[demasoni]

I just got my SFP5's and tried them out of my Mac Mini out. Listening to songs ripped Apple Lossless with eq. and sound check off, I noticed distortion especially on bass notes. There was also a muffled sound to the music. I've read on this forum that my Mac Mini has a Wolfson DAC.

I then switched to my 5G Ipod and the sound out of my SFP5's were obviously better - no more bass distortion and a much more balanced and clearer musical presentation compared to the Mac Mini out. I'm quite surprised by this.

Has anyone ever experienced this or may have an explanation?

 

[Wodgy]

I don't know what an SFP5 is, but if it's a headphone, remember that the Mac Mini does not have an internal headphone amplifier. It just has a line out, like a standalone CD player would. Line outs typically can't generate much current or voltage. The current restrictions would be causing the bass problems you're hearing, and the voltage restrictions are what make the Mac Mini unable to play very loud when driving headphones.

An iPod, on the other hand, has an integrated headphone amplifier on the DAC chip.

 

[demasoni]

OH Geez, right...no headphone amp in the Mac Mini...that would explain the problem. Thanks for input.

 

[demasoni]

BTW, SFP5 stands for Ultimate Ears Super Fi Pro 5 IEM's.

 

[majid]

No, the Mac mini does support headphones, but the specs do mention a minimum impedance of 32 ohms:
http://developer.apple.com/documenta...H207-TPXREF124

The minimum recommended headphone impedance is 32 ohms. Headphones with an impedance lower than 32 ohms may experience a higher level of distortion.

The SFP5 have an impedance of 21 ohms, hence the distortion

 

[demasoni]

Quote:

Originally Posted by majid No, the Mac mini does support headphones, but the specs do mention a minimum impedance of 32 ohms: http://developer.apple.com/documenta...H207-TPXREF124 The minimum recommended headphone impedance is 32 ohms. Headphones with an impedance lower than 32 ohms may experience a higher level of distortion. The SFP5 have an impedance of 21 ohms, hence the distortion

Thanks for the tip. As soon as I get a 1/4" to 1/8" adapter, I will test this out with my Grado's which have an impedance of 32 ohms. What kind of amp is on the Mac Mini line out?

 

[demasoni]

OK, Hmm, to amp my Mac Mini, I connected my Headroom Little amp to the line out of the Mac Mini via a Straight Wire 1/8" plug to dual RCA plug cable which in turn drove my SFP5's. The bass distortion is still there. Mids and highs are clearer than before - but compared to driving my SFP5's out of my IPod, the difference in bass quality is clearer inferior from the Mac. The master volume and ITunes volume are maxed.

Is this a DAC problem? An SFP5 impedance issue as stated above? Anyone ever experience this? I gotta trust my ears...