laugh - it's on the device's data sheet, and has been since they first came out sometime in the late 70s. I remember using the same technique in the 1980s.

What does make a difference however, is the layout: the grounding regime and the charging current lengths and impedances of path. Let's hope I get that bit right...



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Posted By: BackinBlack
Date Posted: 17 May 2017 at 12:14pm
Originally posted by Graham Slee Graham Slee wrote:

A regulator is a regulator is a regulator...

Will my choice sound better? I would doubt that.

What does make a difference however, is the layout: the grounding regime and the charging current lengths and impedances of path. Let's hope I get that bit right...



Add to the layout considerations the choice of the most appropriate components, then you have the reason why your design might well sound better.

I'll watch with interest how this develops and ultimately hope to benefit with a new PSU.


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Just listen, if it sounds good to you, enjoy it.


Posted By: Graham Slee
Date Posted: 17 May 2017 at 1:10pm
Originally posted by BackinBlack BackinBlack wrote:

This PSU could be an upgrade for Raspberry Pi users as well. The Digi + Pro and DAC+ Pro convertor boards for the RPi need 5V and 3.3V supplies. If this is within the scope, then would you please add me to the list for a unit.
 


5V and 3.3V at the same time? OK, that's the other output then.


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Posted By: BackinBlack
Date Posted: 17 May 2017 at 3:20pm
5V 2.5A + 3.3V 500mA would suit my needs, don't know what others may need.


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Just listen, if it sounds good to you, enjoy it.


Posted By: Graham Slee
Date Posted: 17 May 2017 at 7:11pm
Things were going fine until 3.3V was mentioned. Overvoltage protection is easily implemented on the 5V rail by use of a Maxim IC and MOSFET, but as nobody uses them on 3.3V, nobody stocks them. Blame legislation (the EU) which has sent everybody scrambling for switched mode - the thing we want to avoid like the plague here.

Why bother with overvoltage protection?

1. failure of the voltage regulator
2. an inductive load

Both can lift the voltage above a safe level for the ICs being powered and damage results. I don't want to be paying compensation for that sort of thing.

An explanation of the sort of circuit which can cause an inductive load, is when a BJT 555 timer is used without suitable decoupling. The power supply spike it causes can result in an increase of the DC rail. OK if it's one-shot, but say it was used as an oscillator circuit? The spikes are then a continuous thing leading to a gradually increasing voltage rail. That's a user fault, but most users won't see it that way - experimenters can lack the understanding. Best to have overvoltage protection to shut such a situation down before anything costly breaks.

3.3V is therefore the stumbling block as regards overvoltage protection. I am having the idea of driving a 5V overvoltage chip via a charge pump from the 3.3V rail, if only I can ensure the charge pump outputs 5V from it. Often it's a straight voltage doubling which is 6.6 volts, so I need to make it 5V.

Anyway, it's fun (I suppose) to still be doing such crazy things when I thought I was going to be semi-retired... Wink


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Posted By: Graham Slee
Date Posted: 17 May 2017 at 10:17pm
After many hours of thought I think the 3.3V output fed via a diode drop to a ADM660 charge pump will trick a MAX4840A into thinking it is working on a 5V supply. Indeed it will be, as the output of the ADM660 will be very close to 5V. The gate drive output however, will not be driving a MOSFET on this 5V rail - the gate will drive a MOSFET on the 3.3V rail. I think that should work fine. Just need to build it and test it. Could take a week or two as I will need to get a prototype PCB designed and made for it.


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Posted By: Graham Slee
Date Posted: 19 May 2017 at 11:28am
On second thoughts Linear Technology's LTC4365 overvoltage chip looks like it will do 3.3V, but the datasheet contradicts itself saying the input voltage needs to be 3.5V to work, and then goes on to discuss operation down to 2.5 volts Wacko


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Posted By: jwatson
Date Posted: 19 May 2017 at 2:09pm
Hello Graham, I'd also be interested in a 5/3.3 supply for my Raspberry Pi / Hifi Berry Digi + Pro, either as a finished product or kit.

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"I bought some more old vinyl today 'cos old vinyl won't ever let you down"
Majestic DAC -> {Proprius -> Tannoy Stirling | Solo UL -> HD820}


Posted By: Fatmangolf
Date Posted: 19 May 2017 at 11:25pm
I'm still interested in having one of these PSU's please. In making DIY 5V supplies to keep me and Phil going till the proper GSP 5V supply came along I found the Squeezebox Touch is fine with 500mA and 1A is plenty. My PSU's are better sounding IMO than the standard Touch SMPS but are quite crudely laid out and I know from my other GSP gear your expertise in PCB layout will one of several reasons why a GSP PSU is worth waiting for!




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Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: ServerBaboon
Date Posted: 20 May 2017 at 1:10pm
Sign me up

Like Ian I am interested for my Raspberry pi collection.

On a side note there is a bit of market for these with a usb for Raspberry. I only say bit because a competitor or two has the product or people on diy talk about making there own. Not sure if anybody sells them.

The only problem with the Raspberry pi is due to its low cost people tend to be cheap as well.


