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

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#8,421
zfe said:
Speaking of the content of the filt.txt files...
The "current" 1021filt_099.txt at soekris.dk is:

Code: 
-- Format:
-- signature, samplerate, interpolationrate, type, numbercoefficients, multiplier
-- type 1 = FIR1, 2 = FIR2, 16..30 = IIR, 30 = Deemphasis
-- type 4..7 = FIR1 new format, add 1000 for shared filters
-- type 8..11 = FIR2 new format, add 1000 for shared filters
--
-- IIR Coefficients is b0, b1, b2, a1, a2. a0 is assumed to be 1.0000
--
-- FIR1 filters for 44.1K/48K Samplerate

dam1021,44100,8,4,1975,7.8
04 Linear Phase FIR1, 44.1 Ksps, 0-19.7 Khz - 1 db, 22.3 Khz -150db

0
-0.0000000000031857274815944411
...

which only contains filters in the new format (04 etc), but the 0.99 firmware needs the old format.
Click to expand...

Hmm, maybe something have gone wrong handling all those files.... Maybe I should just remove all old files....
 
#8,423
The "old files" are useful, I think.

The 0.99 FW with the old filter format makes it much easier to get exactly the part of the ladder swichted on one want to be switched on. This has its benefits for some measurements. Moreover it is the FW of choice for the hardcore bit-perfect NOS fraction, as long they need no DSD and DAC side volume control ;-)

And the 1.0x FW e.g. is essential for those who have trouble with the current firmware to check if it is a FW issue.
 
#8,427
Poni said:
I have tested two sources USB-I2S and TOSLINK, nothing fancy, standard quality. Both sources work with older firmware.
Whats the revision of the board, i think it has to be 0.99


Date Ordered: 21 September, 2015
dam1021-05: 0.05% resistor version (dam1021-05rev2)
On the board there is number printed: 150629
Click to expand...

Hmm, what does it print when you enter the uManager ?
 
#8,429
Poni said:
That is what I get.... I am running now firmware 1021full_106.skr, as 1.21 doesnt work. The 1021full_099.skr works fine too.


.. here is uManager output:

R0.99
I3
F5
V+00
I3
V-46
...
dam1021 uManager Rev 0.99 20150826 FPGA Rev 1.05 Press ? for help.
Click to expand...

I'm interest in what the 1.2x says, don't really help what the working say....

And get the latest from soekris.dk, at some point there was a mixup....
 
#8,433
I got DSD playing again.
I swapped my ribbon cable connection between the Amanero and the DAM to the normundss input board, which I had laying somewhere in the drawer, and DSD was back again.

So it was probably the I2S signal quality, although I hat no problem e.g. with 192kHz PCM signals.
 
#8,434
bitinhvi said:
Hi Soren,

Those capacitors I mentioned are marked as in the picture below.

I am feeding the DAM by +-9.88VDC and PWR- at J2 is -9.54V.

Suddenly today when I turn on DAC to measure voltage again, voltage at center pin of Q3,Q4 is +-9V, and I got normal output level again.

Not sure this issue comes again, in the worst case, can I remove Q3,Q4 to get normal sound?


Thank you.
Click to expand...

Hi I had same issue few weeks back. It turned one bad resistor on negative rail before second 1000uf cap, it was no power on it. It was no power betwen ground and negative poer pins on J2 marked blue in the pic. Bad esistor location in front of last 1000uf cap marked square red.
 

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#8,440
Just removed the 3.3v LDO and swapped in a lm317/lt3045 combo. Just as analog_sa observed, it's a step backwards not forwards for sound quality. I have replaced that combo with a lt3045 feeding a LifePo4 instead. I think this gets things back on track. Sounds a little fuller than the ldo and just as clean. Also, adding a cap to the clock adjacent via *is* beneficial. At least in this circumstance with this external power combo.

That said, I'd like to have some LDOs on hand in case I want to go back to on-board power. Any recommendations for a decent SOT-223 LDO?

EDIT: I found the original LDO on mouser, but if anyone has any other suggestions feel free to mention them.
 
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