|
Home | Forums | Rules | Articles | diyAudio Store | Blogs | Gallery | Wiki | Register | Donations | FAQ | Calendar | Mark Forums Read |
Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc. |
|
Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving |
![]() |
|
Thread Tools |
![]() |
#1 |
diyAudio Member
Join Date: Jun 2013
|
![]()
Hi,
Anybody knows what is the different in those two types of NFB? What are the advantages of putting NFB ground capacitor in the position A? I saw that NFB in some cassette decks playback amplifier and wonder why they put capacitor at that position. Thanks in advance for answers! |
![]() |
![]() |
#2 |
diyAudio Member
Join Date: Feb 2017
|
NFB B is the usual circuit (with a small cap over the feedback resistor), a separate RC series branch controls the hf-feedback better. NFB A is to bypass the large groundcap (with lesser hf bandwidth) so the hf feedback works even better.
__________________
Y/Yo=(1-X/Xo)exp2 <> Y/Yo=(e)exp(X/Xo){Xo=kT/q} |
![]() |
![]() |
#3 |
diyAudio Member
Join Date: Jun 2013
|
Tnx MarsBravo, that sounds reasonable.
There are even more variations of NFB, one Grundig phono preamp have output cap included in the feedback loop. |
![]() |
![]() |
#4 |
diyAudio Member
Join Date: Mar 2004
Location: Budapest, Hungary
|
Whatever you include in the feedback loop forward path, its nonlinearity will be reduced by the NFB. Whatever you include in the feedback loop feedback path, its nonlinearity will appear at the output.
|
![]() |
![]() |
#5 |
diyAudio Member
Join Date: Mar 2003
Location: Haarlem, the Netherlands
|
There is less signal current flowing through the electrolytic capacitor in case A, so it will distort less (for a given capacitor type).
|
![]() |
![]() |
Thread Tools | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Commercial Solid State Amps with jumper controlled Modes "without NFB" and "with NFB" | tiefbassuebertr | Solid State | 12 | 28th February 2014 05:27 PM |
Source/emitter global NFB amp | jcarr | Solid State | 48 | 19th December 2008 09:22 PM |
NFB and Electron Propagation (from Blind Testing) | mikek | Everything Else | 135 | 29th March 2003 09:31 PM |
NFB volume control | Joel | Tubes / Valves | 5 | 13th December 2002 04:24 PM |
New To Site? | Need Help? |