pcm1702, K grade or not?

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PatPet

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Joined 2004
#1
Hello,

I'm interested in this DAC. But when I look at the price, I start to consider if it is worthwhile to go for the K-grade chips which costs nearly 60% more. Well, it seems 29USD for each 1702-K is too much. But I start to think about balanced/parallel solution but how will 1702-J compare with 1702-K in these situations?

Guys, I'm stuck between the two options, either balanced/parallel 1702-J or balanced/parallel 1702-K. Which one shall I choose?

Thanks

Pat
 
#3
Thank you Benhard,

And which would you prefer, if you have to choose between pcm1702 and pcm56?

I'm deciding which is better for balanced/paralleled application.
The pcm56 is very cheap, around 10USD each, but doesn't rate as good as pcm1702 in dynamic range. But in the datasheet, pcm56 is described as the state of the art chip.
 
#4
Pcm56

PatPet said:
Thank you Benhard,

And which would you prefer, if you have to choose between pcm1702 and pcm56?

I'm deciding which is better for balanced/paralleled application.
The pcm56 is very cheap, around 10USD each, but doesn't rate as good as pcm1702 in dynamic range. But in the datasheet, pcm56 is described as the state of the art chip.
Click to expand...

Hi patpet, The PCM56 is an antiquated chip. I found the AD1851 better and the AD1865J-K much better. Just my personal experience of course.
:bigeyes:
 
#6
Pat,

I have 4 pieces of the 1702 but did not try them yet, performance differs a lot from chip to chip, that is why they are selected.
But manufacturers do not look at the spectrum, only measure total thd 🙁
Also performance may change after burn in.
 
#9
I used to balk at the cost of the 1704U-K (US$36 each), but after the design was done the difference between the K and the J (US$12 each) seemed insignificant. A DAC that can take advantage of the performance of the 1704 will undoubtedly run into the many hundreds of dollars anyway, so why not spend the extra $48?

On the other hand with the 1702 I can understand that you might not be spending as much money on a 44.1kHz/16-bit design as you would be forced to spend on a 96kHz/24-bit implementation.
 
#11
A friend of mine has measured the linearity of a number of B-B
DACs. (he has such a setup as part of his bench equipment since
he deals with converters a lot). There is a significant improvement
in linearity when measuring the high-grade parts, given randomly
chosen samples of each. Whether this translates to audible
improvement is left as an exercise for you the user. I don't
believe that he's tested any ADI DACs, but I would assume the
results are the same.

The reason for the cost difference between high grade and low
grade is the amount of laser trimming of the die at wafer level
(or post-packaging electronic "trim"). The high grade gets trimmed
to tighter tolerances (and/or the low grade may be untrimmed).
 
#12
"I tell you what.........."

The AD1862, when using the MSB trimpot, stays adjusted for as long as I have had them running. That goes back to around '92 or so. The units that come back for upgrades are still set to the precise point. Hasn't drifted at all.

I agree with Brian...........on the bench.......there is a measureable improvement in the selected grades. Some of the "non-selected" ones are terrible, which I why I always use the "high-priced spread".

Whether you can hear that low............more agreement.

Jocko
 
#13
And I tell you

Hi,
An AD1865J-K (highest grade) does sound way better than a MSB adjusted AD1865J-N (lower grade) and does not need an adjustment pot......Yet I prefer a TDA1543. Ha-ha it even does not accommodate a pot. Low-level signal is OK, dunno how they did it.
For those interested in the adjustment I attach a small low-pass filter amplifier adjusted for NON-OS DAC to visualise the low level signal on your scope. The adjustment is difficult to perform without the rig, as the signal is drown in noise.
😎
 

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#14
Hi

Thank you for all of your responses.

In my plan, the ad1865-k are to be stacked in parallel. Which means, by hooking up at least 4 of them in each channel, I may have better "spec", and probably better sound also. The reason I consider parallel solution is that the conversion errors would be reduced and that I may have greater S/N, THD, DR specifications.

This may be quite expensive. But I would invest more on this DAC as I have much expectation from it.

And for the low-pass filter, I must say it is very useful. But I don't have a scope and I'm afraid I have to leave the MSB unadjusted, may be at a expense in low level signal performance. I may consider that the adjustment becomes less useful in parallel DAC situations.
 
#15
Re: And I tell you

Elso Kwak said:
For those interested in the adjustment I attach a small low-pass filter amplifier adjusted for NON-OS DAC to visualise the low level signal on your scope. The adjustment is difficult to perform without the rig, as the signal is drown in noise.
Click to expand...

This is just a joke, isn`t it ?
 
#18
Re: Drowning in a Sea of Noise

Bernhard said:
This is just a joke, isn`t it ?
Click to expand...

Drowning in a Sea of Noise
Sie will ein Fisch im Wasser sein
Im flaschengrünen, tiefen See.
Sie wil mit Wasser sich besaufen
Und ein paar Blasen blubbern lassen
Was Sie dann will, das ist
Mit Neptun schweigen
Und in Ruhe thun,
Was sie sonst nie thut,
Was sie sonst nicht kann & soll.

For our Anglo sax friends, especially MalichiConstant (I know you are browsing this forum), I have translated this:

She wants to be a fish in the water
in the bottle green, deep lake.
She wants to fuddle herself with water
And bubble up a few bubbles
What she then wants, is
being with Neptune silently
and doing quietly
what she otherwise never does,
What she otherwise not can do and has to.

Elso/ Pisces
Courtesy Nina Hagen
:hbeat:
 
#19
 

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#20
PatPet said:
Hi

Thank you for all of your responses.

In my plan, the ad1865-k are to be stacked in parallel. Which means, by hooking up at least 4 of them in each channel, I may have better "spec", and probably better sound also. The reason I consider parallel solution is that the conversion errors would be reduced and that I may have greater S/N, THD, DR specifications.

This may be quite expensive. But I would invest more on this DAC as I have much expectation from it.

And for the low-pass filter, I must say it is very useful. But I don't have a scope and I'm afraid I have to leave the MSB unadjusted, may be at a expense in low level signal performance. I may consider that the adjustment becomes less useful in parallel DAC situations.
Click to expand...

Well PatPet, I certainly do not want to hear more silly jokes about piggy backed or stacked DACs after Lars' dry humour with electronic parts handling.:clown:
As I explained the K-grade is the best and really does not need a MSB adjustment as this makes matters only worse.
In my experience and that of Peter Daniel the highs suffer when DACs are paralleled.
😎
 
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