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DIY Passive Pre & Burson Buffer 160

Hi Guys,

Following up on my DIY passive preamp post and thanks for all the comments and suggestions from everyone here.

I have just returned from my two weeks holiday. Before my departure I have contacted Burson and they have made me a special offer after realizing what I wanted to do with their buffer. The buffer 160 arrived last week and was picked up by our neighbor who luckily was not an audiophile. After spending the last couple of days listening to it, I must say that the combination of the buffer and my DIY passive is no less than amazing!

Using the buffer with my passive is a god send. The buffer bought back a lot of micro detail that once disappeared when playing only with my passive. Midrange texture is now a killer. It really bought a vocal to live. The top end is fuller, sweeter and completely transparent. The bass kicked in with control and extension. This is simply the best sounding preamp setup I have ever heard!

My friend brought over his big gun Rotel RC1070 and he too was shellshock by the result.

But there were drawn backs: Non of them performance related, only on functionality.

1. No remote control
2. Only two inputs at this stage.

What is next?
Well, I hope to add my ALPS pots inside the buffer. That way I don’t need a separated box for my passive and eliminate all unnecessary cabling J I want to also somehow add an input selection switch on the back for additional inputs, but that can be challenging as the Burson buffer case is 6mm thick and I really don’t want to damage this refined case.
chatta
singleendedsingle
664 posts
 
That's interesting. I was just reading over their blog and seems like there are a lot of people who have modified the Burson buffer into a preamp.

Here is one:

http://bursonaudioblog.blogspot.com/2009/12/diy-passive-preamp-with-burson-audio.html

If the buffer is transparent then I think that 3db of gain is very useful.
chatta OP
314 posts
 
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.gif
http://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.jpg
http://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.

PS.
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.
face
516 posts
 
I agree with your impressions of the stock unit, I demoed one only a few days ago.
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