In this article on the recent AVB MOTUs
MOTU 624 und 8A Audio-Interfaces mit Netzwerkfahigkeiten im Test › SOUND & RECORDING
you find this picture
https://www.soundandrecording.de/wp-content/uploads/2017/11/04_MOTU-624-Wandlerchips.jpg
showing a ES9016S
MOTU 624 und 8A Audio-Interfaces mit Netzwerkfahigkeiten im Test › SOUND & RECORDING
you find this picture
https://www.soundandrecording.de/wp-content/uploads/2017/11/04_MOTU-624-Wandlerchips.jpg
showing a ES9016S
ES9016 on the Motu. Not their best, and has some HF noise that pops up, so likely not the best to be using for an analyzer if you're looking at the upper frequency ranges or using something that can't filter it out. Not sure if the noise is from the Motu circuitry or the dac, just that it's there.
The SNR on it is pretty ridiculous, though. The ES9038PRO I think is their current high end chip, which is like -122db THD+N compared to the ES9016's -110.
The SNR on it is pretty ridiculous, though. The ES9038PRO I think is their current high end chip, which is like -122db THD+N compared to the ES9016's -110.
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Thanks to both of you.
There seems to be some discrete noise frequencies at around 75 kHz (difficult to read the frequency from the pictures). I wonder if that could be some image products from the DAC? It seems to be two discrete frequencies close to each other. At first I thought that it could be some noise from e.g. a switch mode power supply, but since it is not there in the IMD measurement, this is probably not the case.
When using the MOTU input it looks like the noise is masked by the noise of the ADC. The ADC seems to have a relatively high level of noise above 50 kHz. Probably no issue for music recording, but not desirable for test equipment.
I have started to look into what performance I can get from an ESS DAC, but it is still early days.
There seems to be some discrete noise frequencies at around 75 kHz (difficult to read the frequency from the pictures). I wonder if that could be some image products from the DAC? It seems to be two discrete frequencies close to each other. At first I thought that it could be some noise from e.g. a switch mode power supply, but since it is not there in the IMD measurement, this is probably not the case.
When using the MOTU input it looks like the noise is masked by the noise of the ADC. The ADC seems to have a relatively high level of noise above 50 kHz. Probably no issue for music recording, but not desirable for test equipment.
I have started to look into what performance I can get from an ESS DAC, but it is still early days.
Here's the video, not sure if this is analog stage or dac, but either way, they have better units than the ES9016. All of the MOTU units of this family have had this noise, whether with the wall wart from the 8a, or with internal psu on the 16a and 1248. I have a feeling the ES9038Pro with a better output stage could make a fantastic generator.
YouTube
This is the HF junk on the output, as well as DC offset.
https://i.imgur.com/31FoNLs.png
https://i.imgur.com/cPgAmTB.png
And the RTX for comparison
https://i.imgur.com/B4VPwq4.png
YouTube
This is the HF junk on the output, as well as DC offset.
https://i.imgur.com/31FoNLs.png
https://i.imgur.com/cPgAmTB.png
And the RTX for comparison
https://i.imgur.com/B4VPwq4.png
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Hi Jens,
Remarkable, as I also observed a peak at about 75.5kHz with three different sound cards: Lyx L22, Waveterminal 192X and Xonar Essence STX. This peak is unrelated to the fundamental.
BTW, Regrettably I've missed the the group buy (as I discovered it too late). So when a next one will be scheduled and/or when a second batch of the RTX6001 will be available?
Cheers, E.
Remarkable, as I also observed a peak at about 75.5kHz with three different sound cards: Lyx L22, Waveterminal 192X and Xonar Essence STX. This peak is unrelated to the fundamental.
BTW, Regrettably I've missed the the group buy (as I discovered it too late). So when a next one will be scheduled and/or when a second batch of the RTX6001 will be available?
Cheers, E.
Attachments
In the sweep there seems to be IM products with a 70KHz tone that seems pretty constant. As the sweep gets closer the IM sweeps down to the audio range with some level. Enough to show on the noise plot. There are two issues. First the source of the 70KHz?? tone. Second where the IM is coming from and why its so strong. The sidebands are pretty strong compared to the tone.
My next test would be band limited noise from say 50 KHz to 65 KHz and look at its audio band products. The IM level seems really high for the analog stage.
My next test would be band limited noise from say 50 KHz to 65 KHz and look at its audio band products. The IM level seems really high for the analog stage.
It is now in full production, and you can order one directly from RTX, the GB was a one shot deal.
Next made some measurements on my 8CH ES9018 DAC which is riddled with issues i have been debugging without a lot of success.
As you can see, there is a strange grass when USB is connected. It seems to disappear in the other measurements with signal.
USB interface is an isolated EXAU2I module.
As you can see, there is a strange grass when USB is connected. It seems to disappear in the other measurements with signal.
USB interface is an isolated EXAU2I module.
