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USB to I2S 384Khz - DSD Converter

Does any one have a idea, is it possible to repair Amanero ?

I have it setup this way;

laptop - Amanero - Najda DSP (i2s input)

at one moment laptop was on low battery so I hookup charger (on live)
at that moment Amanero stop working

now when I power it up, it works for like 1second and then stop working, and the chipset gets very hot...

is it possible to repair it, what to check, or should I just trow it away 😀


I only have multimeter 😀
 
Will join the conversation by asking a question.

I just got me an Amanero board. Works as expected. I hooked it up with no frills to a PCM1793DAC I made. The Amanero is powered by the USB port, the DAC has an external linear power supply.

I do get quite a bit of hum in the 50Hz and its harmonics (I've measured that with an analyzer). I remember the DAC, being fed with another I2S source is much quieter.

I'll put an isolator between the DAC and the Amanero as first measure (ISO7341) to see how that goes, however, I don't mind making a power supply for the Amanero. Question is, where do I input the power, over the USB connector?

Cheers, and apologies if this has been asked before.

Albert
 
@Betocool:

I do get quite a bit of hum in the 50Hz and its harmonics (I've measured that with an analyzer). I remember the DAC, being fed with another I2S source is much quieter.

I'll put an isolator between the DAC and the Amanero as first measure (ISO7341) to see how that goes, however, I don't mind making a power supply for the Amanero. Question is, where do I input the power, over the USB connector?

Cheers, and apologies if this has been asked before.

Albert

Hi Albert,

The Amanero board can be fed directly from either a LiFePO4 battery (appr. 3.35 VDC) or from an external regulator. What I've done is to remove U2 (ADP151) and then connect the battery across C2 (remember the polarity otherwise your Amanero board may be damaged).

I've also connected the external PSU directly to the P3 connector - (don't right now remember which pins but it can be measured). Now my amanero is permanently powered by a trickle charged LiFePO4 battery and it works fine. FYI I've attached a schematic showing the USB related power supply design.

That said my guess would be that you have some kind of ground loop issue either related to the Amanero - DAC connection or in the DAC layout itself (also: if you use a Laptop have you then tried to disconnect the AC mains?). No offense meant, however, I have a PCM1794 DDDAC variant and with the Amanero it is entirely silent - also hum wise powered both from the USB connection and with the battery.

Hope this may help & good luck in your endeavours 😉

Cheers,

Jesper
 

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@gentlevoice, no offense at all, on the contrary, good advice. I don't think there's a ground loop on the DAC board, there's no spikes there when the PC is disconnected. I'll disconnect the PC though see how that goes, might help.

Thanks for the schematic, I'll have a look and play in the next couple of days.

I plan to use that Amanero finally on a Raspberry Pi 3 off a linear regulator anyway, so that's something else I have to try. I have the Pi 3 on a little box, but I'm aiming for a more complex system that includes the Amanero.

I had a proper listen the other day to the PC -> Amanero -> DAC -> Headphone amp chain. No pot based volume, direct out, full blast. Software controlled volume on VLC to keep my ears from ringing though. It sounded very good, very good indeed. At pause, when the Amanero sends only "0" (zero), there was really a minor, minor background noise to be detected, but only on a very close and dedicated listen. Play some music and I didn't even notice.

And of course, my current setup is far away from optimal...
 

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@Betocool: Hi again ... just a brief comment to your setup ... Looking at your wiring from the amanero to what I reckon is your DAC I notice that additional to your twisted pair wires there's a single wire a bit away from the twisted pairs. Might this wire somehow pick up/be part of a ground loop?

Cheers,

Jesper
 
Hi Fellas,

Thanks for all the advice so far. The ground loop issue advice was spot on. I did some measurements.

First, connect a microcontroller that outputs 1KHz I2S signal into the DAC. Clean as a whistle. All those circuits run from the same power supply (uc-DAC.png)

Then, connect the Amanero to the DAC. Lots of noise in the 50Hz area. Bugger! Disconnect the power supply from the laptop where the Amanero is connected. Still same. Bugger twice! (Amanero-DAC-PC.png)

But wait, the measurement system, is PC based as well, on another laptop. Disconnect the power to the laptop and let it run on battery. Now we're talking! That's the last image, laptop -> Amanero -> PCM1793DAC. I'm pretty happy with it now. (Amanero-DAC.png)

I guess I'll not bother with the isolator at this point in time. Especially if the end will be connected to a RaspPi3 all on linear regulators.

Thanks for all the comments so far!

Alberto
 

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Hi All

I have an inetresting problem with my Amanero board that I hope someone can help me with. I need it to talk to my Pmd100 decoder chip in my Dac I am building. The PMD100 uses left justified data and my clock (xti input on pmd100 chip)needs to be between 8-14MHz.
I have used the Amanero config tool software to create a left justified output and it will work(well just) but it has a lot of crackle as I am using the standard MCK rate of 25MHz.
If I use the MCK/2 prescaler, I then get sound at half speed. Adele sounds like a horrible man and the chipmunks sound like Barry White. Well not quite. I notice also at the MCK/2 rate that the actual time shown on Jriver software is also going at half speed.
Does anyone here know what is wrong here or may have some suggestions to try and fix it?
 
Hi All

I have an inetresting problem with my Amanero board that I hope someone can help me with. I need it to talk to my Pmd100 decoder chip in my Dac I am building. The PMD100 uses left justified data and my clock (xti input on pmd100 chip)needs to be between 8-14MHz.
I have used the Amanero config tool software to create a left justified output and it will work(well just) but it has a lot of crackle as I am using the standard MCK rate of 25MHz.
If I use the MCK/2 prescaler, I then get sound at half speed. Adele sounds like a horrible man and the chipmunks sound like Barry White. Well not quite. I notice also at the MCK/2 rate that the actual time shown on Jriver software is also going at half speed.
Does anyone here know what is wrong here or may have some suggestions to try and fix it?

The MCLK of PMD100 must be synchronized with LRCK / BCK / DATA,non-synchronized will produce pop noise or murmurs.
 
I think you miss read my post Keevlin.
My pmd100 works well as I can get it to work with my cs8414 receiver chip using coax digital or optical digital inputs.
It doesnt work well (crackle) at high mck rate of 25MHz as the chip can not handle such high frequencies.
When I use the MCK/2 pre scaler, it works with no crackles, but at slow speed (low pitch) like a record player on slow speed.
At the slow speed I notice that the timer counter in my player software (jriver) is also counting at half speed (maybe driver needs to be changed?)

Cheers

Simon
 
I have solved the issue with the Amanero talking to the PMD100 chip. There was a firmware update for a DF1704 filter chip with reduced clock speeds in the list. I tried that and all is ok. Thanks to Domenico and his multitude of software options, this usb-i2s converter has got to be one of the most versatile of all the current popular converters available at the moment.