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DAM1021 NOS with a 3 Pole passive filter
DAM1021 NOS with a 3 Pole passive filter
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Old 7th February 2019, 01:43 PM   #11
abraxalito is offline abraxalito  United Kingdom
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Quote:
Originally Posted by analog_sa View Post
I have heard about a dozen NOS dacs and they all, without exception sounded dull to me. Irrespective of the dac chip type. Of course there were other issues with the sound as well, but the dull highs were always common.
Its relatively rare to find a NOS DAC that does droop correction for 44k1. I think perhaps AMR has one or more (Thorsten has been a proponent of correcting droop) but I don't know of any other commercial offerings that do it. Ah yes, TotalDac does I think have an option to switch on correction, done with an FIR filter I believe.
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Old 7th February 2019, 05:15 PM   #12
analog_sa is offline analog_sa  Europe
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DAM1021 NOS with a 3 Pole passive filter
Yes, that is exactly how they do it in TD.
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Old 7th February 2019, 05:30 PM   #13
hop.sing is offline hop.sing  Europe
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Such a filter could be done in the DAM1021, so no need for a peaking analogue filter, but what about the mirrors?
The Total DAC has no filtering after conversion?
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Old 7th February 2019, 06:32 PM   #14
analog_sa is offline analog_sa  Europe
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DAM1021 NOS with a 3 Pole passive filter
To the best of my knowledge no, but that does not mean there is no cap at the output of the ladder.
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Old 7th February 2019, 07:33 PM   #15
TNT is offline TNT  Sweden
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Correct?

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Old 7th February 2019, 08:07 PM   #16
hop.sing is offline hop.sing  Europe
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Correct?

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Right (On some publication it was 640 ohms on the ladder, but maybe that changed over time), and the 10k terminating resistance should have a ground symbol on the other side....
to raise the cutoff frequency a little I would have rather used an inductor of 7,5 mH or so, but had none available, it was just a trial though, but turned out fine...

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Old 7th February 2019, 08:22 PM   #17
hop.sing is offline hop.sing  Europe
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Originally Posted by analog_sa View Post
To the best of my knowledge no, but that does not mean there is no cap at the output of the ladder.
A first order LP filter would not dampen 40k very much and on the website they do not talk about a filter at all, so....
Interesting, this 10000 dollar DAC seems to please everybody who listens to it, so the mirrors seemingly do not count.
I am sure my Amp (The Cubie3 design from Juma based on the Pass F5) does not care about those high frequencies, but I suspect the tweeters might produce some intermodulation distortion due to that uncorrelated hf rubbish, but have obviously no evidence...
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Old 7th February 2019, 08:37 PM   #18
janho12345 is offline janho12345  Germany
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I do have a few questions here.
Here is an except from the dam manual:

“The dam1121 upsamples everything to the final 2.8/3.1 Mhz DAC sample rate in two steps, there are three different filters in the dam1121”

I know that NOS filters were made, also by the so called “filter Meister Paul”. The latest was the NewNOS. As I understood from reading the dam1021 filter thread this inserts some zeros but it is still up sampling. If I’m wrong I happy take “no you’re wrong” for an answer.
Till then I’m not sure if the Dam can be considered as a true NOS DAC.

Second question. If you want to filter the high frequency’s with an extra filter after the DAM board, did you remove the onboard C? If not you're filtering twice, on purpose. I do have no problems with that but one seems useless then no?

Sorry if I’m repeating myself of get on someone’s nerves with this RC or “output” C Filter thing.

Last edited by janho12345; 7th February 2019 at 08:40 PM.
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Old 7th February 2019, 10:35 PM   #19
analog_sa is offline analog_sa  Europe
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DAM1021 NOS with a 3 Pole passive filter
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Till then I’m not sure if the Dam can be considered as a true NOS DAC.
If you look at it as a black box, yes, it behaves exactly as a NOS dac. If you dig into the inner workings, then not so NOS. I am unsure how this answers the question whether it is true NOS or not. Soundwise i find it to be a bad NOS imitation.
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Old 8th February 2019, 04:28 AM   #20
hop.sing is offline hop.sing  Europe
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Originally Posted by analog_sa View Post
If you look at it as a black box, yes, it behaves exactly as a NOS dac. If you dig into the inner workings, then not so NOS. I am unsure how this answers the question whether it is true NOS or not. Soundwise i find it to be a bad NOS imitation.
Well it measures very NOS. beautiful steps on the scope, hf loss like predicted. How comes, it sounds like a bad imitation? I believe in „hidden” parameters that are not easily measured, but still color the sound, but what should that be in that case?
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