First circuit, help!

[CZfreqmod]

Hi there, this is my first circuit on a breadboard. A simple op amp buffer using a Tl071 and a schematic from Beavis audio. I can't get it to work. No signal coming through. I think the circuit is connected right, could someone please take a look? The cap at the input isn't per spec, it's just what I had and I'm not entirely sure I have the jack sockets correct. They are stereo, I've tried to wire them as mono but might have done it wrong(they do carry the signal across if I put them in series with no circuit in between) . Any advice greatly appreciated, thanks.

[Vivek]

Welcome to the group !

It appears there are 2 resistors less than normal

Could you post the schematic that you are trying to build ?

[kraal]

Hi there, this is my first circuit on a breadboard. A simple op amp buffer using a Tl071 and a schematic from Beavis audio. I can't get it to work. No signal coming through. I think the circuit is connected right, could someone please take a look? The cap at the input isn't per spec, it's just what I had and I'm not entirely sure I have the jack sockets correct. They are stereo, I've tried to wire them as mono but might have done it wrong(they do carry the signal across if I put them in series with no circuit in between) . Any advice greatly appreciated, thanks.

Hi and welcome. Try to connect orange wire on the left to h3 instead of h4. and verify that your electrolytic cap is connected to h16 (not visible on your picture)

Have a nice day.

[antonis]

Welcome, also.. 

You might need some +9V & GND jumpers..

[CZfreqmod]

Thanks for the replies, I will check all the suggestions. Here is the schematic I'm working from.

[iainpunk]

welcome to the forum


that one looks like it should be moved one over to the left

cheers, Iain

[antonis]

Have you anything against open input circuits, Iain..?? 

:beer:  :beer:  :beer:

[kraal]

that one looks like it should be moved one over to the left

Just wrote it 3 posts above yours 

[CZfreqmod]

Hi all, thanks for your replies. I have checked through all of them and unfortunately not solved it. The breadboard power rails go all the way through, and I plugged them all into the first divide just to make sure it wasn't that. The leg on the input cap is bent in to the hole beneath the orange wire so it's appearance in the pic is deceiving. Also the cap at the end is connected. I'm baffled as to why its not working. 

[duck_arse]

measure voltages on the IC pins, and the supply rail, please. post all here. also, what is the part number of yer IC - partly obscured in the photo.

[Phend]

Turn the chip around ?

[antonis]

what is the part number of yer IC - partly obscured in the photo.

Hmm.. maybe an obscured "2" instead of "1"..

[GibsonGM]

what is the part number of yer IC - partly obscured in the photo.

Hmm.. maybe an obscured "2" instead of "1"..

For reference, the pinout for the TL071 and the TL072 are a few pages in. Note the power pins are different...worth determining if the chip is a '72 instead of '71!

https://datasheetspdf.com/pdf-file/1396328/etcTI/TL071/1

[CZfreqmod]

I tried soldering the circuit to vero board just in case the breadboard was at fault. There is some signal getting through but its terribly inconsistant, really crackly and mostly not there. . Voltage on the rail 9.3v The chip is TL071CP voltage on the pins : pin2 0.03v, pin3 3.09v, pin4 0v, pin6 0.03v pin7 9.31v As I understand it if the bias voltage is at 3.09v going into pin3 then the pin6 should have the same going out right?

[anotherjim]

Starting to look like a faulty chip?
Or... I can't see the power arrangement. If the power supply polarity is reversed and you don't notice a "-" on your meter readout, then it explains the situation you have - that is, bias voltage the right kind of numbers but chip not functional.

[duck_arse]

but we would also like to know the other pin voltages, even if you aren't using those pins. they all count, even the zeros. [not a political comment. not this time.]

[iainpunk]

Starting to look like a faulty chip?
Or... I can't see the power arrangement. If the power supply polarity is reversed and you don't notice a "-" on your meter readout, then it explains the situation you have - that is, bias voltage the right kind of numbers but chip not functional.

if the power supply is reversed the TL07x series tends to get hot and the magic smoke seems to leak out, rendering it broken and really hot.

cheers, Iain

[CZfreqmod]

Problem solved. Had a whole batch of faulty chips. Got some new ones from a different seller and it worked straight away!

[iainpunk]

classic. nice