Yes I would. And probably also the case and front panel. I'm expecting metalwork prototypes any day.flaheu said:
Audio test interface
- Thread starter abbey road d enfer
- Start date
Help Support GroupDIY Audio Forum:
I've submitted the ATI to the AP. Performance is up to expectations:
Frequency response <5Hz-200+kHz BW (+0,-0.5dB)
EIN of the measurement section better than -103dBu@unity gain, -88@20dB gain (22Hz-22kHz BW)
THD+N better than 0.0035% from 20Hz to 20kHz (measurement BW 30kHz)
Residual noise of generator section -108dBu @ 0dB attenuation (22Hz-22kHz BW)
The only performance point I had not been capable of predicting was the real capability of the circuit to drive unbalanced sources with the attenuator in-circuit. Unlike a xfmr-output, the 1646 has a finite CM impedance, which alters the level when on eof the legs is shorted to ground.
I have found this difference to be less than 0.2dB for 50r and 150r output Z, and less than 0.5dB for 600r output Z.
It's not a big problem, but still one has to keep in mind.
Overall I'm very pleased with the results, now I should receive my Q400 next week, as well as the metalwork.
Frequency response <5Hz-200+kHz BW (+0,-0.5dB)
EIN of the measurement section better than -103dBu@unity gain, -88@20dB gain (22Hz-22kHz BW)
THD+N better than 0.0035% from 20Hz to 20kHz (measurement BW 30kHz)
Residual noise of generator section -108dBu @ 0dB attenuation (22Hz-22kHz BW)
The only performance point I had not been capable of predicting was the real capability of the circuit to drive unbalanced sources with the attenuator in-circuit. Unlike a xfmr-output, the 1646 has a finite CM impedance, which alters the level when on eof the legs is shorted to ground.
I have found this difference to be less than 0.2dB for 50r and 150r output Z, and less than 0.5dB for 600r output Z.
It's not a big problem, but still one has to keep in mind.
Overall I'm very pleased with the results, now I should receive my Q400 next week, as well as the metalwork.
Samuel Groner
Well-known member
The EIN should be better at 20 dB gain than at unity? At what level is 0.0035% THD+N, and is it distortion or noise?
Samuel
Samuel
I just ASSumed he was talking output not input noise. -108 @ 20dB gain vs -103 @ unity seems reasonable for the input side.
JR
JR
Yes, sorry. EIN is -108@20dB gainJohnRoberts said:
I had measured at 20dBu output in order to see some distortion. At 0dBu there's nearly as much noise than THD.Samuel Groner said:
RodrigoRocha.RJ
New member
How is the development of the interface?
Any changes in the project?
Any changes in the project?
It's finished. I have put it in operation at the works, where it's used for basic measurements, awaiting development of specific plug-ins.RodrigoRocha.RJ said:
I haven't made any plans for selling it. If enough are interested, I could have a batch of PCB's made. I could also have a batch of front panels made. Cost of PCB's would be about £50 if I have enough orders for a batch of 10.
If that becomes a reality, I would have to start a new thread in the Black Market.
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