Showing 1 of 305 conversations about:
mtmercer
45
Jun 4, 2018
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Sweet looking Resistor Ladder DAC!
1) Is the input upsampled to a certain frequency before being sent to the resistor ladder? 2) Would a adding a 3rd party quality linear power supply add any improvement to the sound quality?
Jun 4, 2018
Zachik
20
Jun 5, 2018
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Post #4 on Head-Fi (by Torq) addresses LPS. Short answer: it does improve slightly the noise floor and sound quality.
Jun 5, 2018
mtmercer
45
Jun 5, 2018
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AliExpress here I come! The Audiophonics 5v USB LPS I like maxes out at 2.5A. So close, but no go!
Jun 5, 2018
Heefty
1328
Jun 5, 2018
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I would imagine using a decent LPS and a your USB decrapifier of choice would work wonders on it. Let us know which LPS you end up with once you've heard it.
Jun 5, 2018
mtmercer
45
Jun 5, 2018
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For reference I have the LPS linked below spec to 28v for my MCTH and it works well. I get no hum with the volume knob all the way up on several cans.
https://m.aliexpress.com/item/32809766032.html?aff_trace_key=b227772f7e3b479aa7f320a7f6ebd78e-1524533954173-08687-VnYZvQVf&aff_short_key=VnYZvQVf&aff_platform=msite
If this DAC I would contact the same AliExpress seller and see what they recommend.
Jun 5, 2018
Wuthoqquan
79
Jun 6, 2018
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Would this LPS also work well with the Massdrop LCX?
Jun 6, 2018
WilliamTse
103
Founder, Airist Audio
Jun 6, 2018
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Hey mtmercer, good questions!
1) We do use some integer-rate upsampling with linear phase FIR filters. This gives us a smoother output waveform and thus a smoother sound. Without the upsampling, we found that lower sample rates could have a harsher edge to the sound from the larger steps between samples.
2) The short answer is: yes! R-2R DACs, especially sign-magnitude versions, need precise, stable voltages for maximal performance. The RDAC has several power regulation circuits inside to stabilize the 5V DC we get from the supplied wall wart, such as the two precision linear series regulators next to the PLD on the top board. With these circuits, even the stock power supply gives good performance. With a better linear power supply, these regularization circuits don’t have to work as hard and the resulting voltages are even more precisely controlled, leading to more resolved sound.
Jun 6, 2018
mtmercer
45
Jun 6, 2018
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Thanks for info!
Jun 6, 2018
mtmercer
45
Jun 7, 2018
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The supplier stated it would be rated for 1.2 amps at 30V DC for the LCX which requires 30V DC and 1.25A. Based on that I would not recommend this model for the LCX. There have a larger model for $200 something that would have enough power though.

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Jun 7, 2018
Wuthoqquan
79
Jun 7, 2018
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Many thanks for the comprehensive answer! Really appreciated, thank you!
Jun 7, 2018
mtmercer
45
Jun 7, 2018
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This would be 1 option for the LCX.
Look what I found on AliExpress http://s.aliexpress.com/eyeE3Yfy
But it that is almost $300 shipped so you have to wonder is it better to just get a more expensive amp to begin with.
Jun 7, 2018
Wuthoqquan
79
Jun 7, 2018
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Yes, you are absolutely right and your comment is spot on... shelling out $300 on a LPS for the LCX would be an overkill, considering the amp has basically the same price. Wonder if there's anything in the $150 ballpark or so...
Jun 7, 2018
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