oscilloscope to stereo receiver without damaging anything?

[oscopenoob]

Heyyo!

First off, please don't hate me: I bought a Tektronix 465 simply to be a "lightshow" while I listen to music. I am not really trying to analyze anything.

I cannot figure out how to connect it to my receiver/amplifier so I can listen to music and watch the oscope at the same time. I've bought a bunch of different adapters that go from BNC to different things, and the only way I can get a signal is connecting my phone through a 3.5mm jack to BNC cable, and that worked just fine. The last thing I tried was getting x and y BNC probes and splicing them to the left and right speaker wires in the middle of the signal, and all I got was "noise" on the screen.

I'm pretty much lost here. My next idea is to get some BNC to RCA cables and connect it to a line level out on the back of the receiver. Would this work? Is it grounding that is the problem?

Any help is greatly appreciated. Both Youtube and Google have no answers for me.

Thanks a lot,

Oscopenoooooob

[jcw0752]

The idea to come from the line out to the oscilloscope is a good one. With the proper range settings on the you should get a good display. This arrangement will not adversely affect your output. Another nice advantage is that the output to the scope will not be affected by the volume control so you can set the oscilloscope settings and leave them. I just hooked up a small handheld to one of the outputs of my receiver and found that 0.1 volts per cm and horizontal scan of 1 millisecond looked pretty good.  It is important to have the grounds in place as this is the reference from which the signal voltage is read. With the grounds unconnected you will see more noise.

John

[oscopenoob]

Wow! Thank you so much! I will try that because maybe part of the problem was I was not grounded... DUH! It needs to complete a circuit, right? Thanks a whole lot!

I will report back with findings.

[Electro Fan]

Try the tape outputs (left and right).  Run a regular stereo RCA patch cord from the tape outputs to the scope inputs (Channel 1 and Channel 2). 

Use RCA to BNC adapters like these on the scope inputs to accommodate the RCA patch cord:
https://www.amazon.com/GW-Security-Female-Connector-10pcs/dp/B001HBOOH6/ref=sr_1_9?ie=UTF8&qid=1510816883&sr=8-9&keywords=bnc+to+rca+adapter

Set the scope for XY mode.  Center the trace(s).  Adjust the voltage and time base to your preferences.  Try turning on and off Ch1 or Ch2 on the scope while in XY mode - you might prefer both channels on or possibly just one.

Happy listening and watching!!