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Post by chinook9 on Feb 25, 2015 14:47:59 GMT
Thanks Frans, I'll do as you suggest. I'll do this before I connect the USB to I2S converter.
I'm not sure I know how to check supply voltages before the shunt but I'll ask how if I can't figure it out.
Would it also be helpful to test disconnected from the Ivy?
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solderdude
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Post by solderdude on Feb 25, 2015 14:56:36 GMT
The voltage before the shunt can be measured across the big smoothing capacitor. That should be at least 1.5V higher than the expected output voltage from the board. If it is just 0.6V higher the drawn current is too high or the transformer voltage/current is too low.
Would leave the IVY connected if it is running from the same trafo.
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Post by chinook9 on Feb 25, 2015 15:36:24 GMT
Thanks Frans. The Ivy is running from a Placid HD BP. I'll try it disconnected also.
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Post by chinook9 on Feb 25, 2015 18:58:29 GMT
The first test I did seems to have had some success but may be an indicator that there are still problems. Not sure.
No load I set: CCS 700, voltage had increased with CCS and I reduced this to 5.26volts, shunt = 686. Connected DAC: CCS 702, 5.26volts, shunt = 113, LED on AVCC is now bright At this point I didn't think of adjusting CCS immediately. I just thought of turning off the power and reducing CCS.
Disconnected DAC and reduced CCS to 625, 5.27 volts, shunt = 609 Connected DAC: CCS 623, 5.26 volts, shunt = 31 Now I increased CCS (643) to bring shunt up to 50 with voltage still 5.27. LED on AVCC still bright
All previous was done with DAC connected to Ivy which is powered by Placid HD BP and appears to be set correctly.
There is not much on the BIIISE board that can get hot and most of it is covered by the Tridents and the AVCC. I checked all of these and did not find anything hot or even warm.
I have to think a bit, and possibly read some, before my next step but I'll probably go ahead and do the checks previously suggested. I'm pretty sure I've read of the Buffalo DACs being operated a decent bit out of spec but I certainly want to move carefully on this.
Recommendations are always appreciated.
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solderdude
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Post by solderdude on Feb 25, 2015 19:18:19 GMT
I would let the shunt have at least 50mA.
You should check the currents when it is running. Preferably on the highest possible bit rate. That should give the maximum current draw.
Measure that current draw and set the shunt so it drains at least 50mA.
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Post by chinook9 on Feb 25, 2015 20:33:28 GMT
Thoughts Javier? Any chance the new AVCC module could be increasing the load? There aren't many of them out there so I haven't read anything about them.
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Javier
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Post by Javier on Feb 25, 2015 21:11:34 GMT
I Have the same problem as you, there are very few of the latest AVCC model around thus also very few comments about them. WHat I can tell you is I had a BII for some time and the heatsinks of the,much older model, Placids HD and BP HD got very hot. To the point where it was not possible to touch them without burning one's fingers. It didn't have the Tridents (that came later) but the AVCC (V. 1.0) never got even remotely warm.
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solderdude
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Post by solderdude on Feb 25, 2015 22:02:56 GMT
Very hot heatsinks may have been caused by a closed enclosure or an incorrectly set shunt current.
The shunt currents must be set slightly above the maximum current that is drawn by the circuits. That way it runs coolest and the shunt reg does what it is supposed to do.
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Post by chinook9 on Feb 26, 2015 3:19:00 GMT
I will put a question over on the Twisted Pear Forum and see if they think a 642mA CCS is OK.
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Post by chinook9 on Feb 26, 2015 14:50:21 GMT
Brian at Twisted Pear said "All seems normal to me."
In retrospect, I believe I might have been the only one who thought the 643mA CCS was significantly out of spec.
I will probably get the USB to I2S installed today. I will also have to install the XMOS driver provided by DIYINHK but that should be no problem.
I do have one slight concern. Their "guide" mentions DAC chips differing in software commands needed to switch between DSD and PCM. I'm assuming the BIIISE will do this automatically. We'll see.
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Javier
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Post by Javier on Feb 26, 2015 16:50:12 GMT
All chips from ESS that are DSD capable have automatic format detction so no need to worry.
On the other hand, many BIIIs have an issue with sample rates higher than 192K PCM, that is 352.8/384 or higher, and DSD faster than DSD128. It is related to how TPA have programmed their BIOS chip and will be solved the moment you pull it out and start using an Arduino I2C controller. Doing so will also open a mind boggling range of configuration that should provide many hours of testing/comparing fun.
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Post by chinook9 on Feb 26, 2015 17:26:30 GMT
Great! I thought that automatic detection would probably handle it.
If everything goes well I will start reading up on the Arduino I2C controller. Sounds like something I'd like to play with.
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Post by chinook9 on Feb 27, 2015 6:23:29 GMT
It works!!
I did not have all the Molex connectors I needed so I had to rig up a few connections, but it worked immediately. The shunt current on the Placid HD BP required no adjustment and I only increased the CCS on the HD about 11mA. The heat sinks didn't even warm up. I will look for some high bitrate music to use to double-check the shunt current.
I listened to all my favorites for about 90 minutes and I am more than satisfied. I just used the K7XX (which I really, really like) tonight. I will check with some other headphones as time permits.
I had really been enjoying, and could continue to enjoy, the $200 Teradak I had been listening to, but I can certainly hear a difference with the BIIISE. Overall I would say it is a clearly more refined, detailed sound with greater dynamic range. I heard many aspects of the music tonight that I had not heard before. I expect this is a result of the extended high end and the dynamic range. Either way, I like it....high without drugs.
Thank you, Javier and Frans for getting me this far. I am sure I will have additional questions as I get more into it.
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Javier
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Post by Javier on Mar 1, 2015 17:32:19 GMT
Glad you like it, it is a very, very good DAC. Some reading to give you a clue what the I2C external uController (Arduino) can bring to the picture: Hifiduino(For future reference Arduino compatible rotary encoder)
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Post by chinook9 on Mar 2, 2015 15:52:24 GMT
Thank you Javier. I started reading a bit but I came down with a bad cold so I haven't done much the last couple of days.
I have done a little testing of the DAC/Ivy but not much yet. So far the shunt current barely changes and the heat sinks are barely warm....and thats with 90mA shunt current on the HD BP.
I hope to hook up the volume control and try the IvyIII driving headphones in the next day or two. I expect headphones may suck up some shunt current.
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