DAC - Opinion needed

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It looks like the insides of my 1960's Tektronix 'scope. Except this design has chips in it.

Messyness isn't necessarily a bad thing as long as you keep track of good design practice. If you maintain good grounding (star or plane), small loop area between signal conductor and return, and minimize crosstalk between digital and analog signals, things should be working fine.

How does the DAC perform if you pause the music and turn up the amp? Any 50/60Hz problems with the lid off?


Regards,
Børge
 
borges said:
It looks like the insides of my 1960's Tektronix 'scope. Except this design has chips in it.

Messyness isn't necessarily a bad thing as long as you keep track of good design practice. If you maintain good grounding (star or plane), small loop area between signal conductor and return, and minimize crosstalk between digital and analog signals, things should be working fine.

How does the DAC perform if you pause the music and turn up the amp? Any 50/60Hz problems with the lid off?


Regards,
Børge

Dead quite. I actually did not make this DAC, it's a my friends design. He is an old school designer, used to design tubes for USSR military. Worked with Vladimir Shushurin back in the day. It's interesting how all of his designs look very messy but sound great.

What surpriced me here is that he hard wired the the input chip CS8412. He basically soldered each leg with silver wire, crazy if you ask me.

Here are a few pics of the amp that he made for me.

DSCN1493.JPG


DSCN1494.JPG


Power supply:

DSCN1506.JPG
 
Birds nest soup

Spdif sucks big time for sure but then so do many of our Brazilian bro's comments! Every time I read a thread he contributes to he's having a sarchastic pop.

I like it. It exhibits the business like craziness of some one who knows what they are doing and is just keen to pull it together so they can listen.

I thought most here had figured out that neat don't mean squat.

Similar to the notion that beautiful women often can't F*** worth a dam.

I once said to a sales person in a generic Hi-Fi shop.

"Look mate, I dont give a stuff what it looks like as long as it sounds fantastic. I don't think you can help me."

He looked back at me bewildered and offered up. "Yeah but everyone likes cool stuff, smart lookin Hi- Fi don't they?"

"Thats the problem" I said. "Somewhere you've forgotten about the music. This is about experiancing and enjoying music in the home, nothing else".

One of the last times I ventured into a shop. Lets face it mostly they sell garbage......
 
oshifis said:
Russian MIL constructors' habit is to drop purple paint everywhere... It prevents loosening the screws in a tank, and acts as a soldering flux at the same time - not joke!


I see you noticed the paint :D. It's not really a paint according to him, it's this special resin like compound, acts as vibro-absorbent and reduces cross-talk as well. Looks even more funky with all joints covered with it. :)
 
Re: Birds nest soup

MJW said:
Spdif sucks big time for sure but then so do many of our Brazilian bro's comments! Every time I read a thread he contributes to he's having a sarchastic pop.

I like it. It exhibits the business like craziness of some one who knows what they are doing and is just keen to pull it together so they can listen.

I thought most here had figured out that neat don't mean squat.

Similar to the notion that beautiful women often can't F*** worth a dam.

I once said to a sales person in a generic Hi-Fi shop.

"Look mate, I dont give a stuff what it looks like as long as it sounds fantastic. I don't think you can help me."

He looked back at me bewildered and offered up. "Yeah but everyone likes cool stuff, smart lookin Hi- Fi don't they?"

"Thats the problem" I said. "Somewhere you've forgotten about the music. This is about experiancing and enjoying music in the home, nothing else".

One of the last times I ventured into a shop. Lets face it mostly they sell garbage......

In the end all that matters to me is how it sounds, that what I go by. plus the box looks nice outside.
 
QSerraTico_Tico said:


QSerraTico_Tico said:
Perhaps I should explain why SPDIF is a bad idea and also executed poorly....


I think the limitations of S/PDIF are fairly well known. However, for some of us, that's all we got to work with. Moreover, there are relatively inexpensive DACs (compared to implementing alternative I2S/clock injection solutions) that offer real improvements over many commercial transports (including cd players and other sources like Squeezebox). I would like someone, perhaps, Mr. Tico, to offer a practical alternative to S/PDIF - giving us all the details. I've seen some of the exotic solutions, and they all involve either considerable expense or unreasonable amounts of expertise for the typical DIYer.
 
ezkcdude said:


I've seen some of the exotic solutions, and they all involve either considerable expense or unreasonable amounts of expertise for the typical DIYer.


Not to mention drilling additional holes in the poor transport :)

Still, i have to agree with Mr Tico: a single box cdp is a lot less compromised than most (all?) two-box solutions


Btw, the input toroid transformer shown in the picture may function well in a T34 tank but is quite useless for spdif.
 
analog_sa said:



Not to mention drilling additional holes in the poor transport :)

Still, i have to agree with Mr Tico: a single box cdp is a lot less compromised than most (all?) two-box solutions


Btw, the input toroid transformer shown in the picture may function well in a T34 tank but is quite useless for spdif.

Can you explain why it's useless? I am not being a smart *** just want to know why you think that way.
 
Faust3D said:


What surpriced me here is that he hard wired the the input chip CS8412. He basically soldered each leg with silver wire, crazy if you ask me.



There is a simple explanation: the board was pre-drilled for a dip 8412/8414 but these days it's much easier and cheaper to find them in soic.


Faust3D said:



I see you noticed the paint :D. It's not really a paint according to him, it's this special resin like compound, acts as vibro-absorbent and reduces cross-talk as well.

It certainly does nothing for crosstalk.



As you wanted opinions on the design i'll try my best to be frank :)


Topology-wise it seems fairly standard for a NOS 1541 without any special attention spent on jitter reduction or exotic PS regulators. Part quality varies but with the exception of the brown russian resitors and the "white coffins" is decent.

Layout and construction quality is pretty dismal, at least compared to similar projects published on this board.
 
analog_sa said:



There is a simple explanation: the board was pre-drilled for a dip 8412/8414 but these days it's much easier and cheaper to find them in soic.


It certainly does nothing for crosstalk.

As you wanted opinions on the design i'll try my best to be frank :)

Topology-wise it seems fairly standard for a NOS 1541 without any special attention spent on jitter reduction or exotic PS regulators. Part quality varies but with the exception of the brown russian resitors and the "white coffins" is decent.

Layout and construction quality is pretty dismal, at least compared to similar projects published on this board.

FYI on the 8412. The board was not pre-drilled. Both boards were hand made just for this project, and the power transformer was actually hand wound. We had about 30 different 8412 chips and this one was picked because it tested better. We actually tried a few of them socketed and soldered, ruined a few chips this way :bawling:

Thanks for your honest opinion, on the DAC as a whole. I seen a lot of very interesting projects this board, but I was actually very impressed by the construction of this monstrosity, but that's just me, I hate neatly assembled PCB boards. :D
 
Faust3D said:


Can you explain why it's useless? I am not being a smart *** just want to know why you think that way.


It is too big for the frequencies involved. Due to parasitics it has limited bandwidth and will deform the spdif square waves. It's easy enough to test if the dac sounds better without it.

Something i can't see on the pics is the type of capacitors surrounding the 1541. I have heard the russian silver-tantalum caps are very suitable in this position.
 
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