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rmpfyf

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About rmpfyf

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  1. rmpfyf

    PDX DAC project

    I’ll back this up. I was on a similar journey with my DAC (TDA1541A) which started with my playing around with my PDX (since sold). I was able to improve the performance of it a ton just by updating the input stage - and my attempts were pretty marginal. I had purchased an Acko board to start with - good but a long way to go - and thought best to enlist a professional. @rawl99 was kind enough to introduce me to @zenelectro, who had done a ton of research into oscillators for earlier reference-grade projects. It’s been a journey since and a lot of learning! For various reasons we settled on 384kHz as an ideal target (NOS). @zenelectro is presently in the final stages of building me two reclockers, one using an Audial kit and the other with iancanada’s kit. Particularly with the latter there is more to it than just the boards as ordered. I’ll leave it to @zenelectro to post pics and talk to performance here. I’ll quite openly state that dealing with him has been an absolute pleasure at very fair rates. (And that as an engineer I’m an absolute PITA of a customer). He’s got a few things in development which go beyond reclocking too. There’s quite a few PDX’s in circulation that have great chips and sound amazing with a well-clocked input the likes of which just wasn’t available when the DAC was conceived. They’re cheap to acquire and, properly upgraded, play well above their pay grade. If there are others beyond @Benjet wanting to take their PDX to the next level I’d suggest getting together for a group buy on a kit developed and fitted by @zenelectro. You won’t look back.
  2. rmpfyf

    PDX DAC project

    When I wrote the above, I meant this: This would be the start of a journey on the tube side of things. Sky's the limit, about as deep as your pockets
  3. rmpfyf

    PDX DAC project

    Bigger buffer on Ian’s. More complexity tho. Not sure max freq in JL. Both take better clocks, which is def where to spend. Ian’s allows you to slot something between USB and I2S. Which is powerful, and can affect clock choice. You will not degrade it. Tested this much audibly. Zenelectro has attested similarly, and his sample size isn’t small.
  4. rmpfyf

    PDX DAC project

    Me? Nup. Evidence suggests a few NOS 1704 projects at 384kHz and 768kHz are doing fine.
  5. rmpfyf

    PDX DAC project

    Clay, I reckon you make a new upsampling/NOS input stage, something that you could re-use in other DAC designs and offer to PDX owners too. Then you do a limited run of 5 PDX's with the new front end. I enjoyed my PDX for the time I had it; I did find the input stage the most limited bit. Admittedly mine was early and at the time it was build a HiFace was about as good as it got, though now that things have moved on there's a lot that can be done. This, and the 1704 is a very very good DAC IC. Last of breed FWIW. (This, or you go all-out on a multi-chip-per-channel one-off design IMHO).
  6. rmpfyf

    PDX DAC project

    Solvable problems. From an upsampling/filtering perspective it's ideal, if a diminishing returns argument. Min phase (or nearly so) is effing glorious in the audible band when at 384kHz... just ask the team at Meridian. I understand there are a few PDX's in circulations sporting JLsounds I2S boards - there's life after Hiface! As you're aware JLsounds has a separate clock board for this sort of hijinks... a SOTA implementation was never intended to use $2 oscillators. Various opinions on the Crystek clocks. A step up, there's other stuff too. Clay, rather than doing something off-the-bat new with your new stock, what about an official upgrade program for the PDX's current in circulation? They're unlikely to turn into a Phasure overnight but I'd think a NOS upgrade kit could get pretty close, and the DAC ICs are good. It'd end up as something that could play DxD no problem and that could do DSD with an input DSP doing the conversion - there's a few boxes in market that can do that, or it'd be just as easy to setup a cheap PC to do it. Clay, I'm updating my Killer to the same spec. Old DACs for the new age. Update the PDX, let the old battle begin anew
  7. rmpfyf

    PDX DAC project

    This is essentially what I’m having put together for mine. I think you’d get a high percentage of the outcome with one board if you tried either JLSounds or Audial boards, and these are considerably less complex. You won’t just need power, you’ll need very carefully regulated power to get the most out of it. A lot will depend on clock quality. Quality is not cheap. You could use Roon for the upsampling, any PC in the middle (what I use) or a dedicated DSP on two-channel I2S (what I’ll eventually move to). if you want a SOTA outcome you’ll run those puppies at 768kHz or as fast as you reasonably can.
  8. rmpfyf

