> we are trying to do a crazy low noise FET amp and sneak it under the radar of the current establishment......
I think you did not mean AD8429 ?
150nA input bias current does not sound like FET input ??
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Good to see this stuff, the FET amp is on the drawing board but I don't see improving on the 2.9nV of the AD743/5. The 50pF input capacitance of that part limits the applications.
A new alternative to 2SK170 / BF862 ?
(Search at the forum return no hits .....)
See also :
Measurements Rate SMT Low-Voltage n-JFETs Under Consistent Conditions | Power content from Electronic Design
Patrick
(Search at the forum return no hits .....)
See also :
Measurements Rate SMT Low-Voltage n-JFETs Under Consistent Conditions | Power content from Electronic Design
Patrick
Dimiti's measurements and the DS don't match. He measured 3nV at 1mA Id, and it should be almost the same as BF862. It seems the graph does not match the table?
Yes, the 743 die is too big (someone here uses it as an avatar).
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Low noise is oddy on topic tho. I still dream one day of finding an MC2000 on ebay for non-silly money. No logical reason but I want one. And I believe JC made one of only about 3 phonos that could handle its output without a transformer.
The MC2000 was nuts. Output of 0.05mV, compliance of a VST-V and possibly the last of the MCs to be truly flat in FR. Oh and looked cool with its ceramic body. It dares you to try and make it actually work.
The MC2000 was nuts. Output of 0.05mV, compliance of a VST-V and possibly the last of the MCs to be truly flat in FR. Oh and looked cool with its ceramic body. It dares you to try and make it actually work.
Ok thanks, there are a couple of things, I'll get back to you on that in a while.
You sneaking 'foreigner' projects past the boss gives me a smile.
In the mean time, it's high time I extract the digit and complete my T&M bench in the garage.
Ideal environment...steel construction, away from RF sources, I can run the whole room on multiple isolated or regenerated AC power feeds and run multiple dedicated earthing stakes.
I'll see what I can come up with....maybe meaningful measurements of BQP too
.Dan.
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Dimiti's measurements and the DS don't match. He measured 3nV at 1mA Id, and it should be almost the same as BF862. It seems the graph does not match the table?
Yes, the 743 die is too big (someone here uses it as an avatar).
I just now measured a BF862 N-jFET with Quan-Tech ----
10Hz 100Hz 1KHz 10KHz 100KHz
4.5nV 1.5 .75 .6 .5nV at 5v D-S/6mA
The noise is worse at 1 mA.
THx-RNMarsh
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I have an original Kondo Audionote Io. Similar output, but the lowest I ever had was an ART (Italy) MC1 (Be Yamamura…..no yoke, very fragile - which is why I no longer have it
). After hours of set up it was probably the best cartridge I have heard.Another measurement... same 5V/6mA and same p/n:
10nV 2.7 .8 .7 .5
[Approx 30nV at 1mA at 10Hz ]
Fantastic device above 100Hz. Even for this device and others which are worse, the noise rise at 10Hz might best be rolled off/attenuated if going into a sensitive ADC.
THx-RNMarsh
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Richard - are your BF862s out of HK or mainland China? Waly found the latter had poorer 1/f noise corner. There's a code on the package indicating provenance.
Waly's post about BF862 markings: 2Ap means HK, 2Aw China.
http://www.diyaudio.com/forums/parts/229827-nxp-bf862-warning.html
http://www.diyaudio.com/forums/parts/229827-nxp-bf862-warning.html
Lets stir the pot a bit
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Transistors :: NXP Semiconductors
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