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Steve

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Various bits of GSP Kit ..well two so far, unless you count the cables that is.


Posted By: peterb
Date Posted: 26 May 2017 at 12:55pm
How timely i came across this thread, I was contemplating breadboarding a LM317 transistor combination to replace the SMPS currently supplying my PI HiBerry DAC, but it seems GS is going to save me the effort! (but not my bank balance!)

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Peter
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Dual 505-1, Cyrus CD T, DIY 80W MosFet amp and PreAmp, 2xKEF 103.2


Posted By: BackinBlack
Date Posted: 26 May 2017 at 2:18pm
So now we have 6 with a declared interest, should we turn this interest into orders to progress things?




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Just listen, if it sounds good to you, enjoy it.


Posted By: ICL1P
Date Posted: 26 May 2017 at 5:43pm
Originally posted by BackinBlack BackinBlack wrote:

So now we have 6 with a declared interest, should we turn this interest into orders to progress things?


Should I want one for each of my RPis?

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Ifor
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Reflex M, CuSat50, Majestic DAC, a Proprius pair.


Posted By: Ash
Date Posted: 26 May 2017 at 6:03pm
I would buy a GSP 5V PSU with a Bitzie power wire to get the very best out of my Bitzie. The difference between Majestic and Bitzie would be smaller than ever and I use USB most of the time anyway.


Posted By: Graham Slee
Date Posted: 26 May 2017 at 7:13pm
Thank you for your support gentlemen! I have now gathered all the parts and I've drawn the circuit diagram. I will be drafting the PCB on one of my CAD programs next.


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Posted By: Richardl60
Date Posted: 26 May 2017 at 7:36pm
Whilst I am not aware I have any audio devices which use this power supply it will be interesting to hear feedback from those that do!


Posted By: msphil
Date Posted: 27 May 2017 at 12:41pm
Originally posted by Graham Slee Graham Slee wrote:

Thank you for your support gentlemen! I have now gathered all the parts and I've drawn the circuit diagram. I will be drafting the PCB on one of my CAD programs next.

 
ClapThumbs Up Thanks to Jon I know that a power supply can make a lot of difference on the Squeezebox Touch in my lounge. I've ordered two from Graham when they can be done, and I'm really looking forward to hearing them on both my systems. I'll be glad to give feedback when I can.


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'You are, through your soul not your body, a human being.'


Posted By: BackinBlack
Date Posted: 27 May 2017 at 4:38pm
From your comments Phil, it sounds as though you're ahead of the game.
As Graham notes in his introduction, one thing that we here should all have come to know is that a good robust power supply lies at the heart of any decent audio device, whether it be digital or analogue.



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Just listen, if it sounds good to you, enjoy it.


Posted By: Graham Slee
Date Posted: 07 Jun 2017 at 12:12pm
PCB artworked and now awaiting the prototype board(s) from the UK manufacturer. As good old Kirchhoff recognised that signal current flows in circles I thought it advantageous to squeeze in the highest voltage reservoir capacitors as possible. The reason being that low voltage capacitors don't have the capacitance stability that high voltage ones have. This means that high signal frequencies see a different capacitance to low signal frequencies, and certainly in analogue the difference can be heard. Digital may be different, but we'll see (erm, hear).


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Posted By: Graham Slee
Date Posted: 11 Jun 2017 at 12:03pm
And now....

Populating the board and starting with the surface mount power management stage which is ridiculously difficult to see without my eyeglass (used to have 3 but can't find one...)

power-supply-management-ic

The small one is the IC and the big one a 9 Amp MOSFET!

Length of IC is 2.9mm, less than one eighth of an inch, and a complete ******* to solder.


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Posted By: ServerBaboon
Date Posted: 11 Jun 2017 at 12:40pm
Sounds like usb microsocope  required.



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Steve

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Various bits of GSP Kit ..well two so far, unless you count the cables that is.


Posted By: msphil
Date Posted: 11 Jun 2017 at 1:49pm
It's great to see things are moving on. Looks good to me.

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'You are, through your soul not your body, a human being.'


Posted By: BackinBlack
Date Posted: 11 Jun 2017 at 2:01pm
Thumbs Up

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Just listen, if it sounds good to you, enjoy it.


Posted By: Ash
Date Posted: 11 Jun 2017 at 5:53pm
I look forward to seeing this product develop. Will be great to have a power supply for the Bitzie.


Posted By: Graham Slee
Date Posted: 11 Jun 2017 at 10:18pm
Next step to wire it all up and test it.



Then "wrap metal" round it.

By the way, it's upside down right now. The heatsink will be at the top.



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Posted By: msphil
Date Posted: 14 Jun 2017 at 4:45pm
You are welcome to try my testing facilities. It's looking really good now. Can't wait!

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'You are, through your soul not your body, a human being.'


Posted By: BackinBlack
Date Posted: 14 Jun 2017 at 5:28pm
Originally posted by Graham Slee Graham Slee wrote:

Next step to wire it all up and test it.



Then "wrap metal" round it.

By the way, it's upside down right now. The heatsink will be at the top.


That's looks like a lot of heatsink - COOL!


