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Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

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#5,843
#5840, additional information.
Please see below what I have done on dam1021 Rev 3 board.

1. removed bridge+rectifier and shorted
2. removed all buffer and balance opamp
3. removed all power rail caps (C20,C17,...)
4. removed mute transistor (Q4, Q3) just beside raw output
5. removed U5, U7 and shorted in/out
6. removed 3.3v LDO and supplying 3.3v from low noise PS
7. removed 1.2v smps and supplying 1.2v from low noise PS
8. Supplying +-5.000v on C16, C31 directly
9. Jumping +-5.000v on J2 +-A

The problem is I cannot get any sound. I checked +-4vref at (C104~C122) but only appears +-0.0106v.. what can I do? please help..
I did almost the same things on Rev1 and it works perfectly.
 
#5,844
WH Fusion said:
#5840, additional information.
Please see below what I have done on dam1021 Rev 3 board.

1. removed bridge+rectifier and shorted
2. removed all buffer and balance opamp
3. removed all power rail caps (C20,C17,...)
4. removed mute transistor (Q4, Q3) just beside raw output
5. removed U5, U7 and shorted in/out
6. removed 3.3v LDO and supplying 3.3v from low noise PS
7. removed 1.2v smps and supplying 1.2v from low noise PS
8. Supplying +-5.000v on C16, C31 directly
9. Jumping +-5.000v on J2 +-A

The problem is I cannot get any sound. I checked +-4vref at (C104~C122) but only appears +-0.0106v.. what can I do? please help..
I did almost the same things on Rev1 and it works perfectly.
Click to expand...

You might need to remove R392, it's part of the new mute circuit which you're trying to disable and powered from PWR_A+, which you seems to have done something to....

I don't know what voltage you have on PWR_A+ now, but either you need to ensure there are minimum 7V, or you need to remove R392 as, as far as I remember, the firmware would then assume you have an old board and not use the early warning power off....
 

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#5,848
lapis05 said:
Is the crossover filter using multiple modules available now? Thanks.
Click to expand...

I'm not sure what you're asking about but:

1) The dam1021 have always had support for up to 14 IIR biquads, the coefficients need to be put in the filter file and downloaded.

2) But it's beyond the dam1021 project how to design and calculate the coefficients, the tiny ARM uC don't have resources for that. There are also no available memory in the FPGA to do delays.

3) The best, as some have done, is to do the filtering someplace more powerful..... You can feed the dam1021 the same word clock and they will sync. There are multi channel USB to I2S interface that should work fine.
 
#5,849
Thanks Soren. It seems do crossover on a PC is the very fast way. I have 3 amanero 384, but not yet find a software or foobar plugin do channel divide to each one? Anyone can suggest a window based software perform crossover to separated USB to I2s interface(not a multi channel I2S interface)?
 
#5,851
lapis05 said:
Thanks Soren. It seems do crossover on a PC is the very fast way. I have 3 amanero 384, but not yet find a software or foobar plugin do channel divide to each one? Anyone can suggest a window based software perform crossover to separated USB to I2s interface(not a multi channel I2S interface)?
Click to expand...

Try ASIO4ALL. It allows using multiple interfaces as a single ASIO device. Any foobar plugin will work.

But you will have a problem with your DAMs not synced to the same bitclock. Better to use a multichannel interface.
 
#5,853
@Soren
Some experiments with unwanted volume changes due to typos (I use screen for the communication with the DAM and the current firmware 1.06)
Va gives V+10
Vb gives V+10
Vxyz gives V+10 (I assume any letter combination does)
V) gives V-7
V! gives V-15
V, gives V-4
V gives V-99
 
#5,855
zfe said:
@Soren
Some experiments with unwanted volume changes due to typos (I use screen for the communication with the DAM and the current firmware 1.06)
Va gives V+10
Vb gives V+10
Vxyz gives V+10 (I assume any letter combination does)
V) gives V-7
V! gives V-15
V, gives V-4
V gives V-99
Click to expand...

Just remember that the serial port is not supposed to be controlled by a human, but a microprocessor....

But it seems like people are using the dam modules in ways I didn't think about, so the runtime commands will get improved error checking in next version.
 
#5,859
aradan said:
jaffar,

What exactly are you trying to achieve in your build?

Multi channel set up is handelled just fine by multi channel usb adapters.
Click to expand...

My build is already using a multichannel interface. Works like a charm.
The question is
lapis05 said:
I have 3 amanero 384, but not yet find a software or foobar plugin do channel divide to each one? Anyone can suggest a window based software perform crossover to separated USB to I2s interface(not a multi channel I2S interface)?
Click to expand...

And the answer is "better to use one multichannel versus three Amanero's" 😉
 
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