Building with the Soekris dam1121

P.S. that is why I asked about the termination resistors ... having an external Si570 only mm's away from J3 connector should not degrade the signal if properly done.

I understand that having a cable to an external board which will be more likely in most cases is not ideal / not recommended.

Just want to get a clear picture of what the options / downnsides are and make a decision then.
 
An additional reason for an external Si570 is pure practical due to my soldering skills.

I am happy soldering smd components to a new board but removing a multi-pin device from any board without destoying something is a different story :rolleyes:

Or I can try to use my hot air paint stripper to attempt flow soldering for removing the Si514 ... hmmm ... not a good idea ... likely burn something else in the process :(
 
I already have the dam1121-02 in house so I will continue with that one.

As there was some discussions about the different clocks between -01 and -02 with the first one having better specs and being possible to have an external LVDS I want to know if it would be benificial to use this option.

If the final conclusion is that it will not make the DAC work better becuase of the earlier mentioned arguments that the advances will be lost due to the bigger distance between the clock and the Spartan controller then I will keep the Si514.

It is not that I definitely want the Si570 but more looking for arguments if it would be an improvement using an external Si570 - of course well implemented and very close to the J3 connector on the Cape board.

Looking at all the replies so far I guess it is not worth the hassle ... I just wanted to be sure :D

I guess the bottom line for having the option to feed an external clock is only for synchronisation of multiple boards ... not designed to feed it with an even better clock as the advances will be lost anyway :rolleyes:

We all agree on that ?? :)
 
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Distance from oscillator to a dam1121 is not a problem, as long as the clock is routed correctly, high speed lvds is critical, but not that hard.

An external si570 can always be used as long as it connected and routed correctly. If using an external si570, place it close to the master and route the clock via a buffer, also placed close to the oscillator, to the slave.

If a dam1121-01 is master and a dam1121-02 is slave, then it will use the master's si570 oscillator.

Multipin SMD parts are hard to remove without the right tools and knowledge how to use them....
 
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Hi Søren,

My main question is if I use a single board -02 (with Si514 onboard) if I would notice any improvements using an external Si570 instead.

I would use a add-on board (like a Cape with Beaglebone) with the Si570 as close as possible to J3.

Thanks in advance.

You can have it as far away as you want, as long:

The clock signal is routed differential with a characteristic impedance of 100 ohms.
No long stubs or terminations, there should only be the onboard 100 ohm terminations.
The signal loss should not be too great.
Also keep the I2C control signals good.

I should note that not many people (if any) can hear any difference between using the Si514 and Si570. But you know how it is....
 
Has anyone encountered the DAM 1121 suddenly unable to lock to the music via I2S?

My unit exhibits this randomly and usually happens between the 2nd or 3rd song. It was working okay until recently. :-(

When this happens, I have to let the unit rest for up to 10 minutes in order to restart it and the problem will occur again.

I think I found an issue with the Salas UBiB supplying the Digital 5V. Seems that the voltage might have dipped as the module warmed up, dropping below the acceptable voltage level. I did a test and increased it slightly above 5V and its been 2 weekends and so far so good.

By the way, using the UBiB is the way to go, I swapped with the LT3042 PS during the troubleshooting and the soundstage literally collapsed, losing the layered presentation.

Thanks to all who helped with suggestions / ideas, much appreciated.
 
Arek8 & Intense-tavda,
The schematic on page 5 in the 1121 manual is pretty clear on how to connect the different SPDIF standards.
If you have a SPDIF Coax signal from your CD-player you need to connect according to the top schematic via transformer, 75 ohm resistor and MAX3280.
Good luck!

So, I thought coaxial digital rca it is possible to connect straight without MAX3280. Now I have another problem, MAX3280 is completely unreachable at me. Has it any replacement? Could it be any other opamp?
 
So, I thought coaxial digital rca it is possible to connect straight without MAX3280. Now I have another problem, MAX3280 is completely unreachable at me. Has it any replacement? Could it be any other opamp?

The ‘straight’ connection as you put it is on the DAM1021. See post 567 earlier in this thread. BTW, MAX3280 is not an opamp, it’s an RS485/RS422 receiver.
 
Hi soren,

Regarding the differences between 1021 and 1121, the two boards have different approaches in clock circuitry, vref and also dac ladder, is that right?
1021 is 28 bit sign magnitude segmented 1msb magnitude, 2 bit thermometer and 25 bit r2r using 7/8x4 shift register outputs

1121 is 32 bit sign magnitude 7 msb thermometer and 25 bit r2r using 8/8x4 shift register outputs.

Is that right?