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Old 17th February 2015, 10:43 PM   #91
TNT is offline TNT  Sweden
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Old 17th February 2015, 10:49 PM   #92
Eldam is offline Eldam  France
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Quote:
Originally Posted by robertrowett View Post
NOS sounds best to me so far, but I like the sound anyway. Coming from MHDT and Metrum models this is the same presentation but better. Except- I am having a little more glare than with other DAM filters. A lot more glare than with MHDT.
Has you been trying this same NOS filter but playing a 16/41 already upsampled with Sox at 384 Khz to compare if hearable differences ?

(I can stay on topic sometimes .... btw I listened this afternoon a TDA1541 DAC in NOS with 16/41 materials and it can sounds clean... to me, but have not tried with Sox yet to push it at 192 or 384 !)

Last edited by Eldam; 17th February 2015 at 10:53 PM.
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Old 18th February 2015, 01:46 AM   #93
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Quote:
Originally Posted by robertrowett View Post
NOS sounds best to me so far, but I like the sound anyway. Coming from MHDT and Metrum models this is the same presentation but better. Except- I am having a little more glare than with other DAM filters. A lot more glare than with MHDT.
Quote:
In the case of the Metrum Acoustics DAC there is a mild 70kHz (first-order) filter just before the signal is sent to the output-terminal.
The DAM1021 has a hardware output filter set at 270khz, and a final software filter which is -80dB @ 240kHz.

Modelling a 1st order filter with a 70kHz corner frequency in rePhase indicates that the Metrum will be -0.31dB at 20kHz, -1.23dB at 40kHz, and -3dB at 70kHz (obviously, as the corner frequency is the -3dB point).

It is easy enough to create this filter and the output should be more like a Metrum, in terms of frequency response anyway.

The filter is minimum-phase but it will make little difference.

Last edited by spzzzzkt; 18th February 2015 at 01:56 AM.
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Old 18th February 2015, 03:30 AM   #94
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Originally Posted by spzzzzkt View Post
It is easy enough to create this filter and the output should be more like a Metrum, in terms of frequency response anyway.
OK, this one is badly distorting at high volumes. I'm not sure if it's messing with the Hypex amp, or similar but it's pretty ugly beyond about V-10.

I'd advise not to use and I've requested mod's delete the attachment.

The original 1021NOS.skr seems to be fine so I'd use that in preference.

Last edited by spzzzzkt; 18th February 2015 at 03:36 AM.
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Old 18th February 2015, 04:36 PM   #95
Eldam is offline Eldam  France
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Is it possible to have a FIR 1 NOS from 10k/15 K hz then a FIR 2 with digital EQ from 10/15 K but with a stronger roll of ? Stronger but stil with a few -DB roll of per octave ? - 1.5 to - 3 DB ???
Why not try something non conventional which impact the ears range directly ! When I listen to an old 16/44.1 chip like the Philips, I can't really hear a lacke of micro informations .... I'm not sure it's straight right to 20 k hz in a 0.5 DB drift range....

Have to say I'm always with the stock filter as I haven't bought an USB to serie RS232 convertor !
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Old 18th February 2015, 06:35 PM   #96
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Quote:
Originally Posted by Eldam View Post
Has you been trying this same NOS filter but playing a 16/41 already upsampled with Sox at 384 Khz to compare if hearable differences ?

(I can stay on topic sometimes .... btw I listened this afternoon a TDA1541 DAC in NOS with 16/41 materials and it can sounds clean... to me, but have not tried with Sox yet to push it at 192 or 384 !)
I use cds so no access to Sox. I did add a 6111 tube buffer to the direct output and the signal has cleaned up nicely. NOS is giving me the tone I am looking for and no drawbacks so I will use it as reference.

I am moving on to output stage and will start a new thread.

