PCB for Nuuk's Buffer

[dsavitsk]

To anyone who has not seen it, Nuuk's buffered passive pre can be seen at http://myweb.tiscali.co.uk/nuukspot/...nclonepre.html

While it is not a difficult design to build on breadboard, a PCB is always easier. Attached is a copy of a slightly modified schematic which adds an input resistor and an input cap as well as small rail caps. You can search this forum to find explanations for each of those changes.

[dsavitsk]

So, I decided to make said PCB design. The input cap is sized for either a Blackgate N series 1uF cap, or a Solen 1uF cap. The output cap is sized for a 4.7uF Solen cap. The rail caps are sized for Wima 0.1uF caps. All resistor spots are over sized such that they hold Kiwame 2W resistors.

As soon as it seems that the board is correct, I'll post the ExpressPCB files.

edit: nothing like posting to find stupid mistakes. corrected pcb attached.

-d

[tobias_svensk]

Hey dsavitsk! Nice work

I'll bet many would like to build that one.

Actually I found that circuit interesting myself so I did a "mono"-pcb some weeks ago to have as a addon-pcb for my "Mr_ED" pcb, have't build it though.

http://www.ettnet.se/~tobias/diy/lm3886/gcbuffer1.jpg

[carlmart]

Originally posted by tobias_svensk


http://www.ettnet.se/~tobias/diy/lm3886/gcbuffer1.jpg

Any chance to get the actual pcb layout?

Why didn't you try to include the discrete regulators at Nuuk's too?



Carlos

[tobias_svensk]

Originally posted by carlmart

Why didn't you try to include the discrete regulators at Nuuk's too?

Are you asking me or dsavitsk?
I have regs onboard.

http://www.ettnet.se/~tobias/diy/lm3886/gcbuf.jpg

Cheers

[dsavitsk]

Originally posted by carlmart
Why didn't you try to include the discrete regulators at Nuuk's too?

I guess that's for me ...

Partly to keep the PS seperate, partly cause I ran out of room. ExpressPCB has a deal where one can get 3 boards of this size for $51. Any bigger, however, and the price goes up.

Anyway, here is a small change to add the ability to use Blackgate N 4.7uF caps on the output.

[carlmart]

Originally posted by tobias_svensk


Are you asking me or dsavitsk?
I have regs onboard.

http://www.ettnet.se/~tobias/diy/lm3886/gcbuf.jpg

Tobias,


Yes, you have regulators. But they are LM3X7s. So I asked why you didn't use the discrete ones suggested by Nuuk.



Carlos

[tobias_svensk]

Aha.. I didn't read that slow enough

I haven't seen that discreet reg. thing yet, I found the schematics on the "A buffered IGC."- tab.

Cheers

Edit:
Ok looked at it, interesting. Don't know if I could fit it on that board if I want it to fit above my Mr_ED will try maybe

[dsavitsk]

Here are a few layout updates.

[Gcollier]

While we are looking at Nuuks buffered pre I figured I would post a pic of my board based on his discrete regulator. This was built following the schematics from his site. As it is, it puts out +/-16.5V rock steady. The LM317/337 "preregulate" the voltage to 22V before it hits the discrete regulators. I have seperate grounds for the +/- rails, although this is likely unnecessary.
This is going to be connected to my OPA637/BUF634 preamp that I completed a while back.

G.