Monday, 5 May 2014

Axess BS-2 Buffer

And seeing as I'm doing little ones tonight, this is the buffer section of the now discontinued (both product and company) Axess BS-2 Buffer/Splitter, and for once isn't just a rehash of a generic unity gain buffer (although to be fair none of these are going to be too far removed).

A charge pump gives the NE5532 a +/- 9V supply and so it is running with a 18V swing.  I'm not sure what benefits you get from running a buffer at a higher voltage, but I'll leave that for those building it to judge.

The trimmer will let you tweak the gain to make sure you're at unity, or wherever you want to be.  If you increase that trimmer to say a 5K then you can get a boost with your buff.  Note that the charge pump IC is mounted upside down from the norm.

Info about the original:
The BS2 has been designed as a solution to several problems that we’ve solved using custom-made buffers/splitters over the past several years. As a buffer, the BS2 should be used as early in the signal path as possible. Ideally it should be the first thing your guitar plugs into to, but unfortunately that can’t always be the case. Some Fuzz and WAH pedals do not like to be fed with a buffered signal. If you find these pedals don't sound right with the buffer in front of them, simply connect the buffer after these devices. In this situation, it would be ideal if these pedals had true bypass switching to ensure the BS2 gets the best possible signal it can... Using the BS2 in this application will prevent the loss of (1) signal level, (2) high end frequency response and (3) low end punch that is caused by cable capacitance and poorly designed input stage/circuitry of some effect pedals.



11 comments:

  1. I see one cut too much, second one on the upperleft side of IC2.

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  2. In light of recent events concerning operation yew tree you may want to edit the first 8 words of your description........ooer missus ;-)

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    1. Haha. "It's a fair cop guvnor"

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  3. Any plans for an updated layout that includes the split and iso'd outputs? Would like to give it a try for my first build.

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  4. Where can I run a wire to tap into the 18v? I'm trying to compare this layout with the 9v to 18v. I think the 18v comes out from pin 3, through 10uf, and out comes 18v, but I'm not sure.

    I want to build a buffer + EP Booster, both running at 18v! :D

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    1. This comment has been removed by the author.

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    2. Oops, according to the pinout it comes out of pin 5! Would that mean I can run a wire from 7660s pin 5 to my EP booster voltage in?

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  5. Just noticed this is unverified. Worked fine for me!

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  6. This comment has been removed by the author.

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  7. Hello :)

    I've just finished build one.

    It's seems ok, but only think is a little bit strange.

    There is a little humming ... It's not a problem with the trimmer, because the humming still here what ever I tune it.

    Any idea ?

    thanks.

    ps . I apologize for my english ;) (From France)

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