This is a review, listening tests and detailed measurements of the Weiss DAC501 balanced DAC, headphone amp and network renderer. It is on kind loan from a member and costs US $9995.
The case is fine enough but not nearly so for what it costs. Stamped steel should have no place in this price range. The LCD is decent size but not very high resolution. It is touch sensitive but wasn't easy to navigate using that. It uses inverse scrolling in that to move the menus up, you rotate the knob to the left, not right. Fortunately a remote control is provided which allows quick random access to inputs and such. Back panel shows what you would expect as far as connectivity:
What distinguishes this streamer becomes visible once you connect to it using a web browser. In there, you see a suite of very useful signal processing components including parametric EQ, vinyl simulation, Room EQ (just a set of filters), etc. Here is the UI for the DSP:
The interface was easy to use and much nicer than screwing around with an app. Here is for example the parametric EQ for Room EQ (you program them manually):
For some odd reason though, when you select headphone out, you loose all that and only get a set of preprogrammed Audeze settings:
Fortunately the generic EQ remains with three filters:
You can create multiple presets and select them on demand using the remote.
There is a DAC502 which is the same but is wider and has balanced headphone out. Otherwise it is the same.
If you are not familiar with the tests that are about to follow, please watch my video on understanding DAC measurements.
Weiss DAC501 DAC and Streamer Measurement
Let's adjust the volume control such that we get 4 volts and measure the output using USB input:
This is good performance but I am left wondering why there are so many distortion spikes. That seems to do with its output buffer stages as lowering the gain there, does improve things:
But as you see, you can no longer reach 4 volt output even at max volume. Using the higher value, the DAC501 lands in our "Excellent" category:
Zooming in:
We have under $100 DACs outperforming it. That said, distortion is at threshold of hearing so likely transparent to the source. Here is the RCA performance with 0 dB Trim:
Since output can go over 4 volts, I ran my sweep of distortion+noise relative to digital level:
As noted, the curve has those ups and downs which I have not seen before. Same thing happened when I ran this test but used the front panel volume control. We will circle back to this later.
Since I know one of you rascals would ask
, here is the vinyl emulation:
I got a kick out of having the noise floor artificially increased in addition to incredibly high amount of distortion.
I was impressed with the noise performance:
Somehow that didn't translate to better performance in IMD vs level:
I liked that multitone distortion was totally frequency independent:
There is no option to change the filter:
Attenuation is good enough to give us a good wideband THD+N vs frequency:
Usually in audio gear distortion increases with frequency but here is slightly backward. A bit strange.
I was surprised (again) that despite low noise floor, the jitter measurement did not reveal the low order bits of the J-test signal on the left:
We also have a series of spikes that should not be there in an audio product in this price level and from an engineering company.
Now check out the linearity measurement:
As Spock would say, "fascinating!" This test simply varies the digital input to the DAC, expecting corresponding change in analog level. A perfect level would produce a line at 0 dB. What we see is that at precise digital input levels, we have a 1 dB error! Cleary the low order bits of digital audio samples are getting corrupted. Yes, I have all effects disabled which should cause the unit to pass the PCM samples through but clearly it is stepping on them. It is likely a software bug that should have been caught during design verification.
EDIT: further investigation shows the above is due to possible data loss/corruption/latency using USB driver. Toslink produces perfect response: https://www.audiosciencereview.com/...01-streamer-and-dac-review.48377/post-1737069
I have reported my findings to Danie Weiss, hoping a fix will be provided.
Finally, for compatibility with Stereophile DAC measurements, here is the performance of 50 Hz tone into 600 ohm load:
It beats an MSB DAC by nearly 18 dB so not bad:
Weiss DAC501 Headphone Measurements
The dashboard once again shows competent performance but not where it should be relative to its class:
I was disappointed in noise performance as it was not great in absolute and was worse in one channel:
There are four trim levels. I tested three of them:
These are OK power levels but again, not befitting of the class.
