LM741, Why the bad rap?????

[csmatt45]

I built an mxr clone, used a 741 (from rat shack), sounds fantastic! I'm a picky mo-fo when it comes to distortion. Why does the 741 have such a bad reputation???

Is it just one of those cases of contempt prior to investigation in the FX world???

matt

[Paul Perry (Frostwave)]

The is noting 'wrong' with a LM741. It's just that it's specifications (noise, offset voltage, distortion, frequency response) is exceeded by many more modern chips.
In most circuits, the modern chip will give a result that is no worse, and may be 'better' in some way. Or not. Occasionally of course, the 'improved' chip will oscillate & wail like a banshee

Aother point: a LM741 made today by national semiconductor is made from better materials, in a cleaner room, and probably to a slightly 'improved' layout, compared tot he first one that rolled off the line a couple of decades ago.

[markm]

I am a BIG fan of the 741 especially in the OD250, it sounds fantastic!

[oldrocker]

Yes I agree the 741 in the 250 does sound great.  It's the pick of choice for most of my recorded material.

[nightingale]

I am a big fan of the 741 OD250 too.

[vanhansen]

I've used the 741 in a couple of things, most recently a few line buffers.  Works great.

[csmatt45]

hmmm...I guess sometimes you just have to use the most complicated testing device on earth to judge something....your ears!!!

thanks guys,

matt

[Paul Marossy]

Yep, Peter makes a good point. I came to that same conclusion as well. A 20 year old opamp won't have the same quality and be manufactured to the same tolerances as a new one, and that's why I have no problem using a new manufacture 741 in a build. I only worry about it if limiting noise is a big concern.

[Mark Hammer]

This is a bit like saying "Everyone keeps going on about how great knives and forks are, and how lousy and dull spoons are.  Well, I tried eating my cereal this morning with a knife and fork, and let me tell you the spoon kicked their asses around the block and back!  Spoons rock!"

The OD250 and Dist+ are essentially designed around the 741.  No small wonder it sounds fine in there.  Not a whole lot of other applications where it will sound better than other contenders, though.  Build a phaser with one and I can pretty much guarantee you'll diss it. Build a compressor with one, and you'll be screaming "Who do I have to sleep with to get this thing out of here!". 

[oldrocker]

I wasn't aware that the 250 was designed around the 741.  Shows U how much I know.  Question, lets say a project you're building requires a TL072 duel opamp or similar and instead I tried using two 741's it wouldn't be a very good idea?

[oldrocker]

I wasn't aware that the 250 was designed around the 741.  Shows U how much I know.  Question, lets say a project you're building requires a TL072 duel opamp or similar and instead I tried using two 741's it wouldn't be a very good idea?  Just wondering about that.

[Mark Hammer]

I wasn't aware that the 250 was designed around the 741.  Shows U how much I know.  Question, lets say a project you're building requires a TL072 duel opamp or similar and instead I tried using two 741's it wouldn't be a very good idea?  Just wondering about that.

Yes and no.  Individual tastes can vary.  In the case of the OD250 and Dist+, users who though they might be able to score a two-fer-one by installing a diode-lift switch were surprised to find that the thing distorted even without diodes.  So, even though it doesn't look like a double clipper on paper, in reality it sort of was - what you feed to the diodes is already clipped.

Since the pedal is going to shave off both the bass and the treble eventually, then there is no real need to have a high input impedance to try and savour every last herz of bandwidth.  Since the thing is not ever going to be used clean, then there is no need to have something that handles large input signal or signal swings easily.  But both WILL work with other op-amps (mine uses a piggybacked pair of 5534 chips but sometimes a 741).  They just won't sound exactly the same.

If a project specifically asks for a bifet op-amp, though, unless the designer has made some sort of error or is just going on the basis of what they heard about op-amps, if it says it needs a bifet then you should probably use some sort of high input impedance chip.  You could use a TL062 or 82 for a TL072, or you could use a CA3240 (assuming you can find them), or an op-275 (if you can afford them), or an LF353, or any of a bunch of FET-input alternatives.  Some things may vary (e.g., an 062 is a little noisier than an 072), but you will at least have nailed some particular design parameter that the designer felt was important in proper functioning.

