Burr-Brown DACs

Is there anything special about the Burr-Brown DAC's?

I have seen their mention in the specs of NAD cdp and Yammy RX-V659 avr.

Savyasaachi schrieb:

well in the US the PCM 1704 costs abt 25$ each. add a 8$ shipping charge and it is almost 30$ a piece. And the OPA627 cost abt 15$ each. So u are looking at over 125$ only in components.

just to add to Sayva's comment - the PCM1704 is a really good DAC for audio because it is implemented as a Nyquist DAC. Accepts 20 or 24 bits data in serial format, MSB 1st.
To my ears those DACs or CDPs implemented using Nyquist DACs sound much better than those implemented using Delta-Sigma DACs.

Savyasaachi schrieb:

Though AKM DACs seem to have better figures in two areas(dynamic range 120dB to PCms 112dB) and more importantly the sampling freqs supported. while the PCM is limited to 96/24 the AKm goes upto 192/24 But thisis of no use at least for the next 4 5 years..u don't have 192khZ sampled software.

LOL! The so-called "hi-rez" formats are dying out....
The fact that the PCM1704 goes *only* to 96KHz should not be taken as a negative attribute.
In fact, going above 96KHz is a very difficult task to implement in the entire signal processing chain. I was discussing this technical aspect with Amp_Nut when he & I were "arguing" about SACD & CD sound. You can refer to that (hijacked) thread called "Delhi Meet" for more details. Briefly, for signals to settle at the 96Khz rate, one needs to have circuits that have bandwidths that are 10X this rate i.e. close to 1MHz. I do not know of many audio circuits that have such wide bandwidths. If anyone does, please share the info. Thanks! So, one can implement using DACs that go all the way up to 192Khz however, if the signal chain cannot provide signals that have settled then the DAC is going to be converting data that has signal-dependent error on it. BTW, signal-dependent error is one of the worst kind of errors you can have as it is very difficult to predict what the error looks like as it is correlated to the input signal. So, merely having the DACs go higher & higher in frequency almost means nothing - the circuits comprising the entire signal chain need to be increasing in freq at the same time.

Savyasaachi schrieb:

The PCM also has better distortion figures. But it would be too close to call. beisdes it depends on so many other things and the PCM is reputed to be one of the best soudning DACs made. Though there are others who claim otherwise(MSB Tech and a couple others).

I wouldn't put too much weight in MSB Tech's opinions because, from what I've heard, their DACs sound a little tizzy on the top-end. High freq distortion often claimed to be "more details"!

Savyasaachi schrieb:

The outpt stage too plays an important part. 'Audiophile' people prefer a tube output stage(though according to me it colors the sound rahter than make it sound 'analog'.

This seems to be a matter of taste.
However, IMHO, this seems to be a cover-up for something else in the chain that is not implemented correctly. The tube swamps out that distortion with its own even-order euphonic distortion supposedly "curing" digititis.

Savyasaachi schrieb:

The PCB layout itself is a challenge..and the rest of the components play a huge part too..like the receiveer(usually a CS8412/4 or the newer CS series)

correct!
Routing signals on a multi-layer PCB paying attention which signal(s) interact with which other signals is a time consuming task that often requires several spins on the PCB layout to ensure that digital signals do not corrupt more sensitive analog signals.

Savyasaachi schrieb:

The power supply also needs to be done neatly...

Forget the neat part! what I mean is that a neat power supply is not the important criteria. One can have a weak power supply that is very well laid out & neat but overloads when current is demanded from it. Hence, being neat is not the defining criteria.
This is where higher end CDPs & DACs excel over budget devices - correct implementation of the power supplies. Separate analog & digital power supplies. Further, separate analog supplies for sensitive circuits, adequate filtering/decoupling, use of Bybee quantum purifiers, adequate current supply, good LDOs, proper layout of the power supply in reference to the client circuit to be serviced, adequate shielding from analog & digital circuits, etc.