@Luke - Rdc only matters in the hypothetical case that the DAC output current is converted into voltage on the primary. Since that clearly doesn't happen, its not really important. Where did you get your estimate for the primary impedance? 800mH gives j100k @20kHz but none of my primaries are anywhere near that.
Yeah, I never got it in a case, so it doesn't get much use, but I like it. I cant decide between this and my Buffalo dac.
Hi Abraxalito, I read one of your posts in this thread that said your primary inductance is 800mH, that explains it I got old data
It wasn't old in fact very up to date. But I was talking about the secondary when I mentioned the figure of 800mH. With GrossDAC I'm using passive I/V so that calls for much higher inductances, up to 250H or so. The primary inductances are in the range of a few mH but these don't determine the voltage on the DAC's output as the L is shunted by the resistor on the secondary (typically 5-10k with passive I/V).
BOM and schematic for PhiDAC SE
It's been a while but finally here are two documents relating to PhiDAC SE (that's the version which drives some headphones direct) - the schematic and the BOM.
PhiDAC SE consists of 4 PCBs in total - the main board plus 3 'pants' boards which each hold 8 low ESR capacitors and are wired beneath the PCB on thick wire 'legs'.
It's been a while but finally here are two documents relating to PhiDAC SE (that's the version which drives some headphones direct) - the schematic and the BOM.
PhiDAC SE consists of 4 PCBs in total - the main board plus 3 'pants' boards which each hold 8 low ESR capacitors and are wired beneath the PCB on thick wire 'legs'.
Ooooooooooooooooooooooooooohhhhhhhhhhh .... you lil' tease, you!!!
But I'm a bit too backed up to read or build at the moment.
How about some free samples?
I give fair reviews. Promise, toots
Review of the Phidac.
matt_garman kindly sent a kit and I must admit, this was my first smd soldering, aside from opamps. Gnat butts and sugar ants. As a noob smd solderer this took the better part of a day and a half.
All the parts were supplied including electrolytic caps. I first put it together with the provided caps (except on the output, which I just could not bring myself to put bad caps there) and gave it a listen.
Years ago I spent some time building cmoy headphone amps because they are so simple and fun. What is best about cmoys is that they teach you to hear each component that goes into them, simply because there are so few components. This is especially true for capacitors. This is why I cannot love Panasonic FM, because they actually have a brittle top end that is fatiguing. SEPF polymer caps are dull with weak bass. Other caps can have sonic holes in the spectrum. etc..
So listening to the phidac with the given caps, it is obvious that the frequency range has dead spots and other problems in it. Out with the old caps and in with quality audio caps.
My favorite combo is Elna Silmics and Nichicon Muse. Those two married together produce a beautiful, clear and rich sound.
After replacing all caps and giving it a listen, it is astonishing! This phidac is absolutely addicting in its presentation. Incredible separation and isolation of each instrument. Great decay on sounds like Markw4 noticed. It almost sounds like a bit of reverb but its not. It does present a real depth to the sound. The detail is better than my es9018 and also shows the 9018 to have a more 2d presentation that has a plastic sheen to it. The details are also less harsh than with the 9018. This betters the 9018 in every way.
Another nice difference from the 9018 which always has an "edge" to sharp sounds is that the phidac can do edge and also do soft.
Abraxalito, you said you are using capacitor banks to try to fix shortcomings in the higher frequencies. (evident in choral works) I think this is just chasing bad sounding capacitors with more capacitance.
The supplied caps are in the 1500uf range and I am using 2x 470uf instead in the given positions. If anything I am wondering if this might be too much. There is a sweet spot for capacitance where too much is also not better. I want to try going as low as 100uf and see if that still works. However, the dac sounds so good right now, my motivation to mess with it any more is pretty low. The bass is deeper, fuller and more textured and the highs more sweetly presented than with the es9018. Intimate voices are spectacular and present in a way that you can place them at the exact distance from you. Every genre of music is played with authority and clarity and stunning 3d, including choral works. (currently listening to Bach, Mass in B minor, nothing confused or muddy about it).
I am feeding the signal to my dc coupled headphone amp and listening on Sennheiser 650.
