After finally having installed my Empeg in the car (after 4 years of proud ownership!) I've noticed that the actual sound quality with music coming from the HD of the Empeg is not as good as when the exact same MP3 file is played through the Empeg's Aux input from my Karma.

I've tried to cancel out all variables such as L/R time-alignment, voladj, EQ, etc. by switching everything off; I also compensated for output level to make a fair comparison. It's obvious, the Karma sounds a lot better: less congested in the midrange, more treble detailing, tighter bass.

It's weird because the Karma goes trhough an additional processing step, A-to-D conversion (I assume all processing in Empeg is done by DSP)- whereas from the HD it should all nicely stay in digital domain so if anything, it should sound worse.

I'm aware of the small hardware error that affects the first MkII units (wrong SMD resistor so reduced channel separation). Does this resistor has an effect on other aspects of SQ also?

After this, I took the Empeg inside and did a similar comparison on my (pretty-decent, if I say so myself) home system. Again, playing the same files, the Empeg sounds consistently worse than the Karma (I'm actually very impressed with the quality from the Karma; it's very close to the original CD).

Another thing that has got me worried is that is seems that the Empeg damages MP3 files... Files that were fine in the past suddenly have excruciatingly loud clicks or bursts of screeches in them; always re-occuring at the exact same spot. How this happens, I don't know, haven't discovered a pattern. Putting the same file back on the Empgeg from the PC restores things. All my music is VBR Lame encoded; extreme setting); using both ID3 V1 and V2 tags.

Has anybody else noticed similar things?

Cas.

Thanks for the IDE cable pointer; my unit is still completely original, including the "warranty void if broken" seal! Guess the time has come to break the seal...

With regards to extra step for external inputs (aux, tuner) I figured that, in order for EQ and other stuff to work, these analogue sources would be converted to digital first.

I noticed that voladj or time alignment don't work with either tuner or extrernal input, thought this was perhaps a limitiation of Hijack...

So, this means that tone control for tuner and HD is done in analogue domain?

If I can't get the sound quality to improve, I'll have to consider Eutronix' digital output kit and a small outboard A/D converter...

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I figured that, in order for EQ and other stuff to work, these analogue sources would be converted to digital first.

Nope, it's all digital domain.

If you have a dodgy cable, then you could have a low-bit order noise issue that is causing the reduced quality you hear.

I did back to back tests with a friend on a Mk2 using PCM playback many years ago to compare the audio quality against a top quality CD setup. Although my hearing is damaged, he reckoned that the sound was as good as his CD setup. Hence, any degradation in audio quality is likely to be caused either by a hardware fault or by a poor rip of an MP3. Don't forget the decoders on the Karma and Car were different.

The outputs of the Mk1 were Burr-Brown DACs, top quality. The output of the 2/2A rely on the Philips DSP.

If you do go for the SPDIF, please be careful about how you do the hardware install.

Thanks for feedback, Schofiel; I'm still a bit confused though...

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Nope, it's all digital domain.

That's what I thought, However I suppose the tuner module puts out an analogue signal, as does the Karma, hence me thinking there's an A-to-D in there somewhere; am I missing something here?

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degradation in audio quality is likely to be caused either by a hardware fault or by a poor rip of an MP3. Don't forget the decoders on the Karma and Car were different.

Ripping is usually done with EAC; all my MP3's play fine on the Karma with excellent quality. I'll have to have my Empeg seen to by your good self, it seems.

Cheers.

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hence me thinking there's an A-to-D in there somewhere; am I missing something here?

The tuner, AUX source, and MIC are all digitised and fed through the same digital signal path.

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The outputs of the Mk1 were Burr-Brown DACs, top quality. The output of the 2/2A rely on the Philips DSP

Hmm I was under the impression and have been telling my friends that all the players, the 2/2a, had the Burr-Brown DAC's in them. How much quality diff. is there between the two?