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Just listen, if it sounds good to you, enjoy it.


Posted By: Fatmangolf
Date Posted: 14 Jun 2017 at 7:45pm
It looks the business!


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Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Richardl60
Date Posted: 14 Jun 2017 at 7:54pm
It is difficult to judge physical size but is there any reason why metal opposed to the PSUs plastic casing?


Posted By: Graham Slee
Date Posted: 14 Jun 2017 at 9:52pm
Circuit board troubleshooting complete. Voltage tests now done along with under/over voltage protection. Next up is the load test.

The PSU will then be tested again using an alternative transformer, but still from our nearby manufacturer (so you can depend on it being British made).


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Posted By: Graham Slee
Date Posted: 15 Jun 2017 at 12:24am
Originally posted by Richardl60 Richardl60 wrote:

It is difficult to judge physical size but is there any reason why metal opposed to the PSUs plastic casing?


British made ABS is rated at 60 degrees celsius whereas Chinese made ABS is rated at a much higher temperature. The exact temperature being whatever is convenient for it to gain underwriters or Canadian approval. Physics doesn't seem to enter the equation.

ABS like uPVC starts to soften at 60 C and any transformer in contact with it - which it would be if mounted in it - must not exceed 60 C.

In a fault condition the fault must be minimised by a protective device (fuse) such that the case does not exceed 60 C. This is why the PSU1 is rated at 200mA output current because the primary fuse had to be rated at 63mA (125mA US) such that in the worst fault possible it would open preventing the unit exceeding 60 C. If the temperature could go higher under worst case fault conditions, the PSU1 could have been rated at nearly 1 amp, like many ABS Chinese PSUs are . . .

The above being required under its IEC60950 approval. That's a proper approval by engineers . . .

With the 5V 3A PSU (now with 3.3V too) we want 3 amps. In a worst case fault condition I can already see the possibility of it getting hotter prior to the fuse opening, so forget ABS (ABS being used for injection moulding).

It is far easier to use a metal case, which also affords heat dissipation. And another thing which makes life easier is to mains earth the metal case such that it complies with IEC60950 without jumping through the many hoops a double insulated PSU requires.

This power supply will not have a IEC60950 approval, but will fully meet with the standard. Why not? If I did get it approved it would cost me £10,000 or thereabouts, and with only around 10 customers it would increase its cost by £1,000, and with margins it would probably end up being priced at £2500.

So this one will not be offered in the main site but on here only.

Since posting the photo I realised that the Proprius style case would not only be a suitable size (there you go Richard - that tells you how big it is), but will probably also heatsink the power supply sufficiently (and look better into the bargain).



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Posted By: peterb
Date Posted: 15 Jun 2017 at 8:34am
Are thermal cutouts not allowed/accepted practice?



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Peter
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Dual 505-1, Cyrus CD T, DIY 80W MosFet amp and PreAmp, 2xKEF 103.2


Posted By: Graham Slee
Date Posted: 15 Jun 2017 at 9:54am
Thermal fuses are allowed, and we now use the resetable type in the PSU1 transformer primary, but it was originally designed with a fuse and to change its rating now would involve it being retested at a cost of £10,000 minimum. It's a bit like a stranger inviting himself into your business and deciding he's profit sharing with you, except that in my case, and the addition of recurring fees, it would be something like 1000%. I think it is called bleeding you dry.


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Posted By: BackinBlack
Date Posted: 15 Jun 2017 at 11:49am
One might ask how they justify testing costs of £10,000 and how even the "larger" UK manufacturers cope with such a cost. Or perhaps they don't?

Curious as ever,
Ian


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Just listen, if it sounds good to you, enjoy it.


Posted By: Richardl60
Date Posted: 21 Jun 2017 at 9:26pm
I am on the mailing list for a Cumbrian Accessories supplier and note in their latest catalogue they have a new multi-voltage, apparently universal power supply.

There are many brands incl GSP in the compatibility list.

It is relatively large and aroun £500 from memory, plus cables I suspect.

Looks like the new power supply has some competition, albeit at a price and size!


Posted By: Chris Firth
Date Posted: 21 Jun 2017 at 9:50pm
Originally posted by Richardl60 Richardl60 wrote:

I am on the mailing list for a Cumbrian Accessories supplier and note in their latest catalogue they have a new multi-voltage, apparently universal power supply.

There are many brands incl GSP in the compatibility list.

It is relatively large and aroun £500 from memory, plus cables I suspect.

Looks like the new power supply has some competition, albeit at a price and size!


It's SMPS, and the likelihood is that it causes more power problems than it allegedly cures.



Posted By: peterb
Date Posted: 22 Jun 2017 at 9:33am
Not that it is any comfort but 'testing' costs are a fact of life for designers and manufacturers. I used to design in the gas industry and it was very galling to pay for the privilege of your design being tested by those who generally knew less about the subject that you did!
I am afraid it is the price that is paid in an attempt to stop the cowboys and the opportunists, in the name of safety. Unfortunately it doesn't stop the criminals putting people at risk.


