SUBSTITUTE for the parts

[joremcute]

hello!!

i am a new builder of a pedal..I went from a electronic shop to buy a parts of the pedal but there was no IC TL072 available here.. Do you have any advice of what shall i do?.. It is possible to have substitue for the TL072?..tnx..  the schematic  image below..Tnxxx

[LucifersTrip]

welcome

you just need to find another opamp with the same pinout...or alter the layout to fit another:



possibly a 4558:

[joremcute]

ok...tnx for the advice...Hope it will workk at this time..

[Mustachio]

I believe most dual op amps will work most have the same pinout. But check the pinouts first. I believe the wiki here has a lil info.

http://www.diystompboxes.com/wiki/index.php?title=Main_Page#Parts_reference

Like Lucifer said the 4558 should be fine.

I built this exact layout and I settled on an OPA2134 sounds great ! Surprised there are no TL072's around you it seems to be the most common dual opamp Ive seen in commercial circuits.

Good luck!

[joremcute]

Tnx for your advices it will help to much..

in R7 it was labeled as LDR is this the type of LDR am going to use?



tnx..

jorem

[frank_p]

yes, don't forget to put enough lead lenght to put it in front of the LED light.

[joremcute]

what is the purpose of LDR in this circuit??

[frank_p]

what is the purpose of LDR in this circuit??

The LDR is a variable resistor.  It is in the negative feedback path of the front opamp.  When the LDR is in the light, the resistance value change.  Since the gain of the amp is function of the feedback resistor, it changes as the LED is being lit on.

[newperson]

that wiki page looks like it has 2n3904 as a pnp

[joremcute]

Hi!

Do you have list of IC diagram that has the same opamp like MC4558, TL072 and etc???..tnx.

[Mike Burgundy]

(almost) all of them, as long as they are *dual* opamps in a DIL8 package. Can't think of anything that's different, really.
TL072, 062 (like 072, low consumption), 082(like 072, high performance), 4558, LM1458, NE5532, sheesh...
That said - the TL07x series (the last number is, you guessed it, the number of opamps inside) is a *real* common opamp - if they don't have that.....
Google dual opamp and get lists and lists of them. To doublecheck the pinouts you can also find datasheets this way.

[petemoore]

  You can buy a photocoupler or build one using discrete LDR and LED.
  Light seal the LED/LDR so the LED emits photons which will strike the LDR...ie face to face against each other.
 The 'wrapping' can be...anything that holds them in position and seals the inside from outside photons.
  I've used: Electrical tape, a portion of ballpoint pen tube, typing paper covered in black gloss paint or electrical tape, anything else that does the trick easier to seal light works.
  Don't obsess over the quality of opamps, the ones I've seen mentioned are all high quality sound devices.

[Mustachio]

I used a VTL5C2 in my flatline build and it worked great! 

http://www.smallbearelec.com/Detail.bok?no=346

[smallbearelec]

I used a VTL5C2 in my flatline build and it worked great! 
http://www.smallbearelec.com/Detail.bok?no=346

A major, bearish Thank You for this note! IMO, the project is Not suitable for a first-build without a clear specification for the photocoupler. Experienced builders can rummage in their spares for the LDR and try a variety of LEDs, but a beginner really should have a recommendation for something that is known to work.

Note to the OP: Supply problems have nade the VTL5Cx parts a lot more expensive. This may be temporary...I am investigating, but don't know yet why the prices have gone nuts. I would still encourage you to spend for the VTL5C2 rather than trying to cobble something together, Unless: I do offer a line of inexpensive LDRs

http://www.smallbearelec.com/Detail.bok?no=711

One of these would almost surely work, but I have not had time to build the Flatline myself, so can't offer a recommendation for LDR/LED. If any of the residents here can do so, reply would be most helpful.

Regards
SD

[frank_p]

http://www.aikenamps.com/VTL5C1.pdf

Data sheet if you want to diy.
If you wanna plug and play go at Smallbear.

[joremcute]

i would like to ask about this circuit..


Is it verified??

tnx

[Keeb]

Yes,
the layout you posted is based on that schematic.

[joremcute]

can i test that cicuit without a switch???

..in which of the circuit i will attach the potentiometer???