Connecting signal generator and TRS 1/4 inch jack.....Will it work OK?

[vandy12]

Dumb newbie question but I wanted to ask if there is any problem connecting a 1/4 guitar jack into a pedal and then connecting
the other end of the cable, BNC, to the oscilloscope? Same question with signal generator.

How can you daisy chain a signal generator thru a pedal (or guitar) and into an oscilloscope and run a signal thru the pedal
into the oscilloscope?

Will this give you a nice clean signal or be problematic? Is there a better way to connect a guitar or guitar pedal to a signal generator or oscilloscope?

What is the BEST way to connect a device using a 1/4 inch TRS into a signal generator or oscilloscope?

Thanks.

Thanks.

[anotherjim]

Lab signal generators can definitely be used.
Your mention of TRS jacks is confusing. You only need mono TS jacks. The pedal probably has a TRS input socket, but the ring contact is used to switch the pedal's power on by shorting ring to sleeve with a TS plug inserted and thereby connecting the supply negative (or positive) to the pedal circuit 0v.

[bluebunny]

There's nothing to stop you connecting (almost) anything you like to your oscilloscope - that's what they're for.  Finding a BNC-¹/₄" jack lead might be tricky.  You could make one up, of course, but my easy way out was to get a BNC-phono (RCA) adaptor, then plug in a readily-available phono-jack lead:

[ElectricDruid]

I've got a set of BNC-to-1/4" cables that I made up on my bench for exactly this purpose.

I often use them with a little box that I also put together that has two sets of three jacks commoned together. One set gets the audio source, one oscilloscope channel, and a lead to the pedal. The other set gets the output from the pedal, the other oscilloscope channel, and a lead to the amp. That way I can listen to what I'm doing as well as see it.

[PRR]

I went the other way. When a badly stripped-out Allen B DuMont oscillograph followed me home, I refurbed it with 1/4" input jacks for used in a music studio. (An alternative is alligator clips, they fit everything; but in that studio the roaches would steal them; I had to keep my technical clip-leads in a locked drawer.)

[iainpunk]

i have plans to make a long lead that has two BNC connectors on one end.
on the other side of one of the BNC is a simple 6.35mm TS plug
the other has both a 6.35mm TS plug and TS jack, so i can tap of the clean signal.
its currently no.6 on my hobby to-do list, so ill probably get to it next month. (no. 3 is finishing my DIY guitar amp)

cheers, Iain

[vandy12]

Thank you Blue Bunny. The 1/4 inch to BNC is kind of a strange connection since I'm new at this and have only used BNC for testing
equipment. I guess the BEST way to connect is using the 1/4 inch and BNC connections. Since I am just starting this
I was trying to be careful with the 1/4 because you don't see them hooked into oscilloscopes often and I was not even
sure if this was OK to do without some kind of mishap. You should be able to do this with probes
too I would think, but I'm looking for the best signal and don't know if probes would be better vs. BNC 1/4 inch combo. Bottom line
question is me trying to learn the BEST connection for running the signal generator thru the pedal or guitar harness into the oscilloscope.
I guess the best way for the best signal is to run bnc from signal generator to pedal with 1/4 and then a second 1/4 coming from pedal output
to oscilloscope BNC. Really like your connection idea using RCA adapter. So this raises the question which connection will give you the better signal
a 1/4 to BNC or 1/4 to RCA adaptor on BNC? First scenario you would have two connections and second you have three. I may be being too picky
here but I'm thinking if you can get the best signal you can it will help with everything you do. Maybe I'm just blowing wind and the
differences between the connection types are so small it is not really that big of a deal when troubleshooting problems. At least now I know the 1/4 will
not hurt the oscilloscope in any way. Appreciate you input.

[ElectricDruid]

The "best way" is the way the suits your style of working the best. That's up to you. There are plenty of options, and to be honest, there's not a lot to choose between many of them - equivalent ways of doing the same thing. house something that suits you and you'll be fine.

No damaging the oscilloscope is only a question of not putting signals into it that it can't handle, but in my experience, audio of *any* type is always within the safe limits of an oscilloscope. They're usually designed to handle much tougher stuff than we ever throw at them!

[FiveseveN]

Maybe I'm just blowing wind and the differences between the connection types are so small it is not really that big of a deal when troubleshooting problems.

Yes, exactly. You're not dealing with high power or frequency so you will not be able to detect the influence of an adapter.
And I must say, troubleshooting usually involves scoping the circuit in many different nodes, i.e. with a probe. There's only so much the output signal can tell you, so I doubt you'd be looking at them long enough to warrant a cable.

[bluebunny]

Assuming you don't get cruddy adaptors, then "best" is moot.  The electrons don't know about adaptors, so they don't care.  And therefore, neither will the oscilloscope.

[vandy12]

Thanks Electric Druid very, very helpful information.

[vandy12]

So five and seven you are saying better to check continuity/signal with probes and you'll get more info?

The info you get running a signal thru a pedal into an oscilloscope will be nominal compared
to just using the probes and scope to check parts of the circuit? Makes sense.

So what are a couple of examples of how you can use an oscilloscope and signal generator to
develop a pedal circuit? How do you use it to alter and fix things? I guess I'll learn some of
that thru time and experience. Electricity is not my expertise area. I'm trying to branch out.
I am hooked on those videos of that crazy Australian dude fixing all kinds of stuff and just can't believe
how he can use this huge circuit diagram, reading it like a book, to trace right down to a small point
where he thinks the problem is just by reading the diagram. I am amazed by this.  Thanks.