Author Topic: Computer transport interface  (Read 21866 times)

Offline Rob181

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Re: Computer transport interface
« Reply #60 on: May 26, 2014, 06:56:52 AM »
Steven,

Yes agreed, all these DAC's are way too complex.

My next DAC for PC playback will not use any commercial DAC chip or digital filter end of story. It will be a fully discrete DAC and designed from ground up with the highest quality logic, clocks,
thru hole parts etc. You can use whatever resistors you like :) WRT less is more, yes, that is why I am going this way. The tricky part is circuit board layout however I have a pretty good
handle on that with a simple noise cancelling balanced architecture. 

That's about all I can say at this stage.

Zen...I will be watching this with interest...more than interest...very keen to see/hear this DAC...

Z

Offline ozmillsy

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Re: Computer transport interface
« Reply #61 on: May 26, 2014, 10:42:37 AM »
The load is acting on the sine wave oscillator before the squaring circuit.

Supposedly the oscillator should meet its spec with any load down to a few hundred ohms but I did notice
the load makes a big difference to the sine wave OP level.  IOW, when 'unoading' the oscillator, the amplitude
gets larger. Remember I am referring to the sine wave OP pre squaring.

So despite what the so called specs say it all appears very interactive. I got best results with the lightest
possible load.
I wonder if our (longer than recommended) i2s connections are part of this?
 
It's all about the music,, not the equipment.

Offline gamve

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Re: Computer transport interface
« Reply #62 on: May 26, 2014, 11:34:43 AM »
Bargain at $380.00. Not sure what you get for the other 37K.  ;D

Offline zenelectro

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Re: Computer transport interface
« Reply #63 on: May 26, 2014, 06:15:53 PM »
I wonder if our (longer than recommended) i2s connections are part of this?
 

No, that should not have anything to do with it. The clock does not drive the I2S directly.

I had plans to do an I2S driver integrated on the zenclock board but I'm not sure it's worth the hassle.

How many people would be interested in this?

There are many things happening ATM, not the least health issues. Full on year to say the least :)





Offline ozmillsy

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Re: Computer transport interface
« Reply #64 on: May 26, 2014, 06:18:58 PM »
Nah, we've already got great performance, not worth the hassle.
It's all about the music,, not the equipment.

Offline zenelectro

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Re: Computer transport interface
« Reply #65 on: May 26, 2014, 06:20:26 PM »
Bargain at $380.00. Not sure what you get for the other 37K.  ;D

Graham - this is the hi end mate, the more things change, the more they stay the same! :)

Cast your memory back to products like Forsell air reference CD transport. They were -very- expensive, I've had one here apart,
you would be cringing at what you get for the money.  A decent clocked, I2S OP CD 94 would leave it in the dust at tiny fraction of the price.

Z

Offline kajak12

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Re: Computer transport interface
« Reply #66 on: May 26, 2014, 11:36:16 PM »
No, that should not have anything to do with it. The clock does not drive the I2S directly.

I had plans to do an I2S driver integrated on the zenclock board but I'm not sure it's worth the hassle.

How many people would be interested in this?

There are many things happening ATM, not the least health issues. Full on year to say the least :)


Z
I2s driver i will have one  :-*
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline ozmillsy

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Re: Computer transport interface
« Reply #67 on: May 27, 2014, 09:38:21 AM »
I2s driver i will have one  :-*
Danny added a I2S output mod to my CD94,  because I insisted on proper CD94->Dac cabling  (not loose wires, I have kids who like to yank at wires).       If signal strength is a concern, then Danny's mod is an option. 

I don't think we can say the long wire run is out of the picture.   The whole chain is in the mix (right back to choice of CD-R and burner).     But there is probably bigger fish to fry than focussing any more time on optimising the I2S part of the chain.   :)
It's all about the music,, not the equipment.

Offline zenelectro

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Re: Computer transport interface
« Reply #68 on: May 27, 2014, 12:08:35 PM »
Danny added a I2S output mod to my CD94,  because I insisted on proper CD94->Dac cabling  (not loose wires, I have kids who like to yank at wires).       If signal strength is a concern, then Danny's mod is an option. 

