orchardaudio Posted March 22, 2018 Share Posted March 22, 2018 The ApplePi DAC will be launching very soon via Kickstarter, for $175 Check out the first review here: http://theaudiobeatnik.com/applepi-dac-review-theres-art-in-this-dac-and-it-shows/ Specs:SNR: 128dBTHD+N: 0.0005%Dynamic Range: >135dB Link to comment
Panelhead Posted March 23, 2018 Share Posted March 23, 2018 What is the digital to analog converter chip? Does it offer digital attenuation. 2012 Mac Mini, i5 - 2.5 GHz, 16 GB RAM. SSD, PM/PV software, Focusrite Clarett 4Pre 4 channel interface. Daysequerra M4.0X Broadcast monitor., My_Ref Evolution rev a , Klipsch La Scala II, Blue Sky Sub 12 Clarett used as ADC for vinyl rips. Corning Optical Thunderbolt cable used to connect computer to 4Pre. Dac fed by iFi iPower and Noise Trapper isolation transformer. Link to comment
opus101 Posted March 23, 2018 Share Posted March 23, 2018 From the linked review, the DACs are PCM1794A in dual-mono. Link to comment
orchardaudio Posted March 23, 2018 Author Share Posted March 23, 2018 10 hours ago, Panelhead said: What is the digital to analog converter chip? Does it offer digital attenuation. Dual PCM1794A's in monaural mode. No digital volume control at this time. Link to comment
orchardaudio Posted April 6, 2018 Author Share Posted April 6, 2018 For those imho may be interested...see attachment. MikeyFresh 1 Link to comment
opus101 Posted April 6, 2018 Share Posted April 6, 2018 I see in the pink box there are a couple of switching regulators and the writing says they're 'very low noise'. How low noise, are there any numbers? Link to comment
orchardaudio Posted April 6, 2018 Author Share Posted April 6, 2018 8 hours ago, opus101 said: I see in the pink box there are a couple of switching regulators and the writing says they're 'very low noise'. How low noise, are there any numbers? <50uV (20Hz to 20kHz) Link to comment
opus101 Posted April 6, 2018 Share Posted April 6, 2018 That's extremely low for a switching regulator - is there a linear post-regulator after the boost converter? Or is it just that all the switching noise isn't included in that figure because its way out of the audio band? Link to comment
orchardaudio Posted April 6, 2018 Author Share Posted April 6, 2018 2 minutes ago, opus101 said: That's extremely low for a switching regulator - is there a linear post-regulator after the boost converter? Or is it just that all the switching noise isn't included in that figure because its way out of the audio band? The noise figure that I listed is in the audio band (20Hz to 20kHz), out of band noise will be higher. There is no post linear regulator, it's not really needed because the PSRR (Power Supply Rejection Ratio) of the audio circuit is better than 100dB. Link to comment
opus101 Posted April 6, 2018 Share Posted April 6, 2018 Better than 100dB over what frequency range? Link to comment
orchardaudio Posted April 6, 2018 Author Share Posted April 6, 2018 2 minutes ago, opus101 said: Better than 100dB over what frequency range? The DAC overall achieves a SNR of 128dB. That would not be achievable if power supplies or audio circuits were not properly designed. If you are that interested about it please look at the OPA1612 datasheet. Also I am starting to get used reviews of this device you can check it out here: http://www.audiocircle.com/index.php?topic=155479.msg1677776#msg1677776"I highly suggest that folks sign up for the tour to hear this wonderful device. I spent a good week listening to it and came away extremely impressed with what Leo has done with this DAC hat. For anyone that is using a Squeezebox Touch or similar unit, they should find this to be an quite an upgrade. I did compare it to a DAC I built with AK4990 DAC chip and Salas shunt regulators DIY modular DAC I really could not pick one over the other. The sonic difference was completely dependent on the file being played. I feel both units are very transparent. For under $250, the combination of a Rpi and the ApplePi DAC board is an outright bargain in today's audio world. When it is released, I will be buying one." Link to comment
opus101 Posted April 6, 2018 Share Posted April 6, 2018 4 minutes ago, orchardaudio said: If you are that interested about it please look at the OPA1612 datasheet. I just did, I note that its PSRR is only over 100dB at low frequencies (under 1kHz). Which rather makes nonsense of a '100dB PSRR' claim when the context is switching artifacts above the audio band. Link to comment
orchardaudio Posted April 9, 2018 Author Share Posted April 9, 2018 Check out another review of the ApplePi DAC by Volumio's founder Michelangelo:https://volumio.org/forum/orchard-audio-applepi-dac-review-t9633.html#p47446 MikeyFresh 1 Link to comment
orchardaudio Posted April 10, 2018 Author Share Posted April 10, 2018 The Kickstarter project has launched:https://www.kickstarter.com/projects/1844799967/applepi-dac-highest-performance-raspberry-pi-dac Link to comment
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