Op amps; Burr Brown or fairchild?

  • Thread starter Thread starter darrin_h2000
  • Start date Start date
I just picked up a 2nd Rane unit (MLM82a) to go along with my current MLM42. I checked the schematic and both use the same INA163.

The nice part about the new Rane is the A+B double bus architecture it uses. Both Ranes are intended for live performance use, so I can use the B bus for micing instruments and direct them to a separate QSC power amp and speaker system to avoid polluting the voice system.

As for caps, I thought ceramic types were the ultimate in cheapness... this is what the instrument manufacturers use in guitars and basses. It is my understanding that film caps are the most desirable. I assume I can judge by price...

:D
 
The OP275 is a "Butler" front end...

Dan Kennedy said:
There is virtually no bipolar opamp application that a FET input can't substitute...
Click to expand...

Yeah...what Dan said!

FETting over everything in Austin,
McQ

P.S. - Besides, the '275 has the input currents of a FET-type, with the long-tailed pair collector currents of a nice bipolar...this is not your father's TL072(type) opamp!
 
Yeah, don't use ceramic caps in the signal path, use film types.

A good place to start is the input caps. Unfortunately they're likely to be too big to be replaced by film caps. A less expensive way to go is to do what Scott Dorsey usually suggests: bypass the electrolytics in the signal path with small .1 u film caps. I had great success with this on an ancient Behringer Ultragain 2000 (the old one without the tube). You can also replace the input electrolytics with "real" bipolar electrolytics. The data sheet of the INA163 actually suggests the use of bipolar elecrolytics as input caps. Unfortunately most manufacturers spare the expense.

Good luck with your mods!
 
It's always amusing to see "newbie" attached to the posts of any (truly) pro audio heavyweights!

How do you guys rate the Burr Brown OPA2604's for use in a mic pre? I'm planning to have a mod done on a DBX 760X shortly.

Chris
 
chessparov said:
...attached to the posts of any (truly) pro audio heavyweights!
Click to expand...
Mr. Chessparov:
I may have my issues with Mr. Kennedy, but I don't find his weight to be one of them! It's too bad you've chosen this forum to point out Mr. K's propensity for water retention...:)

How do you guys rate the Burr Brown OPA2604's for use in a mic pre?
Click to expand...
I'll assume "guys" includes any of us so I'll take a stab at it...too noisy for main gain stage application (10nV/rtHz), but good for any "downstream" amplifier function. One of my clients had all 12 of his RNCs outfitted with these (instead of the stock OP275) and swore by them. Personally, I never heard much of a difference. Nice distortion spec/performance, fairly tame in application (i.e., no additional precautions for many of the typical sockets) and pricey. Nothing I'd go out of my way for, but YMMV.

(Op-)Amped in Austin,
McQ
 
So who are you calling retentive, beerbreath??

I'm with you on the 2604. I've found it to be mildly unpredictable, stability-wise.

The 275 just tends to tick along. For better performance I like the 627/637 from BB, but make sure you've got a gold credit card.
 
Well at least I didn't say "titans of technology".

Thanks for the feedback on the OPA 2604.

Chris
 
You must log in or register to reply here.
Back
Top