Well if Dean Martin, Sami Davis & Frank Sinatra can be call the Rat Pack,
I don't see why you can't name this dac as such & isn't it great to pay a little tribute to the man who puts in the effort & generously share his experiments with us ?
Cheers
Added 3 extra DAC chips to an old PhiDAC SE I had lying around - same kind of improvement in ambience (or bloom or air). Fairly simple mod for anyone who has one (@obscurus maybe?).
Even though PhiDAC (original) isn't designed for driving headphones it does a great job into my HD6XX which are 300ohm and fairly efficient. No need for any more volume than 2VRMS. Mind you I am itching to get a balanced cable set so I can try them with a balanced pair of SE buffs 🙂
Even though PhiDAC (original) isn't designed for driving headphones it does a great job into my HD6XX which are 300ohm and fairly efficient. No need for any more volume than 2VRMS. Mind you I am itching to get a balanced cable set so I can try them with a balanced pair of SE buffs 🙂
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Im getting curious Richard of how your QuadRat-AB sounds like when compared to my 1541 dac . Perhaps will pick up a set when I've the time to build.
Cheer
Cheer
Perhaps we'll do another round of kits for QuadRat DAC if there's interest?
As anyone else interested in having the filter on a plug-in? I was thinking the passive filter would be better suited to that but the NOS droop is handled in the active filter. So it doesn't initially look like a replaceable passive filter can help much with different sample rates. But its early days yet, we can look into that.
As anyone else interested in having the filter on a plug-in? I was thinking the passive filter would be better suited to that but the NOS droop is handled in the active filter. So it doesn't initially look like a replaceable passive filter can help much with different sample rates. But its early days yet, we can look into that.
A few of us are most interested in a DAC for inclusion in a traditional stereo system which is not computer centred! PLEASE do not loose that ability for this DAC! 😉
Many Thanks
🙂
Many Thanks
🙂
Just out of curiosity - not being 'computer centred' means it doesn't need a computer connected to it to set it up (as some DAC chips do, with I2C ports)? If that's your request rest assured I shall always create 'stand alone' DACs. I am at some point thinking of including a small CPU to act as digital filter (2X or 4X oversampling) - if and when I do that it will still be stand-alone.
Hi Richard
Sorry OT question, how serious is the coronavirus now, there seems to be rumors going around that 90,000 are affected. I'm skeptical about the figures though.
Thks
Sorry OT question, how serious is the coronavirus now, there seems to be rumors going around that 90,000 are affected. I'm skeptical about the figures though.
Thks
I'm skeptical of such high figures too. My wife (being Chinese) reads the local information which is surprisingly detailed. There are 32 cases so far in my city (Hangzhou) which has roughly 5million residents - the statistics are broken down into the various localities so I know my locality has 3 and they're all of people who travelled to Wuhan.
As to the overall figures if you include all the people being directly monitored (suspected cases with symptoms but not yet confirmed) plus all those without symptoms being monitored then about 50,000 in total is my understanding. About 40,000 in this last category.
As to the overall figures if you include all the people being directly monitored (suspected cases with symptoms but not yet confirmed) plus all those without symptoms being monitored then about 50,000 in total is my understanding. About 40,000 in this last category.
War criminals are operating in full swing, even before war had been declared.
Replacement filter in this section - sorry my mistake.
Replacement filter in this section - sorry my mistake.
abraxalito,
headline: U.S. diplomats evacuated from China to California. Don't take any chances, be ready to move from China. You can return to China when it is safe to do so. Please take care.
headline: U.S. diplomats evacuated from China to California. Don't take any chances, be ready to move from China. You can return to China when it is safe to do so. Please take care.
This one ? US orders charter flight to evacuate citizens and diplomats from virus-stricken Wuhan — report — RT USA News
Thanks for your concern - I'm prepared to take my chances here though for the time being. I'd get bored very quickly if I went back to UK separated from all my electronics parts and equipment.
Thanks for your concern - I'm prepared to take my chances here though for the time being. I'd get bored very quickly if I went back to UK separated from all my electronics parts and equipment.
Here's the first pass schematic for PhiDAC Quad (or QuadRat DAC whatever). The part that's not really fixed in stone is the CLC filter as the prototypes I built were using SLF7045 inductors selected in value rather than TDK MLFs (too much soldering on the latter!). If that change is responsible for part of the improvement in SQ then the MLFs will have to go....
Do we need magnetically shielded coils?
A goal is to isolate and slow down China economy. If doesn't work, then take my world: You will have no place to hide on this planet.
It seems that the MLF inductors are contributing to higher frequency distortion at high signal levels. I compared distortion between SLF7045s and the original MLFs and found the SLFs contributed less. Not sure whether this is audible yet.
Another thing I have played with is the biassing current source - its better to move that to connect directly to the TDA1387s output rather than downstream on the output of the CLC filter. That way reduces the DC current through the MLFs which I reckon was making an audible degradation, especially to the LF ambience.
So then there's a trade-off here - the MLFs I chose after using SLFs on the original lingDAC because when they're used in series the tolerance of the overall inductance gets better (on average). If we go back to the 20% tolerance SLF7045s then either I need to measure and pre-select inductors for kits (making them more expensive) or DIYers will need an inductance meter and adjust other filter components (mainly NP0 caps) accordingly. Just putting a randomly chosen inductor into the CLC could result in fairly wonky FR.
A third alternative would be to try to source some better tolerance inductors. I'll see what's on offer from Mouser. In the meantime, feedback as to what potential builders of PhiDAC Quad would prefer would be good 🙂
Another thing I have played with is the biassing current source - its better to move that to connect directly to the TDA1387s output rather than downstream on the output of the CLC filter. That way reduces the DC current through the MLFs which I reckon was making an audible degradation, especially to the LF ambience.
So then there's a trade-off here - the MLFs I chose after using SLFs on the original lingDAC because when they're used in series the tolerance of the overall inductance gets better (on average). If we go back to the 20% tolerance SLF7045s then either I need to measure and pre-select inductors for kits (making them more expensive) or DIYers will need an inductance meter and adjust other filter components (mainly NP0 caps) accordingly. Just putting a randomly chosen inductor into the CLC could result in fairly wonky FR.
A third alternative would be to try to source some better tolerance inductors. I'll see what's on offer from Mouser. In the meantime, feedback as to what potential builders of PhiDAC Quad would prefer would be good 🙂
Are there bigger MLF's? Paralleling instead in series? A mixed parallel/series network (in case of going out of the range)?
I agree, multiplying number of DAC chips increase a biasing problem in this design.
I agree, multiplying number of DAC chips increase a biasing problem in this design.
By 'bigger' do you mean larger package or higher value? None larger than 0805 and higher values have even lower current ratings. But on my Mouser search I did come across some quite nice looking TDK wound inductors in 1210 package (3X larger area than 0805). So if and when Taobao comes back to life again I'll get some ordered. They are more expensive but the upside is I won't need quite as many. 47uH looks to be the sweet spot in terms of best Q. Oh and another upside of these will be the current rating goes up by a significant factor, meaning you can stack even more chips without worry of distortion if you're so inclined.