madbeanpedals::forum

Projects => General Questions => Topic started by: poorman on October 07, 2012, 12:45:20 AM

Title: LED and OP Amp Questions
Post by: poorman on October 07, 2012, 12:45:20 AM
Newbie here with stupid newbie questions...

LED power indicator lights:  will any 5mm do?  Does the value matter?  What's the ideal value?

OP Amps:  I'm building an EGOdriver  I want to replicate my FT OCD and it has a Texas Instruments TL082...will any TL082 do, or are there tonal implications (should I seek out a TI chip)?

Thanks,
Dave
Title: Re: Re: LED and OP Amp Questions
Post by: Om_Audio on October 07, 2012, 12:58:07 AM
I am actually going to do some work on my OCD (not EgoDriver)and here is what was suggested to me (mine is too woolly for my taste FYI):
"You might want to start swapping some stuff out of there. I have one I built and I still like it. I would definitely swap that op-amp to a cheap BB amp or a TLE2072. The TL082 is not a very good opamp. I have a Burr Brown in mine. Also the diodes may be something to play around with. For a little more definition you could swap the Ge out with a Schottky. I would socket the diode positions and try a bunch of stuff. It is a good circuit; there just may be tweaking involved to get it how you like it."
Have fun!
Clifford
Title: Re: LED and OP Amp Questions
Post by: JakeFuzz on October 07, 2012, 04:55:07 PM
Hey that's some pretty good advice Cliff!  :D  Yeah that's what I would do.

As for the LED's Yes you can use any 5mm LED (I think the formal package name is T1-3/4). Some are brighter than others or have different viewing angles but overall I find that a 2-10k CLR resistor works just fine for just about all of them. I would say choose a color you like and go with it.

You can use any TL072 and get the same results. They are manufactured at different plants but the die is going to be made with the same processes and same masks. Unless someones quality control is way off then they should be pretty much identical.
Title: Re: Re: LED and OP Amp Questions
Post by: Om_Audio on October 07, 2012, 06:16:32 PM
:) (that was a quote from JakeFuzz in my orig post)
C