|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
In Reply to: Re: okay, and the winner is... posted by eagle1 on January 31, 2002 at 07:44:50:
Well, I did worry a little bit about stability before installing 637's. However, as it will take me longer to study the feedback arrangement of Black Cube than soldering the 637's, I simply went ahead and tried them out. Obviously, so far so good. I'll try 627's when I get the time.Look to me AD825/826 have the potential to be very good. However I have no chance to try them. The SMT single 825 is available from LC Audio as dual configured opamps. Maybe you can report back after comparing 627/637 with 825/826.
By the way, I seem to prefer BB (now part of TI) over AD equivalents. For instance AD746 was listed as OPA637 dual equivalent; and AD823 was listed as OPA2604 equ. on AD's cross reference list. However, in my system these two AD's were no match to their counterparts.
Just my thoughts...
-Ehien
Follow Ups:
Hello again Ehien,I'll try AD826 against 627, but it will take some times. I'll built a newer phono stage soon to incorporate the 50KHz pole and will go full monoblock, batteries PSU too. And no, I wouldn't buy the LC Audio soon, I have enough of op-amp here, there's no way I will pay someone to do a job I can do. But for begginer, the LC Audio solution is easy.
Me too, I prefer BB over AD equivalent. And I've only seen one BB chip going bad so far. AD is not bad, but doesn't give the same MTBF as BB.
Stability have more to do with PS lines than feedback. In my basic design, the OPA627 oscillate. I will fix that today and include it in the match.
Regards,
Daniel Trudeau
no decent op-amp should fail in any decent application! MTBF is a parameter that makes sense in the digital world!unless you are talking about how often a circuit that is on the fringe of oscillation will really oscillate. but this is more a question of design errors rather than op-amp quality
Hi Capslock,Like any digital device, it's a matter of alot of things. You should know that some manufacturers clearly annonce that there products isn't appropriate for life support. Of course, brand new, they should work OK. But because they know that they can't specify enough reliability in rough conditions and the way IC fails, they protect themself. BB products can be use in critical application, even if not in life support. That's what I mean by MTBF for op-amp.
Regards,
Daniel Trudeau
> Stability have more to do with PS lines than feedback. In my basic design, the OPA627 oscillate. I will fix that today and include it in the match.You meant only for OPA627, right? Otherwise for OPA637 since it's not unity-gain stable one has to take care of both feedback (thus gain) and PS to ensure stability.
nt
This post is made possible by the generous support of people like you and our sponsors: