Congratulations on the new dac completion! Hopefully a few people will be willing to try building one and report their listening impressions. Hard to get people do that though, and drastically harder as construction complexity goes up. Also, for reasons that can never be fully understood, some things catch on and other things don't. Regarding typical S-D dacs, I would agree that making one sound really good is quite involved, and most implementations aren't up to a very high level. If you would like to send me one of yours, I would be happy to compare it to the best S-D I know how to make and post how it sounds in comparison. I'm guessing it probably sounds pretty good due to your careful implementation.
Thanks Mark, I'll be happy to send one of the first batch over to you for your appraisal once I've built enough up. It should be something of a David & Goliath comparison against your Benchmark DAC 
In contrast to lingDAC this DAC in theory shouldn't need an LCR meter to help select the right value of inductors. Also no DVM is required to trim the I/V stage DC offset as opamps are inherently DC-stable. These two aspects I hope will make the design more amenable to beginners in DIY digital audio.
In contrast to lingDAC this DAC in theory shouldn't need an LCR meter to help select the right value of inductors. Also no DVM is required to trim the I/V stage DC offset as opamps are inherently DC-stable. These two aspects I hope will make the design more amenable to beginners in DIY digital audio.
Updated schematic
Two PCBs have been built up now, here's the revised schematic which will reflect the next batch of PCBs. Gerbers for those I'll put up in due course. BOM to follow shortly - Taobao price for all parts excluding PCBs is about 16RMB when ordered in sufficient volume so that delivery charges fade into the noise. PCBs are typically 3RMB so the total is 19RMB or $2.77 at today's fx rate.
I'm considering making bulk kits available (say 10 boards' worth as smaller quantities don't make economic sense). Anyone interested?
Two PCBs have been built up now, here's the revised schematic which will reflect the next batch of PCBs. Gerbers for those I'll put up in due course. BOM to follow shortly - Taobao price for all parts excluding PCBs is about 16RMB when ordered in sufficient volume so that delivery charges fade into the noise. PCBs are typically 3RMB so the total is 19RMB or $2.77 at today's fx rate.
I'm considering making bulk kits available (say 10 boards' worth as smaller quantities don't make economic sense). Anyone interested?
Here is the BOM.
I'm wondering about the bulk kits idea - I'd like to encourage more ultra-cheap DACs out into the world and Taobao sourcing is the only way I know of to get this DAC to below $3 in components. As PCBs tend to come in quantity 10 minimum to me it kind of makes sense to kit up for a build of 10 DACs. Then shipping costs won't swamp the parts cost. What I don't know is how much labour's involved in putting together kits so at this stage I can only make a rough guess. Would there be any takers for a 10-off kit priced at $50 (including PCBs)? I'd guess this might be attractive for people who'd like to build multi-channel DACs for digital XO'd active speakers. For those who don't need more than a single stereo DAC, they could potentially sell their 9 remaining built-up PhiDACs to those who prefer not to get involved with soldering, more than recouping the cost of their own DAC.
I'm wondering about the bulk kits idea - I'd like to encourage more ultra-cheap DACs out into the world and Taobao sourcing is the only way I know of to get this DAC to below $3 in components. As PCBs tend to come in quantity 10 minimum to me it kind of makes sense to kit up for a build of 10 DACs. Then shipping costs won't swamp the parts cost. What I don't know is how much labour's involved in putting together kits so at this stage I can only make a rough guess. Would there be any takers for a 10-off kit priced at $50 (including PCBs)? I'd guess this might be attractive for people who'd like to build multi-channel DACs for digital XO'd active speakers. For those who don't need more than a single stereo DAC, they could potentially sell their 9 remaining built-up PhiDACs to those who prefer not to get involved with soldering, more than recouping the cost of their own DAC.
Depends how they sound doesn't it? People would have to be convinced they aren't toys at that price.
Its the old thing inventors always face which is that is that it isn't enough to build a great product and assume people will want it. You have to do some more work to sell it. Word of mouth from happy buyers is always best, but you have to get some out there to see if it can take off.
Its the old thing inventors always face which is that is that it isn't enough to build a great product and assume people will want it. You have to do some more work to sell it. Word of mouth from happy buyers is always best, but you have to get some out there to see if it can take off.