I don't think we can say the long wire run is out of the picture.   The whole chain is in the mix (right back to choice of CD-R and burner).     But there is probably bigger fish to fry than focussing any more time on optimising the I2S part of the chain.   :)

WRT clock loading versus versus I2S cable driving, they are 2 separate things and not really directly interactive.

WRT your I2S cable drivers, in the scheme of things I don't know that it brings much to the party. 
The I2S signal needs to be directly reclocked by the oscillator and as such ideally put on the clock board.

A zenclock would have maybe 10 to 100 x lower jitter than the I2S generating circuitry in CD94. 
So in effect the re clocked I2S driver board may well be a bigger improvement than the clock itself.

There are other issues:

a) 5V logic level is not optimum for feeding I2S of TDA1541
b) There are many different types of logic for driving I2S, some noisier than others. Finding information on jitter
generated by various logic types is very difficult. I've built up  a data base of info on this stuff but it took a lot of
research.

As you can see it's just not quite as simple as first appears.

OK that's enough information for one post - and enough time wasted. Too much to do atm. :)



Offline ozmillsy

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Re: Computer transport interface
« Reply #69 on: May 27, 2014, 12:55:34 PM »
A zenclock would have maybe 10 to 100 x lower jitter than the I2S generating circuitry in CD94. 
So in effect the re clocked I2S driver board may well be a bigger improvement than the clock itself.
Yeah, maybe,,,,, I see your point.   

Put it this way,  the Zenclock into Dannys i2s mod already sounds sooooooo freaking good,  I am loath to change anything about it.   I don't even want to mount the bl00dy thing,  I'm leaving it on that old dirty rag,  because what I have right now is *magic*.   ;)

I still do reckon there are much bigger fish to fry.   
It's all about the music,, not the equipment.

Offline zenelectro

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Re: Computer transport interface
« Reply #70 on: May 27, 2014, 01:00:09 PM »
Yeah, maybe,,,,, I see your point.   

Put it this way,  the Zenclock into Dannys i2s mod already sounds sooooooo freaking good,  I am loath to change anything about it.   I don't even want to mount the bl00dy thing,  I'm leaving it on that old dirty rag,  because what I have right now is *magic*.   ;)

I still do reckon there are much bigger fish to fry.

And only so much time!  :)




Offline kajak12

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Re: Computer transport interface
« Reply #71 on: May 27, 2014, 06:26:04 PM »
Danny added a I2S output mod to my CD94,  because I insisted on proper CD94->Dac cabling  (not loose wires, I have kids who like to yank at wires).       If signal strength is a concern, then Danny's mod is an option. 

I don't think we can say the long wire run is out of the picture.   The whole chain is in the mix (right back to choice of CD-R and burner).     But there is probably bigger fish to fry than focussing any more time on optimising the I2S part of the chain.   :)
i run loose cat 5 wires why? because they are better then coaxial,i also have a 4 year old  trained not to touch my system (so far so good fingers crossed)
Regarding zen reclocking i have nothing to loose its part of the journey i dont spend much on hifi so why not give some to ZEN PTY LTD.
as for bigger fish they will come after entree.
ZEN GET TO WHEN POSSIBLE YOU HAVE A KEEN CUSTOMER I KNOW WHAT YOUR CLOCK DONE SO ANYTHING ELSE IS A BIG FISH FOR ME.
« Last Edit: May 27, 2014, 06:30:31 PM by kajak12 »
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline stevenvalve

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Re: Computer transport interface
« Reply #72 on: May 31, 2014, 10:02:46 PM »
When I get it, I will initially be trying it out for DSD audio. I will integrate it in with my Pioneer DV-989AVi which I modified for 2 channels only. I'll use the DAC in it to stream DSD. It has quite a reasonable BB DAC (PCM1738E) with an analogue stage that's been modified with OPA627's and 2SK170/2SJ74 complementary FET output.
Should be quite interesting.

I imagine the USBtoI2S board will have plenty of potential for upgrade tinkering, especially in the clock re-generators.

Hope to get it soon.  :D

p.s. The board is available from this site too: http://jlsounds.com/products.html
What does it sound like.

