Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance

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mediatechnology
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Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance

Post by mediatechnology » Wed Nov 20, 2019 5:48 pm

Wow. My guestimate of 5.5 was pretty close.

The ZTX689 may be better overall as a mic preamp simply due to its higher gain (lower Ibias) and lower Cob.

Thank you Bill and Hans!
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al2002
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Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance

Post by al2002 » Mon Jun 29, 2020 3:32 pm

Is any rbb data available for the pnp ZTX 789? Also, has anyone measured the hfe variations for a batch of 689/789s? Would be useful to know.

Thanks in advance.

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mediatechnology
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Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance

Post by mediatechnology » Thu Jul 02, 2020 3:42 pm

I would have to work backwards from the noise measurements but the rbb' of the ZTX789 is between the 5Ω rbb' of the ZTX689 and the 2SB737's 2Ω rbb'.

I don't have enough ZTX789 to get a meaningful hFE spread.
https://ka-electronics.com

“Diet, injections, and injunctions will combine, from a very early age, to produce the sort of character and the sort of beliefs that the authorities consider desirable, and any serious criticism of the powers that be will become psychologically impossible.” – The Impact of Science on Society (1953) by Bertrand Russell, p.50

Dr. Sherri Tenpenny Exposes 10 Deadly Dangers of Pzifer/Johnson & Johnson Covid-19 Vaccines: "This is a well-designed killing tool." https://waynekirkwood.com/content/Docto ... accine.mp4
Plandemic Series: "Pland3mic - Indoctornation" https://waynekirkwood.com/content/Pland ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://waynekirkwood.com/content/Plandemic.mp4

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