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Ladder Schumann R2R DAC Review

Rate this DAC:

  • 1. Poor (headless panther)

    Votes: 42 19.4%
  • 2. Not terrible (postman panther)

    Votes: 111 51.2%
  • 3. Fine (happy panther)

    Votes: 48 22.1%
  • 4. Great (golfing panther)

    Votes: 16 7.4%

  • Total voters
    217

amirm

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This is a review and detailed measurements of the Ladder Schumann "FPGA" (R2R) balanced DAC. It was sent to me by Shenzhenaudio and costs US $1,399.
Schumann Ladder R2R DAC USB Stereo balanced review.jpg

The box is solid and has fair bit of heft to it, likely due to power supply transformer. The interface is pretty simple with the exception of the "Mode" button which I could not figure out. There is no manual supplied in my sample (which came back in July), nor could I find one online. It seems to select one of a few oversampling modes (2X/4X/8X) but I could not figure out how to get it to do that (seems to do something in setup). There is a dedicated button and turns off oversampling and filtering.

The main notable thing on the back panel is inclusion of XLR balanced out which you don't always see on R2R DACs:

Schumann Ladder R2R DAC USB Stereo balanced back panel review.jpg


Ladder Schumann DAC Measurements
Let's start with our dashboard using USB in/XLR out:
Schumann Ladder R2R DAC USB Stereo XLR Measurements.png


Distortion spikes match the noise floor of 16-bit content. By traditional DAC standards, that is rather poor but by R2R standards, it is not bad. Performance suffers with RCA due to more power supply noise:
Schumann Ladder R2R DAC USB Stereo RCA Measurements.png


I was about to stop the review here thinking the rest would be along the same line. But I am glad I did not as the noise floor is extremely low:
Schumann Ladder R2R DAC USB Stereo Dynamic Range Measurements.png

Clearly good attention was paid to clean circuit design.

IMD graph shows the variable distortion as one would expect in such architecture:
Schumann Ladder R2R DAC USB Stereo XLR IMD Measurements.png


Then again, when levels are low, distortion-floor is rather low:
Schumann Ladder R2R DAC USB Stereo XLR Multitone Measurements.png


There is jitter but as noted, is below audible levels:
Schumann Ladder R2R DAC USB Stereo XLR Jitter Measurements.png


Linearity naturally suffers at very low levels but otherwise is competent:
Schumann Ladder R2R DAC USB Stereo XLR Linearity Measurements.png


Here is the DAC filter response in the two modes I could figure out to activate:
Schumann Ladder R2R DAC USB Stereo Filter Non-oversampling Measurements.png


And impact on frequency response:
Schumann Ladder R2R DAC USB Stereo Frequency Response Measurements.png


So there is no mode with flat response. People with good high frequency hearing will likely notice lack of that in highest frequencies and may confuse that with better sound.

I was pleased to see that there is little frequency dependence in our wideband noise+distortion test:
Schumann Ladder R2R DAC USB Stereo XLR THD vs Frequency Measurements.png


Conclusions
It seems that frequently when a company decided to make an audio product with a new architecture, they use that as an excuse to butcher the response across the board. They talk about "low feedback" but then give us high levels of noise for example. I was pleased to see such was not the case with Ladder's Schumman DAC. The excellent dynamic range indicates that there is good engineering there, but is saddled with limitations of inexact, R2R DAC architecture. At least they are doing their best to deliver on what audiophiles ask for.

I see no benefit to R2R DACs so I can't recommend the Ladder Schumann DAC. But if you have the itch to get one, this makes a decent offering.
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As always, questions, comments, recommendations, etc. are welcome.

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VintageFlanker

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Thanks, @amirm.

Why did the distributor ask a popular measurement site to measure a DAC that is obviously not designed to please the measurement crowd?
I praise them for this. Better have dealers/distributors that play the game of transparency that way.

R2R crowd won't care for measurements anyway. This unit in particular... far from the worst we've seen in that market. At least, it is suitable for 16bits content.
 

horias2000

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I kind of understand the company's approach here. Why not profit from people that really believe that R2R architecture is superior to delta-sigma chips. Overall, it's a good product in my opinion. Most people (including me) listen to CD quality content (16bit 44.1kHz) and from the measurements it seems it does a fine job of reproducing such content. I personally see no reason for R2R dacs to exist, apart maybe for didactical purposes, but I know some people that swear that R2R is the only type of DAC to listen to. I'll stick with my ES9038PRO dac for now :)
 

Graham849

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Via Facebook: ”No manual or User Guide...not a happy customer...been waiting months and months”
 

Newman

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"FPGA" (R2R) balanced DAC.
Is it possible to have an R-2R DAC that isn't FPGA, and vice versa? Or do the two technologies always go together?
 

solderdude

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One can use other logic devices to drive the 'switches' as well.
One is not limited to FPGA.
FPGA is fast enough and flexible to use for this purpose.
 
Last edited:

Sokel

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Good for the average class but on the other hand we have the 115 SINAD Holo Spring 3.
For a price of course,which is absolutely fair.
 

KSTR

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What was Shenzhenaudio thinking? Why did the distributor ask a popular measurement site to measure a DAC that is obviously not designed to please the measurement crowd?
To show that this product does competently cater for the niche market it is targeted at. To my eyes at least, performance, design and execution appear to be competent. Missing specs and docs from the company is a clear negative, though.
 
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