Receiver as signal source for testing amps etc

[diydidi]

Hi Guys.
I was recently given a beat up Harman Kardon receiver by a friend. Managed to get it working as new.
Ive now got it set up in the workshop on my bench so I can listen to some good music
I would like to tap the preamp out so I can use it for testing powered speakers etc.
Where is the best place to take it from? Mine uses two links between pre and main RCA sockets.
Would be great if there is no sound on my speakers when doing this.
Also any suggestions on "how" to the cabling would be great too. Was thinking just a jack socket on a cable...

I have attached a picture of the rear panel.
Thanx in adcvance..

[mozwell]

just use the REC out from tape 1 with the receiver set to radio.
This way you don't have to stop listening to the Tadio when you do tests
If you have a recorder selector switch, make sure its set to radio > rec1 out.....

[diydidi]

Hi Moz. I will give that a try. Thanks.
Will I still be getting sound from my house speakers? would be great to have them off...
ALSO< How do I get those two RCA signals to ONE mono jack?

[olddawg]

Hi Moz. I will give that a try. Thanks.
Will I still be getting sound from my house speakers? would be great to have them off...
ALSO< How do I get those two RCA signals to ONE mono jack?

My guess is that old beast has a mono/stereo switch. If it doesn't just Y cord it or cord it, or not. You just want the signal. It should have speaker select switches. If you use the line out signal for signal injection make sure you isolate the probe with a cap.

[Brad1]

Hi Moz. I will give that a try. Thanks.
Will I still be getting sound from my house speakers? would be great to have them off...
ALSO< How do I get those two RCA signals to ONE mono jack?

Yeah...just take tape out, and depress the speaker button on the front panel, if it has one. Lacking that, you could build or buy a cheap, simple "Speaker Selector" , or "On/Off" box, and just switch it out.

Also...why would you want to take two RCA out to one mono jack? Wouldn't you be listening to a pair of powered speakers?

It's best NOT to simply "Y", or connect two outputs directly together. It's best to have some kind of circuitry involved if you want to combine left and right to mono. Never a good idea to directly short two outputs of ANYTHING together. "Y" cables are (mostly) for splitting an output to two inputs.

Brad1

[J M Fahey]

FWIW I have used my faithful Lafayette FM tuner (bought around 1970 ) as a signal source, thanks to an added 1.4" jack, just a single channel but with the tuner set to Mono FM .

Still works like a charm

[mozwell]

The record out is independent of the receiver volume control, so if you don't want sound from your speakers, just turn the receiver's volume control down.
You only need an audio signal, so one side of a stereo radio will work fine, a simple RCA to 1/4" will do the job for you.
If you are using this to inject audio into other parts of the amp, and not just its input, you may want to use a blocking capacitor in the lead.
Also, the line out level from the "REC OUT" on the receiver may be higher than a guitar level signal, so a volume pot in your lead will allow you to adjust the level going to the 1/4"

RCA - 50k volume pot - 0.1uF 600V blocking cap - 1/4" jack with 1M resistor to across the two wires on the 1/4" jack (to act as a pull down load for the capacitor)