Dock vs headphone out
March 1st, 2006 by George Tyshchenko Purchase Apple iPod Universal Dock and support this site
iPod mini 1g and Apple Universal Dock
In this test you can see that Apple’s dock does not dramatically affects the quality, but even adds a strange low frequency cut-off(similar to the test of the 4g ipod, which wasn’t published). I am not familiar with the circuit of the universal dock or what causes the roll-off but i think it could be an impedance difference to optimize the signal for various amplifiers.
The important thing I want to point out is that unlike 5g ipod, both mini and 4g ipods truly bypass volume control and possibly headphone amplifier.
| Test | iPod mini 1g | iPod mini 1g dock |
| Frequency response (from 40 Hz to 15 kHz), dB: | +0.01, -0.03 | +0.02, -0.26 |
| Noise level, dB (A): | -95.2 | -98.6 |
| Dynamic range, dB (A): | 89.3 | 90.1 |
| THD, %: | 0.0044 | 0.035 |
| IMD + Noise, %: | 0.011 | 0.042 |
| Stereo crosstalk, dB: | -93.9 | -83.0 |
You can view the full RightMark report here
iPod 5g and Apple Universal Dock
According to my testing 5g iPod behaves differently when connected to the Dock. The click wheel continues to control the signal from the Dock output while some of the earlier models did not work this way. This could mean that 5g models have more components after the DA converter, which could reduce audio quality.
| Test | 5g Headphone out | 5g Dock out |
| Frequency response (from 40 Hz to 15 kHz), dB: | +0.02, -0.09 | +0.03, -0.25 |
| Noise level, dB (A): | -101.3 | -96.7 |
| Dynamic range, dB (A): | 91.2 | 89.2 |
| THD, %: | 0.0053 | 0.036 |
| IMD + Noise, %: | 0.0096 | 0.044 |
| Stereo crosstalk, dB: | -102.5 | -93.0 |
You can view the full RightMark report here
June 2nd, 2006 at 6:22 pm
When you say:
“According to my testing 5g iPod behaves differently when connected to the Dock. The click wheel continues to control the signal from the Dock output while some of the earlier models did not work this way.”
Do you mean it still adjusts the output level?
On my 5G it doesn’t seem to.
October 16th, 2006 at 4:50 pm
On my 5.5G the scroll wheel does indeed control the output level to the dock, much to my surprise.
February 3rd, 2007 at 9:36 am
Many people in headfi says that the headphone out sucks, while Dock out is so much better. I had to agree that after listening both headphone out and dock out, while the dock out is followed by an amplifier, using the same Shure E3C.
But according to your test, headphone out seems even better than dock out. Can you tell me why?
February 14th, 2007 at 10:08 am
My 5.5 controls the volume as does my 1st gen nano.
Looking at the universal dock it apears to have a the same wolfson dac
as the the 5.5 it maybe there is a digital audio signal coming out
of the bottom of the ipod and the implimentation of the dac in the
universal dock is causing the problems. An underspeced capacitor
creating the noticable rolloff in the bass maybe the case.
I’m going to open my dock quite soon and the measurements that you made probably are just the push I need. I do have a question about the measuremnets , was a usb power supply used during the test or was it running from the ipods
battery?
February 14th, 2007 at 10:27 am
@Ian
I don’t know which output is better. Like someone already commented earlier, the loaded tests are more important for determining quality, which i have yet to do. The roll of could be compensating for something when you use a proper amplifier instead of my MOTU828 which i use for testing.
@Jamie
I was running from the battery. Let us know what you find.
November 11th, 2007 at 12:37 am
With regard to dock output, have you had a chance to assess Red Wine Audio’s “iMod”?