Is opa111 unity gain stable?
Apr 27, 2006 at 6:01 AM Thread Starter Post #1 of 6

motu

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I've done some googling, but didn't manage to find any clear information on this. Planinng on testing 3xopa111bm on my ppa.

Thanks for tips
 
Apr 27, 2006 at 7:14 AM Post #2 of 6

thedoctor

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Quote:

Originally Posted by motu
I've done some googling, but didn't manage to find any clear information on this. Planinng on testing 3xopa111bm on my ppa.

Thanks for tips



yes, the OPA111 are unity gain stable. but thinking that if your PPA is in unity gain, then why not remove the Opamp gain stage completely, leaving only the diamond buffers?

there's no saying that the OPA111 isn't stable in unity gain in the datasheet, and there's some application circuit (also in the datasheet) showing the OPA111 working in unity gain, so guess it's stable.
 
Apr 27, 2006 at 7:23 AM Post #3 of 6

MisterX

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Quote:

why not remove the Opamp gain stage completely, leaving only the diamond buffers?


I think his signature answered that one before you even asked it.
very_evil_smiley.gif
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Quote:

PPA (BG, 637BP+627BP, GM Gen2 DB)


Since we are asking silly questions I have to wonder why anyone would use a opamp that sounds worse then a OPA134 in a ppa.
evil_smiley.gif


Regardless of the answer to that:
Yes the OPA111 is unity gain stable
 
Apr 27, 2006 at 12:44 PM Post #4 of 6

tangent

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Quote:

Originally Posted by thedoctor
thinking that if your PPA is in unity gain, then why not remove the Opamp gain stage completely, leaving only the diamond buffers?


The ground channel in a PPA always runs in unity gain. I'm sure that's why the original poster asked.
 
Apr 27, 2006 at 1:28 PM Post #5 of 6

thedoctor

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Quote:

Originally Posted by tangent
The ground channel in a PPA always runs in unity gain. I'm sure that's why the original poster asked.


LoL.. totally forgot bout that. silly me. guess those solder fumes really got into my brains this time.
580smile.gif
 
May 1, 2006 at 7:49 PM Post #6 of 6

motu

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Yup, that's why I asked, thanks for clarification.

Regarding why, the metallic cased opa111 seems to be greatly promoted in chinese hifi forums, claiming them to be a lot more musical than opa627, just wanted to see for myself.
 

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