To everyone who has a phidac, put some good caps in there. Try the Silmic and Muse combo with the bipolar muse on the output. This dac is better than any other I have heard under $300.
So, to sum up, this is my first experience with a NOS dac and I am sold. If this little, inexpensive diy dac sounds this good compared to my other SD dacs then I have caught the NOS bug.
With better caps
matt_garman kindly sent a kit and I must admit, this was my first smd soldering, aside from opamps. Gnat butts and sugar ants. As a noob smd solderer this took the better part of a day and a half.
All the parts were supplied including electrolytic caps. I first put it together with the provided caps (except on the output, which I just could not bring myself to put bad caps there) and gave it a listen.
Years ago I spent some time building cmoy headphone amps because they are so simple and fun. What is best about cmoys is that they teach you to hear each component that goes into them, simply because there are so few components. This is especially true for capacitors. This is why I cannot love Panasonic FM, because they actually have a brittle top end that is fatiguing. SEPF polymer caps are dull with weak bass. Other caps can have sonic holes in the spectrum. etc..
So listening to the phidac with the given caps, it is obvious that the frequency range has dead spots and other problems in it. Out with the old caps and in with quality audio caps.
My favorite combo is Elna Silmics and Nichicon Muse. Those two married together produce a beautiful, clear and rich sound.
After replacing all caps and giving it a listen, it is astonishing! This phidac is absolutely addicting in its presentation. Incredible separation and isolation of each instrument. Great decay on sounds like Markw4 noticed. It almost sounds like a bit of reverb but its not. It does present a real depth to the sound. The detail is better than my es9018 and also shows the 9018 to have a more 2d presentation that has a plastic sheen to it. The details are also less harsh than with the 9018. This betters the 9018 in every way.
Another nice difference from the 9018 which always has an "edge" to sharp sounds is that the phidac can do edge and also do soft.
Abraxalito, you said you are using capacitor banks to try to fix shortcomings in the higher frequencies. (evident in choral works) I think this is just chasing bad sounding capacitors with more capacitance.
The supplied caps are in the 1500uf range and I am using 2x 470uf instead in the given positions. If anything I am wondering if this might be too much. There is a sweet spot for capacitance where too much is also not better. I want to try going as low as 100uf and see if that still works. However, the dac sounds so good right now, my motivation to mess with it any more is pretty low. The bass is deeper, fuller and more textured and the highs more sweetly presented than with the es9018. Intimate voices are spectacular and present in a way that you can place them at the exact distance from you. Every genre of music is played with authority and clarity and stunning 3d, including choral works. (currently listening to Bach, Mass in B minor, nothing confused or muddy about it).
I am feeding the signal to my dc coupled headphone amp and listening on Sennheiser 650.
To everyone who has a phidac, put some good caps in there. Try the Silmic and Muse combo with the bipolar muse on the output. This dac is better than any other I have heard under $300.
So, to sum up, this is my first experience with a NOS dac and I am sold. If this little, inexpensive diy dac sounds this good compared to my other SD dacs then I have caught the NOS bug.
With better caps
I suggested to Abraxalito in an old pm to try also Pan. FR. He told Nichicon was better according to him (without a try)... Nichicons for me are often too muddy and velvett but the cap ypu're talking about and also the bipolars...
Bravo Pelopidas, I can't agree more about what you are saying ! Good job... Yes a good sound is also a good choice of passive parts to weak or wake up some trade offs... whatever the good job around the layout, design and active parts: you DO need this passive parts job for an optimization : it's not liked by designers because they often can not measure it, it doesn't mean it doesn't exist.
I believe in people synergy, it always gives better results than standalone work which is always limited by stupborn, selfisch if not egotic sides of our individual characters !
Bravo again !
Bravo Pelopidas, I can't agree more about what you are saying ! Good job... Yes a good sound is also a good choice of passive parts to weak or wake up some trade offs... whatever the good job around the layout, design and active parts: you DO need this passive parts job for an optimization : it's not liked by designers because they often can not measure it, it doesn't mean it doesn't exist.
I believe in people synergy, it always gives better results than standalone work which is always limited by stupborn, selfisch if not egotic sides of our individual characters !
Bravo again !
