Composite Buffered gc

[Hugh M]

Hi Guys
I did a search and couldn't find anything on this specific design so decided to start a thread to get some better informed input.
I built the cct below and it works but I haven't tried it on my home system. Here at work it seems to sound pretty good.
Based on the composite config from the BB ap bulletin

http://focus.ti.com/lit/an/sboa002/sboa002.pdf

I had planned on buffering my IGC's and came accross this and decided to try it. I'm sure the component values need to be optimized and of course the 627 requires regulating and such. The test version(listening to it now) is running off of +- 18 volts from my bench supply and is using the TL071 I put in so as not to blow up a 627.
It will be a couple of days before I get it ready to try out at home as I have to get some lm317 regs for the 627 as the 78/7915s have max voltage of 35 and my supply is +-39.
I would be interested in any input
Thanks
Hugh

 

[digi01]

MISSION POSSIBLE.

FYI,I have a same design.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=28341&highlight=

ZANG

 

[peranders]

It's not mission impossible but almost....

Hugh, before you can go any further you must draw up a Bode plot to see if there are any possibilites for stability.

The second stage, your LM3886 must be _much_ faster than OPA627.... is that the case