Continuing from my last post here.
I was planning to integrate my passive pre into the audio buffer http://www.bursonaudio.com/burson_buffer_160.htm
and turning it into a low gain preamp that drives my power amp better yet retains the transparent sound I’ve come to love so much. On the last weekend of the holiday, I finally had a chance to sit down and carry out my plan.
Adding a volume control to the audio buffer and turning this incredible little gear into a single ended class A low gain pre amp was easy. However, during the mod, I have learned a few tricks that I think are useful for others.
This is what’s involved:http://i50.tinypic.com/t83dl1.jpg
I removed the top plate and removed the input selection nob.http://i46.tinypic.com/2z68g0x.jpg
Then unplugged this signal output cable from the PCB and striped off one end.http://i49.tinypic.com/xc216b.gifhttp://i45.tinypic.com/2qlzxnc.jpg
Striped off one end in the same way and connected them as per my drawing (Paint Brush is the only graphics program this senior knows how to use…. So don’t laugh)http://i50.tinypic.com/2u7stb7.jpg
The stocked AB-160 had an input selection in front and I had to replace it with an ALPS pot.http://i50.tinypic.com/rbh3qa.jpghttp://i50.tinypic.com/1y5vtd.jpg
To fit the pot properly I had to modify the front plate slightly by enlarging the hold on the left to 8mm. Watch out for the wires and PCB on the other side when drilling!
I have kept the input switch and the two set of input sockets. I think I will move the switch onto the back plate and change it over to a rocker switch later.
But for now, with shorter signal path and less cables, my low gain passive pre is sounding better than ever. It is still very transparent but the low gain bought the bass under control. Mid also sounds fuller and sweeter compared to just the passive. Put it simply, my little preamp now sounds and looks perfect!
If you already have a Burson Buffer and you don’t need a lot of input options then you should consider this weekend project.
I must thank Jack Thomas from Burson Audio for his assistance. Jack has been more than helpful and went out of his way to provide information and supports throughout my project.