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You didn't say what you are using as a digital source, or for a power supply. Those things could possibly make some difference in sound too...
Unable to view the photo of your dac Pelopidas. Which Muse 470uf caps are you using, if they're KZ rated at 25v, pls change to 50v version sit back & listen again.
Btw I really don't understand why so many ppl are in favor of Silmic ll, they don't really sound that great overall. The highs are not nartural & there's an added fatness to the sound including the bass. The original Silmic Ars were better but lacking in highs which sounded a little coarse.
Btw I really don't understand why so many ppl are in favor of Silmic ll, they don't really sound that great overall. The highs are not nartural & there's an added fatness to the sound including the bass. The original Silmic Ars were better but lacking in highs which sounded a little coarse.
@pelopidas - thank you very much for your in detail review. Appreciated, and glad you found the DAC to your liking with your own choice of caps. For PhiDAC I mostly used what caps were cheaply available on Taobao and didn't do any cap comparisons.
@diyiggy - some might get the wrong impression from what you wrote so here is a little bit of background. First, according to my (fallible) memory your PM came along when I was working on PhiDAC SE and you'd said that Pana caps (I don't remember the designation) sounded better to your ears than Nichicon HZ (the designation is important) which you hadn't liked. I recall I expressed skepticism as the HZs were the better measuring ones in regards to ESR. I asked you for more context as to circuit conditions when HZ's hadn't sounded good but I don't remember being given any. In the end I decided to order some Pana FJs based on your praise as they were cheaper on Taobao and more readily available than Nichicon HZ even though the datasheet ESR was poorer. I didn't get the improvement you got but any degradation wasn't significant vs HZs so I thanked you for the recommendation as it saved me a little money. I also tried some other Pana's as output couplers on PhiDAC SE and liked them better than those I originally had used so I changed over.
@sumotan - I can't view pelopidas's pictures either, even with VPN.
@diyiggy - some might get the wrong impression from what you wrote so here is a little bit of background. First, according to my (fallible) memory your PM came along when I was working on PhiDAC SE and you'd said that Pana caps (I don't remember the designation) sounded better to your ears than Nichicon HZ (the designation is important) which you hadn't liked. I recall I expressed skepticism as the HZs were the better measuring ones in regards to ESR. I asked you for more context as to circuit conditions when HZ's hadn't sounded good but I don't remember being given any. In the end I decided to order some Pana FJs based on your praise as they were cheaper on Taobao and more readily available than Nichicon HZ even though the datasheet ESR was poorer. I didn't get the improvement you got but any degradation wasn't significant vs HZs so I thanked you for the recommendation as it saved me a little money. I also tried some other Pana's as output couplers on PhiDAC SE and liked them better than those I originally had used so I changed over.
@sumotan - I can't view pelopidas's pictures either, even with VPN.
Hi Richard,
Speaking of bi polar caps, contrary to what many thinks, they still have polarity in them. Simply measure with dvm & it will show. From my experience, if one connects the neg leg of the cap to the positive pin of a positive rail supply, you'll get better sound. I believe it was Peter Daniels who discovered this & it holds true.
Speaking of bi polar caps, contrary to what many thinks, they still have polarity in them. Simply measure with dvm & it will show. From my experience, if one connects the neg leg of the cap to the positive pin of a positive rail supply, you'll get better sound. I believe it was Peter Daniels who discovered this & it holds true.
I tried to source some bipolar caps on Taobao for my GrossDAC project but couldn't find a reliable and cheap cap so opted to use back-to-back normal polarized 'lytics with a biassing resistor. Its my understanding that a bipolar cap is internally two polarized caps back-to-back, the advantage of making one yourself is you can ensure correct bias.
Sure enough but normally ESR isn't a concern for coupling applications as the impedance is high in comparison to power supplies (where ESR is a concern).
Capacitance halves too by placing two in series so you have to use twice the value cap. Usually that'll have lower ESR than the original one. I think the extra PCB area is more of a concern in practice than the extra ESR.
Capacitance halves too by placing two in series so you have to use twice the value cap. Usually that'll have lower ESR than the original one. I think the extra PCB area is more of a concern in practice than the extra ESR.
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Actually ...
An externally hosted image should be here but it was not working when we last tested it.