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Peter
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Dual 505-1, Cyrus CD T, DIY 80W MosFet amp and PreAmp, 2xKEF 103.2


Posted By: jwatson
Date Posted: 22 Jun 2017 at 1:14pm
The use of an XLR connector for power in an audio system just seems like a connection accident waiting to happen... 

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"I bought some more old vinyl today 'cos old vinyl won't ever let you down"
Majestic DAC -> {Proprius -> Tannoy Stirling | Solo UL -> HD820}


Posted By: Graham Slee
Date Posted: 22 Jun 2017 at 2:48pm
Originally posted by peterb peterb wrote:

I am afraid it is the price that is paid in an attempt to stop the cowboys and the opportunists, in the name of safety. Unfortunately it doesn't stop the criminals putting people at risk.


You will never stop the cowboys, opportunists and "crminals" in the hi-fi industry. There are too many people unwittingly supporting them by buying their products.

A few years ago I was told of a product in which the mains (live and neutral) was applied to a board where the spacing between solder pads was only suitable for signal level voltages. The designer obviously had no knowledge of creepage and clearance distances as required for the safety of the user or for the building in which it would be used (perhaps that could strike a chord with recent events?).

This designer and his company had a cult following and was definitely making good money out of his poor knowledge of customer safety.

But that seems to be the accepted practice these days. It is by luck alone that injury or worse does not happen with most of these products.


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Posted By: Graham Slee
Date Posted: 22 Jun 2017 at 3:00pm
Originally posted by jwatson jwatson wrote:

The use of an XLR connector for power in an audio system just seems like a connection accident waiting to happen... 


There were mains rated XLRs and they look like this . . .



Image courtesy of Canford Audio

However, it looks like these have been outlawed and are no longer manufactured.




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Posted By: Richardl60
Date Posted: 22 Jun 2017 at 6:54pm
Maybe I had missed the point on the XLR I had viewed and presumed it was the same type of socket as from Graham's psu but that is a Din plug I believe?


Posted By: Fatmangolf
Date Posted: 22 Jun 2017 at 8:08pm
It is easy for us to expect and assume GSP's high standards of construction will be to the same standard elsewhere. Best to check things!

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Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Graham Slee
Date Posted: 22 Jun 2017 at 8:15pm
The PSU1 DIN socket is on the low voltage DC output. This is OK. If it were on the mains input side we would be guilty of gross negligence!


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Posted By: Richardl60
Date Posted: 22 Jun 2017 at 8:39pm
Yes as with the XLR on the 'other' product - the mains facing socket is an IEC.


Posted By: Graham Slee
Date Posted: 24 Jun 2017 at 9:55am
James was talking about XLRs used as mains connectors and I illustrated the type which are mains rated, but these have probably been withdrawn over safety concerns, or legislation.

Fully insulated connectors are safer from an electric shock perspective, but plastics will melt and then can cause fires if over stressed.

Power supplies should never be covered or "insulated" with extraneous items which could cause them to overheat. They rely on air being in contact with them to dissipate heat, and on hot days this is more important than ever. We advise not to place a PSU1 on carpet as the pile can contact the base of the case which prevents air flow and results in a loss of cooling.


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Posted By: Richardl60
Date Posted: 24 Jun 2017 at 12:58pm
I must admit I do quite like Graham's tower block arrangement for multiple PSUs and whilst I couldn't accommodate one maybe that is something you could add to your sales catalogue?


Posted By: jwatson
Date Posted: 24 Jun 2017 at 1:19pm
Hello Graham,

I was actually referring to the use of an XLR for the DC connection (but seem to have pushed us off  topic in doing so... apologies for that) .  While I'd agree that there is little doubt that an XLR connector is quite suitable electrically in a low voltage / current application, I'm just not sure that it's the most appropriate choice in an environment in which they’re widely used for audio. I've spent many years round the back of equipment racks in radio stations around the world (including the BBC) and have never seen an XLR used for anything else but audio.  I'm currently engaged in the design of military systems in which all connectors are keyed (i.e. ludicrously expensive) to prevent accidental connections.  To see an XLR used for power just looks wrong...

Kind regards

James


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"I bought some more old vinyl today 'cos old vinyl won't ever let you down"
Majestic DAC -> {Proprius -> Tannoy Stirling | Solo UL -> HD820}


Posted By: Richardl60
Date Posted: 24 Jun 2017 at 2:06pm
I agree though have never seen any with 240v fed through them.


Posted By: Graham Slee
Date Posted: 24 Jun 2017 at 9:08pm
I assume you mean a three pin XLR? What does XLR refer to? Ground Left Right? Well, pin 1 is always ground. But today it is almost invariably used for balanced audio (ground +phase -phase) or DMX (ground -phase +phase).

So is the use of a 5-pin Neutrik plug and socket for DC power wrong? Or a 4 pin mini "XLR"? If so, I am also in the wrong.


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Posted By: jwatson
Date Posted: 25 Jun 2017 at 1:33pm
Hello Graham,

I was specifically referring to the 3-pin XLR seen on the website in the post that kicked off this sub-thread.  This appears at one end of a cable assembly with a DC Power plug at the other.  There’s nothing electrically wrong with this it just seems an unusual choice in a system that uses the same type of  connector for balanced audio.  

