Building with the Soekris dam1121

[roderickvd]

Exactly right, I'm running it as an integrated streaming DAC. I am not feeding it over USB, SPDIF or whatever. Just as a headless player for Spotify and AirPlay. That's what the RPi does, you don't need it otherwise. (Except maybe for serial control if you wanted to.)

So in my case it's simply a stack of RPi > IsolatorPi > Kali Reclocker > dam1121 over I2S.

Note I am not using Ian's FifoPi but a combination of Ian's IsolatorPi and a separate reclocker. I did so because of my power supply configuration:

1x DIYINHK LT3045 5V --> RPi (dirty side)
1x DIYINHK LT3045 5V --> IsolatorPi + Reclocker (clean side) --> dam1121 (digital section)
1x AMB s22 +/-5V --> dam1121 analog section

The LT3045's each on one secondary of a 2x9V transformer, the s22 on both secondaries of another 2x9V tranny.

The latest FifoPi needs 3.3V and I didn't want another PSU just for the dam1121.

 

[InspectorGadget]

Thanks, I'll have a look. There aren't enough hours in the day to keep track of everything of interest and actually build something!

Tell me about it. This place is at times counterproductive to DIY. past a certain point, once you have decided what you want to build that is. I think its best I prioritise building and remove the browser from my PCB design workstation ... lol. ahh the things I need to do to restrain myself in place of actual willpower ... lol

 

[Tankpopper]

Exactly right, I'm running it as an integrated streaming DAC. I am not feeding it over USB, SPDIF or whatever. Just as a headless player for Spotify and AirPlay. That's what the RPi does, you don't need it otherwise. (Except maybe for serial control if you wanted to.)

So in my case it's simply a stack of RPi > IsolatorPi > Kali Reclocker > dam1121 over I2S.

Note I am not using Ian's FifoPi but a combination of Ian's IsolatorPi and a separate reclocker. I did so because of my power supply configuration:

1x DIYINHK LT3045 5V --> RPi (dirty side)
1x DIYINHK LT3045 5V --> IsolatorPi + Reclocker (clean side) --> dam1121 (digital section)
1x AMB s22 +/-5V --> dam1121 analog section

The LT3045's each on one secondary of a 2x9V transformer, the s22 on both secondaries of another 2x9V tranny.

The latest FifoPi needs 3.3V and I didn't want another PSU just for the dam1121.

Thanks roderickvd,

Thank you for the explanation.

May I ask what kind of output stage you implemented? I have a couple of UTC A20 transformers from an old project which im thinking of using as an output stage.

Tank.

 

[nautibuoy]

You don't necessarily need any output stage after the DAM1121, it's output level is healthy and impedance reasonably low - try it without and see how it sounds - maybe less is more?

 

[roderickvd]

Indeed I'm running the unbalanced out directly into a 50KΩ stepped attenuator and from there into a 1MΩ headphone amplifier.

 

[Tankpopper]

Just to confirm - The analog section of the DAM 1121 requires a 5V rail?

 

[TNT]

Hmm - did you read the manual?

//

 

[jphabc54]

What kind of heat sinking do you need for the LT3045 connected to the dirty side of the RPI?

 

[roderickvd]

The analog section requires 5VDC bipolar so both positive and negative! Indeed this is basic stuff from the manual.

The heatsink provided with the DIYINHK LT3045 kit is hot but within specs, it suffices.

 

[Tankpopper]

The analog section requires 5VDC bipolar so both positive and negative! Indeed this is basic stuff from the manual.

Thanks! I know the manual clearly shows that. I wanted to make sure the community didn't come up with a different approach of some sort...

 

[Tankpopper]

Exactly right, I'm running it as an integrated streaming DAC. I am not feeding it over USB, SPDIF or whatever. Just as a headless player for Spotify and AirPlay. That's what the RPi does, you don't need it otherwise. (Except maybe for serial control if you wanted to.)

So in my case it's simply a stack of RPi > IsolatorPi > Kali Reclocker > dam1121 over I2S.

Note I am not using Ian's FifoPi but a combination of Ian's IsolatorPi and a separate reclocker. I did so because of my power supply configuration:

1x DIYINHK LT3045 5V --> RPi (dirty side)
1x DIYINHK LT3045 5V --> IsolatorPi + Reclocker (clean side) --> dam1121 (digital section)
1x AMB s22 +/-5V --> dam1121 analog section

The LT3045's each on one secondary of a 2x9V transformer, the s22 on both secondaries of another 2x9V tranny.

The latest FifoPi needs 3.3V and I didn't want another PSU just for the dam1121.

In that case, I think I will look into the Kali reclocker as well. If I use it between the JLSOUNDS USB board and the DAM, do I need some sort of galvanic isolation like the FIFOPI provides?

 

[nautibuoy]

Why would you do that? You need one or the other, not both, depending on your direction of travel.

If you want a RPi streamer solution, you don't need the JLSounds board.

If you want a USB connection just use the JLSounds board, which has intgrated isolation and reclocking.

 

[lasercut]

There may be some benefit using Rpi as USB source for the JLSounds board rather than a normal PC though. Isolation and reclocking still doesnt guaranteed 100% immunity from source interference.

 

[nautibuoy]

Possibly. I use an Intel NUC as a USB source because it allows me to run it as an HQPlayer NAA, so the main computer is some distance from the audio system.

 

[jphabc54]

The heatsink provided with the DIYINHK LT3045 kit is hot but within specs, it suffices.

Thanks!

 

[roderickvd]

@nautiboy what do you use to accept USB audio in? I mean on the RPi you would need something like Ian's BridgePi right, it's not just like inserting audio USB into a generic USB port is it? (I'm no USB audio aficionado.)

 

[nautibuoy]

For USB connecting DACs the Intel NUC is on the network and I just connect the DAC (with a JLSounds board on the front end) to it via a standard USB cable.

 

[Tesla Audio]

Why to use fifopi reclocker if DAM1121 has already implemented reclocker.

 

[roderickvd]

You can look at the dam1021 thread but be prepared to read a *lot* of pages on it.

Short version: it's not true reclocking, but adaptive clocking, because the programmable clock on the dam side continuously tracks the timing of the incoming data. And when that data isn't precisely clocked, well, then the dam's clock will oscillate.

I was sceptical, thinking "how much of a difference can it make" but really the difference with a Kali Reclocker in front of my dam1121 was not subtle.

 

[Tesla Audio]

Is difference with kali significant or just hard to recognize?
I'm just thinking to chose direction fifopi q3 with Ian es9038 or mybe kali with dam1121.