Need recommendation for circuit for 2 op amps that i have

[Guitarist335]

Hi folks:

I will start by staying that I am a newbie and I am trying to build my first successful overdrive op amp circuit.

I have the following op amps, so i am hoping someone can suggest a particular circuit I can build to achieve overdrive, using one of the following op amps. And because I know being specific is important, I will try to describe these op amps with specificity:

I have the  tl081cp.  on it's face, it has the label: 3BA081M. TL081CP


The other one I have is the 4558D |JRC| 0058T. (I have tons of these ones as I bought them in bulk on Amazon)

I would much appreciate recommendations or links you may have to a circuit that i can build, utilizing one of the above op amps. Being a newbie, this is an adventurous project for me. I plan to breadboard it, but I am not yet used to a lot of the technical language in electronics- full disclosure ;-)

Thank-you!

[FiveseveN]

For most applications any op amp will work just as well. People get a kick out of swapping various vintages of op amps in dirt boxes. So the world is your oyster, you can make any circuit that requires op-amps. Just mind that the TL081 is single-channel while the 4558D is dual.
A good start could be the Son of Screamer, you're bound to find a layout to your liking:

[Marcos - Munky]

The TL081 is a single opamp. You can do lots of stuff with it. Some to name: MXR Distortion+, DOD Overdrive, Runoffgroove Tube Reamer.

The 4558 is a dual opamp. Again, lots of stuff, but more than the single opamp. Basically, you can build almost any Tube Screamer-like with it. My favourite one is the Zen Drive.

[PRR]

The '4558 dual can be used for almost EVERYthing audio.

> this is an adventurous project for me.

Rather cheap low-risk "adventure". Where I sit these are half-dollar chips. When chip opamps first came out I could NOT afford to hurt one, it would take a month to save-up loose-change to replace it. ($7 for a '741, IIRC; when gasoline was $0.33/gal.)

[Marcos - Munky]

You can follow this tutorial (sticked posts) for the TL081: https://www.diystompboxes.com/smfforum/index.php?board=33.0

[willienillie]

4558D |JRC| 0058T

Now, those are fake.  That is, not actually JRC products.  They might still be working dual opamps, so don't trash them.

[Guitarist335]

I plan of giving Son of Screamer a try and I am gathering the parts that i will need for it. A few questions:

1. C2 is said to be a 0.047 Capacitor,,,what is the type. Pf , Uf, nF?  Being a newbie, i don't know what to assume.

2. C3 is 47 P...does that mean 47 pF?

3. R11 is 20K =W. what dos the W signify?

4. R6 is 220. - should I assume Ohms?

5. R7 is 47  Ohms?

6,. Lastly, what does Vr stand for?

Sorry for all these questions. As a new person at this, I am uncertain and don't want to make errors unnecessarily.

You folks have been very helpful. Thanks for all the support and advice.


P.s. One more thing. When there is no pol;arity specified on a capacitor, should I assume it is a film capacitor and if there is a polarity, should I assume it is an electrolytic?

[willienillie]

1.  .047µF, or 47nF
2.  Yes
3.  W taper, an unusual pot taper, sometimes called G taper.  Small Bear and Tayda carry them, specifically for Tube Screamer builds.  You can use 25K Linear with no real change in sound, just different positions of the tone knob, except 12:00 would be the same.
4.  Yes
5.  Yes
6.  Vref, reference voltage, half of supply voltage.
P.s.  Yes and yes

------------

I will add, use a socket for your dual opamp, in case those 0058Ts are no go.

[Guitarist335]

Willienillie

Thank-you for those answers.

I have reconsidered this circuit, as I have now come to understand that it involves 2 op amps.

I think i would be better off with an overdrive circuit that only uses one op amp, preferably one of the ones I listed that i have (although i understand that I can probably use most any op amp provided I pay attention to the pin mappings).

Can anyone recommend an overdrive circuit that involves only one op amp?

Thank-you and sorry to be a pain. I'm in crawl before you walk mode ;-)

[willienillie]

I think i would be better off with an overdrive circuit that only uses one op amp, preferably one of the ones I listed that i have

You listed TL081 (single opamp) and 4558 (dual opamp).  Be aware that the pinouts are different, even though they both come in 8-pin packages.

The Son of Screamer is quite simple and easy to build, even though it uses a dual opamp.  I'm sure there are several verified layouts floating around.

The classic single opamp OD is the MXR Distortion+ (or very similar DOD OD-250).  Those traditionally use a 741 opamp, a TL081 would work too, but it might not sound quite the same as a 741.  You could also build either of those with a 4558, using only half of it, which might sound a bit closer to a 741, if that's important at all to you.

Personally I prefer the sound of a Tube Screamer or Son of Screamer over a Dist+ or 250.  YMMV.

[Guitarist335]

Thank you.  To be honest, I stopped for two reasons. First, the two op amp thing.  Second, I don't have a film capacitor as small as C1.  I may have to refresh my parts inventory.  I have a kit of film and electrolytic capacitors but none with that value

[FiveseveN]

If you're talking about C1 in the Son of Screamer schematic above, any value between 10 nF and as big as you can find will work fine. Especially within the demands of a first project with available parts.
There's more than one breakdown of this kind of circuit: The Technology of the Tube Screamer, Tube Screamer Analysis, I think Brian Wampler had a video on it as well. Having the description and a breadboard on hand allows you to try different values and configurations while hearing the impact and hopefully understanding what's going on in the circuit.

[awgearhart]

The 4558 is a dual opamp. Again, lots of stuff, but more than the single opamp. Basically, you can build almost any Tube Screamer-like with it. My favourite one is the Zen Drive.

Marcos (or anyone for that matter), does that entail you can use the 4558 for the Zendrive? All schematics I can find say it uses the AD712. If you use the 4558, do you have to change out some other components?

[FiveseveN]

Yes, you can use them for the Zendrive and you don't need to make any changes.

[Ben N]

You can use both chips for an opamp Big Muff Pi.

[Marcos - Munky]

Marcos (or anyone for that matter), does that entail you can use the 4558 for the Zendrive? All schematics I can find say it uses the AD712. If you use the 4558, do you have to change out some other components?

There are a good amount of ICs that have the same pinout. 1458, 4558, TL062, TL072, TL082, LM358, TLC2262... just to name a few.

There are a few cases when you have to use a specific one, but usually you can just swap them and you're good to go.

On single opamps, there are the 741, TL061, TL071, TL081, to name a few. So you can use your TL081 to build a MXR Dist+, even it calls for a 741.

[willienillie]

Second, I don't have a film capacitor as small as C1.

If you're talking about C1 in the Son of Screamer schematic above, any value between 10 nF and as big as you can find will work fine.

But what about C2?  That one will make quite a difference if smaller or larger.  If you have two 100n caps, you can connect them in series to make 50n, which is basically the same thing as 47n.

[Guitarist335]

Thanks for all the help. i'll start getting together my parts, now that i know there is some flexibility.

[antonis]

i'll start getting together my parts, now that i know there is some flexibility.

"Flexibility" is in the eye of the beholder..
(as FiveseveN told you about C1 value - without telling you the result of using different value item..)