tubescreamer tragedy

[Al Heeley]

Oh No! Just about to complete a custom tubescreamer build and my box of bits has run out of JRC4558 chips, as has my friendly local supplier!
I have a couple of LM741's as well as a TL072 chip - are these similar enough for me to get away with it? What sort of difference could I expect?

[faptdivers]

http://www.youtube.com/watch?v=bpTv2jAree8&feature=player_embedded

[Al Heeley]

Nice clip, so I can use either 4558, TI072 or LM741 as basically interchangeable within the circuit? (LM 741 not mentioned....)

[jasperoosthoek]

The LM741 doesn't work as it is a single opamp and the other are dual opamps.

In most cases opamps are interchangeable as long as the pinout matches. Search for datasheets on google and compare them .

[Talon5051]

The 4558 is a dual op amp as well as the Tl072.  The LM741 is a single so this will not be an exact replacement.

[Talon5051]

I did not mean to duplicate Jasper's post.  I did not see the new response when I posted.

[petemoore]

  you'll probably have to duel, but it works with any dual
 [just about any standard dual opamp fires up the TS circuit].
 You could set down the tool, 'n use the 072.
 Just ignore pavlov and consume the desirable component you have on the plate.  
 

[MmmPedals]

I just spent a nice chunk of time swapping op-amps in a tube screamer TYPE circuit. It had a lot more gain and the tonestack was altered. what made my experiment interesting is that I had a diode lift switch so I was able to hear the op-amp clipping without the diodes. I did hear very significant differences in op-amps but I am quite sure it was because the op-amp was clipping so hard. In a standard ts-9 I doubt it makes a difference.
Just for the record I ended up with an lm833 because it sounded just as good as any other and was much quieter. The ne5532 was also very quiet but sounded like a farting cat. nothing else was as quiet even the tl072 (which also didnt sound so great). many others sounded great.

[Al Heeley]

The ne5532 was also very quiet but sounded like a farting cat

Thanks - you've just come up with a name for my next fuzz pedal project

[DougH]

Always check the pinouts first. You can google for the datasheets on just about any part number. Most double op amps in the same form factor (dual inline) are interchangeable.

[Al Heeley]

so all the hype about the vintage '80's 4558 japan chips being the only ones for that truly authentic tubescreamer tone is a huge pile of hogwash then? 

[ayayay!]

so all the hype about the vintage '80's 4558 japan chips being the only ones for that truly authentic tubescreamer tone is a huge pile of hogwash then?  

Emphatically, yes.  There is NO difference whatsoever, except for maybe a slight variation in the ink on the stamp, from older batches to newer.   People are probably more likely to hear a slight difference between the TI version and the RC/JRC version, then from RC to JRC.  It's silly what people get off on. 

I myself often prefer TL072's in the TS circuit(s) FWIW.  

[petemoore]

  Use an IC socket so as not to burn the chip when soldering it's connections, use a compatible chip [TS requires standard dual opamp].
  Fiddle with the diode configurations and diodes/cap for more noticable differences, higher clipping thresholds give the opamp more swingroom to 'work', often the TS is used as more of a mid-hump booster than a grit-box, volume up, gain lower, high threshold fits big-boost/less distortion profile. Otherwise with 'gritbox' type sound [lower diode thresholds] the opamps limited swing room was limited enough to make the differences even harder to pick out.
  TL072 was endearing, 4558's sound great too [that's a gleamin' review for a TS tweeker/non user], IME, there's a buncha other ones I could barely tell a difference with, 5532 was dry, LM741...I didn't study into it, but being by far the low performance champion of the choices seems like a good candidate for a dirtbox, works best IME for the DIST/250 type circuits, IIUC it doesn't exhibit it's oddities in the TS 'so much {and it's a single so requires 2, and a different board, I made socket/adapters for 2x 741 = dual. Pretty sure it's been done though.
  So it tends to boil just fine with any the 'often suggested' opamps IME...enough that looking elsewhere is strongly suggested, what plugs into it, what it's plugged into...what that plugs into etc. limits/enables way beyond whatever the TL072 has over the indeminable 4559 [or vice versa.
   

[MmmPedals]

  Otherwise with 'gritbox' type sound [lower diode thresholds] the opamps limited swing room was limited enough to make the differences even harder to pick out.
 

Thats why I believe that the "Myth busters" isn't totally accurate. He had the gain set pretty high so the clipping done by the diodes would mask any difference (If there is any). To really hear the difference in op amps you would need the gain set lower.

[Al Heeley]

Thanks for the insights and clarifications, I will proceed with using up my TI072 chips before buying more 4558's, I have a Tubecreamer + Mosfet boost double pedal to finish as well as a BB Preamp build which specifies use of one TI072 and one 4558 chip in it's 2-chip circuit. One of the chips powers the active treble and bass controls, I did find it puzzling why if the chips are interchangeable, they took the effort to specify one of each in the build details.

[ayayay!]

Simple:  TL072 is specified as more hi-fi.  Would make a more suitable tone opamp. 

[FiveseveN]

so all the hype [...] is a huge pile of hogwash then?

WHAT?! Say it isn't so!

To really hear the difference in op amps you would need the gain set lower.

So you're saying the inherent distortions would be more obvious with more negative feedback?!

[Mark Hammer]

There will be audible differences, I guess, some which may be to your liking and some perhaps a little less so.  But people should not embark upon chip-change exercises expecting night-and-day differences that supercede everything.  Indeed, many differences which can be heard by sane, unbiased, individuals can just as easily disappear when switching from pickup A to B, turning the volume or tone up or down, or simply picking a little differently for a different song.  What a particular op-amp gives you in that circuit, in a way which distinguishes it from others, may only be the case 3% of the time.  I leave it to you to decide whether that 3% is critical or ephemeral.

[MmmPedals]

To really hear the difference in op amps you would need the gain set lower.

So you're saying the inherent distortions would be more obvious with more negative feedback?!

YES! well... sort of. what i am saying is to hear the difference you need to reduce the diode clipping. The diode clipping masks the "sound" of the op-amp.
I also found that the op-amp clipped before the diodes so by reducing gain you can hear the op-amp clipping without the diodes.

[jasperoosthoek]

How can the opamps clip before the diodes? Doesn't that mean that the signal levels don't exceed 1 volt peak to peak?