TL071 sub for LM741? (noob, non-EE)

[Dito]

Hey gang,

I've decided my next build will be an MXR Distortion+. The vero layout I found calls for the legendary LM741 op-amp chip. In my short experience, I've developed a fondness for shopping at Tayda. However, they don't seem to stock the LM741. Instead, they have the TL071 chip, which someone (?) has tagged as "741".

I checked the datasheets and see that the pinouts are the same. I'm not electrically powered enough to comprehend a datasheet beyond that.

These are both made by Texas Instruments, so they're obviously not atom-for-atom identical. But what would change by using one chip over the other? Anything? Like I said, I can't wrap my mind around the datasheets to understand the differences, and even if I did, I have no clue what effect that difference would make.

I apologize if this is a newbie question, but, well, I'm a newbie.

Thanks in advance for the clarifications.


-Dito

[GibsonGM]

Hi Dito,

Yes, go ahead and use a TL071 in place of the 741. It is a better "more high fidelity" chip...faster, better, cheaper (ha ha).  You may think of it as "the 71 can react faster than the 741 to signal changes, and is less noisy".    I think what you may find is that you do not get as much of the "opamp clipping" that the original Dist + had.    I PREFER the 71 for builds like this.  I want my diodes to do the clipping and don't really like OA fuzz...

Let your ears do the proving - but as for pinout and all that, you are safe to simply pop it in as if it were a 741.

 

[slacker]

To add to what Mike said,  99.9% of the time in stompbox circuits opamps are interchangeable, there might be some differences in sound between different ones but they'll all work. There's only a small number of circuits that require a specific opamp or where where certain opamps won't work.
The main thing to watch out for is the number of opamps in the package, eg: a TL071 and LM741 are single opamps, one opamp on an 8 pin chip, you also get dual opamps like the TL072 or JRC4558 which have 2 opamps in an 8 pin chip. The pinouts aren't the same so you can't simply use a dual in place of a single.

[Dito]

When you say the 741 is more "noisy", I presume you mean unwanted circuit noise? Not noise as in distorted guitar tone "noise", right?

I guess my real question is this: will a Distortion+ built with a 071 sound (noticeably) different than one built with a 741? Or would you need an oscilloscope to tell the difference?


-D

ps: I totally want an oscilloscope, even though I have no idea what they're for.

[GibsonGM]

By "noise" I mean unwanted thermal noise and the like.  Not signal.    If you really push a 741 (or any opamp...), it will generate internal distortion of its own; some people swear this sounds great, they swear they can hear a small difference.   In my humble opinion, it may add some "wool" to the distortion, but I don't hear much difference.  Not enough to make me run out for a special (obsolete) 741!  He he. 

Use your 071, see if you like the sound

Learn more about o-scopes...they are great, and you can find old used ones for pretty small money.  I have one from the early 80s I use a lot...it was over $2,000 new, and cost me $99, ha ha.    Start with a computer soundcard software scope, maybe, to learn...another topic entirely...
A scope is used to watch the waveform of the signal you are interested in, essentially.  You can tell a lot about a sound by seeing its shape...and you can measure with it...

[PRR]

> both made by Texas Instruments, so they're obviously not atom-for-atom identical

Opamps are opamps. Like cars; in a class they are all a lot alike. You got seats, doors, an engine which is usually in front. Camry and Accord put the engine sideways and Subaru puts it fore/aft, but more alike than different.

The "741" was Fairchild's tweak of National's LM301, the first really-good chip opamp.

'741 was SUCH a runaway hit that everybody first copied and then improved it.

Also demand for '741 ran so high that Fairchild had to let everybody else make it (on a kickback deal). National probably nicked a few bucks from Fairchild because you really have to stare to see the difference 301 or 741.

