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Review and Measurements of Apogee Groove DAC and Amp

amirm

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#1
This is a review and measurements of the Apogee Groove portable DAC and headphone amplifier. It is on kind loan from a forum member. As small portable DAC+Amps go, its retail price of $295 is quite high. I see factory refurbished ones at $149 though on Apogee website.

Apogee is best known for their professional audio products so their entry into personal audio is quite a departure for them.

As USB audio "thumb drive" form factors go, the Apogee is quite a bit more substantial:

Apogee Groove Portable DAC and Headphone Amplifier review.jpg


Volume wise, it is probably double the size of typical thumb drives. The larger size allows rubberized up/down volume buttons with excellent feel. There is no "plastic" feel to the unit either, making you think you can sit on it and nothing bad would happen to it.

The three LEDs roughly show the volume level. During music playback, they change to color to green and are fully analog. Each has individual intensity which once maxed out, lights up the one above it.

Overall, I am very positively impressed with fit, finish and quality of the physical unit.

Let's get into measurements and see if the high price is justified by objective data.

Measurements
Let's start with our usual dashboard at 2 volts to see the fidelity as if it were a DAC:
Apogee Groove Portable DAC and Headphone Amplifier Measurement.png


Hey, this is quite good for a portable product! It puts it in the tier 2 of codecs tested as far as distortion and noise:

Apogee Groove Portable DAC and Headphone Amplifier SINAD Measurement.png


Let's look at the 2-tone SMPTE intermodulation distortion versus level:
Apogee Groove Portable DAC and Headphone Amplifier IMD Measurement.png


The groove is no match for the Topping DX3 Pro small desktop amp+dac but beats the Chord Mojo at mid to highest levels! The Chord is nearly three times its price with very high claims of objective fidelity so this is quite an accomplishment.

Yes, we see the "ESS hum" which is typical of ESS DACs in most implementations with a rise in mid-level distortion. It is milder here because the noise floor is higher.

Jitter performance is visually disappointing but audibly transparent:
Apogee Groove Portable DAC and Headphone Amplifier jitter Measurement.png


Linearity is also quite good for a portable device, losing accuracy above 18 bits:
Apogee Groove Portable DAC and Headphone Amplifier Linearity Measurement.png


Dynamic range is very good and falls in the middle of pack (max volume):

Apogee Groove Portable DAC and Headphone Amplifier Dynamic Range Measurement.png


Let's look at the all important, distortion versus power at 300 ohm:
Apogee Groove Portable DAC and Headphone Amplifier Power at 300 ohm Measurement.png


Once again, the Apogee Grove comes close to performance of Chord Mojo, producing the same 71 milliwatts of power. To put this in perspective, typical smartphone audio dongle outputs 1 to 10 miliwatts of power. So this is quite an important jump as it relates to high impedance headphones such as the popular Sennheiser HD-650 and its clones.

Same measurements with 33 ohm though, generated odd results:

Apogee Groove Portable DAC and Headphone Amplifier Power at 33 ohm Measurement.png


At around 1.5 volts of output, the unit would shut down. This produced total power of 78 milliwatts which is way short of specified 225 milliwatts. I even tested one channel with the same results.

Channel balance versus volume position was perfect since these combo DAC+headphone amps are able to perform attenuation using the DAC control:

Apogee Groove Portable DAC and Headphone Amplifier channel imbalance Measurement.png


Unfortunately we have some bad news when it comes to output impedance:
Apogee Groove Portable DAC and Headphone Amplifier output impedance Measurement.png


Oh, no. 21 ohms? Why did you do this to us Apogee? You were doing so well.

This means that you should not use low impedance headphones that have variable impedances themselves or else, their frequency response will be modified. This may be a good effect or bad depending on what is exaggerated and your preference for such.

Listening Tests
I started my listening tests with my Sennheiser HD-650. Here, output was clean up to max volume as measurements show. Alas, while comfortable, the bass was not as impactful as I am used with desktop products. Depending on your preference here for volume (I like it loud), you may or may not be satisfied.

Things improved a lot with the Hifiman HE-400i. There was plenty of volume and a very enjoyable time was had listening to a range of music. So maybe with a realistic load and music instead of tones, the Grove is able to produce much more power at lower impedances without shutting down.

Conclusions
The Apogee has the highest quality feel and design of any portable, thumb drive sized, DAC and amplifier I have reviewed. It just feels great in hand and looks good on the table too.

As a DAC, its performance is quite good, nearly a number of desktop products.

As a DAC+headphone product, its performance is variable. Objectively there is something wrong with low load impedances causing it to shut down. But subjectively, it sounded great there. It doesn't have a ton of power for 300 ohm loads but then again, what it has is much, much more than stock headphone amp in your phone.

High output impedance of 20 ohm means you need to be careful about its effect on the sound of some headphones.

All in all, you can tell the Apogee Groove is designed by competent people wanting to produce a premium product in the ultra portable form factor. If they had gotten there without that 20 ohm output, I would give them an A. As it is, I have to take them down a notch and give a guarded recommendation.

------------

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

If you like this review, please consider donating funds to support these reviews using Patreon (https://www.patreon.com/audiosciencereview), or upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
 

helloworld

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#4
Frankly speaking I really don’t know why people buy this kind of portable device since the street is reallly noisy! I would prefer to buy a noise canceling headphone like sony mdr 1000xm3.
 
