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
- Posts: 4688
- Joined: Sat Aug 11, 2007 2:34 pm
- Location: Oak Cliff, Texas
- Contact:
Re: Low Noise Transistors: ZTX851 versus ZTX689B Noise Performance
https://ka-electronics.com
Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4
CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm
Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4
CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm
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
- Posts: 4688
- Joined: Sat Aug 11, 2007 2:34 pm
- Location: Oak Cliff, Texas
- Contact:
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.
https://ka-electronics.com
Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4
CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm
Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4
CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm