3 stage LIN topology - NFB tappings?

[albin]

got the t shirt,

hello everyone
same angst here.bugged me to bits.In the end I realized a pcb was beyond me.I bought some spools of thin solid core and made six "sprays" by twisting one of end of lots short lengths together ie power earth + -
&low power + -
Using a separate wire for every power or earth node I built my amps without a pcb at all.
I used 10 ohms to link low power earth to power earth.
Seems to me now like I was solving my problems with a soldering iron(eh Daniel)
15 years ago tho Karl
ps I used coax for powering the output trannies
regards
max

 

[Mooly]

🙂 I still look in disbelief at those Wireless World PCB's.
Seems like you have found way that works well for you.

 

[albin]

complexity

hello Karl
I was kind of dazed and confused today.It was,nt the self amps I built,mine were much simpler Margan knock offs.My post was OT really,except maybe for the exasperation of everything,even the pros get it wrong,google"naim mr tibbs"
regards
max

 

[Mooly]

Who's Mr Tibbs ?

 

[Mooly]

Oh-- That Mr Tibbs 🙂
I keep saying it, analyse grounding and signal paths and returns as a DC problem and all is revealed. Well nearly all !

 

[albin]

mr tibbs

hi
have,nt a clue,he sure sorted those power supplies though.
max

 

[tiefbassuebertr]

Hi,
Doug Self makes a big play on where to tap off the upper leg of the NFB from the output. But I cannot recall anyone suggesting where best to tap off both the upper leg of the NFB and the lower leg of the NFB.

When the Amplifier is drawn in the same format as a balanced input to unbalanced output, it becomes obvious that the output leg could tap off the speaker terminal (but before the stabilising Thiele network) or as Dr Cherry suggests between the Zobel RC, but where should the lower leg go to?

All the way back to the source? then NFB compensates for the interconnecting cable?
or locate the lower leg resistor at the source component (and the source resistor controls the amp gain, =input 3),
or tapping into the RCA ground at the input to the amplfier casing (= input 1),
or as conventionally done, just to the PCB signal ground point? (=input 2)

Which is likely to give best results and which may be adversely affected by long wires?

After reading this thread I am confused. I don't understand possible advantages for better results when the serial network to the speaker (L1/R5) is within the NFB loop.
check out also this thread:
http://www.diyaudio.com/forums/soli...nagement-power-amplifiers-what-royal-way.html