Hello all,
I've recently built a GGG single buffer, and it's not working correctly
So far as I can tell it's wiried correctly (super low part count).
Here's what's happening, the LED lights but it's not allowing signal to bypass.
I've changed 2 components and I'm not sure it that would cause and issue or not;
1. I swapped the stereo input for a mono as I can't fit a battery in the enclosure,
2. I couldn't find TL071 so it has a TL072 instead.
Here are my Multi meter reads:
R1 4.00 - 8.86
R2 4.00 - 0.00
R3 1.86 - 0.00
R4 0.00 - 0.00
C1 4.00 - 0.00
C2 0.00 - 0.01
IC1 0.03 - 0.19
0.18 - 8.88
4.03 - 0.85
0.00 - 0.92
Power 8.88 - 0.00
Thanks ahead of time for your help!
-JHK
(https://i.postimg.cc/jWkZwtSM/1-EEDF7-D3-0-C4-C-43-B1-9110-7584-B4-BA823-A.jpg) (https://postimg.cc/jWkZwtSM)
(https://i.postimg.cc/0K7fBSd4/E4-C34-AB9-1-E2-A-40-EB-872-E-B67-A1425897-D.jpg) (https://postimg.cc/0K7fBSd4)
(https://i.postimg.cc/Q92mmm55/FCCB7687-60-B9-4660-845-D-A70648-AB49-E1.jpg) (https://postimg.cc/Q92mmm55)
(https://i.postimg.cc/yggn0tJs/FD70796-F-5-BC6-4-D44-B218-4-EF1-B3-F78-CAC.png) (https://postimg.cc/yggn0tJs)
TL072 will not work in this circuit. The TL072 has 2 op amps in it, you want a chip with only one. The TL071 has only one op amp in it.
Quote from: tonyharker on February 17, 2019, 01:30:17 PM
TL072 will not work in this circuit. The TL072 has 2 op amps in it, you want a chip with only one. The TL071 has only one op amp in it.
Just a point for clarity.....The reason this won't work is that the board was etched for a single opamp....if you were making this on a breadboard, or building on perfboard, etc, you could use a '71 OR '72, as long as you accounted for the different pinout and terminated the unused opamp correctly. Each one functions independently, just has separate inputs & outputs.
Like Tony said, best to get yourself a single opamp with the pinout of a TL071...
Ah I see, that makes sense.
Is there any way either the opamp may be
Damaged from plugging it in the way it has been?
Thanks so much guys, this was a huge help!
-JHK
It depends on IC's right output (pin7) BJTs complementary pair ability to withstand the 8.8V VBE reverse bias voltage..
In any case, you'll have, at least, one healthy op-amp.. :icon_wink:
Just to point out, there are many single opamps you can use, you may have a suitable one laying around, doesn't have to be tl071. LM741, tl061, tl081, LF351, and loads more
Awesome!
Thanks you both so much.
I'll dig though and see what kinda spares I've got laying around.
-JHK