Op-Amp Questions

[Schappy]

Im breadboarding a Thor and having a difficult time wrapping my head around how to hook up the Op-Amp. Im looking at two schematics one from Gaussmarkovs site and one from Runoffgroove.

http://gaussmarkov.net/layouts/thor/thor-schem.png
http://www.runoffgroove.com/thor.html

The run off groove uses a single Op-amp(TL071). No connections are made to power and ground in the schematic. Am I to assume that the power and ground should be connected via pin 4 and 7?

The gaussmarkov schematic uses a Dual Op-amp.

Are there any advantages to this?

Also Im confused about the seperate Op-amp schematic. Why would these extra connections need to be made versus the TL071?

[GibsonGM]

Good question, Schappy.

1) Yes, you need to attach pins 4 and 7 to - and +, respectively...they are omitted from most schematics just to keep them simple.

2) I see no advantage in using the dual opamp except that maybe folks have more '72's around than 71's?  If you look at the connection for the 2nd 1/2 of the opamp, it is configured as a buffer going nowhere - this is how you stabilize an opamp section you're not using (good to remember!).  Prevents any issues later on, such as noise/oscillation.

Happy building!
~Mike

[Schappy]

That clears it up. Thanks.