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DC offset inside loop on SSB01??

Started by qusp, December 17, 2009, 03:23:56 PM

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Hi there, I am thinking about implementing the SSB01 as buffer in a soon to be released portable amp by ibasso that has +/- 9v and places for several buffers as well as the opamps. Basically you can buy this amp fully loaded with BUF634 and OPA637bp/au etc and blackgates etc, but you can also buy it without any through-hole caps, opamps or buffers. i'm getting the latter and in planning the parts for the guts I thought of using this great little buffer. I have been asked by another member of the group how much DC offset to expect on the inside of the loop; can anyone tell me this or across which points on the board I would measure this myself.? I have built a couple of these up already, but at this stage have not implemented them, I will do in the next couple of days, but I wondered if there was a way to test this out of circuit or if anyone knows this already??

thanks for reading


The SSB01 itself has a few mV offset if the input is shorted but you have also an input bias current which will add (or cancel) the offset. If the buffer is inside a feedback loop the buffer itself won't contribute to any additional offset.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff


excellent!! thanks, thats all I needed to know. I think 2 of the buffer spots are within the feedback loop of the opamp and the other 2 not. will see when it gets here. I dont have the BOM or schematic, they should be supplying this shortly.