TL07x is a cheapified LF356, the first good FET chip opamp, originated by (either National or) Linear. LF155-LF357 used extra steps and parts to print FETs with BJTs at higher performance than '741 and imitators. TI (or someone) found a simpler way, the TL07x family, which turned out cheaper (less die area) than the '356 and even cheaper than the vastly popular '741.

Fairchild is out of the commodity opamp racket. National (and almost everybody!) was bought-out by TI. Dozens of old friends I know well were developed at other outfits now call TI home.

TL07x "replaces" 741 in most work, with some quibbles. And yes, the '071 pinout is intended to drop-in a 741 socket. (Make it easy for buyers to adopt your chip!)

> an MXR Distortion+

99.44% of the sound of that is in the diodes. The opamp just boosts the signal. Any minor glizz which might be added by the opamp (both '741 and '07x are pretty darn clean) will be whacked-off by the diodes. This is not the sort of distorter which makes different sounds with different chips.

[Guitar Poppa]

hello,

On a pure technological point of vew, TLO71 is better quality than 741... But only on this point of vew, and if you want a sonin fidelity... If a had to build a cheap mixer, I would use TLOs and not 741s...
Just a detail : 741s with the N suffix are low noise, as good as TLOs... Few people know it. The difference is in bandwith, slew rate, linearity.

There is another point of vew : the sonic comportment...
If you decided to stay at the technical point of view, this will look insignificant, and [edit : it's the same] if you do not trust in your ears, [edit : if you don't know how to listen] ... But it is as real as the pure datas...
On this level, the 741N can be interesting : even its deffects can be good deffects in stompboxes. (The same way the LM308 and JRC4558 are cheap and lo-fi components)
--- The narrow bandwith will bring a lowpass filtering over 5kHz to 10kHz, depending on the gain adjustement. It will be a little bit like with tube amplification, or germanium transistors...
--- On the same way, the low gain x frequency product will give more rounded and soft saturation. Exactly as with JRC4558 in a Tube screamer... I don't say the samesound, but the same kind of comportment... You should remember this paradox : cheap OpAmps are sonicaly more pleasant when saturating than middle-class or upper-middle-class OpAmps... 
--- Why do I insist on this ? Because in every overdrive or disto using diodes as load, the IC began to saturate before the diodes clip hard. Consequently, you hear as well the OpAmp's saturation as the diodes saturation when you play gain halway. The clipping of the diodes become preponderant when Gain his adjusted high.

Conclusion : TLO71 is a good medium class OpAmp, 741N are not so bad, NE5534 is a classic, and OPA604 top class... Try them one after the other in the same circuit, play, and compare. The best sound will be the one you feel better with your instrument, your amp, your way of playing... (and the same for the double versions, TLO72 etc...)

Good trials !
Guitar Poppa

[chuckd666]

Yeah if you're shopping at Tayda just use a TL071 because they have them for cheeeeap. But I'd recommend just hitting eBay because the 741 is so widespread you can find them for next to nothing.

[smallbearelec]

Hi--

As other people here have noted, the diodes affect the tone far more than the IC. I would add that a tone stack will give you a wider palette still. Here is a kit:

http://smallbear-electronics.mybigcommerce.com/breadboard-a-vintage-ic-distortion/

for breadboarding this type of distortion with a couple of different chips and a tone stack if you want it.

The How-To is here:

http://diy.smallbearelec.com/HowTos/BreadboardICDist/ICDist.htm

The kit includes both a vintage chip and a TL071. If you order the kit and remind us that I offered, we'll throw in a 741 for drop-in comparison.

By breadboarding first, you'll know what you want to commit to solder. One of my projects for this year is to design a board for a Distortion + type of circuit that will go in the Bare Box #1.

http://smallbear-electronics.mybigcommerce.com/the-bare-box-1/

and I expect to have that ready by the time you are set to build.

[Dito]

The "741" was Fairchild's tweak of National's LM301, the first really-good chip opamp.

I may not be an EE ("sparky"), but I know to pay attention when the name Fairchild Semiconductor pops up. Every good nerd knows that name. A company that was just slightly important...