Output impedance is zero which good but there is just not a lot of current available:
Volume control is digital so no need to run channel imbalance test. But recently people have been doubting this so here it is:
DAC501 Listening Tests
As usual I start with my closed back Dan Clark Stealth headphone. This is a low impedance headphone that requires fair bit of drive. The DAC501 could only get it to moderate levels above which bass notes got distorted. Push harder and distortion kept increasing. It is useable with this headphone for background listening but no kind of foot tapping will follow.
I then switched to Sennheiser HD650 which is high impedance and much easier to drive. Here, the DAC501 managed to produce quite high dynamics to levels that you don't want to listen to for more than a few seconds. I listened to few tracks and sound was quite enjoyable but I did not detect anything euphonic or special about the DAC501. For comparison, I plugged the HD650 into my everyday ADI-2 Pro headphone out and I was now able to play much louder with even more fidelity (strictly due to higher output level).
Conclusions
I did some initial testing of the DAC501 a week ago (basically the dashboard) and then looked at all the processing it provided. I was completely sold on it and was willing to ignore its price and give it very high mark. Today though, those hopes were dashed. There is no reason for a DAC to not do the basics of what it is asked to do: convert digital samples to corresponding analog samples at accurate levels. This test ignores all noise and distortion, and I only measure to 20 bits so a DAC needs to be able to nail it. As noted in the review, the DAC501 clearly has an implementation bug that a simple test would have caught. I am hopeful that the company will fix it with a firmware update. If not, the hardware should be recalled.
The other less than good news is the headphone output performance. While better than a checklist item, it is anemic when it comes to driving lower impedance headphones. It is also rather noisy with one channel being worse that the other.
Finally, going into the review somehow I thought this was a $2,000 DAC/streamer. Today I double checked and was shocked that it was $10,000! I don't mind paying that much if it came in a 20 pound case with machining that would make me drool. And a high resolution display akin to a mobile phone. None of that is provided so I don't see how that price was ever justified. We have higher performance streamers selling for less than $1000 with all of these features.
The one thing this streamer has going for it is its signal processing. With a bit of modification (such as allowing Room EQ filters to be used for headphones), it could be a major advantage over its competitors at lower prices. But they need to fix the DAC before this matters.
I am very saddened as to not be able to recommend the Weiss DAC501.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The case is fine enough but not nearly so for what it costs. Stamped steel should have no place in this price range. The LCD is decent size but not very high resolution. It is touch sensitive but wasn't easy to navigate using that. It uses inverse scrolling in that to move the menus up, you rotate the knob to the left, not right. Fortunately a remote control is provided which allows quick random access to inputs and such. Back panel shows what you would expect as far as connectivity:
What distinguishes this streamer becomes visible once you connect to it using a web browser. In there, you see a suite of very useful signal processing components including parametric EQ, vinyl simulation, Room EQ (just a set of filters), etc. Here is the UI for the DSP:
The interface was easy to use and much nicer than screwing around with an app. Here is for example the parametric EQ for Room EQ (you program them manually):
For some odd reason though, when you select headphone out, you loose all that and only get a set of preprogrammed Audeze settings:
Fortunately the generic EQ remains with three filters:
You can create multiple presets and select them on demand using the remote.
There is a DAC502 which is the same but is wider and has balanced headphone out. Otherwise it is the same.
If you are not familiar with the tests that are about to follow, please watch my video on understanding DAC measurements.
Weiss DAC501 DAC and Streamer Measurement
Let's adjust the volume control such that we get 4 volts and measure the output using USB input:
This is good performance but I am left wondering why there are so many distortion spikes. That seems to do with its output buffer stages as lowering the gain there, does improve things:
But as you see, you can no longer reach 4 volt output even at max volume. Using the higher value, the DAC501 lands in our "Excellent" category:
Zooming in:
We have under $100 DACs outperforming it. That said, distortion is at threshold of hearing so likely transparent to the source. Here is the RCA performance with 0 dB Trim:
Since output can go over 4 volts, I ran my sweep of distortion+noise relative to digital level:
As noted, the curve has those ups and downs which I have not seen before. Same thing happened when I ran this test but used the front panel volume control. We will circle back to this later.