Attachments
Hi Kevin,
RTX send me a quotation: $2495. That is two times the GB price.
No deal.
Cheer, E.
Hi Edmond,
It's true the normal price is 2X what the GB was, but it is very much worth that and more. For me, it would have been too expensive to buy at the normal price, so I really lucked out in a big way.
In my honest appraisal, the build quality is right up there with the $10,000 equipment (mine has arrived and I have been getting use to it). I bought a license for ARTA since that seems to be the program of choice among professionals here.
Another way to look at this is that even if you only used it as a music DAC, at $2,400, it is far less expensive than anything even close in consumer DAC land. Balanced out too. There is one utility that would allow you to use it as a DAC with no additional software but the built in players. It installed with zero fuss, as did ARTA.
I can see the frustration from missing the group buy, but if that buy had never happened I would have attempted to come up with the money anyway. It's thousands less than the next equipment up and performs at a slightly lower (?) level I'm told. What I can say is that it saves me a great deal of time and allows me to get readings well under the noise floor of my HP 339A.
I forgot the biggest thing. It is calibrated for level and the full package for $2,400 comes with a certificate of calibration. That in itself is worth a few hundred. The group buy members did not receive a certification with the unit. I found the levels to be within the tolerance of my own equipment. Which is right? I have no way of knowing short of having the unit certified. That would probably be closer to $500 or more from a calibration lab.
-Chris
It's true the normal price is 2X what the GB was, but it is very much worth that and more. For me, it would have been too expensive to buy at the normal price, so I really lucked out in a big way.
In my honest appraisal, the build quality is right up there with the $10,000 equipment (mine has arrived and I have been getting use to it). I bought a license for ARTA since that seems to be the program of choice among professionals here.
Another way to look at this is that even if you only used it as a music DAC, at $2,400, it is far less expensive than anything even close in consumer DAC land. Balanced out too. There is one utility that would allow you to use it as a DAC with no additional software but the built in players. It installed with zero fuss, as did ARTA.
I can see the frustration from missing the group buy, but if that buy had never happened I would have attempted to come up with the money anyway. It's thousands less than the next equipment up and performs at a slightly lower (?) level I'm told. What I can say is that it saves me a great deal of time and allows me to get readings well under the noise floor of my HP 339A.
I forgot the biggest thing. It is calibrated for level and the full package for $2,400 comes with a certificate of calibration. That in itself is worth a few hundred. The group buy members did not receive a certification with the unit. I found the levels to be within the tolerance of my own equipment. Which is right? I have no way of knowing short of having the unit certified. That would probably be closer to $500 or more from a calibration lab.
-Chris
Hi Kevin,
RTX send me a quotation: $2495. That is two times the GB price.
No deal.
Cheer, E.
We should ask quote for a quantity. If there is a discount for say 10 or 20 units we might try to run a second GB. It might not be as cheap as the pre-sale GB, but still cheaper than getting a single unit.
D.
@ Chris and mbrennwa,
Whether it's worth $2495 depends on your needs and on the equipment you already have at your disposal. As I have already a couple of sound interfaces, to me it means that the RTX6001 will improve my current measurement floor by say 10dB. Is that worth $2495? In my case, I don't think so.
Cheers, E.
Whether it's worth $2495 depends on your needs and on the equipment you already have at your disposal. As I have already a couple of sound interfaces, to me it means that the RTX6001 will improve my current measurement floor by say 10dB. Is that worth $2495? In my case, I don't think so.
Cheers, E.
Hi Edmond,
However, you are the one who determines value for yourself. I hope you guys can get a quantity discount, but make no mistake, this is a calibrated interface with a robust interface and high output levels.
The inputs are rated for 100 V, and will survive 150 V peaks. Sound cards are limited to 5 Vp-p before damage may occur, so you need something like Jan's sound card interface unit. You still don't have a calibrated unit though.
If you need an instrument, you need the RTX. If you are merely doing casual measurements that are more relative, a sound card will be fine. The output frequency response of the RTX is ruler flat way out to 88,200 Hz minimum. I haven't explored the top limit for this parameter.
-Chris
There are other differences that make it worthwhile. I also have a couple of sound cards that do well as measurement devices, but they aren't anywhere close to the performance and capability that the RTX unit has.
However, you are the one who determines value for yourself. I hope you guys can get a quantity discount, but make no mistake, this is a calibrated interface with a robust interface and high output levels.
The inputs are rated for 100 V, and will survive 150 V peaks. Sound cards are limited to 5 Vp-p before damage may occur, so you need something like Jan's sound card interface unit. You still don't have a calibrated unit though.
If you need an instrument, you need the RTX. If you are merely doing casual measurements that are more relative, a sound card will be fine. The output frequency response of the RTX is ruler flat way out to 88,200 Hz minimum. I haven't explored the top limit for this parameter.
-Chris