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Mhdt Labs Pagoda Review (R2R Tube DAC)

Rate this DAC:

  • 1. Poor (headless panther)

    Votes: 245 91.8%
  • 2. Not terrible (postman panther)

    Votes: 4 1.5%
  • 3. Fine (happy panther

    Votes: 1 0.4%
  • 4. Great (golfing panther)

    Votes: 17 6.4%

  • Total voters
    267

amirm

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This is a review and detailed measurements of the Mhdt Labs Pagoda R2R DAC with tube buffer. It is on kind loan from a member and costs (I think) US $1,570 with standard tube.

While I am not a fan of the plexiglass front, the rest of the unit looks good:

MHDT Pagoda review Tube Stereo DAC.jpg


Stock tube is a US made tube. I can't read the branding as it is faded out but the number is 5670. Back panel shows very nice quality connectors:

MHDT Pagoda review back panel R2R Tube Stereo DAC.jpg


Since I had to take the top off to read the tube markings, I figured I show a quick shot of what is inside:

MHDT Pagoda Teardown Tube Stereo DAC.jpg


Two TI/Bur-brown PCM 1704 ladder R2R DAC chips are used. Cmedia CM6631A provides USB interface.

I was surprised to see the fuse in there having different colorations on each side. Is it one of the audiophile fuses that is directional?

Capacitors are private branded and overall build seems very clean.

Mhdt Labs Pagoda DAC Measurements
I let the unit warm up for a bit and then ran our standard dashboard:

MHDT Pagoda Measurements Tube Stereo DAC.png


Combination of relative noise and distortion is so high that it lands the Pagoda DAC at the bottom of our ranking of nearly 400 DACs tested:
best stereo r2r dac review.png


Note that this is not just 2nd harmonic. Even if we assume that is completely inaudible, third harmonic peaks enough to give the unit a SINAD of 55 dB (best case).

Folks who buy this product like to ignore above stat but hopefully the take notice that there is a sample offset between the two channels. One is running ahead of the other (by 4 out of 360 degrees). I say it is a sample delay because if you change the frequency, so does the phase error between channels.

Dynamic range is very poor:
MHDT Pagoda Measurements DNR Tube Stereo DAC.png


Jitter test shows both noise floor modulation and spurious signals not in the test signal (and your music):
MHDT Pagoda Measurements Jitter Tube Stereo DAC.png


Intermodulation graph with dual tones (60 Hz and 7 kHz) is brutal in the way it shows the weakness of this DAC:

MHDT Pagoda Measurements IMD Distortion Tube Stereo DAC.png


If you care at all about transparency, you are way, way worse off than a $9 phone dongle both in pure noise and distortion.

Stepping up to 32 tones to better approximate "music," again steps up to show some of the worst we have ever seen:
MHDT Pagoda Measurements Multitone DAC filter Tube Stereo DAC.png


It would be an inescapable fact that such intermodulation will step on and hide all the low level detail in the source digital bits.

Linearity is bad by any metric:
MHDT Pagoda Measurements Linearity Tube Stereo DAC.png


There is essentially no reconstruction filter. I had to extend the response way out to see any filtering:
MHDT Pagoda Measurements DAC filter Tube Stereo DAC.png


This heavily impacts our THD+N versus frequency with its 90 kHz bandwidth:
MHDT Pagoda Measurements THD+N vs frequency Tube Stereo DAC.png


I had to rescale the graph just to get it to show the results on top!

Conclusions
If you search for PCM 1704 DAC chip, you land on this stereophile brief article on its announcement in 1998: https://www.stereophile.com/news/10221/index.html

"Burr-Brown Breaks New DAC Ground with PCM1704
The DAC performance envelope has been pushed further by Burr-Brown Corporation. The Tucson semiconductor company has just announced the commercial release of its new PCM-1704, an ultra-high-quality digital/analog converter chip boasting a 120dB signal/noise ratio....Its SNR is near the theoretical maximum for all electronic devices, and enables a 112dB dynamic range---a 6dB improvement over the highly regarded PCM-1728"


No question the designers were aspiring for great measured results. Sadly we have an implementation of said DAC so seriously underperforming its capability. I imagine a far better design could have been implemented even around this older DAC chip.

Fair bit of engineering goes into designing and building such a product. It is a shame that it is driven backward by improper audiophile notions of what a DAC should be rather than starting with principals of "first do no harm" to said source signal. These designers need to go and build really useful products for other companies or themselves than chasing this crazy business.

It goes without saying that I can't recommend the Mhdt Labs Pagoda stereo DAC whatsoever.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
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_theLaughingman

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What a waste of resources. All the time invested in designing this product and it left the factory with such poor quality. Looks like a bunch of dudes decided to slap together DIY parts and call it high end. Atrocious.
 
Last edited:

BDWoody

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This is a review and detailed measurements of the Mhdt Labs Pagoda R2R DAC with but buffer.

I bet the but buffer is why it measures like ass.
 

Lambda

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Oh it must sound so Warm i can feel the heat from here.
 

AdamG247

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A new chart topper if you flip it upside down. So, it’s got that going for it! Plus it glows, ohhhhhho_O
 

Matias

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This unit condenses everything ASR is against in a single product. Amazing. :D
 

Vini darko

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Intresting dac thanks for the review Amir. This one will definitely have a intentional sound. Would you be prepared to give it a listen?
 

TOR

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I just noticed from the photo this unit is made in Taipei Taiwan.
On their website, it mentioned "We don't ship to Taiwan"

Does it imply that this is only for export???
 
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