A DIY High Quality Hifi Music Server

[mattjtaylor2809]

Hi Tam,

Many thanks for going to the trouble of outlining the cost go this project. I'm obviously quite naive about hoe much it costs & maybe now understand a bit more why the big boys charge so much.

All this DIY stuff is soo out of my league so it's very interesting to listen to the gurus as you pick up little snippets of info which I think will help me/us in the future make informed decisions.

I'll keep reading with interest.

Cheers

Matthew

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[Tam Nguyen]

Can you tell more about this?   Where you put the added filtering?

 

(I use a firewire multichannel audio interface in my main system.... but a while back I have built a few PCs for people using SoTM PCI card)

hmm, I modified SOTM card, adding filter after USB host controller. Sotm won't warranty when I tell you this

[Tam Nguyen]

Hi Tam,

Many thanks for going to the trouble of outlining the cost go this project. I'm obviously quite naive about hoe much it costs & maybe now understand a bit more why the big boys charge so much.

All this DIY stuff is soo out of my league so it's very interesting to listen to the gurus as you pick up little snippets of info which I think will help me/us in the future make informed decisions.

I'll keep reading with interest.

Cheers

Matthew

Sent from my iPad using Tapatalk

Hi Matthew,

 

Thank you. We all learn from one another.

 

Cheers,

Tam

[davewantsmoore]

hmm, I modified SOTM card, adding filter after USB host controller

 

Yes Can you tell us more?

[Tam Nguyen]

Hi Tam,

Many thanks for going to the trouble of outlining the cost go this project. I'm obviously quite naive about hoe much it costs & maybe now understand a bit more why the big boys charge so much.

All this DIY stuff is soo out of my league so it's very interesting to listen to the gurus as you pick up little snippets of info which I think will help me/us in the future make informed decisions.

I'll keep reading with interest.

Cheers

Matthew

Sent from my iPad using Tapatalk

IMO, the hifi makers need to do their business so it is fine for us to buy good stuff with good money. I just try to avoid the over-priced stuffs and those who provide more false information than true ones.

This is like some have good marketing to sell health/beauty products which have no help nor harm to human bodies with big prices.

 

An example, I made my DC in Main blocker before with under 100$ for good capacitors and some good rating diodes. If putting more capacitance and more capacitors in parallel to reduce ESR and some calculation to handle more than wattage the load needs then that is very safe and no heat. Some make the same one with a couple of capacitors and some diodes with nice case, short 99.999% pure copper wire, etc. and sell for over 1000$. That just does not make good sense. the pure copper wire and nice case have the benefit of marketing only. They does not improve the main functionality of that gear nor cause harms to it either.

 

Looking into good DACs like PS Audio Direct Stream one, they have good ideas, good design, good software, they don't need to use such material stuff because it is not always that the expensive materials improve things. In my music server, I use normal electrical wires with good AWG. If I used silver or gold, they would not make it sound better or worse than normal electrical wire. But if I intend to make things to sell, when I say all the wires I am using inside are gold-plated then people would love my music server more .

Edited July 8, 2015 by Tam Nguyen

[Tam Nguyen]

Yes Can you tell us more?

No special - ferrite beads, chokes, diodes, capacitors but have to be right otherwise, things get worst than improving.

[Tam Nguyen]

Modified Sotm card:

- Replace 12 caps including 3 films replaced by polyester Sprague orange drops and 2 standard USB receptacles by EMI, common mode noise and ESD filtered ones (filters both on power lines and signal lines).

 

5V out from Sotm USB cannot be claimed ultra low noise by measurement. It is low noise but far from being ultra low noise.

Edited August 10, 2015 by Tam Nguyen

[Jventer]

Modified Sotm card:

- Replace 12 caps and 2 USB connectors

Excuse my ignorance please. I thought Sotm is very good, why the need to replace caps and connectors?

[Tam Nguyen]

Hi Jventer,

 

I also think Sotm is good and I like it. But always have room for improvement. My DAC benefits from these modification (DAC's ouput is much less attenuation at high frequencies so the music top end is much stronger and clearer). Maybe some other DACs might not benefit the same by this, I am not so sure.

 

The capacitors used in Sotm are not good quality ones. They are OK but not of the good ones. Basically, not many components in it are of best quality.

 

The USB connectors are standard ones and are OK but you can find better USB connectors/chips (we-online.com) with EMI filter.

 

I am not happy with 5V out from sotm. Eventually I will use another much cleaner 5V (Texas Instruments has some ultra low noise and low ripple regulators which has about 4uV-5uV RMS ripple at current from 700mA up which is good for USB current requirement - about 500mA; the 5V out from sotm is at mV ripple range, not uV) and use only the signal from sotm usb.

