Converters

D

DavidE

Power User
I remember there being discussion in the Helix v. AX8 dribble about whether the AX8 uses better converters. Apparenly they're the same, just 8 channels. Just passing along information since there's so much misinformation.

From Line 6: "But everything else outside the modeling's been improved greatly as well. We're using Cirrus-Logic converters (CS5368 and CS4385, which, unless I'm mistaken, are 8-channel versions of what's found in other high-end modelers), all new analog circuitry before and after conversion, and remember, our Guitar In has 123dB of dynamic range. "

This stuff doesn't mean much to me, but here it is nonetheless. 1 part of the signal path, but I would guess an important part.

FX8: https://www.cirrus.com/en/pubs/proDatasheet/CS4272_F1.pdf
Helix A/D: https://www.cirrus.com/en/pubs/proDatasheet/CS5368_F5.pdf
Helix D/A: https://www.cirrus.com/en/pubs/proDatasheet/CS4385_F2.pdf
 
DavidE said:
I remember there being discussion in the Helix v. AX8 dribble about whether the AX8 uses better converters. Apparenly they're the same, just 8 channels. Just passing along information since there's so much misinformation.

From Line 6: "But everything else outside the modeling's been improved greatly as well. We're using Cirrus-Logic converters (CS5368 and CS4385, which, unless I'm mistaken, are 8-channel versions of what's found in other high-end modelers), all new analog circuitry before and after conversion, and remember, our Guitar In has 123dB of dynamic range. "

This stuff doesn't mean much to me, but here it is nonetheless. 1 part of the signal path, but I would guess an important part.

FX8: https://www.cirrus.com/en/pubs/proDatasheet/CS4272_F1.pdf
Helix A/D: https://www.cirrus.com/en/pubs/proDatasheet/CS5368_F5.pdf
Helix D/A: https://www.cirrus.com/en/pubs/proDatasheet/CS4385_F2.pdf
Click to expand...

Yes I was happy to read that!
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Austin
 
Chris@AxeFxTutorials said:
wow you are really concerned about all of this.
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Not really. Just saw the information and shared it. Got tired of all the misinformation and speculation on TGP and here. I actually stopped reading TGP except once or twice a day to see if there are new demos. The thread over there are just useless. Looking forward to trying some new things with my FX8 this weekend.
 
No, it's good to have the real specs. Nothing wrong with that. I wouldn't call that promotion of a competing product. Just information.

I'm not at all concerned about the AX8 components, but good to know that Line 6 is truly trying to improve.

We know this much, the AX8 is made here in the USA.
 
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humm...interesting.

As Cliff has stated before, the converters used by FAS are differential, while the other are single ended. This alone provides less noise, and other better electric characteristics. There's a reason why microphone preamps with 60dB of ultra-low distortion clean boost use differential inputs.

But the main point is the conversion technology. If you read the "briefings", of the datasheets, theres, some tips:

-FX8 converters are indicated to "hi-end audio", while the Helix ones are for "consumer/car" audio.

-Interpolation and other technologies more sophisticated in FX8 one.

How much this translates in audible better quality? Well, i read a recent topic mentioning this better conversion, less aliasing, etc. and comparing audio files. Was perceptible, and easy to imagine that artifacts being processed by an amp drive sim, generating a bees attack tone (OK I'm exaggerating a bit, but you get the picture).

Said that, the Helix ones appears to be far from ordinary (from specs). Cirrus is not the cheap choice, anyways.
 
philos said:
humm...interesting.

As Cliff has stated before, the converters used by FAS are differential, while the other are single ended. This alone provides less noise, and other better electric characteristics. There's a reason why microphone preamps with 60dB of ultra-low distortion clean boost use differential inputs.

But the main point is the conversion technology. If you read the "briefings", of the datasheets, theres, some tips:

-FX8 converters are indicated to "hi-end audio", while the Helix ones are for "consumer/car" audio.

-Interpolation and other technologies more sophisticated in FX8 one.