Offline dannydigital

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Re: Computer transport interface
« Reply #73 on: May 31, 2014, 10:36:26 PM »
I got it! (Yesterday)

Stayed up till almost dawn tinkering. I got it to work in my Pioneer 989 after a few teething problems with the DAC's DSD configuration and the system muting.
I found that the USB board had to be on-line first for the DAC to configure to DSD, not too sure why since the serial config interface of the DAC is asynchronous to the audio bit clock?
Also I had to kill the players system muting in order to O/P the sound. I can control the muting with the DSD flag pin on the USB board but it's not quite 100% the way it should work.
At the moment it's just a crude setup and good for audio evaluation and I must say that it's looking very promising considering I'm only using the laptop's USB to power the board (not taking advantage of the galvanic isolation), to me this DSD sounds pretty good! (Using a modified Marantz SC-8 as a headphone amp. + Sennheiser HD650's)  :o

D

Offline ozmillsy

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Re: Computer transport interface
« Reply #74 on: May 31, 2014, 10:38:54 PM »
Good news Danny,  following with interest.
It's all about the music,, not the equipment.

Offline ozmillsy

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Re: Computer transport interface
« Reply #75 on: June 01, 2014, 09:53:05 AM »
Danny,  just to be clear on what you've done for all forum members.    You have used this board to add a USB interface to your Pioneer player, essentially turning it into a standalone DAC that can be fed by a computer source.

What this allows you to do,  is playback DSD files on your computer,   bitstream the data to your Pioneer over USB,   and let your Pioneer handle the DAC duties.

Because it's a multi-format player,  you can also bitstream any other source format file. 

Once you sort out the teething issues.   You can offer this mod to anyone who has a hi-res disc spinner, and they want to start using a computer source via USB.   Correct?
« Last Edit: June 01, 2014, 11:43:52 AM by ozmillsy »
It's all about the music,, not the equipment.

Offline kajak12

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Re: Computer transport interface
« Reply #76 on: June 01, 2014, 11:29:57 AM »
I got it! (Yesterday)

Stayed up till almost dawn tinkering. I got it to work in my Pioneer 989 after a few teething problems with the DAC's DSD configuration and the system muting.
I found that the USB board had to be on-line first for the DAC to configure to DSD, not too sure why since the serial config interface of the DAC is asynchronous to the audio bit clock?
Also I had to kill the players system muting in order to O/P the sound. I can control the muting with the DSD flag pin on the USB board but it's not quite 100% the way it should work.
At the moment it's just a crude setup and good for audio evaluation and I must say that it's looking very promising considering I'm only using the laptop's USB to power the board (not taking advantage of the galvanic isolation), to me this DSD sounds pretty good! (Using a modified Marantz SC-8 as a headphone amp. + Sennheiser HD650's)  :o

D
Good to see you know what you are doing if it was me it would be fried by now
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline dannydigital

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Re: Computer transport interface
« Reply #77 on: June 01, 2014, 01:53:39 PM »
Danny,  just to be clear on what you've done for all forum members.    You have used this board to add a USB interface to your Pioneer player, essentially turning it into a standalone DAC that can be fed by a computer source.

Yes, and to still be able to use the player for spinning discs by incorporating a digital line switch. (ie. Discs / USB function)

What this allows you to do,  is playback DSD files on your computer,   bitstream the data to your Pioneer over USB,   and let your Pioneer handle the DAC duties.

Correct.

Because it's a multi-format player,  you can also bitstream any other source format file.
 

Perhaps in the future as this requires a more complicated mod for configuring the DAC into the required modes.

At the moment I use an SACD disc to spin-up in the player in order to configure the DAC into DSD mode. (this is quite simple)

Once you sort out the teething issues.   You can offer this mod to anyone who has a hi-res disc spinner, and they want to start using a computer source via USB.   Correct?

I can offer some help but note that every player can be quite different.

Potentially the plan would be to use this board to build a multi-format "murderDAC!" (USB version) from ground up.   :o :P

D

Offline ozmillsy

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Re: Computer transport interface
« Reply #78 on: June 01, 2014, 02:51:13 PM »
LMAO,    I like it.    ;)

It's all about the music,, not the equipment.

Offline gamve

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Re: Computer transport interface
« Reply #79 on: June 02, 2014, 12:47:03 PM »
Then when it is all sorted we can have an "AssasinDAC"   :o