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JLOP 27th September 2012 06:56 PM

What best value PSU for WaveIO USB=>SPDIF board
 
1 Attachment(s)
Hi all

I am expecting my WaveIO XMOS board from Lucian in the next days. It will feed my AD1865 NOS SRPP from Raindrop Hui, internal or external not decided, depending on your advices for PSU.

My technical skills are limited to soldering, so I am trying to find out what are the good solutions keeping on a reasonable budget (<100 $) as powering through USB port is not advised to deliver a good sound :note::note:.

Many solutions available but I cant find a summary to decide and would be glad to get your thoughts
- non regulated PSU
- LM317 or other IC
- Paul Hynes Regulators
- Jung Regulators
- Belleson
- Sjostrom
- Salas Shunt (several available)
- Super Teddy Regulators
- some chineese boards eg Alimentations - AUDIOPHONICS PSUS2 Module d'Alimentation HiFi T-amp 12V LT1083 (sorry in french), there are probably many
- Simply picking the 5V DC from the raindrop board (*)
- and probably many more

(*) see attachment, I don't even know what kind of PSU it is, and if it is powerfull enough to draw the 0,5 A required by the board) - In this case I guess it is better to have the WaveIO inside the DAC case, otherwise could be an external case.

Other questions
- is it better to have the PSU in the WaveIO XMOS box or outside ?
- What is the most adequate solution :
. to pick the juice after the rectification diodes
. or better to have another bridge
. or possibly another transformer + bridge

Thanks a lot for your help :confused:

BR
Jean-Louis

merlin el mago 28th September 2012 11:52 AM

My vote for Salas BiB shunt regulators.

hochopeper 28th September 2012 12:34 PM

Remember there is local IC regs close to each load on the WaveIO board.

I wouldn't use the 5V on the DAC board, it will not have been designed with an extra 0.5A of load in mind.

Salas regs are very good, but, you need to be aware that the size of the reg + heatsink will not be compact like the waveio.

The sjostrom regs and super regulators are very similar (sjostrom has made some alterations to the super reg and provided a tidy pcb layout) and while they're also good, not really designed for 0.5Amp as their ideal operating load. I think super regs are prone to oscillation if the load is capacitive. ie the caps on the waveio board.

There have been good reports of using the LT1085 and similar chip regs. I am building one with LT1085 for my WaveIO. IMO the regulator does not need to be particularly fancy in this location, and money can be better spent elsewhere, so in my opinion go with the LT1085 or even a well designed LM317 reg.

If you are using spdif output, remember to use the isolated spdif output. This will minimise/eliminate ground noise from the computer and waveio getting into the dac digital ground (another reason to not use the on board 5V).

JLOP 28th September 2012 12:53 PM

Quote:

Originally Posted by merlin el mago (Post 3182224)
My vote for Salas BiB shunt regulators.

Thanks Merlin. I will have a closer look but got lost in the 500 pages in the thread. Where is the good place to find the uptodate drawing and BOM for 5v/0.5 A ? I guess I have to study it. Slightly off topic, do you think the AD1865 NOS SRPP Board I am using need the regulation to be updated ?

Quote:

Originally Posted by hochopeper (Post 3182225)
I am building one with LT1085 for my WaveIO

Thanks for your time hochpeper. Would you share your design with me, I can make a PCB but hopeless for designing ?
btw will you set your WaveIO inside the DAC or in another case, and do you use a separate transformer ?

Kind regards from Paris
Jean-Louis

merlin el mago 28th September 2012 01:08 PM

@Jean-Louis

I used LM317 with WaveIO and Salas is far better.

Link to Salas BiB thread support and all information BOM & manual guide in 1st page

http://www.diyaudio.com/forums/power...airytales.html

Tea-Bag GB with PCBs, mini-kits & prices, link:

http://www.diyaudio.com/forums/group...shunt-reg.html

Cheers

Felipe

hochopeper 28th September 2012 01:34 PM

Quote:

Originally Posted by JLOP (Post 3182282)
Thanks Merlin. I will have a closer look but got lost in the 500 pages in the thread. Where is the good place to find the uptodate drawing and BOM for 5v/0.5 A ? I guess I have to study it. Slightly off topic, do you think the AD1865 NOS SRPP Board I am using need the regulation to be updated ?

