Balanced F5 question - Page 12

EUVL · 09:32 PM

> Yes I am also a fan of the irfp devices.

I am not, but that's well known.
We tried an AX100 Toshiba vs IRFP 3 years ago.
No comparison !!

Patrick

Melon Head · 20th October 2010, 09:25 PM

Thanks Patrick
I will definitely be trying both toshiba and IR devices.

massimo · 20th October 2010, 09:26 PM

Patrick, would you please explain the PS arrangements in your design?
You told us you're using a 650 VA Xfrm, possibly 12+12 V or slightly higher, and then? Diodes, caps, CRC, CLC, etc.
Thank you.

EUVL · 20th October 2010, 09:31 PM

16+16, soft recovery diodes, CRC-Zen 4 regulator-C, 20000uF per C.

Patrick

johnwmclean · 21st October 2010, 01:29 AM

ZhouFangs offerings:

Value match: $14/pair(1 each), $7/pc for 2SK1530, $8/pc for 2SJ201
Precision match: $16/pair(1 each), $8/pc for 2SK1530, $9/pc for 2SJ201
P-N match: $28/pair(1 each)

What option will get me over the line for single point matched as per EUVL’s post 14?

Melon Head · 21st October 2010, 02:37 AM

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.

Melon Head · 21st October 2010, 03:27 AM

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.

EUVL · 04:01 AM

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

EUVL · 21st October 2010, 04:00 AM

> 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

Melon Head · 21st October 2010, 04:09 AM

I will try you method but I have already demonstrated the resistance doesn't change with temperature.
If it does it is below the noise floor of the instrument.

Anyway I will do your method.

20th October 2010, 09:22 PM	#111
EUVL diyAudio Member Join Date: Oct 2003	> Yes I am also a fan of the irfp devices. I am not, but that's well known. We tried an AX100 Toshiba vs IRFP 3 years ago. No comparison !! Patrick Last edited by EUVL; 20th October 2010 at 09:32 PM.

21st October 2010, 03:54 AM	#118
EUVL diyAudio Member Join Date: Oct 2003	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 Last edited by EUVL; 21st October 2010 at 04:01 AM.

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20th October 2010, 09:25 PM	#112
Melon Head Banned Join Date: Nov 2006	Thanks Patrick I will definitely be trying both toshiba and IR devices.

20th October 2010, 09:26 PM	#113
massimo diyAudio Member Join Date: Dec 2002 Location: Milan, Italy	Patrick, would you please explain the PS arrangements in your design? You told us you're using a 650 VA Xfrm, possibly 12+12 V or slightly higher, and then? Diodes, caps, CRC, CLC, etc. Thank you.

20th October 2010, 09:31 PM	#114
EUVL diyAudio Member Join Date: Oct 2003	16+16, soft recovery diodes, CRC-Zen 4 regulator-C, 20000uF per C. Patrick

21st October 2010, 01:29 AM	#115
johnwmclean diyAudio Member Join Date: Oct 2009	ZhouFangs offerings: Value match: $14/pair(1 each), $7/pc for 2SK1530, $8/pc for 2SJ201 Precision match: $16/pair(1 each), $8/pc for 2SK1530, $9/pc for 2SJ201 P-N match: $28/pair(1 each) What option will get me over the line for single point matched as per EUVL’s post 14?

21st October 2010, 02:37 AM	#116
Melon Head Banned Join Date: Nov 2006	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.

21st October 2010, 03:27 AM	#117
Melon Head Banned Join Date: Nov 2006	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.

21st October 2010, 04:00 AM	#119
EUVL diyAudio Member Join Date: Oct 2003	> 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

21st October 2010, 04:09 AM	#120
Melon Head Banned Join Date: Nov 2006	I will try you method but I have already demonstrated the resistance doesn't change with temperature. If it does it is below the noise floor of the instrument. Anyway I will do your method.