Keep in mind that since stompboxes and op-amps were introduced, there have been historical changes in the quality and introduction of certain op-amp types. What that means is that there are plenty of circuits where one op-amp is listed but since the circuit was designed other op-amps have since come to outperform it on spec, or perhaps the price difference between what was used then and what is available now has come way way down.  For instance, when Craig Anderton published Electronic Projects for Musicians, the XR/LM4739 dual op amp had pretty good specs in comparison, was not dramatically costlier than other chips, was not harder to find than other chips, and was cheaper than any FET-based op-amps.  So Craig used it.  Has it been outstripped by other chips that cost a fraction of what the 4739 did then (and especially now)?  You betcha.  A person would be a fool to perseverate over getting a 4739 to make one of those projects instead of simply springing for a 5532 or TL072.

When it comes to distortion, though, pretty much all bets and advisories are off.  Why?  Because making distortion is often about the weaknesses of a semiconductor, not its strengths, and because distortion is very much a matter of ears and taste.  For instance, you will not see the LM308 used very much in audio products or most pedals.  But you will find one in a Rat.  Why?  Because of the limitations of the 308 under the conditions it is being used with.

[Peter Snowberg]

This is a bit like saying "Everyone keeps going on about how great knives and forks are, and how lousy and dull spoons are.  Well, I tried eating my cereal this morning with a knife and fork, and let me tell you the spoon kicked their asses around the block and back!  Spoons rock!"

Thanks for a good chuckle at a point in my day where is was sorely required. 

[Gus]

I once fixed an old + for a friend that is a bass player.  Stock it sounded great with his Jbass.  Same thing with a TS stock they can sound good with a bass. don't change the input or output caps.  Give it a try.  Now you must think about how it will sound in a mix not as it sounds alone.

The next set in building stuff is learning how stuff sits in a mix be it on stage on a CD.  Effect petals and microphones and preamps and compressors.................

[Gilles C]

That's what I used for my Tube Reamer version 1, and it sounds perfect. It's an old 1974 model...



Gilles

[Paul Perry (Frostwave)]

It's interesting that people are saying the 741 sounds better in an overdrive.
Three reasons why this might be so:
1. the 741 runs out of high frequency gain when it is in a high-gain circuit like this (so, you are getting a free hidden high frequency roll-off).
2. might be acting as a slew-rate limiter, again smoothng things out
3. (less likely but possible) when it is momentarily saturated (from running out of gain) the protection diodes on the inputs to the 741 might do some waveshaping.
It all goes to show, that pedals (like most things in life) are more complicated than one might think.

[csmatt45]

Two little tidbits of info here:

One, gus I agree with you, living room vs. stage or studio are two totally different worlds. I've gotten to where I don't even bother getting to jazzed about an effect until I've had a couple full volume rehearsals with it. That's always what separates the "man" pedals from the "boy" pedals so to speak. Also, if you're a fender amp guy (in my case a '63 tremolux) all bet's are off. fender amps are very picky about what they like and don't like. Marshals, vox's, and many others are much more forgiving (of course this is just MHO).

two, don't be afraid to try the "stock" version of a pedal before you go into mod-land. at least that way you know what your modding, and you may just find you don't need to mod at all...

Three (i know, i said 2), the layout for the MXR on dragonfly has an error. I'm not complaining, i appreciate the time it takes to do the layout, put it on the site etc. But just be aware of it (I noted it in the gallery) if you attempt it.

thanks,

matt

[petemoore]

741 in DIST+ 

[StephenGiles]

At line level I'm sure that an average pair of ears, which have been subjected to loud Marshall amps for a few years, could not tell the difference in a unit using 741s and another using OPA2604s (or whatever) - mind you they would not agree over at Prodegy Pro!!!!!

[brett]

Hi
I agree with the sentiment of:

2. might be acting as a slew-rate limiter, again smoothng things out

RG has said that better chips might have "gracefulness" in response and recovery, which I think is a similar thought to the one above.

I've built a few ideal diode circuits, where op-amp gain is varying wildly during the course of a single waveform (or half a waveform, to be exact).  In this case, where grace under pressure is also desirable, a 741 seems to produce a BETTER waveform than chips such as the TL071. 

The main disadvantage that I see in 741s is that for audio signals at high gain, the noise of a 741 (or 4558) becomes a real nuisance.

cheers