post#922
"The measurement is based on an a single sample impulse in a 44.1/16 .wav, which was resampled to 352.8kHz in RX4 standard, then exported as a wav.
The file was then analysed in Fuzzmeasure. I've been using this to check check/plot frequency and impulse response as it is an easy way of overlaying multiple plots. As I've noted the "peak" disappears when the file is up sampled to 2822400z so I have my doubts it's particularly meaningful."
So, about that TNT3 filter...
I finally decided to build a new output stage, based on a simple but trusted standard topology: Balancing via a 5532 op amp with decompensated feedback paths, AC coupled output, fed by +/-15V. I used NJM5532DD, currently the best sounding one availible IMO and ubiquitous in pro audio and quality unipolar electrolytics bypassed by film caps.
Nothing fancy, the same stuff that is in my mixing console and something almost every bit of music you can buy went through.
It turns out the DAM's onboard output stage was the problem. TNT's latest linear filter sounds perfect with the new stage. 🙂 The bass, the power, the movement, the detail and especially the spatial dimension.
Now NOS sounds overly aggressive and grainy in the high end.
Music as it is supposed to sound! Thanks TNT!
Now I wonder if a 4K filter could even improve on this... ;-)
I finally decided to build a new output stage, based on a simple but trusted standard topology: Balancing via a 5532 op amp with decompensated feedback paths, AC coupled output, fed by +/-15V. I used NJM5532DD, currently the best sounding one availible IMO and ubiquitous in pro audio and quality unipolar electrolytics bypassed by film caps.
Nothing fancy, the same stuff that is in my mixing console and something almost every bit of music you can buy went through.
It turns out the DAM's onboard output stage was the problem. TNT's latest linear filter sounds perfect with the new stage. 🙂 The bass, the power, the movement, the detail and especially the spatial dimension.
Now NOS sounds overly aggressive and grainy in the high end.
Music as it is supposed to sound! Thanks TNT!
Now I wonder if a 4K filter could even improve on this... ;-)
If anyone is interested I can provide a schematic. Noise performance is bound to be worse than the DAM1021's output stage, but I haven't noticed it on my monitoring systems. I will do measurements in time.
Good you got it sorted! But, do you really need an output stage? I hope you have tested the RAW outputs.... or... u.. missed... something...
If you haven't - you owe yourself...
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If you haven't - you owe yourself...
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Yes, I need an output stage. Can't connect unbalanced with pro audio equipment. Now that it sounds good I will commission a PCB with 32 channels of output for my studio DAC.
As for bipolars, I would recommend the Nichicon Muse BP (the green ones). The only bad thing I have heard about them is that they may not last very long. I've got 220uf on my output stage with a 22nf Wima MKP in parallel.
Now the vertical presentation with the new output stage and your filter is really something else. I got goosebumps listening to "I'm On Fire". Can't wait to mix through this converter. 🙂
As for bipolars, I would recommend the Nichicon Muse BP (the green ones). The only bad thing I have heard about them is that they may not last very long. I've got 220uf on my output stage with a 22nf Wima MKP in parallel.
Now the vertical presentation with the new output stage and your filter is really something else. I got goosebumps listening to "I'm On Fire". Can't wait to mix through this converter. 🙂
Glad to have you back on my filters - I was sad to learn that you didn't use them anymore 🙂
I'll check those caps - thanks!
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I'll check those caps - thanks!
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analog_sa said:
Actually I think it's the opamp that does the least harm to the signal. That's why it's so ubiquitous in pro audio. I couldn't find anything better either, and I've really tried everything else. I even sum through 5534 in my console rather than via discrete op amps (tried 15 or so different of those).
Hello to everyone. Just aquired second hand Soekris 1421 and want to install that pack of nice custom filters (include NOS filter), what I heard many times about. Can anyone share the link to it and provide some tutorial regarding installation procedure?
Thank you a lot in advance!
Thank you a lot in advance!
Very possible this has already been discussed, but ifi’s GTO filter sounds really nice in my experience. Has something like this been attempted for Soekris? I admit that I know nothing about the subject, but I found their white paper intriguing.
Hmm, that paper mentioned MQA, which immediate caused me to dismiss it as sales crap.... And the filter looks just like a regular butterworth lowpass filter, which some of my filters already are....
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Yeah, I didn’t quite understand why they were mentioning MQA. It didn’t seem to have anything to do with the filter, yet MQA helped them implement? To your point, I’m sure tacking MQA at the end of their write up is a marketing play meant to pique the interest of reviewers and the average audio layperson.
That makes sense regarding the butterworth comparison, as that’s been my favorite of your filters.
It's a very short minimum phase filter. The closest to it I would say is the Nyquist C128 filter made by Paul, although that's linear phase.
I'm just a hobbyist myself, but most DSP engineers will tell you that the iFi reasoning is wrong, that the ringing produced is from an impulse that is illegal in a band-limited system i.e. one with a competently designed ADC.
Whatever sounds good is good of course, but I'd suggest not to be take the technobabble in the iFi document as gospel.
Ah, that’s good to know. They do seem to approach the topic as “hey, we figured it out!”, which always suspect to begin with 🙂
Dear forum members, please help me with understanding of filter updating process for Soekris 1421, as I read all of the instructions and tutorials, but still lost in some steps of the procedure.
Let's say, I'm going to install the filter pack from this post
Filter brewing for the Soekris R2R
And use tutorial fro here - to do the installation process
randytsuch's audio page: Soekris R2R Dam DAC
I have a problem with understanding - how to assign the specific filter from the list I'm going to flash (please, check the attached picture) - to the specific led light color, in charged for this filter on my 1421?
In the tutorial it says that all of the filters has to be assigned to F4, F5, F6 and F7 values. In Soekris 1421 there is 4 led light color modes, which shows the specific type of filter - what is using now: red - linear phase, orange - mix of linear and minimum phase, green - minimum phase and light off - soft minimum phase filter. As far as I see - F4, F5, F6 and F7 = red light, orange light, green light and light off on 1421. So, to change the filters I need to use the part of the tutorial - wherebit clearly says how to do it (see the attached picture). However, in the filter list of the pack, I mentioned above, there is far more then one filter of each type (04, 05, 06, 07). More then that - there is 08, 09, 10, 11 and even 30 Denafrips filters. How I can specify - what exactly kind of (lets say) 04 filter I want to set to red light on my 1421? And how can I add 08, 09, 10, 11 and 30 filters?
Really hope for your help!
Let's say, I'm going to install the filter pack from this post
Filter brewing for the Soekris R2R
And use tutorial fro here - to do the installation process
randytsuch's audio page: Soekris R2R Dam DAC
I have a problem with understanding - how to assign the specific filter from the list I'm going to flash (please, check the attached picture) - to the specific led light color, in charged for this filter on my 1421?
In the tutorial it says that all of the filters has to be assigned to F4, F5, F6 and F7 values. In Soekris 1421 there is 4 led light color modes, which shows the specific type of filter - what is using now: red - linear phase, orange - mix of linear and minimum phase, green - minimum phase and light off - soft minimum phase filter. As far as I see - F4, F5, F6 and F7 = red light, orange light, green light and light off on 1421. So, to change the filters I need to use the part of the tutorial - wherebit clearly says how to do it (see the attached picture). However, in the filter list of the pack, I mentioned above, there is far more then one filter of each type (04, 05, 06, 07). More then that - there is 08, 09, 10, 11 and even 30 Denafrips filters. How I can specify - what exactly kind of (lets say) 04 filter I want to set to red light on my 1421? And how can I add 08, 09, 10, 11 and 30 filters?
Really hope for your help!