I want to thank everyone for their input. It's all very fascinating.

I placed my order yesterday, for 071s.

(I also spent way too much time doing metric conversions between picofarads and microfarads. I took an extra math class in 6th grade to learn the metric system - the late '70s. Drives me nuts that the US still uses imperial units.)

I plan on putting my op-amp chip in a socket, so maybe I'll scrounge around for a couple 741s just for giggles. But if, as you guys say, it's mainly the diodes (which were easy to find)... maybe I'll just skip it.

I'm looking forward to my first Vero build. And building without a detailed step-by-step handholding tutorial. Everything is ordered; should be able to start in a week or so.

Rock on.

-Dito

[PRR]

> Fairchild Semiconductor pops up. ...A company that was just slightly important...

"Slightly" is under-stated. Shockley collected the finest minds in the field, taught them, made very good parts.... and then drove them crazy. Sherman funded the defectors.

But later Fairchild management again made the wizz-kids antsy, and many left to found their own companies. Hoerni, Moore, Noyce, Widlar, and others are best known in other companies. The many Fairchildren basically built the semi industry.

Oddly, of the hundreds of semi companies which once existed, and the dozen or so which have not been bought-out by TI, Fairchild is *still* in business and doing OK. Also oddly, the proto-fab is not in the West, but in suburban Boston (Portland Maine). Rather than messing with commodity chips, Fairchild develops custom solutions for broad applications.

OOPS! Recent news: Fairchild may have sold itself to ON Semi a few weeks back. Unless a better offer appears. In any case, this probably means the historic (antique) fab off Portland harbor will be shut down.
http://www.pressherald.com/2015/11/18/fairchild-semiconductor-to-be-sold-to-arizona-company/
http://www.pressherald.com/wp-content/uploads/2015/11/752911_60851-20151118_Fairchild_02.jpg

OTOH, TI has sometimes been super-good at Production. When WE GE RCA and even IBM were assembling transistors one by one by hand, TI developed a continuous process that spat a transistor every few seconds. They did the same with chips. Which is probably why TI now owns about all the analog semi brands not owned by ON Semi (the former Motorola operation).

[amptramp]

This is your chance Paul!  Buy the defunct old semiconductor foundry and start making BBD chips of all sizes.  Convert part of it to run germanium and you will have your new company name and location:

Germanium Valley

You will probably be able to get government grants for "new research" held over from 1950.  You may be able to get funding from the city of Portland and the state of Maine.  If you line up funding > operating costs, you might not even need to come out with a product.  You could sail to work on nice days (just like the Miller-Stevenson execs) and take your new Rolls-Royce in bad weather.  You might even make enough to become a sponsor on this forum.

Your life could get interesting.

[stringsthings]

 

[GibsonGM]

This is your chance Paul!  Buy the defunct old semiconductor foundry and start making BBD chips of all sizes.  Convert part of it to run germanium and you will have your new company name and location:

Germanium Valley

You will probably be able to get government grants for "new research" held over from 1950.  You may be able to get funding from the city of Portland and the state of Maine.  If you line up funding > operating costs, you might not even need to come out with a product.  You could sail to work on nice days (just like the Miller-Stevenson execs) and take your new Rolls-Royce in bad weather.  You might even make enough to become a sponsor on this forum.

Your life could get interesting.

We could put it out to a bond issue...sure to pass!!!  lol

[smallbearelec]

You will probably be able to get government grants for "new research" held over from 1950.  You may be able to get funding from the city of Portland and the state of Maine.

Government money always has strings attached; you could find that you have to pay twenty bucks an hour to people who take out the trash and/or that your product has to be sold at a loss to politically-favored constituencies.

[Dito]

We could also follow Colorado's method. I lived there until a few years ago, but long enough to vote "yes". Now I hear they're absolutely smokin' in the tax revenue department!