It's digital distortion that is immediate upon start up, all volumes and through both spiff and i2s.
I'll measure a test tone later today.
I'm also having noise problem on DDDac recently built for a friend. The noise can be heard as slight "hiss" from speakers when dac is not playing music and also as some coloration/annyoance at HF when playing music.
Measured about 40-50mV noise with osciloscope before and after Cinemag transformer.
Also instead of having "ladder" on sine wave only at 10khz - there's "ladder" even at 1khz...
Will try other digital sources (SPDif etc.) maybe it's the connections...
Measured about 40-50mV noise with osciloscope before and after Cinemag transformer.
Also instead of having "ladder" on sine wave only at 10khz - there's "ladder" even at 1khz...
Will try other digital sources (SPDif etc.) maybe it's the connections...
Only i2s
I need only I2S and think about to build a crossover based on one dddac per channel. Due to the fact that I don’t need spdif, i don’t need all
the extra parts for spdif on the mainboard.
To build a board just with the 5 shift registers is not such a big deal... but on the blue mainboard there are some additional parts... are they needed?
Or is ist possible to get just the blue mainboard without the spdif parts?
Thanks and greetings
Christian
I need only I2S and think about to build a crossover based on one dddac per channel. Due to the fact that I don’t need spdif, i don’t need all
the extra parts for spdif on the mainboard.
To build a board just with the 5 shift registers is not such a big deal... but on the blue mainboard there are some additional parts... are they needed?
Or is ist possible to get just the blue mainboard without the spdif parts?
Thanks and greetings
Christian
Hi everyone, hi doede,
This is my first post in this forum. Beside being a diy-er for a long time (mainly speakers and amps), I want to join the masses in congratulating you for this very fine dac!
I built a 2-decker with i2s-input via Dante (as chriss0212 #wink# ).
Unfortunally, the output ist too low comparing my other setup (running a home cinema without preamp).
So I‘m thinking about using the balanced output possibility. Is it right, that I don‘t need any caps out there? I don‘t want to use any transformers in the first step.
Best regards,
Thorsten
This is my first post in this forum. Beside being a diy-er for a long time (mainly speakers and amps), I want to join the masses in congratulating you for this very fine dac!
I built a 2-decker with i2s-input via Dante (as chriss0212 #wink# ).
Unfortunally, the output ist too low comparing my other setup (running a home cinema without preamp).
So I‘m thinking about using the balanced output possibility. Is it right, that I don‘t need any caps out there? I don‘t want to use any transformers in the first step.
Best regards,
Thorsten
There may be situations where you can do without caps or transformers. However, I would not recommend this at all. You may be better off going balanced with the Sowter transformers, which provide some 2.5x voltage gain. I am not sure if two DAC boards are ok for this, or if it's better to use 4 DAC boards.
I am getting things together to try to get 16 Tent boards working. In view of Mbrennwa`s comments about the 12 Dacs using 3.5A, I have fitted a 300VA transformer that will give me 6A capability.
Funny thing is, that it has rather unexpectantly made my old board 16 stacks sound even better especially the low level resolution ... a nice bonus
Funny thing is, that it has rather unexpectantly made my old board 16 stacks sound even better especially the low level resolution ... a nice bonus
Cool! Let us know how it goes!
Funny thing is, that it has rather unexpectantly made my old board 16 stacks sound even better especially the low level resolution ... a nice bonus
What is the exact set up of this PSU? Just a 50/60Hz AC --> rectifier --> smoothing caps?
I am using the DDDAC power supply but modified with: 2 x 25v secondaries, 2R2 100w resistor between the smoothing caps which are Mundorf 10000uF. R22 100w second smoothing resistor.
The transistor changed to TIP142, then the final smoothing resistor is another R22 100w. Now the transformer is 300VA, 2 x 25v secondaries into the original rectifier with the largest heatsink that I could get, 63.5 mm tall.
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Do I measure them against the "common" pin on each channel?
If so then I'm unsure as to what the answer is. As I put the probe on I get a reading between 0.9v and 0.2v which then decreases rapidly toward zero, it falls to 0.008v after 30 seconds.
Left channel +ve starts at 0.9v and drops to 0.008v after 30 seconds.
Left channel -ve starts at 0.25v and drops to 0.006 after 30 secs.
Right channel +ve starts at 0.2v and falls to 0.006 after 30 secs.
Right channel -ve starts at 0.31v and falls to 0.008 after 30 secs.
Music is distorted at startup and doesn't change, I'd say it's digital crackling and at all volumes, the crackling increases in a linear manner as volume increases and it is the same from both spdif and i2s.
I am using a Salas shunt with a 15v transformer, this outputs 20v (approx) without load and 12.1 with load attached. It has a 500mA capability.
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Anyone having/had or can help with the noise issue? Constant, not loud, but quite noticeable hiss at high frequencies, starts as soon as any digital source is connected, about 40-50mV (which is a lot) on osciloscope. Checked everything - all is ok. Power supply/rails noise is VERY low (using TPA Placid shunt regulator), so it's somekind of digital related noise.
What i really want to know if it's a problem, or is it common for this DAC and i have to think of some kind of additional filter (already have optional 5uF C output filter cap on the board - doesn't help much)
Using single deck and 130ohm load resistors btw..
What i really want to know if it's a problem, or is it common for this DAC and i have to think of some kind of additional filter (already have optional 5uF C output filter cap on the board - doesn't help much)
Using single deck and 130ohm load resistors btw..
What is your digital source? Does it output an active I2S data stream (with all zeros) if there is nothing playing? If so, what you see might be the internal noise shaping process of the DACs working on the "all zeros" I2S data stream.
I am not very familiar with the Salas shunt regulator, but I would expect it to be more stable than that. Maybe it's working at its limits, messing up the DC supply to the DAC? Can you try with another power supply (e.g., a lab bench supply) to see if that changes anything?
It's either I2S (WaveIO) or SPDif, no difference. Bitrate (44.1 or 192) also makes no difference. As long as there's digital connection/stream (music playing or on pause) it's there.
If it's DACs working...i'm happy for them, but is there any way to get rid of it? It's quite a lot of noise. I assembled this DAC for a friend and he complained about the hiss right away so i began to search for a problem but haven't found anything and haven't had an idea that this could be normal under any circumstances
Does adding more decks can help to attenuate it at least? If output doubles and noise remain at the same level it won't be as noticeable at least.
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The Salas shunt 1.1 (a.k.a. "BiB") (judging by the pic that was posted) should be very stable, as long as the current that is demanded of it does not increase past the max CCS current (that is set by a resistor on the BiB). When the load asks for more current than the max set, the output voltage will drop. But testing with a light load (like 50mA) versus a heavy load (say 450mA) should make no change to the output voltage, as long as the CCS is set to a current over ~500mA.
But it appears that in this case the BiB is outputting 20V to the DAC board.. there's something wrong here.