Another one is made, thanks Scott for the circuit and Patrick for the PCB design 
Attached (second picture) the ARTA measurement of the noise level (gain is set to 1000 in ARTA). Yellow one is when input was shorted at the BNC, green one is when input was connected to a 1k resistor. The 1k resistor should have a noise of 4nV/rtHz, with the yellow line being 14dB lower, this amp should have a noise of 0.8nV/rtHz if my computation is right.
To get a clean graph, I had to hide it within another grounded metal box, last graph is measurement of the 1k resistor (green) without the extra metal box, where the aluminum case is already grounded.
Attached (second picture) the ARTA measurement of the noise level (gain is set to 1000 in ARTA). Yellow one is when input was shorted at the BNC, green one is when input was connected to a 1k resistor. The 1k resistor should have a noise of 4nV/rtHz, with the yellow line being 14dB lower, this amp should have a noise of 0.8nV/rtHz if my computation is right.
To get a clean graph, I had to hide it within another grounded metal box, last graph is measurement of the 1k resistor (green) without the extra metal box, where the aluminum case is already grounded.
Attachments
We have been asked by PM about PCBs.
We have some left, and you can have them for HKD100 each including Paypal fees, packing and registered post.
But it will make life easier for us to pack and send them in one go (sort of GB).
So those interested please make a list of subcribers here.
We'll wait 3 weeks or so before closing and giving you further instructions.
Thank for your interest,
Patrick
We have some left, and you can have them for HKD100 each including Paypal fees, packing and registered post.
But it will make life easier for us to pack and send them in one go (sort of GB).
So those interested please make a list of subcribers here.
We'll wait 3 weeks or so before closing and giving you further instructions.
Thank for your interest,
Patrick
the 2 box screening makes a big difference.Another one is made, thanks Scott for the circuit and Patrick for the PCB design
Attached (second picture) the ARTA measurement of the noise level (gain is set to 1000 in ARTA). Yellow one is when input was shorted at the BNC, green one is when input was connected to a 1k resistor. The 1k resistor should have a noise of 4nV/rtHz, with the yellow line being 14dB lower, this amp should have a noise of 0.8nV/rtHz if my computation is right.
To get a clean graph, I had to hide it within another grounded metal box, last graph is measurement of the 1k resistor (green) without the extra metal box, where the aluminum case is already grounded.
I have seen others suggesting the 2 box method and they used different materials for the two boxes, one included Fe for better magnetic coupling screening.
Is your black box aluminium, or steel?
Please help us by adding to the list yourselves.
AndrewT UK 1x
as_audio DE 1x
jackinnj US 1x
RNMarsh USA 1x
Running total 4
Almost ready for the Mouser BoM tool-- i think Pete Millett used it for one of his projects:
http://www.mouser.com/BOMTool/
Boards have been sent to the following members:
AndrewT (RC428293415HK)
as_audio (RC428293407HK)
bkdog (RC428293424HK)
The numbers in the bracket is the item number, the reference no. for getting tracking status from the following (it may take a day of two for the status to become available):
http://www.hongkongpost.hk/en/mail_tracking/index.html
Thanks and regards.
AndrewT (RC428293415HK)
as_audio (RC428293407HK)
bkdog (RC428293424HK)
The numbers in the bracket is the item number, the reference no. for getting tracking status from the following (it may take a day of two for the status to become available):
http://www.hongkongpost.hk/en/mail_tracking/index.html
Thanks and regards.