FFT vs THD+N vs Linearity vs Cutoff Importance

[Jazz3006]

Hey all,

I am looking at the E30 and the D10S.

My observations are as follows, but I'm not sure how important each measurement actually is:

D10S
has a better FFT @1k
a sharper cutoff
lower on the low end, but higher up top for THD+N

E30
higher RMS level
seems to have a SLIGHTLY better dynamic range
lower intermodulation
Very slightly flatter linearity
a flatter, but worse on the low end, THD+N
better FFT @12k

There is a $40 difference with the E30 acting as a preamp, but the D10S looking to be reasonably flat for the SUB input. The list of pros for the E30 is a bit longer, but is it actually better? Is there enough of a difference for it to even be audible? I think with either of these, the weak point will be the amp (A07) because I think the speakers should be able to hold up better than said amp (A130s).

Does anyone have some advice here, or am I just royally overthinking an entry-level unit?

Thanks!

 

[3125b]

or am I just royally overthinking an entry-level unit?

You are. It's certainly good to weigh your options, but desktop DACs are a solved problem, the top performers at ~100$ are more than transparent. Get whatever you like best for features, looks or whatever else.
The limiting factors in your chain will be the amp for noise and the speakers for distortion, those are orders of magnitude worse than those DACs.
For comparison: The E30 has harmonic distortion at -120dB, that's 0.0001%, the A07 has distortion products as low as -90dB, that's 0.003%. The A130 have low distrotion for speakers, but still about 0.3% @1kHz @86dB.

 

[Jazz3006]

You are. It's certainly good to weigh your options, but desktop DACs are a solved problem, the top performers at ~100$ are more than transparent. Get whatever you like best for features, looks or whatever else.
The limiting factors in your chain will be the amp for noise and the speakers for distortion, those are orders of magnitude worse than those DACs.
For comparison: The E30 has harmonic distortion at -120dB, that's 0.0001%, the A07 has distortion products as low as -90dB, that's 0.003%. The A130 have low distrotion for speakers, but still about 0.3% @1kHz @86dB.

Thanks! I have a tendency to do that with most everything...

Ok, one more question, if you don't mind. Amir posted a set of data for volume control on the D10S, but the E30 is the actual preamp. I guess I don't understand what the difference is there and most anything I am finding for a preamp is related to a mic, not speakers. I understand the premise of a preamp is to boost the signal to, ideally, override any distortion from EMI. I'm just not sure what it means in terms of a DAC if you were to adjust the volume either at the DAC or at the source rather than using the amp.

 

[JohnYang1997]

Thanks! I have a tendency to do that with most everything...

Ok, one more question, if you don't mind. Amir posted a set of data for volume control on the D10S, but the E30 is the actual preamp. I guess I don't understand what the difference is there and most anything I am finding for a preamp is related to a mic, not speakers. I understand the premise of a preamp is to boost the signal to, ideally, override any distortion from EMI. I'm just not sure what it means in terms of a DAC if you were to adjust the volume either at the DAC or at the source rather than using the amp.

Preamp here just means a volume control.
With E30, there's a remote control and you can control the volume using it. D10s is simpler and only displays the sample rate.

 

[JohnYang1997]

You are. It's certainly good to weigh your options, but desktop DACs are a solved problem, the top performers at ~100$ are more than transparent. Get whatever you like best for features, looks or whatever else.
The limiting factors in your chain will be the amp for noise and the speakers for distortion, those are orders of magnitude worse than those DACs.
For comparison: The E30 has harmonic distortion at -120dB, that's 0.0001%, the A07 has distortion products as low as -90dB, that's 0.003%. The A130 have low distrotion for speakers, but still about 0.3% @1kHz @86dB.

There's still a final piece. I couldn't find a sufficiently good dac with balanced output for cheap. One thing is that you can get ground loop pretty easily from the USB when the downstream device is earthed. D10 Balanced was said to come soon for months. It's actually coming now.

 

[dougi]

I see your amp has fairly low gain (21.5dB?). Which is good and bad. Good in that it won't amplify the DAC noise as much, but bad in that you may not be able to drive it to full power (if you need to do that). So the DAC with the highest output may be the right choice if you do want to use all of the range of the amp.

 

[Jazz3006]

There's still a final piece. I couldn't find a sufficiently good dac with balanced output for cheap. One thing is that you can get ground loop pretty easily from the USB when the downstream device is earthed. D10 Balanced was said to come soon for months. It's actually coming now.

How much of a difference would this actually make? I am very much planning to hook up via USB.

 

[Jazz3006]

I see your amp has fairly low gain (21.5dB?). Which is good and bad. Good in that it won't amplify the DAC noise as much, but bad in that you may not be able to drive it to full power (if you need to do that). So the DAC with the highest output may be the right choice if you do want to use all of the range of the amp.

I only ever play to a max of like 1/2 of the current output max. These are being used for desk speakers, so I don't have a reason to go nuts.

 

[JWAmerica]

I'm no EE, but I'd place more importance on low frequency response and worry less about high frequency roll off. Do you believe you can hear 20khz or higher?

 

[Jazz3006]

I'm no EE, but I'd place more importance on low frequency response and worry less about high frequency roll off. Do you believe you can hear 20khz or higher?

Not sure where this is coming from. None of the data that I was looking at was above 20k. It's all the frequencies that lead up to it.

 

[JWAmerica]

My apologies. You mentioned the sharper cutoff on the D10S and many people seem to be concerned with bandwidth/linearity above 20khz for their "Hi-Res" audio. I'm in the minority who like to see a filter that cuts off output above 20khz.

 

[Jazz3006]

My apologies. You mentioned the sharper cutoff on the D10S and many people seem to be concerned with bandwidth/linearity above 20khz for their "Hi-Res" audio. I'm in the minority who like to see a filter that cuts off output above 20khz.

Nope, it was a pro. The E30 appears to waste energy and potentially introduce unnecessary harmonics into the mix by not cutting sharper/sooner.