Op amps; Burr Brown or fairchild?

  • Thread starter Thread starter darrin_h2000
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darrin_h2000

darrin_h2000

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I was thinking about modding a pre I have and I was wondering which one would be a better choice.

This is a question suited for engineers who have done this type of thing, so please tell me how your project turned out.
 
It has to be a proper match or you will have problems.. what are you replacing, exactly, down to the part number? What pre?
 
Burr Brown Op-Amps...

and remember, you can get up to 8 of them for free from www.ti.com

sign up to TI&Me and order them as samples :)

if have any questions regarding the burr brown op-amps etc, feel free to email me, or leave a Q here. I'll be glad to try and answer them.

cheers

R
 
Actually the question was a little loaded, the Preamp I was considering doing this mod to already has the Fairchild op amps, I was wondering if the Burr Brown Op amps would be a significant Improvement over them.

The unit is a Yamaha Mla7 and the current opamps inside are Fairchild #NJM4558DY and they are dual 8 pin configurations according to the online schematics.

I only asked about this because some of the top pres in the buisness are Fairchild pres- and Maybe they are connected somewhat.
 
Okay guys, we now know who made the first IC-Op-Amp, but - Pop quiz...

who made the first IC? and which company did he work for?

:)

Letters on a postcard!!
 
Don't have no postcard. :D

Jack Kilby, Texas Instruments.

At least thats the most often quoted answer to this question. It could of course be a TI propaganda victory. :p
 
I think that Fairchild amp is a pretty old design. Something like the TLE214 might be an improvement. Just make sure whatever you use has bipolar inputs like the Fairchild - not FET.

barefoot
 
TI - Propoganda???

Nahhhhhhh.... NO such thing in the SC industry...

Although I will say this... TI's Op-amps are used in mackie mixers...

I'm afraid i'm not really allowed to say any more. :D

cheers

R
 
4558 is a pretty generic bipolar opamp.

A good safe substitute that has much better output drive current (important in EQ circuits), good phase margin (ditto),
lower offset, better bandwidth, yet not really suseptible to oscillating in bad PC layouts is the Analog Devices OP-275.

It's noise characteristics are not enough worse to worry about, except perhaps as the summing amp, in which case use the 5532 or if you feel rich use a Linear Technology LT1468. Or whatever their dual version is.

The 5532 is also a reasonable substitute. Not classy in today's "what IC is hot" debates, but a good TI '32 is cheap, fast, quiet and reliable.

Remember, the 4558 is a $.15 opamp
designed to be a cheap and dirty plug and play audio device, the 5532 is $.45 and was designed for serious audio. Even in the '70's they knew what was important at Philips where it was designed. In a Mackie, or Kelsey, or other commodity mixer, that couple of pennies mattered, but it doesn't to the modifier.
 
I'm an idiot, and in no way an engineer, and know very little if any about electronics. So this question may be REALLY stupid.

From the above information I get this question.
Can I replace pre-amps in my Mackie 1604 VLZ with better ones? (like this burr-brown that everyone talks about) It would be cool to do it to like 4 channels on the board to be able to have a different sound.

Please forgive my ignorance on this matter.

H2H
 
Thanks Mr. Kennedy, Im really honored you chimed in with advice on modding this unit. Ill look into the lt1468, and if thats not availible the 5532, Ill have to check first if the pinout is the same.

Hard 2 hear ; I think that someone said earlier that the makie allready used Burr Browns.
 
Dan Kennedy said:
.....A good safe substitute that has much better output drive current (important in EQ circuits), good phase margin (ditto),
lower offset, better bandwidth, yet not really suseptible to oscillating in bad PC layouts is the Analog Devices OP-275....
Click to expand...
NE5532 and the LT1469 might be appropriate replacements, but I wouldn’t recommend the OP275 in this case. The OP275 is a good op amp, but it has JFET inputs and possibly would not work right in a circuit designed for bipolar input amplifiers.

barefoot
 
Hard2Hear said:
....Can I replace pre-amps in my Mackie 1604 VLZ with better ones? (like this burr-brown that everyone talks about)....
Click to expand...
You would have to find out what chip(s) the Mackie is using then look on the TI (Burr-Brown) website to see if they offer a pin compatible replacement.

barefoot
 
After checking On-line I found out that the suggested opamps didnt pinout, but I did some reasearch and found a couple of Burr Browns that did. OPA2604, and OPA2134, the specs on these way out do the specs of the 4558 ( which the mic pre has now and its pretty good )

Anyhoo I ordered samples from TI for free and will recieve them in a couple of days. the only problem now is they only came three instead of 8. (which is how many I need to do all 8 channels.)
 
Darwin -

Give the TI PIC a call, tell them what your doing, and that you'd like to try and make a business of it. Tell them your volume will be less that 500 units per year...

They should send you a few more.

BTW - if anyone is interested, I'm currently developing my own Mic-Pre based on INA163 mic pre chip from TI. If your interested, check out www.shoeboxstudios.co.uk

If your not interested, just skip to the next thread :)

Cheers

R
 
There is virtually no bipolar opamp application that a FET input can't substitute. At least a good one like the OP-275. The reverse isn't true however.

Most bipolar opamps have significantly higher input bias currents, which translate to input offset problems in many circuits. Because FET input opamps have miniscule bias currents they don't care much whether the input loads are balanced or not, which bipolars typically do.

The place the FET types fall down is usually in noise. But again a good one is quiet enough to not matter in many applications. In truly low noise applications a bipolar can excel, but the circuit impedances have to be right for the amp to matter, in most audio circuits where the various feedback network components are higher than 5 to 10K, the noise of the network exceeds that of the opamp, FET (good one) or bipolar (5532 or 833).

Where do you run into problems with FET types substituting for Bipolars?
 
I'm reviving this really old thread.

I have a Rane MLM42 that uses the Burr-Brown INA163 op-amp, and am thinking about acquiring a 2nd Rane unit.

Anybody got an opinion on the quality of this IC, say compared to a Soundcraft M-series?

[ edited for typos ]
 
bgavin said:
I have a Rane MLM42 that uses the Burr-Brown INA163 op-amp, and am thinking about acquiring a 2nd Rane unit.

Anybody got an opinion on the quality of this IC, say compared to a Soundcraft M-series?
Click to expand...

Nothing at alll wrong with the 163. Some fine mic pres utilizing them, including the Grace Design. If you're looking to upgrade something that is already build around a solid opamp, then the next likeliest place would be the capacitors. Using higher-quality ceramic and/or film caps can really clean up the sound -- and it's a place where most of the cheaper ones cut corners.
 
chessrock said:
you're looking to upgrade something that is already build around a solid opamp, then the next likeliest place would be the capacitors. Using higher-quality ceramic and/or film caps can really clean up the sound -- and it's a place where most of the cheaper ones cut corners.
Click to expand...
Yeah, this is good advice. Replace those all too common cheap electrolytic caps in the signal chain and it will likely be the biggest improvement you can make to the basic circuit. But don't get hooked into those vastly overpriced "Musi-Wonder-Multicap" jobbies. 99.5% hype.

Thomas

http://barefootsound.com
 
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