The Rise of NOS

NOS - Non Over Sampling - and classic good old 16-bit audio seems to be the buzz word of the moment.  Musical Fidelity new M3 CD player is saying it is just 16-bit, no more.  PS Audio Perfectwave DAC, although ultra modern, is saying that it is best in native sample rate, bypassing SRC (sample rate converter).  How much music in your library is 24bit 96khz anyway?


Back in the '80s, when CD promised perfect sound forever, the clever engineers at Sony and Philips devised a method to increase resolution while moving digital noise out of the audible audio band.  The method is widely used in following CD players where digital signals are 2x, 4x, 8x, and even 128x (the most common) over-sampled.  Most popular super bit chips today utilize oversampling, upsampling delta-sigma conversion built-in.  Without a doubt, these modern interpretations do sound better than older CD players, no contest.  However, over the past 2-3 years, DIYers have been suggesting that music are even better WITHOUT over-sampling.  This can be achieve by using older New Old Stock multi-bit (16-20 bits) chips, buying them el-cheapo off ebay, design a good R-2R conversion, and stick a simple filter and they will give you that "analog" sound we have been craving-for forever since the inception of digital music. 


The chips that can be modded for NOS operations are usually one of the following:

• Philips TDA1541A (16-bit, some say its the best DAC chip ever made)
• Philips TDA 1543
• Analog Device's AD1862, AD1865
• Burr-brown's PCM63, PCM1704

Primer on over and up-sampling here and here.  Up-sampling and over-sampling are not the same thing, and "Over" seems to be the bad cop here.  But let's leave that for another post.

Now several manufacturers, with DIY roots, are out with a NOS product so you don't have to be a DIYer to be able to enjoy one.  Do they sound better? I do not know yet, but will try to find out and let us see what's there to acquire and then I will try to get a sample of the current champ of the super-bit modern camp, the Weiss DAC202 ($6,000), and will flesh it out.


Redwine Audio Isabellina LFP-V ($1,500)

This is a non over-sampling, non up-sampling DAC with dual-triode 6922 tube output stage and off-the-grid battery power.  It has USB, Coaxial and Toslink inputs. Supposed to sound spectacular.  There's also a pre amp and an integrated amp version.


MHDT Laboratory Havana  ($872)

The Taiwanese-made Havana DAC uses PCM63P with a Crystal CS8414 receiver chip which runs in non over sampling mode. Also sporting a tube output stage with GE5670 as default tube.  The main facade is semi-transparent acrylic which is pretty cool. USB input also provided and converted into SPDIF internally (The Redwine coverts USB to i2S). Balance version also available.

Satch Max DAC ($930)

This is provided as kit and also fully assembled with Tesla ECC88 tube output stage.  The DAC chip used is classic TDA1541A. The circuit is classic DIY-style and the output stage is based on the Lampizator's modifications.  Thorsten Loesch's design which was based on his original ideas on tubes output stage for digital audio, first published back in 1999 in the Newsletter of the London Live DIY-HiFI Circle.

Teradak Chameleon ($500)

This is a two box DAC with a separate power supply unit.  The DAC chip used is Philips NOS TDA1543.  Not only one chip, but 16 of them! The designer states that this increase linearity and dynamic range while lowering the noise floor.  While the 1543 is no 1541, I heard good things about it from a trusted source and it is priced well!.  The Taiwanese are just amazing.

Tranquility DAC ($2,395)

This DAC is quite elusive on how it works.  It is an USB only DAC, no other inputs.  No details on circuits or chip used, just that it is NOS and uses discreet components plus some proprietary USB implementation.  There are reports on various forums on the internet that it rival the best vinyl gear in terms of "realness" and is very analog like in its presentation.  I ordered the SE signature version and their specialist "essential SE" USB cable designed to work with the DAC.  So this will be my reference NOS DAC in my desktop system. (if it ends up winning the Bel Canto DAC 2.5)

So please let me know if you suggest a different contender!