Beginner: I picked up a TL072 and want some suggestions...

[monomatic]

I have so many questions, but Ill just go with these for now...

I've been messing around with simple BJT circuits since I started doing this a few weeks ago. Im loving experimenting with them, but I decided to grab a TL072 the other day and see what these op-amp things were about.
Any suggestions on a beginner-level project that utilizes a TL072? (or even a general way to start experimenting?) I'd like to be in the realm of OD/dirt/distortion but Im open to other ideas, especially ones that lend to experimentation and learning, but don't involve a million parts.
Perhaps even some general guidelines on how they are used might be helpful as well.

Secondly, Im having trouble locating J201 JFETs. They seem to be popular among OD/Dist builds, but is there a sub-part that will work in place of the J201 in almost any situation - and is readily available from Tayday or similar? I don't have a particular project in mind as of yet, but more than a few interesting ones Ive come across that Id like to tackle soon use them.

Lastly, I also picked up a BC108. Can I just throw this in place of any other NPN BJT and expect that it will work? For example, yank the MPSA13 or 2n3904 from a Bazz Fuss I have on my breadboard and throw the BC108 in its place? Or will it set free the 'magic smoke?'

I hope these questions aren't asked too often. Ive done some searches and can't be sure if the info Ive found was applicable or not. heh. N00bz - what are ya gunna do, right?

Thanks folks!

[karbomusic]

Ref TL072: I think you should build a non-inverting buffer, then an inverting buffer, then both again but with gain. That's four very simple circuits which comprise the very basics of most any more complex dirt and tone circuits etc.

[mth5044]

Check this out.

http://www.generalguitargadgets.com/how-to-build-it/technical-help/articles/design-distortion/

Transistors will have different pinouts. Look at their data sheets to make sure the transistor is compatable with the circuit (max voltage specs) and the pinout, then give it a try. You might have to fuss with resistors around the transistor, but I'm guessing this is on breadboard anyway.

[smallbearelec]

You could try Paul Cochrane's Timmy:

http://diy-fever.com/effects/the-ultimate-overdrive/

but without the crazy number of clipping diodes. With those reduced to two, it's fairly simple. A Tube Screamer would be similar.

Fakes of the J201 have become a plague. I charge more for it than some on-line shops. However, I guarantee that what I sell came from franchised distributors.

The BC108 is a reasonable sub for the 2N3904 in Electra-type boosts. Would not have the gain of an MPSA13, but I would still expect it to work.

Regards
SD
www.smallbearelec.com

[monomatic]

Karbomusic - From reading the GGG article that MTH5044 posted, I can see that your suggestion is solid. Thank you both!

SmallBearElec - Your store is quite popular around this place! I went ahead and made an account so I can order some of the J201's when they are back in stock. Thanks! BTW, thats an awesome selection of Moog-style knobs. Definitely grabbing some of those.
I look forward to checking out the Ultimate Overdrive link once I get my head wrapped around the info in the GGG article posted above.
Again, big thanks to all of you.

[Brisance]

Aha, perfect opportunity for self promo, here's my recent design utilising one: http://www.diystompboxes.com/smfforum/index.php?topic=110699.0