DIY Audio Analyzer with AK5397/AK5394A and AK4490 - Page 305

1audio · 20th December 2020, 12:16 AM

Quote:

Originally Posted by zfe

For measuring electrostatic headphone amps I would like to increase the input attenuation.
Would it be good practice to add a, say, 900k resistor in series to the single ended input? This would make a 10:1 divider with the 100k input impedance of the RTX6001. A hight input impedance is desired for electrostatic amps anyway.

For most electrostatic headphones (Stax or similar) you will need a differential measurement. 1 Meg is a significant load and you need more like 10M or even 100 M. And you need to compensate the capacitance. Fortunately the voltage swing is on the order of 200V or more so a divide by 100 probe is not an issue and the RTX has enough gain. Stray capacitance at the probe point is also an issue since the headphones are on the order of 100pF and the stray can be significant. Also use several resistors in series to reduce the voltage and associated voltage coefficients across them.

Keep in mind 200V at 20 KHz can pack quite the punch even with limited current.

zfe · 20th December 2020, 03:08 PM

My idea was to measure without headphone connected and add some capacitance in parallel so simulate the headphone. This way the stray capacitance and the input capacitance of the RTX6001 could be part of that capacitive load. Are there objection on doing so?

JensH · 20th December 2020, 04:28 PM

The capacitance of the headphones is in the order of 100 pF, equivalent to an impedance of 160 kohm at 10 kHz, so I don't think that a balanced load impedance of 2 Mohm will be a problem.

I built a KGSS amplifier some years ago. It has output resistors of 5k11 in series with each output.

DualTriode · 17th January 2021, 10:05 PM

Hello All,

Looking for help with the installation of the shielding kit for the RTX6001 that was mailed to me.

Inside the box with the analyzer I have had the unopened envelope with the shielding inside. Are the shielding installation instructions posted here anywhere?

Thanks DT

diyaudnut · 17th January 2021, 10:12 PM

Check the first page of this thread. Jens has placed links to all the mod descriptions.

DualTriode · 17th January 2021, 10:58 PM

Thanks I have got it now.

popeman · 24th January 2021, 04:45 PM

Please excuse my ignorance but it's almost impossible for me to read all 305 pages at the moment.

I've been looking in getting an audio analyzer and I'd like to ask if this is a product/project that I can still purchase and if so, where can I find more information like price,where to buy, etc...

Many thanks!

JensH · 26th January 2021, 07:38 AM

Unfortunately the RTX6001 has been discontinued. Your best chance of getting one is probably buying one from a member of this forum.

popeman · 26th January 2021, 08:02 AM

I see. Thank you very much JensH.

BTW, is this product somehow related?

RTX6001 Audio Analyzer with Multi-Instrument Full Package | Virtins Technology

Seems still available.

jan.didden · 26th January 2021, 08:09 AM

It is the same, but try to order it ;-)

Jan

17th January 2021, 10:05 PM	#3044
DualTriode diyAudio Member Join Date: Aug 2009 Location: Nor Cal	Shielding installation instructions? Hello All, Looking for help with the installation of the shielding kit for the RTX6001 that was mailed to me. Inside the box with the analyzer I have had the unopened envelope with the shielding inside. Are the shielding installation instructions posted here anywhere? Thanks DT

26th January 2021, 08:09 AM	#3050
jan.didden diyAudio Member Join Date: May 2002 Location: Westende Resort, BE coast	It is the same, but try to order it ;-) Jan __________________ Linear Audio - Articles - SilentSwitcher - Treg hi-voltage regulator - Hi-voltage delay unit - AutoRanger

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20th December 2020, 03:08 PM	#3042
zfe diyAudio Member Join Date: Dec 2014	My idea was to measure without headphone connected and add some capacitance in parallel so simulate the headphone. This way the stray capacitance and the input capacitance of the RTX6001 could be part of that capacitive load. Are there objection on doing so?

20th December 2020, 04:28 PM	#3043
JensH diyAudio Member Join Date: Jul 2009	The capacitance of the headphones is in the order of 100 pF, equivalent to an impedance of 160 kohm at 10 kHz, so I don't think that a balanced load impedance of 2 Mohm will be a problem. I built a KGSS amplifier some years ago. It has output resistors of 5k11 in series with each output.

17th January 2021, 10:12 PM	#3045
diyaudnut diyAudio Member Join Date: Feb 2015	Check the first page of this thread. Jens has placed links to all the mod descriptions.

17th January 2021, 10:58 PM	#3046
DualTriode diyAudio Member Join Date: Aug 2009 Location: Nor Cal	Thanks I have got it now.

24th January 2021, 04:45 PM	#3047
popeman diyAudio Member Join Date: Jan 2016	Please excuse my ignorance but it's almost impossible for me to read all 305 pages at the moment. I've been looking in getting an audio analyzer and I'd like to ask if this is a product/project that I can still purchase and if so, where can I find more information like price,where to buy, etc... Many thanks!

26th January 2021, 07:38 AM	#3048
JensH diyAudio Member Join Date: Jul 2009	Unfortunately the RTX6001 has been discontinued. Your best chance of getting one is probably buying one from a member of this forum.

26th January 2021, 08:02 AM	#3049
popeman diyAudio Member Join Date: Jan 2016	I see. Thank you very much JensH. BTW, is this product somehow related? RTX6001 Audio Analyzer with Multi-Instrument Full Package \| Virtins Technology Seems still available.