nickquick

So the HDPLEX supply is LC filtered but not regulated ? That would explain the large C reservoir, with the LC values I guess it will be about 3-5 mv ripple assuming something like a 3 amp average load. I have seen other designs taking this approach but not had chance to hear one as yet. I think high processing power is the way to go for sound quality. It comes with issues for the PSU but worth the effort I think. I have done some serious server builds on different PC architectures incorporating bespoke electronics. My advice a when you move to higher processing power is select mother board chipset very carefully. I see folks obsessed about CPUs models and thread counts then select a motherboard architecture almost at random. The CPU does count but the ultimate potential and foundation of a sever that can exceed the performance of the most expensive commercial servers is the right chipset selection. Iv spent way too much time reading Intel data sheets over and over :-) The psu your building is very interesting, it will be good to hear how you get on particularly if the DC ATX is an unregulated LC supply. Keep us posted on how things sound :-)

I looked again at the pictures of your supply in its chassis. For my comments on capacitance values to apply I had assumed that the HDPLEX was being supplied by one of the s11 modules or another linear supply circuit that is not visible. If there is no linear regulation in line with the HDPLEX then the cap values are not going to apply well. What are you using to in the design to supply the HDPLEX ?

Hi, That is a very nice looking build. I am a few years into developing a linear power setup pcbs upwards. Your linears look like Sigma 11 type units, is that right ? If I might offer some thoughts based on experience here which 200,000uf is a LOT on the input of the HDPLEX. Here with a very similar design I am finding that as little as 15,000 after the bridge and 12,000uf after the linear supply feeding into the 400w hdplex is where the sweet spot lies (low esr caps in both locations). Too much capacitance and the sound gets very solid / slow and dynamics and detail really suffer. Feeding the HDPLEX for good SQ seems to be as much about speed and transient response as it is about ripple performance. The HDPLEX 400W IMHO is an amazing piece of kit, its hard to credit the level of performance available from it if its fed with a really well optimised linear supply. If you havn't already voiced the setup with different levels of capacitance I would at least give it one try tuning this can be it can be night and day in terms of SQ. Another point you might want to consider. I can see that your HDPLEX is a V2.0x but it may be worth checking exactly which version. HDPLEX recently bought out v2.01 of their 400W DC ATX. I was frankly shocked at the difference in sound quality compared to the earlier v2.00 and have been poking around at board level of the units to work out what is driving the change to SQ. As the component cost of building such a nice linear supply is pretty high its probably a good investment of $95 to get the 2.01 version if you don't already have it. It will be nice to hear how it all works out for SQ.

Time to chip in after about a month using the Lush. The lush cable is something of a land mark for USB music reply. I say this from the point of view of one who has been modifying pc mother boards, dacs, usb interfaces etc for far, far too long. I am listening to the Lush in exceptionally transparent music system in no small part down to its very refined USB setup. The Lush is simply an incredably transparent transmission cable for USB audio. IMO what ever you hear with a Lush cable installed, it will not be down to the Lush cable creating excessive transmission stream errors and the associated sound quality artifacts that these cause. With this comes a freedom from the somic signature caused by poor USB cable transmission and much more enjoyable music as a result. Bang for the buck ? Here the cable is simply no brainer. Very highly recomended.

A very interesting comparison and order of preference for the sound of the four DACs. First thing to say is that I believe that the reporting reflects the way people heard the performances of the DACs. Sounds like collectively the assembled listeners have some unusual and very interesting kit and I am sure many years listening experience so I just believe what was heard and reported. I have to point out that I have only heard the Phasure from the list of DACs tried, but I'm very familiar with NOS1, XXHE and it's windows platform requirements. Reading the follow up posts a couple of interesting / important points have been made. 1) to access the Phasure NOS1 performance you need the right music server. I accept that all of the DACs were driven by the same MAC based front end. However the Phasure system is almost unique in that it is designed and optimised "end to end" by Peter including software, windows platform and the DAC hardware and firmware. To hear what the Phasure NOS1 is capable of it HAS to be auditioned using XXHE and a properly specd windows platform. Until this is done the comparison results are interesting but very unlikely to be representative of the absolute performance that the Phasure is capable of. This is not me being defensive as a NOS1 owner myself it just a statement of fact, you just need to use the components the NOS1 was developed with to access its performance. 2) Regards the comments on the richness of other Killer DAC vs the Phasure, here I have a foot in both camps. Version 1.186 of the XXHE software made massive steps forwards in respect of the richness and immediacy (realness) portrayed by the NOS1. So again it would be worth trying the Phasure with XXHE to assess NOS1 fully. Having said this there have been times when I missed the richness of my Audio Note DAC 4 when I moved to the NOS. I have always just got on with and enjoyed the Audio Note family sound. Peters work on XXHE over the years has massively narrowed the richness gap between my DAC 4 over the years. Even so the desire for more warmth and tonal colour were in part reasons for embarking on the development of the my modifications to the NOS1, which to my ears (and the few others that have now applied the modifications) have taken it to an quite exceptional place. Personally if i were making decisions on what to invest my hard earned UKPs in I would wait until the Phasure is compared using XXHE and a good spec windows server. I know this is how Anthony's system is setup perhaps there is an opportunity there ? Anyway, Bill thanks for the report it's very interesting to hear how things compared on the day. Regards, Nick.

