The Bass is the best that I have ever heard on my system. The soundstage is very large. Both Voltage and Current modes sound great. But I find that in voltage mode, the sound is just subjectively more "alive" sounding. I haven't performed any measurements yet, so I don't know if this is simply the result of possibly preferring higher distortion by running in voltage mode or not.
I just find that there is more of an emotional connection to the music in voltage mode using my op-amp modules. Plus there is amazing impact on transients such as bass drum.
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For the moment, just the supplied op-amp stage, using only the cheaper of the two recommended op-amps. However I plan to try several other output stage topologies before I am finished.
My point was that that even the supplied op-amp output stage sounds different (and IMO noticeably better), if you simply switch the jumpers and run it in "voltage mode", as apposed to what is loosely being termed "current mode".
Hi Quanghao,
I'm about to send you my remaining payments (sorry for being late, I've been away for some time). Before that, I would like to know :
Does Vietnam post provide tracking number or not ? If not, I'll choose Fedex.
Do I have to add some money for the shield and the connector+wire to the output board?
Is there still any chance to order the transformer from you ?
Thanks in advance, I'll sent payment tonight if I get the answer from you today.
I'm about to send you my remaining payments (sorry for being late, I've been away for some time). Before that, I would like to know :
Does Vietnam post provide tracking number or not ? If not, I'll choose Fedex.
Do I have to add some money for the shield and the connector+wire to the output board?
Is there still any chance to order the transformer from you ?
Thanks in advance, I'll sent payment tonight if I get the answer from you today.
My DAC won't lock upper than 44.1 KHz on coax input
- R63 replaced with 100, 560, 1 000 or 1 500 ohm : the DAC is always noisy.
I try soon with C36.
- R63 removed : the DAC is now able to lock up to 96KHZ but the sound is sizzling and crackling.As told before the spdif inputs of this DAC accept without problems 96KHz or higher... If your source is not able to drive the standard spdif load (75 ohm) remove the R63 resistor and test it.
The lmv7219 amplify and square the spdif input to convert it to a TTL 3.3V signal so C36 is necessary for the correct functionality of the circuit.
In some cases abnormal ciruit modifications can create a better sound.
- R63 replaced with 100, 560, 1 000 or 1 500 ohm : the DAC is always noisy.
I try soon with C36.
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Hi Quanghao,
have you read my previous post (#1123 )?
Is there still any chance to purchase the transformer from you ?
I also have problems with the coaxial input, locked only up to 88KHz, with or without C36 and R63.
I have tested with a RME pro audio sound card and the onboard audio card of the pc asus motherboard, with the same result.
...but if I connect the coax cable from onboard card to the test optical input (under amanero module), signal locked up to 192KHz. No lock with the RME card.
PS: DAC sounds fantastic with amanero module in V mode.
Thanks
have you read my previous post (#1123 )?
Is there still any chance to purchase the transformer from you ?
I also have problems with the coaxial input, locked only up to 88KHz, with or without C36 and R63.
I have tested with a RME pro audio sound card and the onboard audio card of the pc asus motherboard, with the same result.
...but if I connect the coax cable from onboard card to the test optical input (under amanero module), signal locked up to 192KHz. No lock with the RME card.
PS: DAC sounds fantastic with amanero module in V mode.
Thanks
I have a bug to report:
My DAC will successfully sync up to 96kHz via the toslink connector. However it will not quite sync to a 192kHz signal. When I input a 192kHz signal over the toslink, the DAC will give a few seconds of sound followed by a second or two of silence, and then another few seconds of sound, and a second or two of silence, repeatedly. When it does this, the screen reports that it is receiving a 191kHz signal, NOT a 192kHz signal. Is this just a display bug, or does this represent the actual clock frequency of the receiver?
My DAC will successfully sync up to 96kHz via the toslink connector. However it will not quite sync to a 192kHz signal. When I input a 192kHz signal over the toslink, the DAC will give a few seconds of sound followed by a second or two of silence, and then another few seconds of sound, and a second or two of silence, repeatedly. When it does this, the screen reports that it is receiving a 191kHz signal, NOT a 192kHz signal. Is this just a display bug, or does this represent the actual clock frequency of the receiver?
Hy everyone,
I have cut the trace on the PCB between the pins of C36 and installed a capacitor "Wima 1.0uF 50V". The 75 ohms resistance is still removed : the DAC can now lock at 96 KHz without not any noise at all.
- Very good bass and very accurate sound with I/V board in V mode (OPA627AU x 8).
I still have to report bugs :
- Often, "+" and "-" of the volume are reversed on the remote. I don't know if it is randomly or not but when I press "-" volume increases and vice versa.
- At 1% on the display, the volume remains very loud. I would like it mutes. Is it possible to reset something ? If I can't do that, it is impossible for me (and specialy because of my wife) to use this DAC.
I have cut the trace on the PCB between the pins of C36 and installed a capacitor "Wima 1.0uF 50V". The 75 ohms resistance is still removed : the DAC can now lock at 96 KHz without not any noise at all.
- Very good bass and very accurate sound with I/V board in V mode (OPA627AU x 8).
I still have to report bugs :
- Often, "+" and "-" of the volume are reversed on the remote. I don't know if it is randomly or not but when I press "-" volume increases and vice versa.
- At 1% on the display, the volume remains very loud. I would like it mutes. Is it possible to reset something ? If I can't do that, it is impossible for me (and specialy because of my wife) to use this DAC.
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Hi Quanghao,
I will try 4.7uF 50V "Black Gate" non polarised capacitors from Rubycon... It can be quite good too.
Did you try with the cap and the 75 ohm resistor?
SPDIF is 75 ohm characteristic impedance, so it should be terminated.
Now that you added the cap, I think you can add the resistor back.
I am rather concerned by these reports of problems with spdif. My understanding is that optical is rated to 24/96 but can go up to 24/192 in some cases eg. Audiolab mdac. There should be no trouble with 24/192 on coax. I did like my mdac but returned it because I wanted DSD support. 24/192 on coax is important for me and I hope the guarantee on the completed DAC includes this. I dont have a lot of time to tinker and would simply like to enjoy my music. Still plan to get standby and trigger functions though - to replace my current preamp.
I wouldn't be too concerned, so long as you are competent with a soldering iron. I'm betting that these bugs will be solved in short-order with all of the diy types who have purchased these kits. You should probably consider this DAC in its present form to be a beta design. And we are the beta testers. I'm sure that these issues will be solved soon, and that the fixes will be posted here.
For anyone who expects a 100% completely trouble-free product, you might want to wait for the next release when I think that it is reasonable to expect that most of these teething issues will have already been addressed.
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Black-gate caps may sound good at audio frequencies, but I would not trust them to be non-inductive at RF frequencies.
I can confirm the remote control behaviour. It somestimes does not execute the button I am pushing. When I push a different one the first one gets executed. Though since I have adjusted the IR receiver for better reception the problem seems to have gone - at least I didn't notice it much lately.
At 1% my DAC is dead silent.
What about mute?
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