Meier Audio Corda Soul - TOTL DAC/AMP/DSP
Aug 19, 2019 at 11:34 AM Post #121 of 358
@Jan Meier

All I’m saying is at least consider building just a DSP version. I’m sure there are a number of others who feel the same way.

Yes, i am in the same camp. I want a DSP-only element usable in the most transparent chains. The "best" Jan can do. It has to be upgrade-proof. I even would pay what will cost this budget DSP/DAC/Amp for a TOTL DSP. I'm not sure to be in the market for the current design.

ps : there's a Country thread :

https://www.head-fi.org/threads/corda-country.909626/
 
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Jan 9, 2020 at 2:34 PM Post #122 of 358
Today I bought the Meirer audio corda soul and it sounds so dam great, it is a big big battle between it and hugo tt2, what a great dac amp the corda soul is. Although I had the hugo tt2 about a month ago , when I heard the corda soul I could not let it go and bought it on the spot. To be honest I never thought anything can touch chord tt2, but man was I mistaken the Corda Soul, per its name gives soul to the music in an unprecedented way. It just grabs your attention to how great of an amp dac Corda Soul is. Had I not bought chord hugo tt2 a month ago, i would easily have settled with joy with the Cord Soul. the naturalness of the sound, and the big control on the dynamics of the music using the Corda soul is unbelievable, this is giving the chord hugo tt2 a big competitor to battle against. The amazing details in the highs, immediately grabbed my attention ,and the beautiful placement of the mids was simply put perfect. The bass is solid and tight, and what an amazing sound stage it has. It sounds as if the music I am listening to is not digitally processed but full naturalness and richness to the sound is what i am hearing

I used my Hifiman HE1000SE and some others and it is simply an amazing dac amp period

In what is corda soul is slightly better than hugo tt2
1- the mids and highs. The vocals are detailed and smooth, and not recessed or too forward, they are simply perfect. They are more rich and full on the corda soul than on hugo tt2. Then in the high notes there are sparkling details that are just a joy to listen to. This dac amp never ever gets harsh or metallic sounding, it is simply a joyful amazing smooth, detailed, rich organic sounding dac amp

In other areas both chord tt2 and Corda soul are very very very very close

All my listening was without any dial in of the dsp, so I am looking forward to dive more into the capabilities of this dac amp
 
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Jan 9, 2020 at 3:46 PM Post #123 of 358
... the Cord Soul. the naturalness of the sound, ... The amazing details in the highs, ... the beautiful placement of the mids was simply put perfect. ...
I too have observed that the Soul has a natural smoothness and clarity to the mids and highs that I haven't heard with other amps. The Oppo HA-1 for example sounds just a hint grainy in comparison to the Soul, even though it is not a grainy sounding amp.

I suspect this is due mainly to the Soul's FF, or frequency shaped feedback, which reduces bass "unloading" the signal as it passes through the DAC and the analog gain-feedback loop, than boosts it back to normal on the output. But I don't know for sure. It could also be its unique volume control. With most amps, when you turn down the volume you also turn down the SNR because they have fixed gain with attenuation. With the Soul, the volume knob actually reduces gain so the SNR remains very high even at low volume settings.
 
Jan 13, 2020 at 4:35 AM Post #124 of 358
after comparing for 5 days I decided to sell my Hugo TT2 as to me Corda Soul won me over totally
 
Jan 16, 2020 at 2:49 PM Post #125 of 358
hi everyone enjoying the amazing corda soul, I have just one question what do those 2 switches in the pic do, when up or down


IMG-1101.jpg
 
Jan 16, 2020 at 3:19 PM Post #126 of 358
The one on the R selects what kind of anti-aliasing filter the DAC uses. Up is minimum phase, having asymmetric impulse response. Down is linear phase, having symmetric impulse response. More on that here: http://mclements.net/blogWP/index.php/2019/12/24/corda-soul-wm8741-dac-filters/

The one on the L controls the function of the rotary knob to the left of it. When up, it engages a digital notch filter to compensate for the resonance spike that many headphones have (-6 dB, Q=2.0) and the rotary knob controls the center frequency of that filter. For example, with the Sennheiser HD800 you might enable this and set the frequency to 6 kHz. When down, the rotary knob to the left of it becomes a L-R balance control.
 
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Jan 16, 2020 at 3:31 PM Post #127 of 358
The one on the R selects what kind of anti-aliasing filter the DAC uses. Up is minimum phase, having asymmetric impulse response. Down is linear phase, having symmetric impulse response. More on that here: http://mclements.net/blogWP/index.php/2019/12/24/corda-soul-wm8741-dac-filters/

The one on the L controls the function of the rotary knob to the left of it. When up, it engages a digital notch filter to compensate for the resonance spike that many headphones have (-6 dB, Q=2.0) and the rotary knob controls the center frequency of that filter. For example, with the Sennheiser HD800 you might enable this and set the frequency to 6 kHz. When down, the rotary knob to the left of it becomes a L-R balance control.

so up means classic filtering (phase correct, brickwall)
and down means a filter-mode without pre-ringing (with a slightly softer, more analog sound).
 
Jan 16, 2020 at 3:35 PM Post #128 of 358
so up means classic filtering (phase correct, brickwall)
and down means a filter-mode without pre-ringing (with a slightly softer, more analog sound).
The reverse of that. Down is classic filtering, phase correct. It is a brickwall (sharp) filter only at sampling rates 48k and lower. At 88 and higher, it is still phase correct, but has slow rolloff. Up is the minimum phase filter that most people describe as having the softer more "analog" sound. This is what the icons on that switch suggest: asymmetric (soft) on top, symmetric (sharp) on bottom.

