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γ3 On the Move

gamma3, gamma24 (plug-in for the γ3)

γ3 On the Move

Postby cobretti » February 25th, 2016, 1:44 pm

I still have not much to show, but just finished my remote control. I re worked some old-new Sony remote that I got on eBay for $10.
Some photoshoped vinyl label will do just fine 8-) After trying 3 different remotes, I decided to go with Sony because those IR codes work the best with LCDuino. I am waiting for power supply rear panel, that was previously screwed up by manufacturer. Will see.
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Re: γ3 On the Move

Postby cobretti » February 28th, 2016, 9:23 am

Finally, almost done. I just slap it on together but still missing couple of things, like ground on the PSU chassis, knob on the volume pot. Also, I will have to augment my heat sinks for constant 5V power supply, they are getting too hot, more hot than when I tested them with my electronic load to full 400mA. I think actually it is more than 400mA being drawn from that constant 5V PSU. I will have to measure it.
I didn't have any troubles with building it and I didn't have to troubleshoot anything other then tweak 2 trim pots on my power supplies to compensate for wire run length and umbilical cable to bring it exactly to 5.00 and 10.00 volts.

Here is one thing I noticed. As someone already described: I was getting 1 sec popping noise when music played through USB and I was switching to other inputs (all inputs unconnected, just USB pugged in). Looked like a crosstalking. Then, when I connected coax from my CD player (USB still connected and music played through it), the phenomenon disappeared. Go figure. All grounds checked. Only the LCDuino 5V ground goes to chassis through the screw next to the power connectors. Everything else is isolated.
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Last edited by cobretti on February 28th, 2016, 9:35 am, edited 1 time in total.

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Re: γ3 On the Move

Postby cobretti » February 28th, 2016, 9:34 am

Now, On the sound side.
As expected, my Theta CDplayer is obsolete! I was using my y1.5 as DAC and PC as my source. I was expecting some improvement over the y1.5 but :shock: what a difference! The sound is more open, wider and more detailed. I really didn't expect that much improvement. It is just fantastic. I had DAC from Benchmark some time ago, and as far as I remember the Benchmark DAC sound was pretty much the same as Theta CDplayer itself. The gamma3 is 2 levels above that! I am happy camper, at least for now. I just put my Dali Epicon speakers for sale, blaming the poor sound on them. But I think I will actually keep them! Every song I play sound different now. Wow. :o Amazing!
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Re: γ3 On the Move

Postby amb » February 29th, 2016, 1:16 am

Very cool! :ugeek:
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Re: γ3 On the Move

Postby cobretti » March 6th, 2016, 2:22 pm

I am experiencing the popping noise again. I am wondering if it's just me.
This happens on USB. DAC is in UAC2, de-emphasis AUTO, upsample 192kHz.
Just USB connected and music played. Then, when switching to another input I can hear the popping noise in 1 sec or something like that constant repeating intervals. Once I connect my CDP coaxial cable and play music, popping disappears and all is quiet. It looks like crosstakling from USB to other channels. But once the DAC receives signal from another channel(source), the phenomenon is gone. Anyone else experienced this? I am using Foobar2000, win7 64bit.

Just to be clear that the USB playback is OK. No popping noise while listening to USB itself. The popping noise comes from other channels while music is being played through USB.
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Re: γ3 On the Move

Postby hagak » March 6th, 2016, 2:48 pm

I currently only have tried UAC1 and have not experienced this issue when using my coax. Do you get this with UAC1?
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Re: γ3 On the Move

Postby amb » March 6th, 2016, 3:21 pm

Even though I have not experienced this, I now have a hunch on what might be happening. Look at the SRC4392 datasheet (on my copy which is revision December 2012, on page 63) for DIR control register 0E. The bits of interest are LOL and RXAMLL.

Currently the γ3 v1.01 firmware sets all bits of this register to 0x00 on startup (line 337 of gamma3_hw.cpp). Then, when you switch to port 1-4, it changes the register contents to 0x18 (line 655 of gamma3_hw.cpp), enabling the LOL and RXAMLL bits. If you can compile and flash the firmware, change line 337 also to 0x18 and see if it makes any difference. Or, play with different combinations of the settings of these two bits at both locations and see if you observe any changes in behavior.

I don't know if this is barking up the wrong tree, but worth a try.
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Re: γ3 On the Move

Postby cobretti » March 7th, 2016, 1:49 pm

Thanks, Yes. It will really be something small and stupid like you describe. I am almost 100% sure it is software fixable. I know there is nothing wrong (hardware-wise) with the unit, so it will be something like that. I will have to play with it when I have time. I can re-compile it and flash it no problem.
BTW. I was playing with LCDuino power supply adding ferrite chokes on both positive and negative rails, right after the LCDuino board.
I know that LCDuino power is isolated from the rest of the stuff on the board, I was doing it just for the good feeling :) ........... anyway,
When tested on the bench, I could get the noise from 250uV down to 22uV. The LCDuino injects a lot of noise on power supply rails. The 5VDC power supply is very low noise, like 8uV with 400mA dummy load.
Once I put those chokes there the noise went down by 100uV, but I had the display last digit (after the decimal point) flickering and the LCDuino slowed down and occasionally froze. Potentiometer didn't respond well either. I know you decribed this issue earlier. So now we know it could be power supply related.
just giving my 2c
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Re: γ3 On the Move

Postby cobretti » March 7th, 2016, 5:59 pm

I just tried that, changing 0x00 to 0x18 doesn't cut the mustard, unfortunately. :cry:
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Re: γ3 On the Move

Postby bk_856er » March 7th, 2016, 7:39 pm

VFD not LCD, correct?

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