DINs have always been a free for all in terms of application / pinning.  The last time I came across one was on a site a few weeks ago on some older equipment where it was used for RS232 remote control.  Previously I’ve only seen them used for audio interfaces on commercial equipment, generally with vendor specific pinning.

Wikipedia notes that 3-pin XLRs are used for power connections so if it helps kill this sub-thread off I’m happy to withdraw my original comment (but they still wouldn’t be my first choice :-) )

Kind regards.

James


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"I bought some more old vinyl today 'cos old vinyl won't ever let you down"
Majestic DAC -> {Proprius -> Tannoy Stirling | Solo UL -> HD820}


Posted By: Graham Slee
Date Posted: 25 Jun 2017 at 1:39pm
I agree that it doesn't seem right using 3-pin XLRs for DC power. It's something I wouldn't do. When I use 5 pin or 4 pin mini "XLRs" for power I always use them counter convention - outputs are usually on pins - inputs are sockets. I use them the other way round, and it makes sense to do so because "inline" sockets aren't easy to short out.


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Posted By: Graham Slee
Date Posted: 11 Jul 2017 at 3:38pm
Initial test results imminent!


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Posted By: BackinBlack
Date Posted: 11 Jul 2017 at 3:43pm
Clap I await with interest...

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Just listen, if it sounds good to you, enjoy it.


Posted By: msphil
Date Posted: 11 Jul 2017 at 4:00pm
Looking forward to getting mine! Thumbs Up

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'You are, through your soul not your body, a human being.'


Posted By: Graham Slee
Date Posted: 11 Jul 2017 at 11:03pm
Here goes.

5V rail tested at 3A.
Output with OV/UV protection 4.84V
Without protection 4.93V

5V rail tested at 2.2A.
Output with OV/UV protection 4.88V
Without protection 4.95V

5V rail tested at 1.5A.
Output with OV/UV protection 4.92V
Without protection 4.97V

5V rail tested at 10mA (no load).
Output with OV/UV protection 5.01V
Without protection 5.01V

Output with OV/UV protection means the measured output after the MOSFET switch which is driven by the overvoltage/undervoltage (OV/UV) detector IC.

Like all MOSFETs it has a finite on resistance which will affect the load regulation. Here at 3A the MOSFET on resistance makes load regulation worse by 2% so load regulation becomes 3% (max).

OV/UV protection can be left off if the best possible load regulation is required, but there would be no protection against over voltage or under voltage should the power supply develop an internal fault. Or if there was an ESD (static on mains) glitch sufficient to overcome the regulators.

The on resistance and therefore the output resistance with OV/UV protection is 0.031 Ohms.

3.3V rail tested at 3A.
Output with OV/UV protection 3.17V
Without protection 3.29V

3.3V rail tested at 10mA (no load).
Output with OV/UV protection 3.305V
Without protection 3.305V

See above notes about load regulation versus output OV/UV protection.

In this case because of the lower gate drive on the 3.3V rail MOSFET the load regulation is slightly worse at approx. 4%. The on resistance/output resistance being 0.04 Ohms.

Again, OV/UV protection can be left off at the customer's own risk.

The OV/UV protection currently set opperates at

5V rail: OV 5.24V; UV 4.3V measured off-load

3.3V rail: OV 3.65V; UV 2.75V measured off-load

These voltages subject to the load regulation percentages quoted above. EG they will fall on load by the quoted percentages.

A power-on LED is provided. Additionally OV/UV fault LEDs, which will only light in the event of a fault such as a damaged voltage regulator.

Each voltage regulator has built in protection against shorts or over temperature.

Each voltage regulator (5V and 3.3V) is an adjustable low noise extended high frequency ripple rejection device. The usual 10uF capacitor which further reduces noise (as indicated in its data sheet) decouples the adjust pin to ground.

The input circuit is a toroidal transformer with conventional bridge rectifier and reservoir/filter capacitors.

There is a tendency for PSU manufacturers to boast about the number of micro-farads of capacitance. Provided the capacitance is sufficient to minimise the ripple voltage such that the dropout voltage of the regulators is not breached, then excess capacitance is simply a waste.

By using the correct calculated values it has been possible to use higher voltage capacitors which have the advantage of greater capacitance stability with increasing frequency.

Additionally, the dielectric absorption is lower because of the lower tangent of loss angle/dissipation factor.

As all currents flow in circles the dynamic signal current returns to its origin at the filter capacitor positive terminal via the capacitor itself - where else could it go? Therefore the chosen capacitance and voltage should provide better performance than an excess capacitance design.

The filter capacitors are rated more than adequately for the ripple current.

Ceramic capacitors are positioned strategically to provide a low impedance return path at high frequencies.

The next stage will involve corrections to the PCB and the dimensioning of the front and rear panels to have some made.

All comments or questions will be appreciated.

(I must add that the power supply will do a total current of 3A, and not 3A each rail, which would make 6A)



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Not simple enough for Google-Bot to understand...


Posted By: Ash
Date Posted: 12 Jul 2017 at 12:01am
Price and availability date TBC?

