Building with the Soekris dam1121

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janho12345

Member
Joined 2016
TNT said:
OK, so maybe one isn't completely bonkers... :)

How would you describe the differences?

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I have to say that there is a little more ease to the heights like more light . And for me was also a better to differentiate sound stage.

I‘d say that soeren should definitely try it out by himself and probably try to find sth else than the current solution - as it is just degrading SQ of our very nice 1121
 
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janho12345

Member
Joined 2016
spikestabber said:
Technically you would be summing the HF components to cancel them out, at least that's the idea. Yes, fully differential.
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Well I must say I do so. My tube buffer is a summing buffer (BCF) with SE output. But the Caps are not primary for filtering HF noise from outside (that would have the same phase on both differential signals and so cancel out) but they are for cancelling any high frequency’s that „arise“ by the DAC. No?

The Idea behind that was to eliminate any common mode ripple on the diff. signal introduced by powersupply. Of course together with other benefits of a buffer. The signal is then conversed to balanced again by a transformer to ensure CMRR on cables.
 
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D

dewdrop

Member
Joined 2004
Help needed

I wired up my 1121 but it does not have any sound, need to figure if my wiring to my Raspberry Pi is correct, I used:
Raspberry Pi J12 <-> I2S BCLK_I
Raspberry Pi J35 <-> I2S LRCK_I
Raspberry Pi J40 <-> I2S DAT_I

Have strapped CFG 0-3 with 3K3 to GND.

Powered VCC5D on P1 and P2 at J2

Powered VCC5A on P1 at J3
Powered VEE5A on P15 at J3

Any advice?
 
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derekr

Member
Joined 2009
dewdrop said:
Yes I did
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Hmm....then I guess the usual steps - can you confirm (via another DAC) that your RPI is working via its i2s out? Are you measuring plus and minus 5V on the analog power pins on the 1121? And plus 5V on both digital power pins?

Assuming your strapping resistors are all good and going to ground (one or multiple grounds? Not that it should matter but double check them) I’d hook up a terminal program and check you’re getting the correct readout on power up.

Doesn’t hurt to connect the PWR_LED as well. Finally, what’s downstream? Is that amp/speakers or whatever working with output from another DAC?

Good luck.
 
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dewdrop

Member
Joined 2004
@derekr, I appreciate you trying to help.

I have checked the +/-5V rails and they are all good.

Double checked on:
Raspberry Pi J12 <-> I2S BCLK_I
Raspberry Pi J35 <-> I2S LRCK_I
Raspberry Pi J40 <-> I2S DAT_I

I have added the PWR_LED and it remains unlocked even when there is content playing so it has nothing to do with the downstream equipment.

The next thing is to swap out the Raspberry Pi board with one that definitely works as well as to setup the terminal program to see the board status.
 
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dewdrop

Member
Joined 2004
Success! Well kind of...

Thanks guys for all the suggestion. Finally gotten the 1121 to play music on 96/24 FLAC and WAV files. Yah!

The culprit was the Raspberry Pi/Moode software. I swapped them wholesale from a working setup. I will investigate if its the board or the software later.

I have a new issue. I tried to use the MoOde 4.4 software to play DSD over DoP , although the LED shows that a locked status, there isn't any music. When I turned off the DoP setting, even though the LED blinks in the unlocked state, there is music but it stutters.

Anyone has experienced this before?
 
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Arek8

Member
Joined 2018
I'm back with balanced 2xdam1121. It is working with amanero usb but it does not work with spdif input. I have connected coaxial RCA input straight to spdif input on master board. I see in the soekris manual once it should be connected to SPDIF pin without comparator MAX3280 and next schematic RCA to RXD pin by MAX3280. So what is right? I would like to use coaxial input from cd player.
 
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