Very interesting project, with all the persons interested to buy this analyser could you indicate if you will reach the 50 pieces target and make it available for less than 1'000$ as announced? I think this information could generate even more demand
Thanks for the very nice and professional instrument!
Marc
Thanks for the very nice and professional instrument!
Marc
I have seen some preliminary results. While its not a APx555 its remarkably close (given 1/20 the price especially) and is about as good as you can get from the ADC. Possibly 15-20 dB better than a QA401 under ideal circumstances. It will also be a fully professional assembled product. No futzing with incomplete and unfinished details.
Hi Demian,
That's what the performance was looking like. Your word on the subject absolutely proves this for me, but I didn't have any doubts before either.
Thanks for chiming in on this. Everyone else can rest assured that this is the best we can afford and better than an old, used piece of equipment.
-Chris
That's what the performance was looking like. Your word on the subject absolutely proves this for me, but I didn't have any doubts before either.
Thanks for chiming in on this. Everyone else can rest assured that this is the best we can afford and better than an old, used piece of equipment.
-Chris
Thanks Demain that's good to know. I was already convinced that it will be a professionally executed unit; the care and attention to detail will make sure of that. It is a great accomplishment, I will say that without reservation.
But it is still a bunch of money for most of us and in the end there's no way around some sort of spec sheet. The quicker it is available, the faster the order book will fill up!
Jan
But it is still a bunch of money for most of us and in the end there's no way around some sort of spec sheet. The quicker it is available, the faster the order book will fill up!
Jan
This afternoon I received the final front plate with a wear resistant foil. So the parts are finally coming together.
A spec. sheet is one of the next tasks on my to-do list. Hopefully I can have at least a preliminary version during this week. I can post it here. If you feel that parameters are missing, just let me know and I will try to include it. There are many parameters that could be included, but I also would like to keep it readable.
The basic features are still what is listed in the first post of this thread.
A few measurement results:
With a 1V balanced output from the generator (-20dBFS) looped back to the analyzer, I have measured a THD of just below -130dB average over the 18 units that have been built so far.
The worst measurement in this test was -127.8dB. The best one was -133.7dB.
This was measured at a sample rate of 48 kHz.
If only one input channel is used the distortion seems to drop by 1 or 2 dB.
At higher levels the distortion does increase. This is primarily caused by the AKM DAC and ADC.
The equivalent input noise on the sensitive settings is around 0.6uV over 20 kHz or 4nV/rtHz.
I posted a comparison with the AP2722 generator here http://www.diyaudio.com/forums/equipment-tools/277808-diy-audio-analyzer-ak5397-ak5394a-ak4490-63.html#post4893502
I have attached a typical loop-back measurement at a sample rate of 96 kHz. Only the left channel is used in this case. The noise at the high frequencies comes from the DAC.
A spec. sheet is one of the next tasks on my to-do list. Hopefully I can have at least a preliminary version during this week. I can post it here. If you feel that parameters are missing, just let me know and I will try to include it. There are many parameters that could be included, but I also would like to keep it readable.
The basic features are still what is listed in the first post of this thread.
A few measurement results:
With a 1V balanced output from the generator (-20dBFS) looped back to the analyzer, I have measured a THD of just below -130dB average over the 18 units that have been built so far.
The worst measurement in this test was -127.8dB. The best one was -133.7dB.
This was measured at a sample rate of 48 kHz.
If only one input channel is used the distortion seems to drop by 1 or 2 dB.
At higher levels the distortion does increase. This is primarily caused by the AKM DAC and ADC.
The equivalent input noise on the sensitive settings is around 0.6uV over 20 kHz or 4nV/rtHz.
I posted a comparison with the AP2722 generator here http://www.diyaudio.com/forums/equipment-tools/277808-diy-audio-analyzer-ak5397-ak5394a-ak4490-63.html#post4893502
I have attached a typical loop-back measurement at a sample rate of 96 kHz. Only the left channel is used in this case. The noise at the high frequencies comes from the DAC.
Attachments
The sample to sample variation looks pretty reasonable and probably better than I suspect is typical of most reasonably priced sound cards which form the basis for the sort of partially home brewed measurement system such as the one I currently use, and so much simpler/easier to use than mine. (M-Audio 24192 with heavily modified Millett sound card interface [mono only], isolation transformer on PC power, and WE REP 111-C on the audio lines to kill common mode noise from the PC.)
I'm in
I have been following this for a while. I couldn't wait and needed an Audio Analyzer for the amps I build so I purchased a beautiful dScope IIIA. It will be listed in the Test Equipment Section for sale. I think I'll get 2. One for each hand....
JensH, I'm sending a PM to get on the list
I have been following this for a while. I couldn't wait and needed an Audio Analyzer for the amps I build so I purchased a beautiful dScope IIIA. It will be listed in the Test Equipment Section for sale. I think I'll get 2. One for each hand....
JensH, I'm sending a PM to get on the list
So, the real harmonics are -110dB below the fundamental @1kHz -20dBFs?
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