DAC chipsets, whats the difference

Im toying with buying a dac off ebay as an experiment as much as anything. The one Im interested in, lite audio is advertised 3 with three different chipsets PCM1704U-K, PCM-1702 PK and PCM-63PK does anyone know the characteristics of the chips?

The units look pretty well made, dont cos the earth and I think it could be a good project to mod.

 

Rob,

In a properly implimented dac (With the dacchips are in parallel and have quality decoupling+seperate supply rail), the PMC63 (K denotes the top grade of the genre) The 63 propduces a lively and flowing musical presenation, if a little rough and lacking a bit of detail compared to the newer chips sets.
I personally feel the 1702's generate a very musical presenation, a higher resolution rate than the 63's, they have the ability to make great music, with quality bass and timing abilities.
The 1704, is generally touted as the 'top dac', with a a lot of the upper level players using this chipset inconjunction with the 1704 digital filter.
Initally I never found it that engaging, plently of detail and staging, lovely low level detail retrieval, however for me not ultimately that involving.
Though Now (after a few mods) I'm changing my mind
Having owned all 3 chipsets in quite a few various players, they each have the strengths & weaknesses, though its all down to the particular application its used in and the implimenation of said device.
In essence 63/1702's are 48Khz only the 1704's are 96khz.
However if you like me, I still find 44.1khz 16 bit the best. Wm

 

Thanks WM my copland has 2x 20 bit converters Burr-Brown PCM63 with 8x oversampling 20 bit digital filter and 2x 20 bit linear interpolater (upsampling?)

The one I'm looking at uses Burr Brown PCM 1702 PK Burr Brown. Uses DF1704, 24Bit/96kHz, 8X Over-sampling Digital Filter a CS8414 Crystal, 2 x R-Core transformers, a pair of 6922 tubes for output and uses parts from OS-con and Dale Resistors.

I find the copland a bit laid back in my system, Im wanting to inject some life and a little more detail would be nice. Neither the nos or superdac really did it for me at the bake off and Im not in dac64 teritory financially at the moment.

Im not expecting big things from this cheap dac, just something to get my soldering iron out and play with but it has to improve on the copland or whats the point. I notice it has a clock CS8414 Crystal does this mean it re clocks ignores any clock in the copland?

Thanks

 

The superDAC uses the CS8414, and you've heard the effect that transport clock has on that...

 

l agree with WM, l still prefer 16 bit 44.1khz the best

Thats why l have chosen to heavily modify my Audio Note DAC which would have been made around 10 years ago. it utilises the K grade of the PMC63. An increase in detail and reduction in noise can be had from these by piggybacking them (see pic) A worthwhile upgrade for the cost.

Cheers

 

Thanks I will try that my pmc's do not have the K on them like yours, can I desolder and swap with piggy backed k grades?

Where can I source 8 of these chips?

 

The only place I know that still has them is Monarchy Audio (US), be sure you use like for like (IE K grade for K grade), and get someone compedent to solder them, it was a little tricky in the Wadia 15
Also bear in mind that you WILL increase current draw on the digital power supply when doubling up the dac chips, maybe some subtle mods will help there as well.
Also look at the analogue output stage too, good gains can be had from cap/opamp changes.
Personally Rob, I'd stick with the copland until you can afford a better player (really) or if you still impatient mod the Copland. Wm

 

Sorry Rsand,

My tech supplied the chips. The only other suggestion l have is ebay

Cheers

 

See Here Rob Pmc 63 K's (In components for sale)

 

So I cant upgrade to K grade from these

One thing I have noticed is the right chanel is quieter than the left, which I have always put down to my ears but looking at the dac/output board there is an extra resistor piggy backed on the right chanel. Could this be what Im hearing? The player was repaired a while ago and the extra is judging by the soldering a late addition. Should I remove it or add one to the other side.

 

Unless you change all eight dac chips, expensive, the resistor addition could be, purely as the chap didn't want to remove the board to do the job, just piggy back it, else adjust the values. Wm

 

Yes 240 USD + P&P is expensive. I will take your advice and change the op amps, caps and a clock NC PSU upgrade.

I will also add a resistor to the left chanel see what that does?

Thanks for the help. Again.

 

Do these photos look similar?
ebay DAC PCM-1702
and
diyclub.biz
The latter can be found at eshop.diyclub.biz

us$210 kit
us$280 complete
from HK

Maybe of interest...

I've also found Audio Workshop which seems to have some interesting bits and pieces (well, interesting to me) but hard work reading through site

 

The self same ones Chris