Trying to read my first schematic, Boogie 5 band Eq

[Zanius]

I posted a request earlier this month, but I see that requests come by 2 or 3 a day, so I figured I won't have any luck. So I decided to give it a go myself, but I'd like some help :)

Here are the two schematics I found, first is probably straight out of the Mark Iv Mesa Boogie Amp circuit
http://guiguijones.free.fr/Electronique%20&%20Bouine/electronique/Schema%20Amplis%20Effets%20etc/Amplis/Mesa%20Boogie/mk4-5.gif

and another one witch seems more likely to be one of a standalone pedal
http://music-electronics-forum.com/attachments/6566d1255072615-mesa_eq.jpg

....aaaand here is what I got after some work


I didn't come here to get my layout checked, I'm pretty sure it isn't right since it is my first attempt to read schematics. However I want to ask one or two things I'm not familiar with.

Inductors. I have been reading all around about them and they don't seem to have a place in diy effects.  I remember reading a post at some point in this forum on what technique is used to deal with them. I can't seem to find that post anymore :(  Tayda has some inductors in resistor form, but the values don't seem to fit the schematic's needs.  Do I need to keep searching or is there another way to "override" their usage?

LDR. I've seen those being used in layouts but there is always  a LED around. If there is no light the resistance will never drop, isn't that right?

-13volts? Am I reading this right? I've seen 12 and even 15 + and - but never 13.

I don't think I will actually build this anytime soon, I just thought it would be nice to learn some things from you guys, and maybe someday create my own layout :)

P.S. After designing that layout I deciphered that the caps used after the LDR should be polarized tantalum (I think).

[induction]

 

Zanius wrote

Inductors. I have been reading all around about them and they don't seem to have a place in diy effects.  I remember reading a post at some point in this forum on what technique is used to deal with them. I can't seem to find that post anymore :(  Tayda has some inductors in resistor form, but the values don't seem to fit the schematic's needs.  Do I need to keep searching or is there another way to "override" their usage?

Inductors are expensive, hard to find, and hard to measure. We get around them with gyrators, which use op-amps or transistors to mimic the response of an inductor. Most modern graphic eq pedals (like this one) use gyrators instead of inductors, which I think you should consider doing also. Here's something you should read, if you want to learn more.

LDR. I've seen those being used in layouts but there is always  a LED around. If there is no light the resistance will never drop, isn't that right?

That looks like some kind of bypass switch. You can replace it with a jumper if you plan to use a the standard offboard wiring.

-13volts? Am I reading this right? I've seen 12 and even 15 + and - but never 13.

The precise voltage doesn't matter that much. 9V - 24V is fine, as long as your electrolytics are rated high enough. Higher voltage gives more headroom.

P.S. After designing that layout I deciphered that the caps used after the LDR should be polarized tantalum (I think).

They don't have to be polar. Film or ceramic will do fine. The schematic shows the correct orientation (note the negative supply voltage) if they are polar, but it's not a requirement.

[Zanius]

Induction discussing inductors. That's fun!
Seriously, thank you. You are always helpfull, to the point and have the proper links!
I will study that and propably come back with more questions!