How much this translates in audible better quality? Well, i read a recent topic mentioning this better conversion, less aliasing, etc. and comparing audio files. Was perceptible, and easy to imagine that artifacts being processed by an amp drive sim, generating a bees attack tone (OK I'm exaggerating a bit, but you get the picture).

Said that, the Helix ones appears to be far from ordinary (from specs). Cirrus is not the cheap choice, anyways.
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I don't know anything about anything, but on Cirrus' website they list both of the Helix's converters as being differential and the PDF describes the CS5368 as being suitable for "high-end and pro audio systems". Not to mention the "special sauce" Line 6 says they have applied to them. I'm fairly confident that if I find the Helix lacking, it won't be because of the converters.

Not that it matters of course. Either the Helix is up to snuff or it isn't (and of course this is up for each player to decide for themselves unless they've been brainwashed by the hive mind). No explanations/justifications needed really.
-
Austin
 
Just good to have the facts to go on.

Ultimately, the decision is up to the user, hopefully with some level of objectivity (that can be the hard part).
 
atquinn said:
I don't know anything about anything, but on Cirrus' website they list both of the Helix's converters as being differential and the PDF describes the CS5368 as being suitable for "high-end and pro audio systems".
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My fault. Thanks for the feedback.

At first sight the Helix one don't mention differential analog path. I don't checked the site, just the datasheets first pages descriptions and briefly. Conversion technology is still different, though. The marketing focus is clearly different too, as one is towards pure performance and the other describes integration, convenience. The page 12 performance numbers in both datasheets confirmed this. Again, don't know how much would be perceived by ear.

The Helix one certainly are not mediocre, anyway. THD+N alone is even a bit better. The main perceived difference will be certainly the algorithms and product life circle ;)
 
DavidE said:
Yes. Lots of simultaneous paths. I was interested in whether the conversions were same specs. Now I'm just confused. :)
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Main, general specs, like dynamic range, bits resolution, sampling rate, etc. are similar.

Conversion methods (important to avoid aliasing, preserve harmonic subtleties, etc.), and more detailed performance specs (see pg. 12 of both datasheets), are different (in lab measures and paper, at least).
 
I
philos said:
humm...interesting.

As Cliff has stated before, the converters used by FAS are differential, while the other are single ended. This alone provides less noise, and other better electric characteristics. There's a reason why microphone preamps with 60dB of ultra-low distortion clean boost use differential inputs.

But the main point is the conversion technology. If you read the "briefings", of the datasheets, theres, some tips:

-FX8 converters are indicated to "hi-end audio", while the Helix ones are for "consumer/car" audio.

-Interpolation and other technologies more sophisticated in FX8 one.

How much this translates in audible better quality? Well, i read a recent topic mentioning this better conversion, less aliasing, etc. and comparing audio files. Was perceptible, and easy to imagine that artifacts being processed by an amp drive sim, generating a bees attack tone (OK I'm exaggerating a bit, but you get the picture).

Said that, the Helix ones appears to be far from ordinary (from specs). Cirrus is not the cheap choice, anyways.
Click to expand...

'm not shure about what the differential conversion in ax8 could mean. There is only one signal and one ground in the ax8 input. The balanced (differental inputs) you are talking about in mic preamps usually require two signals and one ground.
 
Thomas Larsson said:
I


'm not shure about what the differential conversion in ax8 could mean. There is only one signal and one ground in the ax8 input. The balanced (differental inputs) you are talking about in mic preamps usually require two signals and one ground.
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Why necrobump to reply a 2015 comment?
 
Thomas Larsson said:
I'm not shure about what the differential conversion in ax8 could mean. There is only one signal and one ground in the ax8 input. The balanced (differental inputs) you are talking about in mic preamps usually require two signals and one ground.
Click to expand...

The converters themselves have differential inputs and outputs. The single-ended inputs are converted to differential and the differential outputs are converted to single-ended. Differential converters, when used in a true differential configuration, have better dynamic range, distortion, dc accuracy and immunity from coupled noise compared to single-ended implementations. The downside is that it costs more to implement.
 
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