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Post by MartinT on Feb 16, 2019 18:52:51 GMT
This board has now been despatched from AliExpress. Hopefully it'll get here within a week or so from China. With the level of performance I'm getting from S/PDIF now, I'm having trouble thinking of how I 2S can improve on it. However, it'll be fun getting the Audiophonics box properly setup and tidying the cable routing. speedysteve , I'm catching up!
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Post by speedysteve on Feb 16, 2019 19:25:56 GMT
Yes, come on Martin! Faster, faster! Be very interesting to see how it works and what you think! It's different to my route in. You have the the interface or conversion board in the stream path but then you have SPdif to I2S converters in your DAC at the moment.. Mine is out I2S from RPi (reclocked by Kali Goddess of time (I love saying that) - messy Pi ) and then straight into Najda's (pronounced Nazjda) I2S bus after which I understand the DAC's internal use of the datas is transported around the DAC with I2S. I'm no expert on the inner workings of DACs though..
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Post by MartinT on Feb 16, 2019 19:44:45 GMT
The key with I2S is not the transport mechanism as much as keeping the clocks and data separate. S/PDIF mangles them together and gives the DAC the work of separating them again. How audible this is remains to be seen, but I agree with your previous post that I2S is the way to go given the choice.
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Post by MartinT on Feb 16, 2019 22:58:43 GMT
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Post by speedysteve on Feb 17, 2019 8:56:24 GMT
DIYaudio is a great place. I don't understand some of it, but the advice is great. Threads there have been a great help with horn making, esp tapped horns, Najda and I2S connecting for WaveIO / RPi.
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Post by MartinT on Feb 26, 2019 8:52:12 GMT
Yippee! This'll be on the kitchen table tonight. Soldering iron at the ready!
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Post by speedysteve on Feb 26, 2019 16:18:29 GMT
Fingers crossed for you
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Post by MartinT on Feb 26, 2019 23:01:34 GMT
I got it working. The physical wiring in was relatively straightforward and I kept the I 2S lines as short as possible. It took a while to power it up and set it up for I 2S/Pi DAC and then on reboot I got the lovely Volumio startup tune. There are many variables: HDMI cables, LKS settings, placement, isolation and cable dressing, that it took me half the night to work out what's what. The good news: it works and works well while playing music. Resolution is higher than S/PDIF. In fact, resolution is quite gobsmacking and noticeably better with both Qobuz and Spotify sources. Focus within the soundstage is better defined. I still haven't got to grips with balance and tonality but I sense that the Audiophonics, comprising a new Pi 3, Allo Kali and HDMI board, needs some running in so I've left it on overnight. I also have yet to get the QP-1 PSU modified for a 5V feed from the high quality output (previously set for 15V for the SEG DAC) for the Kali, while powering the Pi section from the USB output. The bad news: I'm getting pops when the LKS goes into unlock at the end of the music. During this 'free-wheeling' time when it's unlocked I sometimes get a burst of interference. I've played with the DLL sensitivity but that's not really helping. Changing volume steps gives me clicks, which suggests that the LKS DAC is putting a little DC on the line to the preamp. Once locked, everything works perfectly and changing the volume does not cause clicks. I shall investigate and ask on the Head-Fi forum for ideas. I shall also ask Allo if it's possible for the Kali to send a clock signal continuously. For now, then, a good start and it's the basis of an excellent front end to my system.
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Post by nrg on Feb 26, 2019 23:31:54 GMT
Good work Martin, I must get going with my Kali reclocker. The clicks and pops are a little worrying though...
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Post by MartinT on Feb 26, 2019 23:36:07 GMT
Yes, in S/PDIF mode on the BNC input the LKS mutes perfectly on unlock. I'm asking in various places so I'll get an answer to it eventually.
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Post by John on Feb 27, 2019 6:13:01 GMT
Hopefully, you can the clicks sorted out as it sounds like a nice step up
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Post by speedysteve on Feb 27, 2019 9:18:13 GMT
Great work. Good to keep the grey matter busy with new challenging projects..
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Post by MartinT on Mar 8, 2019 9:59:11 GMT
My balance issues are virtually solved by setting the LKS to 0dB volume rather than bypassed. It should sound the same but it doesn't, as has been noted by others in the Head-Fi forum. Now the tonal balance is spot on and I2S really shows its advantage in amazing resolution and good balance from treble detail all the way to subterranean but punchy bass.
The Kali reclocker helps with the tight, metronomic timing, matching my previous findings with the DigiOne and SEG in that accurate clocking at both ends of the connection pays dividends. Kali plus LKS femtoclock really delivers. This is probably more important with I2S lines since multiple clocks are carried in parallel and you want them to arrive at identical times to be latched at the same part of the waveform in the DAC. It also explains why the HDMI cable quality is important.
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Post by nrg on Mar 8, 2019 10:17:09 GMT
Good result Martin, enjoy!
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Post by MartinT on Mar 14, 2019 14:22:56 GMT
One thing I'm going to try which speedysteve got from Allo is to set Volumio to upsample everything to 32/192. It may just fix my pops whenever the LKS gains or loses sync lock. I'll try it tonight.
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Post by speedysteve on Mar 14, 2019 15:19:19 GMT
One thing I'm going to try which speedysteve got from Allo is to set Volumio to upsample everything to 32/192. It may just fix my pops whenever the LKS gains or loses sync lock. I'll try it tonight. I'm on 32 / 96.. Sounds better to my ears. No pops here.
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Post by MartinT on Mar 14, 2019 15:34:42 GMT
Ah - so it's the word length that Allo are focussed on? My concern is that I stream up to 24/192 from Qobuz and I don't want it downsampling. 32/192 upsampling does seem extreme so I'll see how the Pi handles it, using TOP to view CPU usage.
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Post by speedysteve on Mar 14, 2019 17:25:40 GMT
Yeah worth a try. I didn't have any glitches at all on 24/192 or 32/192..
I remember pops when playing in to my DPA Enlightenment DAC testing with RPi and HifiBerry +. Never had it with Najda...
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Post by MartinT on Mar 14, 2019 17:35:28 GMT
Perhaps the Najda mutes on I2S input as most DACs do on S/PDIF? The LKS mutes perfectly on S/PDIF so you wonder why they didn't put the clock detect somewhere where it would mute on ALL inputs.
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Post by speedysteve on Mar 14, 2019 17:44:46 GMT
Could be so. I can ask. It didn't pop with just RPi I2S straight in either, now that I think about it..
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