Thanks for the great work on the filters guys we all appreciate it!
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Old 18th February 2015, 08:24 PM   #97
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Quote:
Originally Posted by Eldam View Post
Is it possible to have a FIR 1 NOS from 10k/15 K hz then a FIR 2 with digital EQ from 10/15 K but with a stronger roll of ? Stronger but stil with a few -DB roll of per octave ? - 1.5 to - 3 DB ???
Why not try something non conventional which impact the ears range directly ! When I listen to an old 16/44.1 chip like the Philips, I can't really hear a lacke of micro informations .... I'm not sure it's straight right to 20 k hz in a 0.5 DB drift range....

Have to say I'm always with the stock filter as I haven't bought an USB to serie RS232 convertor !
Perhaps you should spend the 10-15 euro on a USB -> Serial interface. It seems a bit pointless endlessly speculating about variations when you haven't listened to any of the modified filters.
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Old 19th February 2015, 12:18 AM   #98
Eldam is offline Eldam  France
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Ah, I just tryed to follow the comments that's all . Sorry if you get upset with it !

I'm a little busy on some other dacs building... And my Dam1021 is always for sale in the swap meet section FOR SALE : SOEKRIS dam1021 / 0.02%, have to fax to my bankeer to decide if it's worth to buy a USB to serie adapter (and ask for a little more to buy a Valium tablett to let it work ! ). The first listening just give me the envy to finish first my others dac as this one is too much time consuming ! .... And before trying the other digital filters improvements (more listening sessions, etc !)

What can I answer to you Paul ? Thank you for sharing ! Your efforts are much appreciated and far above my personal skill...BTW I updated the memory aid first page for new readers Soekris 's DAC implementations

At least it seems this DAC is a good war tool as well ; You will excuse me about this off topic but your message called for an answer !

Last edited by Eldam; 19th February 2015 at 12:23 AM.
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Old 19th February 2015, 12:46 AM   #99
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OK, I am a noob at DACs and have been reading to try to understand. If I understand correctly, the DAM has no filter when fed 352.8 or 384 kHz input. Reading the John Swenson posts about upsampling externally using SoX, it seems like the interpolation filter used by SoX would have quieter alias' than upsampling of zeros added in the Dam as described by Soren. I'm not sure how rephase works.

I was wondering if any of you filter kings have compared a high res sample (192 or greater) with the NOS using 44.1 that you have been experimenting with? The hi-rez sample should sound cleaner, in theory, than the NOS, even if it was upsampled using a program like SoX.

My current concept is that the DAM Dac is an excellent choice when used with externally upsampled music, but I haven't gotten far enough to try any hardware.

Thanks in advance for you comments and experience.
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Old 19th February 2015, 04:38 AM   #100
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Quote:
Originally Posted by Eldam View Post
Ah, I just tryed to follow the comments that's all . Sorry if you get upset with it !

I'm a little busy on some other dacs building... And my Dam1021 is always for sale in the swap meet section FOR SALE : SOEKRIS dam1021 / 0.02%, have to fax to my bankeer to decide if it's worth to buy a USB to serie adapter (and ask for a little more to buy a Valium tablett to let it work ! ). The first listening just give me the envy to finish first my others dac as this one is too much time consuming ! .... And before trying the other digital filters improvements (more listening sessions, etc !)

What can I answer to you Paul ? Thank you for sharing ! Your efforts are much appreciated and far above my personal skill...BTW I updated the memory aid first page for new readers Soekris 's DAC implementations

At least it seems this DAC is a good war tool as well ; You will excuse me about this off topic but your message called for an answer !
Not upset, but without hearing what the different filters sound like in your system it's as useful as picking your favourite flavour of ice-cream on the basis of what someone thinks is good. I hate aniseed, banana and passionfruit but you might love Pernod, so are you going to avoid Pernod ice-cream because I don't like it? Following someone else's opinion - no matter how stridently it's expressed - might well deprive you of something you will enjoy...

As pos says "pick your poison" but you can't do that without listening....
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