    PDX DAC project

    Keep the Pink Faun card. It'll be useful in other projects. I went through this with my current build, came very close to purchasing the PF but I wanted 384kHz (being the limit of my DAC IC), which isn't natively possible. Had some long chats with CMedia and PF alike about how it would be possible, and it's a cluster. The upgrade path from the company that makes the core chip in your PF is actually USB with proper reclocking. NOS is great. Aside from the extra speed (the 1704's will do 768kHz if you like!) you can flip from 8x oversampling to modern filtering - there's a ton of good upsampling options out there from min phase through linear and back again. You can end up playing most tricks MQA does if you like. The results are a genuine step forwards from filtering as implemented when the DAC IC's were first shipped. You can apply far more computational grunt than the DF allows at very little money today. You'd not be the only DAC in town doing this with a 1704UK, the (very highly regarded and extremely accurate) Phasure NOS1 does the same (albeit with 8x chips - which you don't have - so live with a little more noise). You can do the upsampling cheap with a PC or a DSP alike. Whilst there you can pre-feed it some room correction or whatever too. Lots of fun to be had. Hell, run it at 768kHz and use XXHighEnd. You'll basically have a Phasure with more noise. USB doesn't mean so much when you treat the data within it properly. An Amanero is not 'properly'.
  9. @Zaphod Beeblebrox Agreed. There's probably money in a device audiophiles can buy, plug in and log/test power quality. There's market for it. Cheaper than calling over a proper power engineer with a $50k Yokogawa and time. I've got people that can develop this. Interested in collaborating?
  10. Easy there. Whilst the mainland keeps frequency within our tolerance requirements, compared to many grids our frequency regulation isn't that tight. In a relative sense we don't do so well. Whether it's good enough, or at all audible, is another matter. Huh? Most homes are reticulated at considerably less. I've logged a 1-second maximum of just under 12kW including electric HVAC, dryer and car charging.
  11. rmpfyf

    PDX DAC project

    USB isn't a fantastic format for audio at all, though remember what's being attempted here - buffering and reclocking. If you were going straight in without buffering or logic-based reclocking (happens surprisingly a lot) then yes, I2S is likely to sound better, particularly if it's off a PCI card with a dedicated interrupt. If you're streaming into a large buffer and using logic to clock out of that then your design effectively resets jitter at that point. Yes, it's all a little cleaner going I2S all the way but as stated by others there's also a lot to get wrong with I2S over distances it was never intended for. Agree with @davewantsmoore here - in this instance USB is more practical, and the proposed setup makes it inconsequential.
  12. rmpfyf

    PDX DAC project

    Yes if NOS... can actually go quicker than that too.
  13. Had mentioned this. Common to many audiophile builds (don't quite run it myself, there's a little more to be had in not being fully tickless, but it's the right direction). Still vote partial BIOS issue - even w/tickless can get TSC and HPET running here quite happily. You will notice a change in kernel tick audibly.
  14. rmpfyf

    PDX DAC project

    Save your money - just use the Amanero into the I2S board. It'd be heading into a buffer anyway. You will want better clocks for the dual XO board. If upsampling (see below) I'd go single clock. Get the simultaneous board and drop the DF - run NOS to 384kHz - https://www.diyaudio.com/forums/digital-line-level/220407-drive-nos-ad1865-62-pcm1704-02-63-tda1541-fifo-universal-i2s-pcm-driver-board.html Consider feeding it 384kHz upsampled at any rate, that'll give you excellent filtering options either out of a PC or a resampler between that and the PC. Min phase, f'rinstance, sounds excellent at high frequency. The Pink Faun board won't pass 192kHz - that's the main reason to move beyond it - the CMedia chip on it is the limitation. There are higher speed CMedia chips that will do 384kHz, though they're effectively PCI>USB anyway, at which point you'd just go USB. You could convince Pink Faun to support 384kHz by interleaving adjacent channels on their 8-channel variant, but it's a lot of work.
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