Still interested in this combined with a Powerwire for my Bitzie.


Posted By: Fatmangolf
Date Posted: 12 Jul 2017 at 10:53pm
I'm not quite licking my lips at this but my ears are ready to audition the new PSU. Well done Ash for asking the questions for me!


-------------
Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Graham Slee
Date Posted: 13 Jul 2017 at 12:09pm
Originally posted by Ash Ash wrote:

Price and availability date TBC?


Correct, TBC.

I don't want to speculate. There are changes which will have to be made to make testing a lot easier, because we like to test every function so the received product is truly professional. We also have another transformer which has been designed to make the product fit a Proprius style case (for the heatsinking). We also need to find out from our transformer manufacturer if an internal resettable winding fuse can be incorporated. Lots to do, as usual.


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Not simple enough for Google-Bot to understand...


Posted By: msphil
Date Posted: 05 Aug 2017 at 4:06pm
Originally posted by Graham Slee Graham Slee wrote:

Originally posted by Ash Ash wrote:

Price and availability date TBC?


Correct, TBC.

I don't want to speculate. There are changes which will have to be made to make testing a lot easier, because we like to test every function so the received product is truly professional. We also have another transformer which has been designed to make the product fit a Proprius style case (for the heatsinking). We also need to find out from our transformer manufacturer if an internal resettable winding fuse can be incorporated. Lots to do, as usual.

Any progress on this yet Graham? I'm happy to try out any prototype and post a report. Alternatively, you can always pop over and see what it sounds like here. 

Remember I have two of the final product on order. Thanks to Jon I know how good a better power supply can sound on my Squeezebox touch.


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'You are, through your soul not your body, a human being.'


Posted By: Graham Slee
Date Posted: 05 Aug 2017 at 7:37pm
I'm going to have to modify the board to put in some trimmers so the voltage can be set, or upset to test the under/over voltage protection. Also I'm testing a different transformer in the hopes we can use the same style case as a Proprius. With that done I then need to get a front and rear panel punched and tried out, and if everything fits and seems to make sense it will take a trip to Chesterfield for a couple of weeks of Phil testing Big smile




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Posted By: msphil
Date Posted: 08 Aug 2017 at 1:28pm
Sounds good to me.

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'You are, through your soul not your body, a human being.'


Posted By: ICL1P
Date Posted: 08 Aug 2017 at 4:56pm
Originally posted by msphil msphil wrote:

Sounds good to me.

But you haven't heard it yet Phil.

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Ifor
=====
Reflex M, CuSat50, Majestic DAC, a Proprius pair.


Posted By: msphil
Date Posted: 08 Aug 2017 at 7:00pm
True, but then I have heard a temporary version that Jon kindly made for me that didn't have a case but made a noticeable difference to the sound of my hi-fi. Based on this I asked if John C could do one for me. This in turn has led to Graham kindly becoming involved.

When you consider that  everything in my hi-fi system, with the exception of the Squeezebox Touch and my PMC Fact 8 speakers, are made by GSP you will appreciate my faith that they will get it right.  any forum member who is going to be in the Chesterfield area is welcome drop me a private message and call in and hear for themselves.


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'You are, through your soul not your body, a human being.'


Posted By: Fatmangolf
Date Posted: 09 Aug 2017 at 9:52pm
Phil is right I am sure about the potential benefits of a GSP 5V PSU for the Squeezebox Touch we both use in our hifi's. I knew Phil would appreciate a copy of the PSU I had made for my system and was surprised by how much better my DIY unit sounded than the Logitech PSU when I heard the comparison through Phil's Fact 8 loudspeakers. With those improvements in the music I heard taken to another level (or three!) by Graham, I am looking forward to getting a production model myself and think Phil's input will help us all.



-------------
Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Graham Slee
Date Posted: 09 Aug 2017 at 10:35pm
Such faith Shocked


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Not simple enough for Google-Bot to understand...


Posted By: Fatmangolf
Date Posted: 09 Aug 2017 at 11:31pm
Graham, it's been rewarded every time!



-------------
Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Ash
Date Posted: 10 Aug 2017 at 12:50pm
I'll buy it straight up and blind, like all the other GS products I've purchased.


Posted By: msphil
Date Posted: 10 Aug 2017 at 5:54pm
I have no complaints about any of the other GSP kit I've bought so why should this be any different?

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'You are, through your soul not your body, a human being.'


Posted By: BackinBlack
Date Posted: 10 Aug 2017 at 9:34pm
Our faith in Grahams products is well founded, they simply deliver good sound, nothing added, nothing taken away. What more might you want?


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Just listen, if it sounds good to you, enjoy it.


Posted By: Ash
Date Posted: 24 Aug 2017 at 8:19pm
Any progress? My Bitzie is eagerly waiting... Wink


Posted By: Graham Slee
Date Posted: 25 Aug 2017 at 1:49pm
Had a lot of other duties recently which have prevented progress but hopefully those are at an end (he says with bated breath...)


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Not simple enough for Google-Bot to understand...


