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Review and Measurements of NuPrime uDSD DAC/AMP

amirm

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#1
This is a review and detailed measurements of NuPrime uDSD DAC and headphone amplifier. I purchased this summer of last year from Amazon for USD $179 including Prime shipping.

This is a cute and very sturdy portable amp and dac:

NuPrime uDSD DAC and Headphone Amplifier Review.jpg

It has really beefy RCA connectors in the back, the likes of which I have only seen in Khadas Tone Board. They would feel at home in gear retailing for a lot of money.

The enclosure is metal and while it is sturdy, cables can pull it around some.

Let's get into measurements and see if she is worth the extra premium over cheaper offerings.

Measurements
As usual I start with Dashboard measurements and there, I was initially very unimpressed with the results:
NuPrime uDSD DAC and Headphone Amplifier Max Volume Level Measurements.png


Remembering that some devices deteriorate in performance when their volume control is at max -- even though I am testing RCA out -- I lowered the volume to min and the situation improved significantly:
NuPrime uDSD DAC and Headphone Amplifier Measurements.png


This is now pretty decent with respect to distortion and noise:

1547685804819.png


Jitter and noise likewise is very good:

NuPrime uDSD DAC and Headphone Amplifier Jitter Measurements.png


Broadband THD+N shows elevated noise in lower frequency but good performance in highs:

NuPrime uDSD DAC and Headphone Amplifier THD vs Frequency Measurements.png


Intermodulation distortion shows similar issue with respect to noise:

NuPrime uDSD DAC and Headphone Amplifier IMD Measurements.png


Our 32-tone signal cause the uDSD fair amount of pain, resulting in elevated noise in low frequencies again and source sensitive noise modulation:
NuPrime uDSD DAC and Headphone Amplifier Multitone Measurements.png


Switching to headphone out, we see an "OK 5.7 ohm output impedance (prefer less than 1 ohm):

NuPrime uDSD DAC and Headphone Amplifier Output Impedance Measurements.png


The real disappointment is in power output as this 300 ohm load demonstrates:
NuPrime uDSD DAC and Headphone Amplifier Power at 300 Ohm Measurements.png


Just 7 milliwatts of power in a desktop/portable product? Can we hang our hat on at 33 ohm?

NuPrime uDSD DAC and Headphone Amplifier Power at 33 Ohm Measurements.png


Nope. Power remains quite low relative to competition. And this is on top of much elevated noise and distortion levels. Heck the Topping DX3 Pro beats it handily even in low gain mode!

Listening Tests
I started testing the NuPrime uDSD with my Sennheiser HD-650 headphones. Here the mid-range power was just enough but the moment the bass notes came in, the uDSD got severely distorted. Avoiding that distortion caused the output level to be totally unsatisfying.

Switching to HiFiman HE-400i did not change the situation a lot. At modest levels, it could drive them fine but if you push it even slightly, the bass notes got distorted almost as badly as HD-650.

Conclusions
The DAC portion of the NuPrime uDSD is fine as is its unique and quality build. The problem is in its headphone output which simply does not have enough power. Competing products like Topping DX3 Pro which go on sale at nearly the same price have far more features and tremendously better headphone output subsystem. As such, I can't really recommend this unit.

My NuPrime uDSD is available for sale. Start a conversation with me if you are interested.

-------------
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maxxevv

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#4
Looks like it was designed for high efficiency headphones and IEMS in mind. I could see it being a viably good DAC Amp for that sort of usage. But anything like a planar headphone getting plugged to it will wring it to pieces.
 
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#5
The problem is most iems are very low impedance, and this thing has high output impedance. A better match is something like HD595's 598's.
 

Jimster480

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#7
Another product with middle of the road performance....
105 SINAD though is pretty decent, its just got pitiful headphone power....

I really think this is how Schiit got so many customers. Just offering amps with tons of power that "make everything sound better" just because everything becomes louder vs these products with poor power output.
 
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#8
The flaw in your reasoning is that this is not really a desktop amp. It is a USB powered device. Most (not all) are limited to about 2V RMS output. They really should be thought of as usb dacs, with a weak headphone amp thrown in for free. If they have low impedance output, then there is the other usage scenario with iems and cans made for portable use.

For portable, and less price, the Topping NX4 DSD provides great performance and power, as do DACPORT HD and others above $200.

A real desktop amp will drive just about anything. Not just the Schiits. Easy to do with a wall plug for power.

You need to compare apples to apples. If your listening position is fixed, then a full-sized amp is beyond obvious.
 