"Normal" listening to the Soul is both switches down. That disables the EQ and uses the "standard" digital filter. By "disables EQ" I mean the notch filter. The 4 tone control knobs to the right always work regardless of the position of these 2 switches.
 
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Jan 16, 2020 at 3:44 PM Post #129 of 358
The reverse of that. Down is classic filtering, phase correct. It is a brickwall (sharp) filter only at sampling rates 48k and lower. At 88 and higher, it is still phase correct, but has slow rolloff. Up is the minimum phase filter that most people describe as having the softer more "analog" sound. This is what the icons on that switch suggest: asymmetric (soft) on top, symmetric (sharp) on bottom.

"Normal" listening to the Soul is both switches down. That disables the EQ and uses the "standard" digital filter. By "disables EQ" I mean the notch filter. The 4 tone control knobs to the right always work regardless of the position of these 2 switches.

can i ask another question, i am using the soul sometimes with my stax amp, what is the most recommended volume to set the corda on when used as a preamp, and does it matter if i use low,mid or high gain on my corrda soul to avoid clipping with my stax 007tii amp
 
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Jan 16, 2020 at 4:07 PM Post #130 of 358
With most DAC preamps, that would be an easy question: set the volume to max, or as high as possible. That's because as you turn down the volume, the SNR drops with it. The max SNR is at full volume. That's because most preamps have a fixed gain ratio and the volume knob just attenuates the signal.

But the Soul has a totally different design. Its volume knob changes the analog gain. That's why it clicks as you turn it; that's the sound of relays clicking on and off as it swaps the resistors in the analog gain-feedback loop. The net effect is that as you turn down the volume, it reduces gain, which means the SNR stays very high. Benefits of this (A) SNR remains high at all volume settings, (B) perfect channel balance at all settings, (C) lower noise (no potentiometer in signal path).

So what volume position gives the best output depends on the Stax amp. It looks like it has an analog potentiometer volume control. These usually have the best sound quality and channel balance in the top half of their range. So a good place to start might be to set the Soul volume knob to whatever position puts the Stax volume control around the 12:00 to 2:00 position (maybe even max, depending on the Stax amp's gain and volume knob). Adjust from there using recordings with very wide dynamic range.

Note: this is the opposite of what one would normally do, which is to have volume maxed close to the source, then set the listening level using the volume control furthest downstream. This is due to the Soul's different design. Nobody listens at full scale volume. Whatever level of attenuation you need, say -16 dB or whatever, the Soul is likely to give you that attenuation with less of a reduction in SNR, than the Stax amp. Of course, if the Stax amp has audible hum or sounds bad at full volume, turn it down until that goes away.
 
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Jan 16, 2020 at 4:38 PM Post #131 of 358
With most DAC preamps, that would be an easy question: set the volume to max, or as high as possible. That's because as you turn down the volume, the SNR drops with it. The max SNR is at full volume. That's because most preamps have a fixed gain ratio and the volume knob just attenuates the signal.

But the Soul has a totally different design. Its volume knob changes the analog gain. That's why it clicks as you turn it; that's the sound of relays clicking on and off as it swaps the resistors in the analog gain-feedback loop. The net effect is that as you turn down the volume, it reduces gain, which means the SNR stays very high. Benefits of this (A) SNR remains high at all volume settings, (B) perfect channel balance at all settings, (C) lower noise (no potentiometer in signal path).

So what volume position gives the best output depends on the Stax amp. It looks like it has an analog potentiometer volume control. These usually have the best sound quality and channel balance in the top half of their range. So a good place to start might be to set the Soul volume knob to whatever position puts the Stax volume control around the 12:00 to 2:00 position (maybe even max, depending on the Stax amp's gain and volume knob). Adjust from there using recordings with very wide dynamic range.

Note: this is the opposite of what one would normally do, which is to have volume maxed close to the source, then set the listening level using the volume control furthest downstream. This is due to the Soul's different design. Nobody listens at full scale volume. Whatever level of attenuation you need, say -16 dB or whatever, the Soul is likely to give you that attenuation with less of a reduction in SNR, than the Stax amp. Of course, if the Stax amp has audible hum or sounds bad at full volume, turn it down until that goes away.

thanks so much for all these great answers
 
Jan 17, 2020 at 4:52 PM Post #133 of 358
Do you have the Soul user manual? I'm sure Jan Meier can send you a copy if you ask.
not really is there a pdf version of it. I still am not using any dsp functions. And it will be good to have one in pdf to read about all these dsp settings
Every day passes and my adoration to corda soul increases.
 
Jan 17, 2020 at 6:33 PM Post #134 of 358
I don't think it violates any confidentiality since most companies publish their manuals for anyone to download. And the manual doesn't say copyright or do not distribute. So here it is (attached).
 

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Jan 21, 2020 at 5:08 PM Post #135 of 358
I know this is unlikely, but if anyone is willing to sell their Soul to the Devil (me) please PM me. I'll pay full pre-order pricing assuming as new cosmetics and functionality, shipped within (or to) the United States.

I just now saw this was a WM8741 chip based DAC, which is by far my favorite chip out there, and I'm sure Jan's output stage is brilliant. I'm gathering the amp section is rock solid as well. Any impressions with Utopia?
 

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