Posted By: Ash
Date Posted: 04 Sep 2017 at 10:29pm
Do you think this will be released next year?


Posted By: Ernie
Date Posted: 09 Sep 2017 at 8:57am
Hi All,
Just joining the thread to get updates. I'm interested in powering a Raspberry Pi.

Btw question for RPi users, optical or coax?

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There are 10 kinds of people. Those who understand binary and those who don't.


Posted By: ICL1P
Date Posted: 09 Sep 2017 at 9:14am
Originally posted by Ernie Ernie wrote:

Hi All,
Just joining the thread to get updates. I'm interested in powering a Raspberry Pi.

Btw question for RPi users, optical or coax?

CuSat50

-------------
Ifor
=====
Reflex M, CuSat50, Majestic DAC, a Proprius pair.


Posted By: BackinBlack
Date Posted: 10 Sep 2017 at 5:20pm
Originally posted by ICL1P ICL1P wrote:

Originally posted by Ernie Ernie wrote:

Hi All,
Just joining the thread to get updates. I'm interested in powering a Raspberry Pi.

Btw question for RPi users, optical or coax?

CuSat50


+1 for CuSat50


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Just listen, if it sounds good to you, enjoy it.


Posted By: Ernie
Date Posted: 10 Sep 2017 at 5:34pm


+1 for CuSat50
[/QUOTE]

Interesting, thought a bit of isolation would have been better and would have gone optical.

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There are 10 kinds of people. Those who understand binary and those who don't.


Posted By: BackinBlack
Date Posted: 10 Sep 2017 at 7:31pm
The Majestic SPDIF inputs have an input isolation transformer, so no need to worry about extra isolation.


-------------
Just listen, if it sounds good to you, enjoy it.


Posted By: Ash
Date Posted: 09 Oct 2017 at 4:47pm
Any more progress on this product Graham?


Posted By: Graham Slee
Date Posted: 09 Oct 2017 at 7:36pm
John was supposed to be taking a lash-up round to Phil's for comment. No good productionizing it if it doesn't do the business. Awaiting results.


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Not simple enough for Google-Bot to understand...


Posted By: Ash
Date Posted: 09 Oct 2017 at 11:04pm
Great. I'd like to hook it up to my Bitzie via a Powerwire so I get the very best sound out of the Bitzie.


Posted By: msphil
Date Posted: 10 Oct 2017 at 1:23pm
Originally posted by Graham Slee Graham Slee wrote:

John was supposed to be taking a lash-up round to Phil's for comment. No good productionizing it if it doesn't do the business. Awaiting results.

I will be happy to see John any time he is able to get here. I’m really looking forward to trying it out and will give feedback as soon as I can.



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'You are, through your soul not your body, a human being.'


Posted By: ServerBaboon
Date Posted: 23 Nov 2017 at 9:06am
Originally posted by Ernie Ernie wrote:



Interesting, thought a bit of isolation would have been better and would have gone optical.

I recently switched to an Allo Digi One and they have removed the Optical on their board for for Jitter reasons. They have spent a lot of time and effort on jitter reduction (their words).


Any updates on the 5v PSU? Smile


-------------
Steve

-------------

Various bits of GSP Kit ..well two so far, unless you count the cables that is.


Posted By: Ash
Date Posted: 24 Nov 2017 at 10:03pm
Yeah, any progress with this PSU? I want to try my Bitzie with a top notch power supply...


Posted By: msphil
Date Posted: 05 Dec 2017 at 9:04pm

One or two forum members such as Ash and Steve have recently been asking whether there is any progress in the 5v 3A PSU that Graham has been developing. As some of you may know I was asked and if I could test the prototype on my 2 Squeezebox Touch's. I have now had a fully workable version of the 5v PSU for about two weeks now and I've been giving it an opportunity to partially burn in before writing this early review.


My first impressions have been extremely good and my main feeling, since starting to use it, is that my hi-fi has never sounded better. To be honest if you had told me a couple of years ago that a different power supply could make such a difference I would not have believed it possible. However, the sound that I am getting with this prototype is now unbelievably detailed, vibrant and musical compared to the PSU that originally came with the Squeezebox.


A short while ago my eyes were opened by Jon (Berg) who kindly made me a temporary Squeezebox PSU to his own design. This produced a much more detailed sound and it made me notice things that I had never heard before in my music. Now however the prototype that Graham has produced extends on this even further by making the music more detailed, with warmth, fullness and with a bass that extracts every grain of depth and vibrancy available. As it has burnt in it seems to have become much more musical and satisfying as is the way with all GSP equipment.


Exactly when this power supply will become available I am not sure. There are probably decisions to be made on the casing and other details. However, in its present state, I do know that it is already worth having. It certainly works beautifully with my Squeezebox and it is something that I've been waiting to get for quite some time.



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'You are, through your soul not your body, a human being.'