Headphonaholic

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#10
The flaw in your reasoning is that this is not really a desktop amp. It is a USB powered device. Most (not all) are limited to about 2V RMS output. They really should be thought of as usb dacs, with a weak headphone amp thrown in for free. If they have low impedance output, then there is the other usage scenario with iems and cans made for portable use.

For portable, and less price, the Topping NX4 DSD provides great performance and power, as do DACPORT HD and others above $200.

A real desktop amp will drive just about anything. Not just the Schiits. Easy to do with a wall plug for power.

You need to compare apples to apples. If your listening position is fixed, then a full-sized amp is beyond obvious.
I think that is fair. So you're suggesting that in the event the device is usb powered and has a headphone amp it's in the same category as a Schiit Fulla or the other small usb devices? Maybe we'll need a new classification system.
 

vitalii427

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#11
Thank you for your quick response, Amir. I use only DAC part with raspberry streamer as a little transportable source. And it sounds transparent to me. Will check if I can hear any difference with amp on/off.
 
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#13
Thank you Amirm for doing the measurement. I like the is brand and I used to own a uDSD and one of their class D stereo amp, they sounds fine to me.

NuPrime's class D amp is designed in-house, not using some off the shelf module, and Nuprime's product is great for people who have a limited budget. If you have a chance please do review their stereo.
 

Shadow12347

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#15
I noticed that it also has digital out. Would you be able to measure this to see if it's effective for converting USB to Coaxial SPDIF?
 

graz_lag

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#16
Every one knows NuForce ... especially thanks to NwAvGuy' reviews ...
In 2014, NuForce sold its high-end audio line to NuPrime Audio, headed up by Mr. Jason Lim, one of the original founders of NuForce.
So, no doubt the principle of continuity is still there ... premium $ for a device, which cannot afford the comparison with the cheapest of the Toppings ... :facepalm:
 

Roen

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#17
Is NuPrime a Chinese company? Or is it something else? I think it's the latter, but if someone could correct me.
 

graz_lag

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#18
From Taiwan, I would like to say ... which normally was equaling to products with more technical content compared to the ones Made in Red China ...
Recently however, things are changing at the speed of light ...
There are some outstanding Chinese manufacturers, which give powder in the face of their Taiwanese cousins ...
 
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Jimster480

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#19
The flaw in your reasoning is that this is not really a desktop amp. It is a USB powered device. Most (not all) are limited to about 2V RMS output. They really should be thought of as usb dacs, with a weak headphone amp thrown in for free. If they have low impedance output, then there is the other usage scenario with iems and cans made for portable use.

For portable, and less price, the Topping NX4 DSD provides great performance and power, as do DACPORT HD and others above $200.

A real desktop amp will drive just about anything. Not just the Schiits. Easy to do with a wall plug for power.

You need to compare apples to apples. If your listening position is fixed, then a full-sized amp is beyond obvious.
Yes and no... when you start looking for headphone amps you will find tons of amps that cost hundreds of dollars or you will find lots of cheap chinese amps from no-brand companies with high output impedance and poor power output.
As Amir has tested some of these random products, we can see the performance is pretty pitiful on many of them...

Even the Topping A30 which I consider to be a "great value" headphone amp (atleast before JDS Atom) has a high output impedance which can swing the response of lower impedance headphones in a way that the listener may not enjoy.

That really leaves just one option at the cheap end of the spectrum.... the JDS Labs O2 (now basically replaced by the Atom) and it still comes out around $150 in 2016.

I can tell you as a noob I ended up with Schiit products myself.... I just wasn't impressed with them and looked elsewhere.
Thankfully I found the FiiO K1 (which was my first product) and I could justify spending just $40 on a external DAC/Amp to enjoy my headphones with.
Since they were low impedance and reasonably efficient it actually drove them perfectly fine and I used this every day for months until I decided I would "upgrade" to the Fulla2. Only to find that it sounded worse than the K1, so then I went for the Topping A30/D30.... But had I not decided to think outside of the box and give Topping a chance (at this time it was completely unknown, as I literally was the one to write the first review on the A30 on Head-Fi).... I would have probably bought a Modi/Magni setup because most other brands were offering items only at $250+.
Even the O2 + ODAC was $275 shipped at the time from Mayflower Electronics...

It wasn't until later that I found JDS Labs and decided to buy a custom O2 from them.
I did see iFi but their prices are all over the board, their descriptions are not always so great and they are mostly mobile products vs desktop products which is what I was looking for.

So yes products like these NuPrime products (also reviewed those prior to purchasing D30/A30) with poor amp characteristics (basically ties the FiiO K1) but a higher price won't impress people.... especially "traditional" headphone buyers that get a Sennheiser or Beyerdynamic headphone only to find that it sounds wimpy (and not realize that it needs a real amp to come to life)..
 
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