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Hi everyone. Just finised putting together my new BuffaloII. After an exploded cap and some misplaced transistors, it's making music... GREAT music.
This is a really fantastic DAC!
I'm sitting back, enjoying the music and then... silence. For a couple of seconds. The lock LED has gone out and the DAC sits quiet briefly before lock is reestablised and the music goes on.
I'm sure this is a fixable problem... reading around seems to suggest I could benefit from having the PLL bandwidth adjusted but I'm not sure I have the tools to do this.
I'm using an I2S connection from a dddac USB->I2S board (http://www.dddac.de/files/dddac-usb-1543-dac32.pdf) based on PCM2707 pretty similar to the one on TPA but I already had this one so wanted to use it. I have disconnected power from the TDA1543 on that board, however, as it isn't being used.
I have a placid and a placid BP powering BuffaloII with Volumite and Legato. The wiring seemed pretty straightforward, I don't think I would have screwed something up though I suppose it isn't impossible.
Can anyone suggest how I should proceed? Thanks
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Rank: Member
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I rarely lose lock with BII-Volumite combo under i2s connection. That can handle 44.1~192khz playback easily.
I've used Juli@, QLS QA-550 SDcard player, and SDtrans192, all via i2s and worked fine.
It is said that and I think volumite works quite well for stable locking playback under i2s.
Have you tried other source equipments?
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Pictures might help here. Often time this sort of problem can be sorted out with some wire grooming.
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Rank: Member
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Sorry it's not the best picture in the world, but here you go: http://img40.imageshack.us/img40/5443/img0198hp.jpgEssentially the wiring is as follows: Transformer -> Placid BP -> Legato Transformer -> Placid -> Buffalo II, DDDAC USB-I2S board (PCM2707), IR motorpot controller board Alps Blue motorpot -> Volumite -> BuffaloII I2C headers I initially thought for some reason that it might be the transformer fields interfering with the DAC operation so went out and bought some shielding... not incredible but the best they had at my local DIY store. You can see this on the transformers (not creating a shorted turn, I have checked continuity). Also the USB-I2S board (standing vertically in the picture) has been mounted to a metal plate from the rear where the PCM2707 is soldered. This chip seems to be quite sensitive to stray fields so I thought this would give it some extra shielding as well as providing a very solid mounting for the board. I2S wires were kept as short as practically possible. I think the extra load of the USB-I2S board is a little taxing on the Placid (gets quite hot), but it is still shunting 40ma which I believe is really plenty and certainly shouldnt be causing issues like this. The IR controller board draws almost no current, but I have tried disconnecting it anyway, it didnt help. The chassis is grounded but I believe (I should check) that the grounds are floating on the PSUs and Buffalo/Legato. Certainly I have made no connection between their ground and the chassis earth so unless the conductive standoffs are providing this it is not there. Thanks very much to you both for your replies. I love this DAC, I just really want to get it working properly! Edit: I should also mention that the DAC suffers the same issues with the volumite disconnected. Edited by user Monday, May 30, 2011 1:03:53 PM(UTC)
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Hmm ok so since it seems to happen even with no controller present it is not a DPLL bandwidth issue... Also the PCM2707 only does up to 48khz sample rate so that would never come into play.
How much current is running through the placid? Do you have another PS you can try?
Do you possibly have another I2S source to test with?
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Rank: Member
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Unfortunately I don't have another source. PC is the only source I ever use...
I thought I had found the issue today when I was triple checking all the connections and discovered the BCK connection wasn't that solid.
Reattached it rock solid this time but unfortunately that didn't do the trick :(. I was sure I'd found the problem for a moment there!
I guess I will have to see if I can rig up another PSU and get the USB board on dedicated power
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When you say "without Volumite" do you also leave the original uP out?
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I did, I'm wishing that was the solution. I reckon I might just be best switching to SPDIF input.
I can probably get a decent enough output with a reasonably priced soundcard otherwise my pc has optical out which I can use with a little converter.
I love this DAC and really want to use it and I think that may just be the easiest way to get it going.
Thanks for all the help. I do still welcome any other suggestions that may be forthcoming!
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I just swithced the wiring about a bit.
I have put the 7806 back into the DDAC USB-I2S board and am feeding it from the placid BP that is powering Legato instead of the Placid that is powering BuffaloII.
The issue remains. I feel like I have tried everything!
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Not sure there is much to do except try a different source or try SPDIF into the DAC.
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I noticed that if I poke the coaxial cable or anything involving ground that the lock goes out for about two seconds before resuming music. Very early on I got horrible crackling on the left channel with the Buffalo II and my amplifier, and it was due to improper/nonexistant grounding of the RK27. The crackling stopped but the poking and losing lock remains. I switched the coaxial cable 180° (swapped ends), and the other side seemed to have a firmer grip on the RCA jack, and haven't had problems since then.
Your Placids are properly tuned, correct? When I had crackling/lock problems, the Placids were shunting around 120mA or so, so I lowered the CCS down a bit.
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I'm resurrecting this thread, because after 6 months, I have finally managed to resolve the issue. I ended up abandoning this problem as I had run out of ideas. A couple of days I came back to it with fresh resolve to find a solution. I decided that the DAC must be ok, and started googling around to find a solution with the computer. I came upon this thread: http://www.head-fi.org/t...dio-jitter-distort-issueI'm using windows 7 64-bit and thought it would be worth giving this a try. I adjusted windows to use maximum power, no CPU throttling etc. That didn't help. I then went into my BIOS and scoured the settings, I found a couple of settings related to CPU power management (C1, C6 suspend, thermal throttling, EIST) and disabled them. I also updated my Intel USB drivers and my USB3 drivers. The problem has gone away! It seems there is nothing wrong with my DAC other than dropping lock when the jitter is unacceptable. The CPU power management must somehow cause temporarily high jitter when it transitions between power saving modes and this caused my troubles. I have now been listening to beautiful music several hours without any dropouts (before I never made it through a song). Anyone who is struggling with this, disable you CPU power/frequency management and see if it helps! Edited by user Sunday, January 8, 2012 12:52:17 PM(UTC)
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