Posted By: Ash
Date Posted: 06 Dec 2017 at 9:15am
Superb. This product is going to lift the Bitzie to an even greater performance level. Permanent power on, well regulated supply, not a SMPS so reduced noise too. I will pair this with a powerwire and then the Bitzie will probably pretty much match the Majestic USB. I look forward to seeing it take shape. Geek


Posted By: Ash
Date Posted: 08 Dec 2017 at 12:10am
Any idea on a release date for this Graham? I have the dosh waiting. Smile


Posted By: Fatmangolf
Date Posted: 08 Dec 2017 at 12:59pm
I foresee a happy birthday for JB

-------------
Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Ash
Date Posted: 16 Dec 2017 at 8:28pm
I must say that I'm really looking forward to more news on this product. Embarrassed


Posted By: msphil
Date Posted: 17 Dec 2017 at 6:58pm

For a short while now I haven't been able to listen to any music. However over the last couple of days I have been able to get back to it and have been surprised that there have been some noticeable changes to the sound I am getting. I can only put this down to the fact that the PSU is now reasonably well burnt in. I have now had the power supply for just under four weeks. As a result I thought I had better make a second report to those of you that are interested.


As you know, I was very impressed with the improvement in sound that I was getting with the new PSU which now powers my Squeezebox Touch (see my first report above). Before it was very detailed and had improved the bass and general musicality. Now however I am surprised to find that whilst retaining all its past benefits I am in addition getting a fullness, depth, improved balance and a greater feeling of ambience and location in the music. The sound has a greater cohesion and naturalness. It is to some extent less analytical than it was which applies over a whole range of music.


Most music, even from older vintage recordings sound more natural. I have heard some Ella Fitzgerald and Etta James that have improved greatly. Newer recordings have a presence and a silence which puts you amongst the music which has in turn improved the sound stage. It is very hard to explain but if you hear it I'm sure you would immediately notice the difference. In some recordings it is as if, because of the naturalness in the sound, some elements of the music have become less prominent and have taken a more natural place in the general balance. Because of this I believe that my music has taken on a sound that is, unbelievably, even more musical than it was.


As you will appreciate all of this is very subjective and subtle but was very noticeable to me when I returned to my hi-fi after not listening to it for over a week. As I've said before I cannot vouch for the effect that it would have on other pieces of equipment but I can say I thoroughly recommend it for the Squeezebox Touch. I can also say that for me it is worth every penny that it will cost. I intend to have two of the finished versions. One of them will be for my speaker system in the lounge, and the other for my bedroom headphone system which also uses a Squeezebox.



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'You are, through your soul not your body, a human being.'


Posted By: Richardl60
Date Posted: 17 Dec 2017 at 7:18pm
Phil this is what I have tended to find with cable burn in; the sense of integration and naturalness.


Posted By: Fatmangolf
Date Posted: 18 Dec 2017 at 5:18pm
Thanks Phil, great to hear how much you are enjoying it. For those of us looking for this performance boost including myself, I must comment that good things come to those who wait. Approve



-------------
Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Ash
Date Posted: 16 Jan 2018 at 10:51pm
Any news?


Posted By: Ash
Date Posted: 12 Feb 2018 at 11:05pm
Progress? Embarrassed


Posted By: Graham Slee
Date Posted: 13 Feb 2018 at 3:00am
Just awaiting Phil to tell me if the inclusion of the resettable output fuse has made any difference to the music. In a short test when John fitted the fuse Phil said he couldn't tell any difference, but I'd like him to tell me/us if after a longer session if he can hear any difference.

The resettable fuse is there so I can fit a crowbar circuit on the output to open the fuse in the event of the power supply voltage going over-voltage (faulty), as I would not want to be sued for the cost of replacing the equipment being used with it.

The first attempt at overvoltage protection used series MOSFETs but their on resistance didn't do any favours to the sound, and the driver chip also detected under-voltage and when the load pulled current the voltage dip triggered it which shut Phil's Squeezebox down. He was rather frustrated by that.


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Not simple enough for Google-Bot to understand...


Posted By: msphil
Date Posted: 13 Feb 2018 at 5:59pm

Hi folks, it has been just a short while since John fitted the resettable fuse. I would have got back to Graham a little earlier but for the fact that my computer has been playing up and will be going back to the Apple workshop to be checked next Monday. As a result I have only been able to play my music intermittently. I have however managed to clock up a few hours of listening.


As I've mentioned in previous posts the PSU has made an enormous difference to the sound of my hi-fi. Especially when you compare it to the standard power supply provided with the Squeezebox Touch. The overall sound has very noticeably improved in all areas. The bass is deeper, detailed and more vibrant. The top and midrange has become more natural and is again very detailed and musical. To my mind there has been no deterioration or difference in the sound quality since the resettable fuse has been fitted. The sound is fantastic and is now better than it has ever been!




-------------
'You are, through your soul not your body, a human being.'


Posted By: Ash
Date Posted: 13 Feb 2018 at 7:43pm
Great. Graham, let me know when I can purchase this product from you. Really want to pair it with my Bitzie and a Lautus powerwire. Then, apart from a different chipset performing the digital to analogue conversion, it will more or less be equivalent to the Majestic.


Posted By: Graham Slee
Date Posted: 13 Feb 2018 at 8:54pm
Aha, 4 projects at once and I was heading for semi-retirement at that LOL


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Not simple enough for Google-Bot to understand...



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