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!
Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance
- mediatechnology
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Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance
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.
Thanks in advance.
- mediatechnology
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Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance
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.
I don't have enough ZTX789 to get a meaningful hFE spread.