Fred: 1015 taps is the maximum numbers of taps that the DAM can currently use for FIR1. For a FIR, the more taps, the better to manipulate (filter) the signal.
The original 44.1kHz filter has 383 taps. This number can be increased to 1015 taps at 44.1kHz and provide performance benefits (greater attenuation, ripple reduction,...).
(The original filter file contains over 1200 taps for the various fs configurations. 1276 taps)
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Søren, as a content user of a Soekris net-board and interested reader of this thread (as well as one or to other that may turn into a Best-buy DIY-Dac) I feel I have to respond to your answer to rickmcinnis.
Søren, not to be offensive but you started posting about your dac in the Digital Line Level-forum, asking for inputs to your construction.
It seems there´s still some work to be done regarding filters, which you kind of ask the DIY-community to help you with (= maturing your commercial product for the benefit of all, non-DIY´ers (and yourself) included).
Revealing the location of the regs asked for doesn´t mean supporting the mod; I´ll image you´ll advise against it. I´m also sure rickmcinnis as well as others who intend modification of the board itself are aware of the risks involved..
With the deepest respect for yours and forum-members´ combined efforts in this product
Regards, Finn (satisfied user of modified to - and improved - battery-power dac)
Søren, not to be offensive but you started posting about your dac in the Digital Line Level-forum, asking for inputs to your construction.
It seems there´s still some work to be done regarding filters, which you kind of ask the DIY-community to help you with (= maturing your commercial product for the benefit of all, non-DIY´ers (and yourself) included).
Revealing the location of the regs asked for doesn´t mean supporting the mod; I´ll image you´ll advise against it. I´m also sure rickmcinnis as well as others who intend modification of the board itself are aware of the risks involved..
With the deepest respect for yours and forum-members´ combined efforts in this product
Regards, Finn (satisfied user of modified to - and improved - battery-power dac)
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The dam1021 FIR1 is operating at 352.8K/384K and each filter can have up to:
1016 tabs at 44.1K/48K input sample rate
508 tabs at 88.2K/96K input sample rate
252 tabs at 176.4K/192K input sample rate
124 tabs at 352.8K/384K input sample rate, but normally bypassed
FIR2 is operating at 2.822M/3.072M and can have up to 120 tabs, with input sample rates 352.8K/383K.
All upsampling is done by zero insertion, therefore gain need to be set to match oversampling rate.
There can be multiple of each filters in the 1021filt.txt filter file, but minimum one need to be there for each input sample rate. Currently just the first one for a given sample rate is used, in later firmware releases you will be able to choose between different filters.
Again, you need to know what you're doing if you want to do your own filters, it's not that simple and there aren't much error checking in the tools....
1016 tabs at 44.1K/48K input sample rate
508 tabs at 88.2K/96K input sample rate
252 tabs at 176.4K/192K input sample rate
124 tabs at 352.8K/384K input sample rate, but normally bypassed
FIR2 is operating at 2.822M/3.072M and can have up to 120 tabs, with input sample rates 352.8K/383K.
All upsampling is done by zero insertion, therefore gain need to be set to match oversampling rate.
There can be multiple of each filters in the 1021filt.txt filter file, but minimum one need to be there for each input sample rate. Currently just the first one for a given sample rate is used, in later firmware releases you will be able to choose between different filters.
Again, you need to know what you're doing if you want to do your own filters, it's not that simple and there aren't much error checking in the tools....
After having listened to 44,1 via the filter made by pos, I'm confident that this can turn out really good. This filter make the DAM sound quite laidback, almost soft. Havent got my speakers back so I enjoy this throgh a pair of Philips SRC HP980 via the active output of the DAM. I will try to make one myself starting form the pos filter design and see where it may end up. I hope I can not destroy the DAM in any way by loading strange filter. Ears migth have to be protected.
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What is the name of your product please ?
Does this one linked should be enough ?
Trendnet - Convertisseur USB vers Série, TU-S9: Amazon.fr: Informatique
Dear finnogangela,
Thanks for your note.
In deference to Soekris I would like to say more about this.
I was worried, in this litigious age, that Soekris had legitimate fears that anything he says could be construed as an "OK". I wrote him a PM and he kindly responded.
His main comment was that my request for information might be a little too close to his IP, he calls it his "secret sauce", and I surmise, since the only thing that could explain where they are, is that they are intertwined with the FIR chips and I am guessing there are twenty of these supplies (ten of each polarity? I do not know) which would make it quite impossible for me to replace them with batteries.
So after all is said and done I agree with Soekris's position even though I wish he would have just made it plain but ... We can think of this as a community project and that is an aspect but it is still Soekris's idea and implementation and we have no choice but to respect how much he is willing to reveal.
Nonetheless, thanks for sharing my frustration but I have to say on this Soekris is right, just a little cagey!
Thanks and take care,
Thanks for your note.
In deference to Soekris I would like to say more about this.
I was worried, in this litigious age, that Soekris had legitimate fears that anything he says could be construed as an "OK". I wrote him a PM and he kindly responded.
His main comment was that my request for information might be a little too close to his IP, he calls it his "secret sauce", and I surmise, since the only thing that could explain where they are, is that they are intertwined with the FIR chips and I am guessing there are twenty of these supplies (ten of each polarity? I do not know) which would make it quite impossible for me to replace them with batteries.
So after all is said and done I agree with Soekris's position even though I wish he would have just made it plain but ... We can think of this as a community project and that is an aspect but it is still Soekris's idea and implementation and we have no choice but to respect how much he is willing to reveal.
Nonetheless, thanks for sharing my frustration but I have to say on this Soekris is right, just a little cagey!
Thanks and take care,
Maybe Michael “Pflash” Pflaumer's patent Filter for D to A converters could be of some help?
The reason for using 1015 rather than 1016 is that rePhase has a bug when using an even number of taps.
The changes to the txt file are straight forward to make. Export from rePhase as 32bit mono float, and paste to replace the existing FIR coefficients immediately after the relevant header.
You would then need to alter the first line of the section header to reflect the number of taps filter you have inserted.
Code:
dam1021,44100,8,1,[b]1015[/b],8
Input FIR, 44.1 Khz Samplerate, 0-19 Khz +- 0.01 db, 24 Khz -110db
0.0000000000000000000002205955035956718
-0.000000000003583024540513104
-0.000000000009705691392355318
....
0.00000000002827615964380067
0.000000000005400389449492969
-0.0000000000000000000001631140623808514
dam1021,48000,8,1,319,8
Input FIR, 48 Khz Samplerate 0-21 Khz +- 0.01 db, 28 Khz -110db
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No access to the uManger
When I open Z term I see: ATE1 V1) so it seems to see the Dam1021, but when I type +++ nothing happens, what else can I try?
Thanks for help.
Tobias
Hi I am on a Mac also and followed your advice, but I just do not see the uManager.
When I open Z term I see: ATE1 V1) so it seems to see the Dam1021, but when I type +++ nothing happens, what else can I try?
Thanks for help.
Tobias