Barco neck board mod.

gregstv Full Member Posts: 244	Barco neck board mod. Aug 27, 2016 18:48:01 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by gregstv on Aug 27, 2016 18:48:01 GMT -5 Has anyone tried replacing the OPA688 with a OPA698 on the 9 series neck board? On the spec sheet the 698 is an upgrade of the 688.

gjaky
Master Tech

Posts: 642

Barco neck board mod. Aug 28, 2016 1:56:13 GMT -5

Quote

Post by gjaky on Aug 28, 2016 1:56:13 GMT -5

I haven't done it, but looking at the datasheets the differences between the two are marginal, so I'd not expect much difference. The only reason those opamps were used is because of their limiting feature. The best would be if you could omit that ic entirely and substitute the voltage limiting feature with a DIY circuit around the CF opamp (then no signal inverting is needed etc.).
My experience tells me that simple part swaps rarely give noticeably better result in the end.
And still the output hybrid is the real bottleneck...

gregstv Full Member Posts: 244	Barco neck board mod. Aug 29, 2016 1:39:35 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by gregstv on Aug 29, 2016 1:39:35 GMT -5 I have some so I will have a play. I have found that improvements are small with each change but they all work together it makes a bigger improvement.

gjaky Master Tech Posts: 642	Barco neck board mod. Sept 10, 2016 11:41:36 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by gjaky on Sept 10, 2016 11:41:36 GMT -5 BTW I just realized that I have a 909 neckboard here that has OPA698 by factory, it is on a board made in 2006.

Casethecorvetteman Master Tech Posts: 1,219	Barco neck board mod. Sept 14, 2016 1:24:36 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by Casethecorvetteman on Sept 14, 2016 1:24:36 GMT -5 I have two different neck board types here, ill have a look.

Casethecorvetteman Master Tech Posts: 1,219	Barco neck board mod. Sept 14, 2016 1:28:07 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by Casethecorvetteman on Sept 14, 2016 1:28:07 GMT -5 All mine have 688

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Post by gregstv on Aug 27, 2016 18:48:01 GMT -5

Post by gjaky on Aug 28, 2016 1:56:13 GMT -5

Post by gregstv on Aug 29, 2016 1:39:35 GMT -5

Post by gjaky on Sept 10, 2016 11:41:36 GMT -5

Post by Casethecorvetteman on Sept 14, 2016 1:24:36 GMT -5

Post by Casethecorvetteman on Sept 14, 2016 1:28:07 GMT -5

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