Edited August 10, 2015 by Tam Nguyen

[AccuTidal]

Tam,

Thanks for sharing! This is interesting. We have a team here in W.A, currently exploit CA to its max! Pity your is on other side, else it would have been great collaboration!

Chanh.

[Jventer]

Thanks for sharing Tam, I am learning so much

[Guest]

Cool thread, well done

Cheers

Matt

[TP1]

Thanks for sharing Tam!

[TP1]

I am not happy with 5V out from sotm. .

Have you tried turning off SOTM 5V power and injecting clean 5V power from another source using an interface such as this?. ( There are a number or ways to do it)

Sent from my iPad using Tapatalk

[Tam Nguyen]

Tam,

Thanks for sharing! This is interesting. We have a team here in W.A, currently exploit CA to its max! Pity your is on other side, else it would have been great collaboration!

Chanh.

Thanks, Chanh for this.

Tam

[Tam Nguyen]

Have you tried turning off SOTM 5V power and injecting clean 5V power from another source using an interface such as this?. ( There are a number or ways to do it)

Hi Tasso,

 

Nice cable. May I know where to get that one?

 

I have done that from 5V out from another port of SOTM USB card (one port for signal only and 1 port for 5V only; 2 cables running from 2 ports and will be terminated at DAC side with a small board with filters on it for both signal and power, to make sure any RFI picked up on the cable being cleaned again just before the DAC, and USB 2.0 type B male connector. The idea is not allowing signal and power running together in the same cable). However, I don't consider 5V from Sotm card clean enough to the grade which the DAC needs.

 

I have ordered this evaluation regulator board from TI ( http://www.ti.com/tool/LP38798EVM#Technical Documents) with good specs and enough current for my DAC.

Ultra-Low Output Noise: 5 µVRMS (10Hz to 100kHz)

High PSRR: 90dB at 10 kHz, 60dB at 100 kHz

Maximum Operating Input Voltage: 20.0V

Maximum Operating Output Current: 800mA

 

When it comes I will put it in the music server for 5V out.

 

I also use a couple of this one along the way for filtering out EMI on DC on the PSU of the music server

http://www.farnell.com/datasheets/1481605.pdf.

 

It can reduce EMI down to 60-80dB. I put one at the end of my DIY USB cable right before going to DAC to make sure RFI picked up on cable if any will be cleaned on 5V before going to the DAC.

 

 

 

 

Edited August 11, 2015 by Tam Nguyen

[TP1]

Hi Tasso,

 

Nice cable. May I know where to get that one?

 

I have done that from 5V out from another port of SOTM USB card (one port for signal only and 1 port for 5V only; 2 cables running from 2 ports and will be terminated at DAC side with a small board with filters on it for both signal and power, to make sure any RFI picked up on the cable being cleaned again just before the DAC, and USB 2.0 type B male connector. The idea is not allowing signal and power running together in the same cable). However, I don't consider 5V from Sotm card clean enough to the grade which the DAC needs.

 

I have ordered this evaluation regulator board from TI ( http://www.ti.com/tool/LP38798EVM#Technical Documents) with good specs and enough current for my DAC.

Ultra-Low Output Noise: 5 µVRMS (10Hz to 100kHz)

High PSRR: 90dB at 10 kHz, 60dB at 100 kHz

Maximum Operating Input Voltage: 20.0V

Maximum Operating Output Current: 800mA

 

When it comes I will put it in the music server for 5V out.

 

I also use a couple of this one along the way for filtering out EMI on DC on the PSU of the music server

http://www.farnell.com/datasheets/1481605.pdf.

 

It can reduce EMI down to 60-80dB. I put one at the end of my DIY USB cable right before going to DAC to make sure RFI picked up on cable if any will be cleaned on 5V before going to the DAC.

 

 

 

 

 

 

That cable is just one that Teradak use with some of their PSU's.  I am now thinking that a better option is a single USB cable with one end hard wired  into the Sotm ( for DATA) and the USB  power wires  to a PSU ( for power).  I have also noticed benefits from hard wiring a  silver power input cable to SOTM card directly and removing the Molex Connector. 

 

In terms of PSU , we have noticed outstanding results using choke input to reduce AC ripple as much as possible. 

[acg]

 

In terms of PSU , we have noticed outstanding results using choke input to reduce AC ripple as much as possible. 

 

Tasso, I believe that the choke is effective in changing the shape of the ripple, rather than the size of the ripple.  Although it does reduce the height of the ripple there are much easier and less expensive ways to lower ripple than with a choke.  From what I understand the shape of the ripple following the bridge rectifier is sharp (meaning the presence of high frequencies in the ripple) but the choke after the bridge should leave the ripple looking like waves on an ocean which contain much less high frequency noise and is probably the reason why the linear regulators are more effective.  

