Review and Measurements of Apogee Groove DAC and Amp

[elvisizer]

lol group jinx!

 

[Veri]

indeed

 

[threefour]

Or you could get a real Amp. There is no way in hell the MacBook drives a 250ohm at any decent volume. Apple headphone jack outputs have been just okay for years... My friends 2016 MacBook pro barely drove his 80ohm DT770s to a good volume.. You must have literally 0 bass response with a 250ohm.

See https://support.apple.com/en-us/HT212856
"For headphones with an impedance of 150 to 1k ohms, the headphone jack delivers 3 volts RMS."

For normal audio sources with recordings that have been normalized the volume is fine; but when I'm working in my DAW the levels often haven't been normalized, so I'm an edge case.

 

[Jimster480]

@Jimster480 the new Apple silicon MacBooks can output 3Vrms into high impedance loads. That's plenty loud enough for most high impedance studio headphones e.g:
-ATH-R70x: 113.5dB SPL Peak
-DT 990 Pro 250Ω: 106.5dB SPL Peak
-DT 770 Pro 250Ω: 110.5dB SPL Peak
-HD 650: 114.5dB SPL Peak
-HD 800 S: 115dB SPL Peak


Why would there be a change in frequency response?

Typically from the lack of power.

 

[openbaffle3278]

I picked up one of these to drive my Sony Z1Rs. Now I'm curious about the output impedance affecting the frequency response of my headphones.

The impedance is pretty low compared to the 20 ohm output impedance of the Groove, but also pretty flat, rising a bit in the last octave. Is this something I should be worried about?

Here are the Z1R measurements: https://www.stereophile.com/images/SonyMDRZ1Rsn3922.pdf

 

[Head_Unit]

Is this something I should be worried about?

You should be lying awake nights, fearing the negative sonic connotations!
Really, it is what it is. I *think* very few headphone amps have near-zero output impedance like solid state amplifiers do, I suppose for short circuit protection and because outputting a lot of current is expensive. The headphone jacks on receivers used to often be the speaker outputs wired via like a 1000 ohm resistor or such to the headphone jack! If it sounds lovely, enjoy! If not, ya need a different amp.

 

[Stilgar]

I picked up one of these to drive my Sony Z1Rs. Now I'm curious about the output impedance affecting the frequency response of my headphones.

The impedance is pretty low compared to the 20 ohm output impedance of the Groove, but also pretty flat, rising a bit in the last octave. Is this something I should be worried about?

Here are the Z1R measurements: https://www.stereophile.com/images/SonyMDRZ1Rsn3922.pdf

hi; is there any problem z1r with the apogee groove? i am thinking to buy groove for my z7r which s 70 ohm.