Paging all interested parties : please contribute to this thread (or PM me) if you're of the view that @hollowman has contributed content to the discussion.
The challenge
I suggest Barxy send me pre-built implementations of both Phi and Ling (two of EACH would we ideal so we could eliminate sample-to-sample variations).
I would then incorporate each of them into the same CDP shown in #84, and compare/contrast Phi/Ling to the default implementation, as well as all my other CDPs and DACs, including my ultimate reference -- a souped-up SAA7220/TDA1541A Philips CD-60.
It was back in post #84 that I graced this thread with highly-insightful comments and pics of my TDA1387 implementation.
I suggest Barxy send me pre-built implementations of both Phi and Ling (two of EACH would we ideal so we could eliminate sample-to-sample variations).
I would then incorporate each of them into the same CDP shown in #84, and compare/contrast Phi/Ling to the default implementation, as well as all my other CDPs and DACs, including my ultimate reference -- a souped-up SAA7220/TDA1541A Philips CD-60.
Braxy:
Package it up with jacks and an attractive case. Send samples out to 6 Moons, Stereophile, Head-Fi, etc., etc.
I dare ya' ... I double dare ya!!!!!!!!!!!!
Those buyin' in on this .... why'd y'all needz 10? Cuz they're cheap and y'all ain't yet graduated from your Hoarding Anonymous program, right?
Seriously, y'all only needz one or two ... the rest will populate the ol' junk drawer. Even that one or two will get all but a few listens until it, too, heads into da pile-o-been-there-done-thats.
BTW.... Y'all are welcome. All this metaphiliosohy iz on da house. I know how much Braxy luuuuuuuuuvs wizdumb ... it's in his sig line.
Package it up with jacks and an attractive case. Send samples out to 6 Moons, Stereophile, Head-Fi, etc., etc.
I dare ya' ... I double dare ya!!!!!!!!!!!!
Those buyin' in on this .... why'd y'all needz 10? Cuz they're cheap and y'all ain't yet graduated from your Hoarding Anonymous program, right?
Seriously, y'all only needz one or two ... the rest will populate the ol' junk drawer. Even that one or two will get all but a few listens until it, too, heads into da pile-o-been-there-done-thats.
BTW.... Y'all are welcome. All this metaphiliosohy iz on da house. I know how much Braxy luuuuuuuuuvs wizdumb ... it's in his sig line.
This isn't a highly insightful idea for the surprisingly simple reason that publications have rules about items they'll review. Stereophile requires it to be a product (i.e. in production) and available at a minimum number of outlets. Makes sense to me that an item has to be fairly easily available for them to review it - why create frustration in readers unnecessarily by writing an impeccable report of a DAC that readers have no hope of finding? 6moons has a policy of requiring advertising to be placed before they'll do a review - what is there to advertise when there's no mass-produced product?
As for Head-Fi, I dunno what their rules are - anyone know and willing to chip in? Does anyone know of any publication that reviews DIY-only kit?
Coolio Mark - you're already at the head of the line for receiving one of the v2 DACs. Hopefully the bare boards will turn up in the next couple of days, then I'll have the Chinese New Year holiday period to build a few up, test and measure and get them sent out 🙂
FREE advice!!!!!!!!!
If the product gets a lotta attention in posts/threads, it may grab the attention of "professional" reviewers ... or just some Chinese manuf. that's willing to mass-produce it for sale on Amazon/eBay/Taobao.
** The "plain ol' member" should have a decent post count, and been an active member for several years. I ain't sure about other trades/deals -- a lotta stuff happens in PMs and private exchanges.
You're welcome for all this FREE advice!!!!!!!!!!!
... so I assume my DACs are in the mail?
At Head-Fi (or similar sites like SBAF or Computeraudiophile or even some YouTube vlogs), you just send the product to a plain ol' member** and they'll post their experience with it. If the "review" is favorable, the product will attract attention. Nothin' new, folks ... DIYA has many "product" threads like this (and nothin' wrong with that).
If the product gets a lotta attention in posts/threads, it may grab the attention of "professional" reviewers ... or just some Chinese manuf. that's willing to mass-produce it for sale on Amazon/eBay/Taobao.
** The "plain ol' member" should have a decent post count, and been an active member for several years. I ain't sure about other trades/deals -- a lotta stuff happens in PMs and private exchanges.
You're welcome for all this FREE advice!!!!!!!!!!!
... so I assume my DACs are in the mail?
