agree ;
I have some in my drawer , matched ..... with already soldered leads several times
but - as reply to thanh1973's question - if you're novice - build it with parts picked with left hand behind back ; then enjoy in muzak and build something else ...
if you have some mileage , spend 3 years while laser trimming parts and build it ;
but - be happy if pleasure in building is bigger than advance in sound quality .... meaning - do not expect heaven and hell difference
I have some in my drawer , matched ..... with already soldered leads several times
but - as reply to thanh1973's question - if you're novice - build it with parts picked with left hand behind back ; then enjoy in muzak and build something else ...
if you have some mileage , spend 3 years while laser trimming parts and build it ;
but - be happy if pleasure in building is bigger than advance in sound quality .... meaning - do not expect heaven and hell difference
exactly ; that's what I meant and wrote several times ....... you can use even witch's tooth , if you want and know how to use it .
no , tnx ; I already does that too much ;
no matter what amount of knowledge is there , price is just too big for my liking
Update
I did the resistor measurement again with an Agilent 34401A meter
and 4 wire kelvin probes.
The resistance value I get this time is 0.471 Ohms.
I also tried to do the TCR measurement with the better meter and basically got the same result. That is there is quite a bit of noise when you get into the microOhm region so it is very hard to confidently measure anything below 1 milliOhm. All I can say is the resistors are better than 50ppm.
I will try TCR again with a 100 Ohm resistor.
Sorry if this is off topic, but I thought some people might be interested.
I did the resistor measurement again with an Agilent 34401A meter
and 4 wire kelvin probes.
The resistance value I get this time is 0.471 Ohms.
I also tried to do the TCR measurement with the better meter and basically got the same result. That is there is quite a bit of noise when you get into the microOhm region so it is very hard to confidently measure anything below 1 milliOhm. All I can say is the resistors are better than 50ppm.
I will try TCR again with a 100 Ohm resistor.
Sorry if this is off topic, but I thought some people might be interested.
Just to give you an idea of how good the tolerance is on a 5% tolerance specified resistor (Dale CPF3).
Here are the values of 10 resistors taken at random.
0.470, 0.468, 0.470, 0.467, 0.469, 0.471, 0.469, 0.470, 0.474, 0.474
That is quite a bit better than 5%. Hopefully that puts things into perspective for people.
So it shouldn’t be too hard to match resistors to 1 mOhm.
Hopefully 1 mOhm is good enough.
Here are the values of 10 resistors taken at random.
0.470, 0.468, 0.470, 0.467, 0.469, 0.471, 0.469, 0.470, 0.474, 0.474
That is quite a bit better than 5%. Hopefully that puts things into perspective for people.
So it shouldn’t be too hard to match resistors to 1 mOhm.
Hopefully 1 mOhm is good enough.
thanh,
Try my method. What you are testing is basically the repeatability of the measurement.
It does not address different tempco between different resistors at say 70°C.
The 5% accuracy normally refers to absolute accuracy (deviation from absolute 0R22, e.g.).
Device variation is a lot lower.
Patrick
Try my method. What you are testing is basically the repeatability of the measurement.
It does not address different tempco between different resistors at say 70°C.
The 5% accuracy normally refers to absolute accuracy (deviation from absolute 0R22, e.g.).
Device variation is a lot lower.
Patrick
Last edited:
> What option will get me over the line for single point matched as per EUVL’s post 14?
Ask him by PM for NNPP match, and if you want to be perfect than NNNNPPPP match (all to 10mV).
He would ask for a premium, which I consider fair.
But please refer him to this post.
Zhou,
I hope you would be kind enough to help F5X builders out by offering NNPP sets without too much extra premium.
I am sure your large matching batch can accommodate this without too much problem.
Best regards,
Patrick
Ask him by PM for NNPP match, and if you want to be perfect than NNNNPPPP match (all to 10mV).
He would ask for a premium, which I consider fair.
But please refer him to this post.
Zhou,
I hope you would be kind enough to help F5X builders out by offering NNPP sets without too much extra premium.
I am sure your large matching batch can accommodate this without too much problem.
Best regards,
Patrick
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