Since I know one of you rascals would ask
, here is the vinyl emulation:I got a kick out of having the noise floor artificially increased in addition to incredibly high amount of distortion.
I was impressed with the noise performance:
Somehow that didn't translate to better performance in IMD vs level:
I liked that multitone distortion was totally frequency independent:
There is no option to change the filter:
Attenuation is good enough to give us a good wideband THD+N vs frequency:
Usually in audio gear distortion increases with frequency but here is slightly backward. A bit strange.
I was surprised (again) that despite low noise floor, the jitter measurement did not reveal the low order bits of the J-test signal on the left:
We also have a series of spikes that should not be there in an audio product in this price level and from an engineering company.
Now check out the linearity measurement:
As Spock would say, "fascinating!" This test simply varies the digital input to the DAC, expecting corresponding change in analog level. A perfect level would produce a line at 0 dB. What we see is that at precise digital input levels, we have a 1 dB error! Cleary the low order bits of digital audio samples are getting corrupted. Yes, I have all effects disabled which should cause the unit to pass the PCM samples through but clearly it is stepping on them. It is likely a software bug that should have been caught during design verification.
EDIT: further investigation shows the above is due to possible data loss/corruption/latency using USB driver. Toslink produces perfect response: https://www.audiosciencereview.com/...01-streamer-and-dac-review.48377/post-1737069
I have reported my findings to Danie Weiss, hoping a fix will be provided.
Finally, for compatibility with Stereophile DAC measurements, here is the performance of 50 Hz tone into 600 ohm load:
It beats an MSB DAC by nearly 18 dB so not bad:
Weiss DAC501 Headphone Measurements
The dashboard once again shows competent performance but not where it should be relative to its class:
I was disappointed in noise performance as it was not great in absolute and was worse in one channel:
There are four trim levels. I tested three of them:
These are OK power levels but again, not befitting of the class.
Output impedance is zero which good but there is just not a lot of current available:
Volume control is digital so no need to run channel imbalance test. But recently people have been doubting this so here it is:
DAC501 Listening Tests
As usual I start with my closed back Dan Clark Stealth headphone. This is a low impedance headphone that requires fair bit of drive. The DAC501 could only get it to moderate levels above which bass notes got distorted. Push harder and distortion kept increasing. It is useable with this headphone for background listening but no kind of foot tapping will follow.
I then switched to Sennheiser HD650 which is high impedance and much easier to drive. Here, the DAC501 managed to produce quite high dynamics to levels that you don't want to listen to for more than a few seconds. I listened to few tracks and sound was quite enjoyable but I did not detect anything euphonic or special about the DAC501. For comparison, I plugged the HD650 into my everyday ADI-2 Pro headphone out and I was now able to play much louder with even more fidelity (strictly due to higher output level).
Conclusions
I did some initial testing of the DAC501 a week ago (basically the dashboard) and then looked at all the processing it provided. I was completely sold on it and was willing to ignore its price and give it very high mark. Today though, those hopes were dashed. There is no reason for a DAC to not do the basics of what it is asked to do: convert digital samples to corresponding analog samples at accurate levels. This test ignores all noise and distortion, and I only measure to 20 bits so a DAC needs to be able to nail it. As noted in the review, the DAC501 clearly has an implementation bug that a simple test would have caught. I am hopeful that the company will fix it with a firmware update. If not, the hardware should be recalled.
The other less than good news is the headphone output performance. While better than a checklist item, it is anemic when it comes to driving lower impedance headphones. It is also rather noisy with one channel being worse that the other.
Finally, going into the review somehow I thought this was a $2,000 DAC/streamer. Today I double checked and was shocked that it was $10,000! I don't mind paying that much if it came in a 20 pound case with machining that would make me drool. And a high resolution display akin to a mobile phone. None of that is provided so I don't see how that price was ever justified. We have higher performance streamers selling for less than $1000 with all of these features.
The one thing this streamer has going for it is its signal processing. With a bit of modification (such as allowing Room EQ filters to be used for headphones), it could be a major advantage over its competitors at lower prices. But they need to fix the DAC before this matters.
I am very saddened as to not be able to recommend the Weiss DAC501.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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