Video op-amps for audio?

[Freq Band]

I come across several video op-amps (board pulls) . I've heard
Jim Williams of Audio Upgrades likes to use these.
http://www.audioupgrades.com/pl1.html

What's to keep in mind when reading the datasheets?....or choosing for a project?

I also ask, because I've got a handfull of AD811 's, and others.

http://www.analog.com/UploadedFiles/Data_Sheets/AD811.pdf

=FB=

 

[dale116dot7]

Stability, grounding, decoupling. A video op-amp is well into RF territory here. Other than that, they can work for audio. One of TI's headphone amplifiers (TPA somethingorother) is based on a video op-amp/line driver. But you can't go throwing 100k feedback resistors in there. Make sure you have access to a good, high-frequency, high-bandwidth 'scope to make sure you have no oscillations or ringing. Impedances and trace lengths need to be very short. SMD parts work better from an RF standpoint so you might need to think about that.

-Dale

 

[Svart]

LOVE THEM.

but I've mentioned their usage before and been told in nice ways that you cannot use them because you are not conforming.

I digress..

Watch out for gain structures and feedback of course. Watch out also for the TYPE of feedback needed. A lot of video/highspeed opamps are current feedback or a hybrid type and need totally different values for the feedback networks. Also, CCF opamps cannot be used with a cap in the feedback, read up on it as I don't have time to explain here right now.

Watch your INV and NI usage too.

Read your datasheets and appnotes carefully.

 

[solder_city]

sounds like someones got an analag style persecution complex.


i dont recall anyone saying 'conform' and dont use video opamps. i do remember a couple of people pointing out some potential pitfalls and advising caution/careful layout and you getting all bitchy and defensive about it.

 

[ciminosound]

Conform or be assimilated! :evil:

If you can make it work and it SOUNDS good (and behaves properly technically on the bench to a reasonable degree) that's what's really important here! :thumb:



:sam: :sam:

 

[Svart]

you getting all bitchy and defensive about it.

lies. No one got bitchy or defensive. Simply stating the facts.

There have been plenty of folks giving me **** for trying to use highspeed ICs, I didn't specifically mention forum threads, PMs, emails or real life conversations ( what?? conversations other than the forum?? NO WAY!!) so for you to assume I meant any specific instance and your immediate jump to arms is indeed what I am talking about.

Calling all Witch hunters to this thread!

 

[khstudio]

I did not find Svarts post offensive in the least.

The truth is they can be sensitive bastards so you have to know what your doing. I spoke with Dave Derr from Empirical Labs about 2604's and he mentioned having stability issues & he seems to know what he's doing.

Sorry to butt in.

If you can make it work and it SOUNDS good (and behaves properly technically on the bench to a reasonable degree) that's what's really important here! Heck Yeah!

Good point

Kevin