My only concern for the salas reg for this relatively high current load is that you will be creating a lot of heat and need a lot more space inside your enclosure for it. Will the extra cost in the better reg result in a corresponding audible improvement when using spdif out to drive this DAC? I am not confident that this is the best place to spend the money and it could be spent elsewhere for larger improvement potentially.

Quote:

Originally Posted by JLOP (Post 3182282)
Thanks for your time hochpeper. Would you share your design with me, I can make a PCB but hopeless for designing ?
btw will you set your WaveIO inside the DAC or in another case, and do you use a separate transformer ?

Kind regards from Paris
Jean-Louis

I have basically used the design that is in the datasheet. I had a pcb for LM317 design here that I used for the LT1085 so I don't really have a design that I could share unfortunately. I also used predominantly surface mount parts in mine.

I will have LT1085 with datasheet resistors R1 = 392 ohm and R2 = 1.2k ohm.

I used the +VE side of the psu pcb that was part of this (no longer available) GB - "The Wire" Headphone Amp Build Wiki - diyAudio

There is a PSU schematic and bom attached to that which will give you an idea of +VE LM317 reg design. Though I'm not sure if you're keen on working with surface mount and you'd need to find your own pcb designs as those pcb designs are not published, just the schematic.

For my DAC build I have had made a custom toroid with 6 secondaries to avoid having half an enclosure taken up by transformers. This meant I was able to chose voltage and power ratings for each secondary to suit my needs. So I have a separate secondary that is only supplying the WaveIO.

I am using the WaveIO i2s output with 50mm u.fl leads so I have my WaveIO inside the same enclosure. With SPDIF it is probably much less important.


Chris

merlin el mago 28th September 2012 02:29 PM

@Chris

"My only concern for the salas reg for this relatively high current load is that you will be creating a lot of heat and need a lot more space inside your enclosure for it. Will the extra cost in the better reg result in a corresponding audible improvement when using spdif out to drive this DAC? I am not confident that this is the best place to spend the money and it could be spent elsewhere for larger improvement potentially."

About Salas shunt the amount of heat is the current not spent by the load, if you design in the right way can't be a lot of heat. About where is more important to spend money is only your opinion, as always I think is better to try and after decide if it's worht the money or not.

hochopeper 28th September 2012 02:51 PM

Quote:

Originally Posted by merlin el mago (Post 3182403)
@Chris
About Salas shunt the amount of heat is the current not spent by the load, if you design in the right way can't be a lot of heat. About where is more important to spend money is only your opinion, as always I think is better to try and after decide if it's worht the money or not.

salas reg Q101 heat is dependent on full CCS, in this case I'd be designing for 550mA. Q106 heat will fluctuate with load current changes, impact of this is less. With a rough quick calc using the SSLV spreadsheet, I've just done you have ~8-9W of heat between the two to supply WaveIO. In many cases this is ok, and a price well worth paying.


Chris

JLOP 28th September 2012 02:51 PM

You are right Merlin. I guess in reading thoroughly the thread you have copied I can find a kind of calculator. I will join the GB which will be closing end of october. Until then to test my wave IO I will try a cheaper version as Chris recommends, however the LT is not so cheap.

I will reuse the trasfo (12v or 9v 1A to fit both) and possibly some other components. If the Salas is not conclusive for me, anyhow I will have many opportunities to reuse the 3 boards, including in my DAC.

I'll post you for the differences I hear if some on my Tannoys.

Thanks a lot for your inputs
Jean-Louis

Jogi 28th September 2012 02:52 PM

I can also vote for Salas reg. Very good sound, better as a big stabilized power supply, and better as LT reg. It does make a substantial difference.
Its not that big, PCB is 128x42mm, and the heat producing transistor could be mounted on the enclosure bottom. But it is not that much heat anyway and one can use a small heatsink.
If possible, I would use those to power even my toothbrush:cool:


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