Which good discrete R2R multibit DAC & why NOS ?


In another thread concerning upsampling and upconversion in servers, mention was made by georgehifi :
¨Should just have a good listen to Redbook 16/44 PCM converted through a "good" discrete R2R Multibit nos dac.¨
Which would these be and why NOS ? Are there no R2R multibit DACs being made today ?
My Reimyo CDP777 although quite old has the K2 conversion and being one-box and top-loading made sense  to me at the time of purchase.
Most importantly, would adding an external R2R bring a noticible improvement or just be sidestepping ?

Thanks in advance

rost
In this instance NOS means non over sampling not new old stock.
Also you own a great CD player I would think most Dac's would be at best a lateral move.
Thanks jond for the clarification on NOS.
Should have deducted as much considering context.


rost OP

Which good discrete R2R multibit DAC


Can't remember where I found it, but here a list of today's manufacturers making R2R Multibit dacs, and this is getting old I think.

If you have more to add please post them up and the price, and the numbers are slowly growing.

 

Up to $3k:

Border Patrol, Monarchy, Denafrips, Audio-gd, MHDT, Holo, Soeskris, Metrum, Schiit

$5-$15K:

Audio Note, MSB, Metrum, Computer Audio Design, Aqua, LessLoss, Totaldac, Lampizator

$15K+:

CH Precision, Aries Cerat, Light Harmonic, Audio Note, MSB, Totaldac, Lampizator

**Special mention to MSB, Monarchy and Audio Note, who never gave up on R2R. Even after the short lived takeover of delta-sigma, for doing PCM Redbook conversion.

 

Cheers George


@rost,

You are probably one of the very few luckiest owner of this amazing player. IMHO, with CDP-777 there is no need to search for a R2R external DAC, your player is already outfitted with a SOTA converter.

You will pay through the nose to hear uptick in performance, if any for CD playback. Just to clarify further, the thread concerning upsampling and upconversion in servers, R2R NOS DAC’s mentioned by @georgehifi was said in context with digital streaming. Unless you have plans to dive into digital streaming, buying an external DAC with CDP-777 makes no sense.
Thanks George for that informative list.

Thank you also Lalitk 
Your views echo my concerns as to how much of an improvement, if any, an external DAC plus the added cable expense would make.
As of yet, no immediate plans to get into streaming, too many lps & cds.

Just further on the K2 of the Reimyo, I had many moons ago the flagship JVC K2 player, it used the Bur Brown R2R PCM56P dac chips in it.

Also today the Zanden Model 5000 MkIV is a K2 player also, it uses the R2R Philips TDA1541 double crowns in it.
But I can’t find what the Reimyo uses for dac chips, my guess would be the R2R PCM1704K’s, I don’t think it’s discrete R2R

The Zanden didn’t get much love from JA on the Stereophile test bench. For one I can’t believe how much it was rolled off in the bass
https://www.stereophile.com/content/zanden-5000-mkivsignature-da-converter-2000-premium-cd-transport-measurements

Cheers George
US-based Mojo Audio makes R2R NOS dacs.  Their Mystique V3 has won a few awards.  It uses the 20-bit, AD1862 R2R chips.  They have dacs from $2500-7500.

I thought I had read somewhere that the Reimyo DAP 777 used PCM63's, but now can't find anything on it.   I sometimes look for old dacs that have that chip, and I remember the Reimyo being on my mental list.






Yes Mojo also do good R2R Multibit dacs now.
They wrote a great article a few years ago on DSD vs PCM and the d to a conversion to do each. R2R (multibit) vs Delta Sigma (single bit)  Here's what they said.
When a PCM file is played on a native DSD single-bit converter, the single-bit DAC chip has to convert the PCM to DSD in real-time. This is one of the major reasons people claim DSD sounds better than PCM, when in fact, it is just that the chip in most modern single-bit DACs do a poor job of decoding PCM.
https://www.mojo-audio.com/blog/dsd-vs-pcm-myth-vs-truth/

Cheers George
@veroguy  

https://www.ebay.com/itm/202167842535

I use this seller's AD1865 DAC and I really like it. I would like to know what the PCM63 DAC sounds like. 

The link below is for a PCM56P-K DAC that I'm also considering just for the sake of trying something different. 

https://www.ebay.com/itm/362843900577
Some of the best very expensive Wadia dacs use PCM56 and PCM63 chips in them, with what they called the discrete "Sledgehammer" output boards.
They also had what I found to be the best way to link it to their transports with AT&T glass BNC optical link, using a dab of very expensive "optical indexing fluid" on both ends, so there was no air gaps to the AT&T receivers

And Accuphase used the AD1865 in great numbers their top line expensive dacs also.

Mark Levinson, Linn and Naim were a big user of the (best I felt PCM1704’s) in their top end players and dacs.

Naim got amazing sound from the CD555 and PS555 power supply combo. Even today you won’t get this pairing cheap anywhere. https://www.naimaudio.com/product/cd555

Cheers George
The Reimyo CDP 777 used 2 PCM1704 and Nippon SM5847AF filters and JVC K2 DSP which is why it was a good CD player it wasn’t NOS and made use of good filtering and up sampling which any decent R2R implementation needs to do.
Please enlighten:

@georgehifi 
"But I can’t find what the Reimyo uses for dac chips, my guess would be the R2R PCM1704K’s, I don’t think it’s discrete R2R"
What is the difference between a discrete R2R & non discete R2R DAC ?

@djones51
" it wasn’t NOS and made use of good filtering and up sampling which any decent R2R implementation needs to do."
Please explain further, I thought R2R implied NOS or upsampling.

Thanks


What is the difference between a discrete R2R & non discete R2R DAC ?

A discrete R2R uses individual (discrete) close tolerance resistors in the R2R ladder. The non-discrete uses an IC with those resistors on the die of the IC where they're trimmed by laser after fabrication.
@rost 
The R2R PCM1704 chip doesn't do the oversampling it's the K2 DSP and Nippon filters that pass the over/up sampled signal to them. R2R is the DAC architecture there is more going on in a good DAC or CD player. NOS is in some kind of nostalgia thing right now but as you can see with your Reimyo the best even 20 years ago didn't do NOS without proper filters, Why? It didn't sound very good.

While each of the corporations contributes to the overall sound of the Reimyo, it is the K2 processor that gives it its heart and soul. The K2 processor, operating with 24-bit resolution, takes the incoming digital signal and oversamples it to 176.4kHz. From there the digital signal is passed on to the digital filters, which upsamples the signal 4 times to 705.6kHz before being passed on to the twin PCM-1704 digital to analog converters. The DAC's are multi-bit in operation. As a result, every CD that is played through the CDP-777 is reproduced at an incredible 705.6kHz, which is among the fastest sampling rates available from any CD player on the market today.

http://www.enjoythemusic.com/superioraudio/equipment/0304/combakreimyocdp777.htm