Hi JMF - the answer is yes to both questions. There's a phase inverting switch on the DAC which allows it to generate the anti-phase half of a balanced DAC. So the $50 would in effect give you 10 single-ended or 5 balanced DACs. Although I'd have to admit here that the improvement in PSRR from a balanced DAC would be lost when running from two separate supplies (as each board has its own dedicated PSU regulator). That's something for me to bear in mind for a future design - ideally a single DAC board would be configurable to stereo/SE or mono/balanced.
Great to hear @obscurus, that's excellent news. Do you have a use for all ten DACs yourself or would you be offering some kits or built up DACs for sale to others?
In a spare moment I had this afternoon I started costing the BOM using small quantity pricing from Mouser. It looks like that's going to be in the region of 20X the price from Taobao sellers, but I've not completed the exercise yet.
In a spare moment I had this afternoon I started costing the BOM using small quantity pricing from Mouser. It looks like that's going to be in the region of 20X the price from Taobao sellers, but I've not completed the exercise yet.
Those who are interested in getting individual DACs had better talk sweetly to those thinking seriously of ordering kits
As regards lingDAC kits, I think its not so suitable for kitting. There's quite a bit more labour involved in selecting inductors for the filter so the price would have to reflect that additional labour.
Some good news for those interested in the PhiDAC - I've just today found out that the tendency of the soundstage to 'hang around' the speakers leaving the central portion less well lit-up was actually due to the output caps I was using. A simple change of those to Nichicon (from a local Chinese brand) has improved that considerably.
As regards lingDAC kits, I think its not so suitable for kitting. There's quite a bit more labour involved in selecting inductors for the filter so the price would have to reflect that additional labour.
Some good news for those interested in the PhiDAC - I've just today found out that the tendency of the soundstage to 'hang around' the speakers leaving the central portion less well lit-up was actually due to the output caps I was using. A simple change of those to Nichicon (from a local Chinese brand) has improved that considerably.
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I have plenty of places to place a DAC, not all ten but I'm ok with it. Do you live in Hangzhou? Then it is easier to ship to my country, I think.
Hi Abraxalito, you can count me in if you launch the process.
By the way, in my TAS3251 project ([design log] Neat 2x170W I2S in, I2C controlled, integrated DSP amp (TAS3251)), I will follow your advice to increase the cap for AVDD to 220uF with about 0.1ohm ESR. If you have other advices on the project or improvements for TPAxxxx, I will be happy if you post there.
Best regards,
JM
Yes, I'm firmly in Hangzhou. Where are you? Can't see any indication on your posts or profile
@JMF - I will take a look.
Yes, I'm firmly in Hangzhou. Where are you? Can't see any indication on your posts or profile
@JMF - I will take a look.
I'm from Viet Nam, very close right
I think shipping from China to my country is quite easy!
Cheap digital source makes for killer music player
I've just hooked up one of these Bluetooth/SDcard players to my DAC and I'm impressed. No clicks or nasty noises just gentle fades in/out when switching between Bluetooth source and SDcard. Plug in the card and it just plays (tried FLAC, not sure if it supports APE yet though) - volume control is included so PhiDAC can drive a poweramp direct using this. Couldn't be happier and the price is just 88RMB (about $13). There's even an APP to control from phone, not downloaded that yet.
??C20 ??4.2 ??SD? U???? ????USB?? I2S??-???
I've just hooked up one of these Bluetooth/SDcard players to my DAC and I'm impressed. No clicks or nasty noises just gentle fades in/out when switching between Bluetooth source and SDcard. Plug in the card and it just plays (tried FLAC, not sure if it supports APE yet though) - volume control is included so PhiDAC can drive a poweramp direct using this. Couldn't be happier and the price is just 88RMB (about $13). There's even an APP to control from phone, not downloaded that yet.
??C20 ??4.2 ??SD? U???? ????USB?? I2S??-???
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I'm from Viet Nam, very close right
Yeah right next door to Yunnan province. Which is a fair distance from here. Where in Vietnam? I was there for a holiday in 1999, very impressed with the food and culture
Hanoi was my favourite city overall but for art work I think Hoi An was the place.
Yeah right next door to Yunnan province. Which is a fair distance from here. Where in Vietnam? I was there for a holiday in 1999, very impressed with the food and culture
Im from Ha Noi 🙂 And I also think Hoi An is a nice place to travel, have been there several times.