The obvious advantages of 1121 in 2-channel mode:
- integrated inputs, including usb
- simplified controls for input/filters which do not require a micro
- reclocking after FPGA
A possible disadvantage is the inability to directly drive headphones. It also requires an external source of dc.
Judging by the 1941 i would expect it to sound considerably better than a 1021 under similar conditions.
- integrated inputs, including usb
- simplified controls for input/filters which do not require a micro
- reclocking after FPGA
A possible disadvantage is the inability to directly drive headphones. It also requires an external source of dc.
Judging by the 1941 i would expect it to sound considerably better than a 1021 under similar conditions.
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Couple of differences.
1021
Wider range of Powerability Direct AC 7 or 8V or DC from +/- 7 to 15V.
Buffered outputs via an opamp or direct ladder out
Isolated and non-isolated serial connections
larger board
only operates asynchronously
I2S, 2 SPDIF inputs
1121
+/- 5V DC power input
direct ladder out
can be operated asynchronously or synchronously with an external clock (only using an Si570)
can operate multiple boards synchronously
I2S, one SPDIF input
Smaller board
1021
Wider range of Powerability Direct AC 7 or 8V or DC from +/- 7 to 15V.
Buffered outputs via an opamp or direct ladder out
Isolated and non-isolated serial connections
larger board
only operates asynchronously
I2S, 2 SPDIF inputs
1121
+/- 5V DC power input
direct ladder out
can be operated asynchronously or synchronously with an external clock (only using an Si570)
can operate multiple boards synchronously
I2S, one SPDIF input
Smaller board
1121 is actually cheaper and comes with more precise resistor values as I see it..1121:
- hard to access -and use- tiny connectors;
- cost is relatively high (compare to 1021).
My 1121 is in the box, I bought 1941 (as "early bird").
Am i wrong thinking the 1121 is reclocked after the FPGA? This alone may be sufficient for better sound.
Clocking scheme is as follows
Si5xx===LVDS====> u2——ttl——>U8,U11——>stcp pin12 of shift registers
| ^
| Fpga
| ^
|___ttl______|
U2 lvds to ttl converter
U11,u8 flip flops
Also, dam1021 is using 7/8x4 shift register outputs,so a sign magnitude segmented dac with 1msb, 2 bit thermometer, 25 bit r2r (as per soekris)
Dam1121 is using 8/8x4 shift register outputs. So 7 msb are thermometer like, 25 bit r2r?
AD3-F3706-5863-4-F28-9-D4-F-BF5470-A35-E1-C — imgbb.com
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Am i wrong thinking the 1121 is reclocked after the FPGA? This alone may be sufficient for better sound.
No, this is correct. Big blunder not to in the 1021...
I own both borads and to me, there was no doubt about the advantage for the 1121. Change/take away the output cap and you are good to go.
//
Clocking scheme is as follows
Si5xx===LVDS====> u2——ttl——>U8,U11——>stcp pin12 of shift registers
| ^
| Fpga
| ^
|___ttl______|
U2 lvds to ttl converter
U11,u8 flip flops
Also, dam1021 is using 7/8x4 shift register outputs,so a sign magnitude segmented dac with 1msb, 2 bit thermometer, 25 bit r2r (as per soekris)
Dam1121 is using 8/8x4 shift register outputs. So 7 msb are thermometer like, 25 bit r2r?
AD3-F3706-5863-4-F28-9-D4-F-BF5470-A35-E1-C — imgbb.com
So both are 25b r2r? What is the net difference really?
One would hope U11 and U8 are from Potato!?
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So both are 25b r2r? What is the net difference really?
One would hope U11 and U8 are from Potato!?
//
Take a look at figure 3a in this article, where a segmented dac is used as example https://www.analog.com/media/en/training-seminars/tutorials/MT-016.pdf
The thing that confuses me is how Soren is using the 7 resistor array of the thermometer segment of dam1121. As 3bit from 32(8x4 shift register outputs) or as 7bit from 32?
In either way using thermometer dac for msb it’s really usefull. Thermometer dac is inherently monotonic and not so sensible at resistor tolerance, so having say 3 bits from 16 resolved by thermometer, the rest of 13lsb are resolved by r2r segment, and for 0.01% tolerance resistor this is a doable task...
Could any help?
Taking your advice seriously, the 2 output caps are going away soon!No, this is correct. Big blunder not to in the 1021...
I own both borads and to me, there was no doubt about the advantage for the 1121. Change/take away the output cap and you are good to go.
//
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