madbeanpedals::forum

Projects => General Questions => Topic started by: skypn on July 05, 2020, 07:39:20 PM

Title: What IC Is This?
Post by: skypn on July 05, 2020, 07:39:20 PM
I'm having a hard time getting the transistors (2N5457) used in the blending portion of my pedal, so I spent most the afternoon looking for an alternative circuit. I believe I may have found it, but it doesn't name the IC.

(https://i.ibb.co/CwN73vV/Blender-Post.jpg) (https://ibb.co/FhNwLJ8)

I would guess a TL072, but I'm wouldn't know.
I also tried to get a schematic of S. MacCellen's B Blender, but I closest I could get was a PCB layout with no values. I would be willing to try either one. 8)
TIA
 
Title: Re: What IC Is This?
Post by: cooder on July 05, 2020, 08:14:49 PM
A TL072 or similar opamp should do the trick as far as I can see.
Title: Re: What IC Is This?
Post by: skypn on July 05, 2020, 09:27:13 PM
Thank you cooder. Do you know what the difference is between GRD and GRD(T)?
Title: Re: What IC Is This?
Post by: mjg on July 05, 2020, 09:58:36 PM
I'd say there is no difference between GND and GND(T), just connect them together.

The schematic you've found there will be good, that sort of blend circuit is pretty common.

For your original question about 2n5457, they are still available as SMD parts, so one option would be to buy some of them and some SMD converter boards.  But personally I'd stick with the op-amp build.
Title: Re: What IC Is This?
Post by: skypn on July 07, 2020, 02:03:00 AM
mjg. thanks for the input. I was hoping this would work. I play Bass, and try to build for that, but when I asked my guitarist to try my pedal, he really liked the blend. I don't think the SMD thing would work for me, heck, I have enough of a hard with through hole 8) 
Title: Re: What IC Is This?
Post by: aion on July 07, 2020, 01:33:00 PM
The GND(T) label is from the (very old) gaussmarkov Eagle libraries and its descendents. It's just a schematic symbol with a PCB pad attached. On the schematic, the T can be ignored.