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#7
Frankly speaking I really don’t know why people buy this kind of portable device since the street is reallly noisy! I would prefer to buy a noise canceling headphone like sony mdr 1000xm3.
As far as I'm concerned, I found two flaws with the 1000X. First: soundwise, it doesn't match at all my Ultrasone Signature DJ: soundstage, clarity, bass extension, imaging etc. It is probably one of the best wireless cans available but cannot compete against competent wired closed backs.

The second is about sound leak. At high volumes, people seated at your side (in a train, for example) will hear your music. While ANC is excellent, it a pity that isolation doesn't work in the other side.

While my Sig DJ have excellent passive isolation and no sound leak to speak of, even at very high listening level. I use these, paired with a Cayin N3 and I cannot see any wireless solution that may reach this level of performance.

It does but won't fit in the pocket like the Groove does.
I may be wrong, but I believe the Apogee doesn't even have a battery. I think it is designed to be a desk solution only.
 
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BurritoJustice

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#9
@BurritoJustice
In another words, it is ok to use with high impedance headphone.

With headphone higher than 160 ohm should work fine is it?
Correct, it will also be fine for planar magnetic headphones as they have a linear impedance over the frequency range. But being unable to properly use an amp with the vast majority of headphones which are <100ohm and dynamic, there just isn't enough upside to make that worth it.
 

graz_lag

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#10
From the Groove web page :

Apogee Groove 30th Anniversary Models
Apogee celebrates 30 years of digital audio excellence
To commemorate Apogee’s 30 years of digital audio excellence, the Groove 30th Anniversary Edition features performance enhancements and a custom machined aluminum body available in silver and gold.

You asked for the Price, right ? $595 ... :eek::eek::eek: I am sorry Mr. Apogee, but for the Gold version I pretend to pay more !!!
 
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#11
Frankly speaking I really don’t know why people buy this kind of portable device since the street is reallly noisy! I would prefer to buy a noise canceling headphone like sony mdr 1000xm3.
I have a portable unit for work. Although I could leave a desktop unit there, like the DX3Pro, I prefer to bring it home with me.
 
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#12
I use mine as a dac, paired with a tube amp where the output impedance is much less critical. I have also found it to be one of a very few portable units with enough drive for the 600Ohm Beyers. I don't use them while on a plane, but it is nice to have a compact setup for use in hotels when you are stuck somewhere for the week.
 
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#13
Thanks a lot. Was waiting for this review. Now I'll happily purchase the groove. it looks like a pretty good performing unit and, for the current asking price of 149 refurbished and its portability, I'm getting it.

How does a current drive differ from a voltage drive amp? Do the gain equations etc differ..

What I remember from my electronics basics about opams are the gain = load||op impedance / input impedance.. not sure how it'll translate to this. From what I know, current drive circuits are definitely not meant for crossover circuits like multi ba iems.
 

BurritoJustice

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#14
Thanks a lot. Was waiting for this review. Now I'll happily purchase the groove. it looks like a pretty good performing unit and, for the current asking price of 149 refurbished and its portability, I'm getting it.

How does a current drive differ from a voltage drive amp? Do the gain equations etc differ..

What I remember from my electronics basics about opams are the gain = load||op impedance / input impedance.. not sure how it'll translate to this. From what I know, current drive circuits are definitely not meant for crossover circuits like multi ba iems.
What headphones do you own? The output impedance is extremely relevant for any headphones under 160ohm and with a dynamic driver (aka "standard").
 
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#15
With Apogee's history as a professional Audio company, it really doesn't surprise me that the Groove is best used with high impedance cans. Pretty much all the classic cans used as studio references are 150 Ohm or higher. (And a lot of them are a lot higher)
 
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#16
What headphones do you own? The output impedance is extremely relevant for any headphones under 160ohm and with a dynamic driver (aka "standard").
Shure srh1540.. low impedance only. But i'd still pull the trigger. Can you explain how a current drive is different from a typical amp.. because from the equations I remember if this is a different type of circuitry, the equations would change and it may not really impact low impedance cans as much.
 
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#17
Frankly speaking I really don’t know why people buy this kind of portable device since the street is reallly noisy! I would prefer to buy a noise canceling headphone like sony mdr 1000xm3.
I'm sure my case is _very_ specific, but... My employer gives us ATH-M50x cans to use at work (or wherever I suppose). It is also an open floor plan office without offices or formally assigned work spaces. I use a Topping NX2 with the ATH's while working, but I commute wearing a pair of Sony WH1000xM2's. I wouldn't trade the ANC capabilities of the Sony's for any level of sound quality on the subway platform or train. At the office, the noise is focused in the speech bands, which ANC doesn't do much to attenuate anyway.

Sure, I could use the Sony's all day, and sometimes I do, but who turns down a free pair of M50x's? Given the diminutive size of the NX2, its a tiny penalty to carry it and a USB-C to micro-USB cable, and I can leave the M50x's safely stashed in my team's room. That gives me the option to use either set of cans with my phone or work issued macbook pro. I understand its not strictly practical, but we are hanging out on an audio forum, so I assumed we weren't all doing things to be practical :)
 

Nango

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#20
I use mine as a dac, paired with a tube amp where the output impedance is much less critical. I have also found it to be one of a very few portable units with enough drive for the 600Ohm Beyers. I don't use them while on a plane, but it is nice to have a compact setup for use in hotels when you are stuck somewhere for the week.
So you are using an (headphone) output which is already amplified into a 2nd amplifier?
 
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