I think Richard understood your sense of humour the first time, no need to repost, and definitely no need to use bigger and bolder fonts. Can we please continue with the DAC design discussion? Not sure if you already had some discrepancies with him in the past, but it's quite violent for the rest of us and adds nothing to the conversation. Thank you.
New PCBs are in da house
Yeah, let's do that. The v2 PCBs (although I began the numbering at v0 so these are marked v1, I'll call them v1 from now on) came earlier than I expected. They also sent about double the quantity we ordered (and paid for) so I could be quite busy stuffing over the next week 😀 The v1 is easier to stuff because the parts are laid out in a more orderly fashion, I reckon it'll take between 1 and 2 hours per board to get loaded.
Here are the first three boards with the semis and FBs already on, in process of caps being soldered. Incidentally the new one is also lower power than the original, having deleted a current source its draw is a little over 60mA @ 9V.
Once I have a tested working and characterized v1 then I'll update the BOM and start the process of creating kits. Is there any interest in a Mouser BOM incidentally? It'll be fairly expensive to order just 1 off from there, my guess is between $40 and $50 and that won't include the DAC chip because that's not a production item.
Yeah, let's do that. The v2 PCBs (although I began the numbering at v0 so these are marked v1, I'll call them v1 from now on) came earlier than I expected. They also sent about double the quantity we ordered (and paid for) so I could be quite busy stuffing over the next week 😀 The v1 is easier to stuff because the parts are laid out in a more orderly fashion, I reckon it'll take between 1 and 2 hours per board to get loaded.
Here are the first three boards with the semis and FBs already on, in process of caps being soldered. Incidentally the new one is also lower power than the original, having deleted a current source its draw is a little over 60mA @ 9V.
Once I have a tested working and characterized v1 then I'll update the BOM and start the process of creating kits. Is there any interest in a Mouser BOM incidentally? It'll be fairly expensive to order just 1 off from there, my guess is between $40 and $50 and that won't include the DAC chip because that's not a production item.
Attachments
Hi abraxalito!
I'm intrigued of your general thinking about audio stuff. I would very much like to test a creation which implements them. May I line up for buying one of your working development/test builds once you don't need it but still approve on it's performance?
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I'm intrigued of your general thinking about audio stuff. I would very much like to test a creation which implements them. May I line up for buying one of your working development/test builds once you don't need it but still approve on it's performance?
//
I dug out a much older TFcard I2S player and was surprised it works with the Android APP. A killer bargain-basement combination with PhiDAC - hard to beat these ATS2825 players (with the right firmware, not all such players on Taobao are equivalent).
The first three v1 PhiDACs are now working well, next up is checking their frequency responses to verify the two on-board filters are behaving as intended (NOS droop correction in particular). I plan to do this by generating a chirp using Audacity and recording the output with my SDcard recorder then examining the resulting .wav file with Audacity. Simply feeding the output into my AC voltmeter won't work well enough I fear because the image filtering doesn't suppress ultrasonics fiercely enough. As a result the HF energy gets falsely boosted by the inclusion of images.
The first three v1 PhiDACs are now working well, next up is checking their frequency responses to verify the two on-board filters are behaving as intended (NOS droop correction in particular). I plan to do this by generating a chirp using Audacity and recording the output with my SDcard recorder then examining the resulting .wav file with Audacity. Simply feeding the output into my AC voltmeter won't work well enough I fear because the image filtering doesn't suppress ultrasonics fiercely enough. As a result the HF energy gets falsely boosted by the inclusion of images.
Attachments
Hi abraxalito,
I think your filter curve is quite steep. Even my simple filter can reach -70dB at 1Mhz (-150dB @ 100Mhz). I can't imagine how these HF energy can pass through it.
Poting
Hi Poting
Its ultimately a very steep filter but close to the audio band it hasn't got extreme sharpness because having a sharp filter entails high Q and that makes the circuit very sensitive to component tolerances. LingDAC's filter is much higher Q (steeper at the band edge) and that's what makes it more tricky to build.
I do plan to connect my RF analyser to the PhiDAC to see what it puts out above the audio band. When I get a plot I'll put it up.
Its ultimately a very steep filter but close to the audio band it hasn't got extreme sharpness because having a sharp filter entails high Q and that makes the circuit very sensitive to component tolerances. LingDAC's filter is much higher Q (steeper at the band edge) and that's what makes it more tricky to build.
I do plan to connect my RF analyser to the PhiDAC to see what it puts out above the audio band. When I get a plot I'll put it up.