Hifial hi, The NOS1 used TentsLabs clock Modules then Peter changed the module type. The datasheet of the new clock module reads like an “ideal” device and sound quality took a big step forwards with the new clocks. I have used a number of after market clocks in various equipment and made up a few clocks based in carefully chosen VCXO and TCXO modules. In the end I selected Dexa Nutron Star clocks (with Dexa PSUs) for my NOS1 audio and USB clocks. IMHO the Dexas are capable of reference level performance. For me the performance of a Dexa as an audio clock just exceeded the latest audio clock Module fitted to the NOS1, however with carful attention to how the Dexa is implemented I now clearly prefer the Dexa. Generally with respect to the NOS1 my experience has been that it is a first rate source in standard form but is responds exceptionally to modification revealing significant headroom in sound quality. The modification that I have developed for the NOS1 need to be applied end to end, replace just the clocks or don’t treat all of the PCBs and you hear improvements but it’s the package that moves the listening experience from listening to reference level “hifi” to having a musical performance just take place in the room in front of you. I hope your trial goes well, I very much doubt you will be disappointed with the NOS1 but keep in mind the performance headroom that can be accessed should you wish. Regards, Nick.

Anthony hi, The schedule of NOS1 mods I have shared with folks so far includes is applied to a number of areas of the NOS1 including upgrades to clocks in the PC's PCIe USB 3 interface and the NOS1's USB interface. In my case whilst developing the modifications I have also run an upgraded audio 22.5mhz clock within my NOS1 for getting on for a year now. I have not recommended people make this audio clock modification to date. Personally I have always felt the upgraded audio clock to be an improvement so was happy with the cost, but until recently it did not offer “clear water” between its performance and the (very good) standard NOS1 22.5mhz clock. As a result I was hesitant to recommend the NOS1audo clock ,this is no longer the case. From the outset of testing the clock upgrades to the USB system and NOS1 audio clock I have meant for a number of reasons to pay very careful attention to how all of the clocks are implemented. This implementation work is now done and the sound quality results are quite stunning, to the extent that I would now recommend use of three Dexas, (2 on the USB link and the 22.5mhz clock within the NOS1 (note this gives only play red book)). For information - Schedule 1 NOS1 mods to the USB clocks, the USB – I2S pcb, DAC pcb and IV pcb comes to a parts cost of about £1470 (UKP). Schedule 2 (audio clock and optimized clock implementation) which I am finalizing details of at the moment will be about £600 (UKP) in parts. I only spend money where the audible returns are to be found. The costs of these modifications is quite high but IMHO the result is a quite unique and exceptional source component. Nick.

Hi Paul, I’m thinking based on conversations taking place on another forum that the “monkeying” around with the bit perfectness of audio stream data could be happening in a number of places in the replay chain. The OS (Windows in my case), the audio player application, USB transmission, FPGA processing in DACs etc. I agree with your point that the data needs to be compared “end to end”. Iv been sniffing I2S data as it is sent to the 1704 chips in my DAC for other reasons and have been planning / asked elsewhere to capture I2S data as it is sent into my 1704 DACs decode and compare with the WAV file being played. I can only do this up to sample rates of 176kbs-1, which is unfortunate because it would be good to prove (or not) bit perfect data processing end to end up to 707kbs-1 bit rates which is the rate I use most of the time with XXHighend up sampling. Ill post back if I can get the test to work. Nick.

Hi, I m not a regular contributor here but this tread caught my eye, its a really interesting discussion. Personally I subscribe to the point make above in the thread that we do not hear jitter directly but rather effects of jitter being applied in some particular signal type and at some particular point in the audio replay chain. To go a little further. Audio Distortion = Fn(signal jitter spectrum, response of audio subsystem element to Jitter) If this is a sensible statement, is means that the effect of jitter which may occurring in many signals contributing to the process of music replay at different points in a system is a many headed beast to try to pin down. The audio distortion experienced being dependant on how the Jitter enters the replay chain (clocks, data streams, PPLs etc) and where in the chain this happens. For instance a jitter spectrum on the BCLK line of I2S data entering will produce distortion levels in the audio waveform based on the specific and characteristic of the jitter spectrum and manor in which the DAC chip responds to jitter on its I2S inputs. Whilst jitter spectra entering audio replay chain further back in the audio replay chain in an audio USB link for instance can cause different characteristic audible distortion. Recently I’v been playing about with various “improved” clocks on USB audio link transmitting and receiving chipsets. The effect on audio quality of replacing the standard $2 xtal oscillators at each end of the USB link with clocks which (I hope) have vastly improved noise and phase noise performance has been profound. Assuming the change is due to improved clock phase noise performance the jitter spectrum in the USB clocks is linked in some way to the performance of the USB link with audible effect. When we discuss Jitter I’m thinking it’s important to state in what signal the Jitter spectrum is occurring and into what sub-system of the audio replay chain it is being applied. Subsystems in the audio chain respond differently (ie induce downstream audio stream jitter, or increased data transmission errors rates etc) and produce their own characteristic audio distortions. Regards, Nick.

Jud hi, I spotted your post over or Phasure. I cannot comment on the"ripple eater" supply but I have had some problems using R-Core transformers. I placed a couple R-Cores in my gainclone amp (within the same case) and have only resently cottoned onto the nasty problems that hum fields from the transformers have been causing the amp. R-Cores are great for low capacitive coupling of their secondries from the mains supply but really try to mounted a long way loom PSU and DAC circuitry. The fix for me has been to build a new amp this time using toroids which are mounted in a separate case. Just something to think about. Cheers Nick.