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Review and Measurements of Spectra X DAC & Amp

amirm

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#1
This is a review and detailed measurements of the NextDrive's SPectra X Dac and Amplifier USB dongle. It was sent to me by the company and costs $USD 189 including Prime shipping on Amazon. Clearly this is a lot more money compared to $9 dongles from likes of Apple and Google.

The spectra X makes a very good first impression as dongles go:

NextDrive Spectra X DAC and Headphone Amp Review.jpg

It is far more robust than the flimsy phone dongles. It is a metal tube and feels nice in the hand.

The Spectra X comes with different end connectors. I asked for the USB-A version so I could test it using my computer.

Spectra X was UAC2 compliant meaning you don't need driver. In my case though I got bit by the ASIO4ALL wrapper issue where the device for some odd reason shows up as a 16-bit device. NextDrive provides a set of drivers but it quickly quit saying I already have a more up to date eversion of "bravo HD" driver. I tried to use that but it quickly hung my Audio Precision analyzer application. I got around this partially but did limit the testing I could do.

Measurements
Per above, I could not use the ASIO interface to control the Spectra X. So instead, I played my 1 kHz tone through Roon which faithfully output 24 bit samples:
NextDrive Spectra X DAC and Headphone Amp Measurements.png


We get a SINAD (signal over distortion and noise) of about 102 dB on average. Turning on the level by a few notches (in software) produced as high as 107 dB which is quite good for a dongle. As it is, it lands in our 2nd tier of all DACs tested:
NextDrive Spectra X DAC and Headphone Amp SINAD Measurements.png

Unless my eyes and memory are failing me, this is better distortion specs than all the other dongles I have tested. So the unit lives up to the stated "high-resolution" audio standard, able to beat 16 bit distortion requirements (96 dB).

We also have a nice 2 volt output which makes it as good as any desktop DAC for driving external amplifiers. Many dongles fail to get above 1 volt.

Next I ran the J-test signal in Roon and measured jitter and noise:

NextDrive Spectra X DAC and Headphone Amp Jitter Measurements.png


There are fair number of spurious tones which doulbe jitter or other sources of noise. I like to see these tones below 120 dB but here they are as high as -106 dB or so. Still, I don't consider them problematic. Compare this to the output of Apple and Google Pixel V2 adapters (inset) which are horror shows compared to Spectra X.

Given the restrictions I have, I did not try to run more DAC tests. Let's jump into headphone amp measurements then starting with power with 300 ohm load:

NextDrive Spectra X DAC and Headphone Amp Power at 300 ohm Measurements.png


Note that these tests are in 16 bit noise so elevate the measurements some. That aside, there is more power here with Spectra X which is very important. We get 14 milliwatts against Apple's 4 milliwatts for example.

Switching to 33 ohm we get:
NextDrive Spectra X DAC and Headphone Amp Power at 33 ohm Measurements.png


Ah, was wishing the same power advantage here but did not get it. We have 49 milliwatts which is more than Apple's 31 so it is higher, just not multiple times higher.

How does this compare to other dongles tested? Here you go:

NextDrive Spectra X DAC and Headphone Amp Audio Dongle Power Bar Graph Measurements.png


Graph is sorted by 300 ohm power so the Spectra X finishes third there. It beats Dragonfly red which is a good thing. But loses big time to DACPORT HD which is a power monster in this class. Apogee Groove also produces more power.

Output impedance is also comfortably low at just 0.9 ohm:
Untitled-1.png


Listening Tests
As usual I started testing with Sennheiser HD-650. Here, power was clean up to max volume. This was listenable and just a hair loud. Bass was good but no match remotely for any desktop product.

The situation with Hifiman HE-400i was a bit better with slightly more volume. I could listen at 75% to 80%. Again, I could not detect distortion at max volume which was good.

Conclusions
The Spectra X delivers on pride of ownership and good DAC implementation. On the headphone amp side, there is more power than ordinary dongles but we are talking about a price that is 20 times higher. The DACport runs circles around it on this front but is ugly as sin compared to Spectra X.

If you want to go with a dongle and money is not an object, the Spectra X is a good alternative to cheap throw-away ones both on performance and durability. Personally I would have wanted to see a lot more power out of it. But that is me. See Z reviews below on subjective power.

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

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WondrousHippo

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#3
Yeah, seems like you're paying a bit extra for its functionality, but at least you get what you pay for.

Also, it supports Nintendo Switch, which is handy. The built-in headphone output on the Switch has noise with sensitive IEMs.
 

gvl

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#4
Unlike the DACPort which is a power hog, the Spectra can likely be powered and used with a mobile phone on the go.
 

pwjazz

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#7
Integrating a USB cable into the design seems like a poor choice. USB cables can go bad. When they do, I prefer to replace just a $5 cable instead of a 200$ DAC.
 

WondrousHippo

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#8
Integrating a USB cable into the design seems like a poor choice. USB cables can go bad. When they do, I prefer to replace just a $5 cable instead of a 200$ DAC.
Yeah, I think I'd like to see a USB-C female port on the dongle there, but I also get the appeal of having the cable built in too.
 

Jimster480

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#12
Looks good other than the attached cable...
My K1 literally has a micro USB port, this should have the same if not a USB-C port!
 
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#13
Z review and comparison to HIDIZS Sonata which I also have and will review later:
Curious to see what you find with the HIDIZS Sonata. I had one (two if you count the replacement) for a little bit and ultimately ended up returning it for a refund due to some annoyances.
 

Johnb

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#14
Integrating a USB cable into the design seems like a poor choice. USB cables can go bad. When they do, I prefer to replace just a $5 cable instead of a 200$ DAC.
I find that female connectors can get loose just as easily. A good quality cable, which I assume this is, is probably preferable.
 

PuX

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#15
ok so there are two versions: X and non-X.

but even their own site seems to have no information about the difference between them...

here's an image from amazon, I wonder if this noise filter etc. is some real technology or just marketing, because otherwise they are the same:
 
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#16
@amirm thx for the review but your version of the spectra X dac amp is the same as the amazon one or not? Because I am checking out the product page and the seller is saying that the output impedance is 10ohms Edit= referring to the product page on amazon .
 
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#17
ok so there are two versions: X and non-X.

but even their own site seems to have no information about the difference between them...

here's an image from amazon, I wonder if this noise filter etc. is some real technology or just marketing, because otherwise they are the same:
if the picture is true then the gaming support alone is good for me, I need a dac/amp to improve the sound quality on my ps4 and switch
 

PuX

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#18
if the picture is true then the gaming support alone is good for me, I need a dac/amp to improve the sound quality on my ps4 and switch
their website says you have to flash a special (limited) firmware to use with ps4 and switch. you will be limited to 16 bit / 48khz when you plug it in anything. kind of a useless feature unless you only use it with a console.
 

amirm

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#19
@amirm thx for the review but your version of the spectra X dac amp is the same as the amazon one or not? Because I am checking out the product page and the seller is saying that the output impedance is 10ohms Edit= referring to the product page on amazon .
I don't know as the company sent it to me. The answer on 10 ohm though is from a seller who may not know any better.
 
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#20
Seller here. Thanks for your review! It's really nice to see some hard data on the NextDrive Spectra.

Can you tell us how you performed the output impedance measurement? The spec is definitely 10Ω.

Other questions / comments welcome. We're friendly! We can also relay any questions to NextDrive if needed.

- TrueToSource Customer Care Team
(Disclosure: We are the official seller of the NextDrive Spectra / Spectra X on Amazon and work directly with NextDrive)
 
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