no, nothing like that.
This was just an attempt to view the distortion components with a low end ADC (realtek motherboard chip) when the DAC is playing a -60db signal so it can be trimmed (a feature of the DAC chip to reduce distortion at these very low signal levels).
Most of the DAC distortion was being buried in the noise of the ADC.
Since this was testing a low -60db signal I adjusted the gain of the DAC output stage to try to bring the distortion and noisefloor of the DAC above the ADC noise floor.
I am not sure if that THD figure the software was giving is even accurate (the THD+N figure is clearly bogus) but it doesnt matter anyway as it was later discovered there was fault causing the DAC to distort which is now fixed.
Hi All,
I finally received the rest of the parts needed to complete a very compact multiple output voltage PSU perfect for this project and others as long as current draw does not exceed the DC converters maximum. With the help from member jhofland, this psu outputs +/-5, 12 and 15vdc, nicely suited for digital, analog and opamp supplies.
A single transformer 12vac secondary feeds an LT4320 Ideal Rectifier then on to an LM317 regulator fixed at 12vdc. 12vdc powers a pair of DC/DC converters that output +/-5vdc and +/-15vdc. An LC network is on the outputs to tame any converter noise. There is a parallel +/-15v that feeds a TPS7A LDO regulator fixed for +/-12vdc output for the analog power.
The psu has been hooked up this evening and it works fantastic!! This DAC sounds excellent and the combo is so small.
I finally received the rest of the parts needed to complete a very compact multiple output voltage PSU perfect for this project and others as long as current draw does not exceed the DC converters maximum. With the help from member jhofland, this psu outputs +/-5, 12 and 15vdc, nicely suited for digital, analog and opamp supplies.
A single transformer 12vac secondary feeds an LT4320 Ideal Rectifier then on to an LM317 regulator fixed at 12vdc. 12vdc powers a pair of DC/DC converters that output +/-5vdc and +/-15vdc. An LC network is on the outputs to tame any converter noise. There is a parallel +/-15v that feeds a TPS7A LDO regulator fixed for +/-12vdc output for the analog power.
The psu has been hooked up this evening and it works fantastic!! This DAC sounds excellent and the combo is so small.
Attachments
Hi,
In your shoes I will try several scenari without soldering the caps first but giving them 20 hours of listening for each : of course check the leads spacing according the pcb holes - I haven't bomed yet s can not help more for the moment :
Local - Panasonic FR : 25 to 100 uF 25V to 35V
or - Panasonic FC : idem
or - Black Gate if you have some
Advise remains for your main reg pcb with Elna in plus before low noise chips (TS7A...) : so 4 scenari for the pcb regs before the dac board, then according to that set up the pcb with the 3 scenari. try the 3 , then work around that according your tastes and hifi : you will have a huge headroom for the last flavors with that 3 scenarios and mixing of them. There are of course many choices but I will beginn like that, at least I will for myself.
No FM. No Silmic II, No Nichicon KZ. Let's the theoricians aside
... but of course try them if you have on hands without soldering the leads during your listening tests.
squared mkp: try the blue Vishat Roederstein or the FKP2 (non metalized) for the last the capacitance value is limited but I haven't the bom on hands so sorry if you need more uF. You should try 0805 size case smd if the width is possible to putt between the two vias as a good alternativ (better?) choice : Cornel Dublier acrylic PPS advised, but be aware the tolerance is huge and the soldering must be rapid and fast not to change it more.
In your shoes I will try several scenari without soldering the caps first but giving them 20 hours of listening for each : of course check the leads spacing according the pcb holes - I haven't bomed yet s can not help more for the moment :
Local - Panasonic FR : 25 to 100 uF 25V to 35V
or - Panasonic FC : idem
or - Black Gate if you have some
Advise remains for your main reg pcb with Elna in plus before low noise chips (TS7A...) : so 4 scenari for the pcb regs before the dac board, then according to that set up the pcb with the 3 scenari. try the 3 , then work around that according your tastes and hifi : you will have a huge headroom for the last flavors with that 3 scenarios and mixing of them. There are of course many choices but I will beginn like that, at least I will for myself.
No FM. No Silmic II, No Nichicon KZ. Let's the theoricians aside
... but of course try them if you have on hands without soldering the leads during your listening tests.squared mkp: try the blue Vishat Roederstein or the FKP2 (non metalized) for the last the capacitance value is limited but I haven't the bom on hands so sorry if you need more uF. You should try 0805 size case smd if the width is possible to putt between the two vias as a good alternativ (better?) choice : Cornel Dublier acrylic PPS advised, but be aware the tolerance is huge and the soldering must be rapid and fast not to change it more.
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PP: 505-MKP20.1/100/5 ,, 505-MKP2D031001FJI00 ,, 505-MKP2D031001FJO00
Elyt Nichicon (FG, or KW):
4u7: 647-UFG1H4R7MDM1TD
47u: 647-UFG1E470MEM (6.3mm) or 647-UKW1V470MDD (5mm)
100u: 647-UKW1V101MED
or try different brands, not sure about the sound impact ... or try something from Aluminium Organic Polymer Capacitors and let us know about the sound
These could be Tantalum - Polymer SMD, the pins have to adapt with a wire:
C15, C25: 4u7: 80-T521B475M35ATE150
C16, C26: 47u: 80-T521D476M025ATE65
Elyt Nichicon (FG, or KW):
4u7: 647-UFG1H4R7MDM1TD
47u: 647-UFG1E470MEM (6.3mm) or 647-UKW1V470MDD (5mm)
100u: 647-UKW1V101MED
or try different brands, not sure about the sound impact ... or try something from Aluminium Organic Polymer Capacitors and let us know about the sound
These could be Tantalum - Polymer SMD, the pins have to adapt with a wire:
C15, C25: 4u7: 80-T521B475M35ATE150
C16, C26: 47u: 80-T521D476M025ATE65
... This DAC project is a Tweakers delight
You can compare the sound with some delta-sigmas, whose parameters are better on paper or scope
I'm happy some one say that before I die one day ... that are the ears that finally listen to music ... though some have some brain excitation to listen to with eyes with a scope !I chosed my bias, lol
Ah, please no organic polymer, mayb he didn't understand the joke
Frankly I would avoid the Nich , also the low leaking ones will give someone a marmelade mellow sound that are good to hide certain todays dac chips, but this RTWOR disearve better and more precise, neutral... well : "neutral", sorry
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for reference, here are my current setting
c7, c8, c17, c18, Silmic II 100uf
c11, c12, c21, c22 nichicon 68uf rr71c680mdn1
c27, c28, c32, c33 silmic II 100uf or blackgate std 50v 100uf
c9, c10, c13, c14, c19, c20, c23, c24, c29, c30, c34, c35 vishay roderstein MKP-1837 0.1uf "partsconnexion"
opamp i tried, opa627, opa128, muses03, ti5534, lm49710, lm6171, opa828, ada4627, some discrete opamp from china, still waiting ada4989.
all ok, but these two opamp gave me wow surprise, ada4627, opa828.