On Wed, 2 Mar 2011 14:55:18 -0800 (PST), Fred Bloggs
wrote:
On Mar 2, 4:33*pm, John Larkin
wrote:
On Wed, 2 Mar 2011 12:03:38 -0800 (PST), Fred Bloggs
wrote:
On Mar 2, 11:40 am, John Larkin
wrote:
I've always sort of liked the classic "GE" tape head/mic preamp
circuit:
ftp://jjlarkin.lmi.net/GEcircuit.jpg
but it occurred to me that it might also make a nice headphone amp...
ftp://jjlarkin.lmi.net/GE_headphone_amp.JPG
Audio tends to be nonsense, but at least the audio guys have fun
playing with circuits, whether they make a lot of sense or not.
John
Bizarre??? Just a standard buffered input CE with negative feedback DC
bias to stabilize the operating point against Vbe and reverse leakage
collector current change with temperature- a textbook circuit...
Which textbook?
John- Hide quoted text -
- Show quoted text -
Just about any textbook that goes into bias point sensitivity analysis
of transistor circuits- you remember the S- functions, mainly ICQ
stability. The big three were HFE, VBE, and ICBO. Then the rest of
your circuit is just ac-bypass and the shunt-series feedback for
signals. I've seen it dozens of times.
I bet you haven't seen the bipolar+mosfet version, with inductive
pullup, used as a power amp.
John