 

I am no expert on power supply design, but that is my amateur take on the situation. 

[TP1]

Tasso, I believe that the choke is effective in changing the shape of the ripple, rather than the size of the ripple.  Although it does reduce the height of the ripple there are much easier and less expensive ways to lower ripple than with a choke.  From what I understand the shape of the ripple following the bridge rectifier is sharp (meaning the presence of high frequencies in the ripple) but the choke after the bridge should leave the ripple looking like waves on an ocean which contain much less high frequency noise and is probably the reason why the linear regulators are more effective.  

 

I am no expert on power supply design, but that is my amateur take on the situation. 

 

 

Thanks for that.  The thing about the choke was the greater extent of improvement this brought over other refinements.  John Swenson, a well renowned electronics designer  and expert in this field  recommends choke input for server PSU design as well as for SBT applications. He has done extensive testing  with this and  from what we have experienced, his conclusions seem very compelling.  

[hochopeper]

Thanks for that.  The thing about the choke was the greater extent of improvement this brought over other refinements.  John Swenson, a well renowned electronics designer  and expert in this field  recommends choke input for server PSU design as well as for SBT applications. He has done extensive testing  with this and  from what we have experienced, his conclusions seem very compelling.  

 

Try a CRC filter between transformer and diode bridge. The CRC network is  0.01uF || 0.15uF + 1k all sitting across the diode bridge wires from the transformer. These values are close enough most of the time, but can be adjusted for specific transformers as necessary with some measurements if you've got the gear. See - http://www.diyaudio.com/forums/power-supplies/243100-simple-no-math-transformer-snubber-using-quasimodo-test-jig.html 

 

This could be done in addition to the choke without issue and is low cost (3 components) and easy to remove if you'd like down the track. The link above goes through a procedure to fine tune the value of the resistor to suit your specific transformer to get it optimal, the values above will not give worse (measured) performance.

Edited August 11, 2015 by hochopeper

[acg]

Try a CRC filter between transformer and diode bridge. The CRC network is  0.01uF || 0.15uF + 1k all sitting across the diode bridge wires from the transformer. These values are close enough most of the time, but can be adjusted for specific transformers as necessary with some measurements if you've got the gear. See - http://www.diyaudio.com/forums/power-supplies/243100-simple-no-math-transformer-snubber-using-quasimodo-test-jig.html 

 

This could be done in addition to the choke without issue and is low cost (3 components) and easy to remove if you'd like down the track. The link above goes through a procedure to fine tune the value of the resistor to suit your specific transformer to get it optimal, the values above will not give worse (measured) performance.

 

Chris, do you need that CRC filter if using Schottky diodes?

Edited August 11, 2015 by acg

[hochopeper]

Chris, do you need that CRC filter if using Schottky diodes?

Yes.

Anything other than a textbook ideal transformer has parasitic inductance and every real world diode has parasitic capacitance. So there is always a resonant circuit present. Think of it as a bell. The only difference is some diodes may strike the Bell with a padded malet but the Bell will still ring.

There is no penalty for having it there so no reason not to try it IMO. There is one on the PCB that I gave you too.

Edited August 11, 2015 by hochopeper

[acg]

Yes.

Anything other than a textbook ideal transformer has parasitic inductance and every real world diode has parasitic capacitance. So there is always a resonant circuit present. Think of it as a bell. The only difference is some diodes may strike the Bell with a padded malet but the Bell will still ring.

 

 

Got it.  Excellent example by the way.

 

 

There is no penalty for having it there so no reason not to try it IMO. There is one on the PCB that I gave you too.

 

 

Yes, I saw it there.  I will have to figure something out for some trafos in my other project.  Will read the thread.

 

Thanks Chris!

[Malcolm]

@@hochopeper

Hi Chris

I'm wrong are you talking about a diode snubber ?

Cheers

[TP1]

Try a CRC filter between transformer and diode bridge. The CRC network is  0.01uF || 0.15uF + 1k all sitting across the diode bridge wires from the transformer. These values are close enough most of the time, but can be adjusted for specific transformers as necessary with some measurements if you've got the gear. See - http://www.diyaudio.com/forums/power-supplies/243100-simple-no-math-transformer-snubber-using-quasimodo-test-jig.html 

 

This could be done in addition to the choke without issue and is low cost (3 components) and easy to remove if you'd like down the track. The link above goes through a procedure to fine tune the value of the resistor to suit your specific transformer to get it optimal, the values above will not give worse (measured) performance.

 

 

Thanks Chris - worth a try!