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I want to sell a Sansui receiver I have and would like to make sure the phono section works. I only have a CD player and FM tuner as sources, but no turntable. Any simple way to test the phono section?
Edits: 07/21/11Follow Ups:
go through a lot of trouble. Just take a small screwdriver or other metal object that will fit into the RCA jack hole and touch the metal and positive terminal jack with the metal at the same time.
If you get a nice full-throated hum/buzz, it's working.
Make sure the volume is turned down first and then turn it up slowly.
Doug
I have done this "trick" too. The ungrounded buzz trick will tell you you have gain, but it does not "test" the response of a music signal. While inputting a low level full range signal, from a cdp, tuner, tape deck, MP3, etc. will sound muffled and boomy, at least the unit's phono function can be semi-judged. Since the OP wants to sell the unit in good faith, maybe some music might be a better test ?
If your cd player or tuner do not have level controls, I would not plug them into a solid state phono preamp; for fear of overloading and damaging the sensitive phono inputs. Be careful with those phono inputs...
...is not difficult, but not an exacting practice. Like others have already said, the phono EQ raises bass; plus it cuts treble; so any full range sound plugged into the phono jacks, at a very low level please, will sound strange; boomy and nasal plus lacking highs.
So, if your cd player has a volume control, turn it way down, like near zero. Turn the receiver volume way down, as well. After plugging into the phono jacks, slowly and carefully raise the volume control on your cdp, as well as the receiver. If you hear the "muffled boomy music" you are in...Do NOT raise the cdp volume until you hear distortion; since you might fry the sensitive phono preamp. If you hear the muffled music at a low level, you have tested fine...Good Luck...
One poster advised using an MP3 player or actually any other source that you can set to very low volume. He should have also mentioned that under those conditions a properly functioning phono preamp should sound awful. It should be all bass and no highs.
Another way of testing is to use a great little device sold by MCM Electronics available online for about $10-$12. It's a passive inverse RIAA filter. It takes as input a line level source such as tuner or CD player or MP3 player and makes it a phono signal. It doesn't sound all that great, and its performance will depend to some degree on the output impedance of the device feeding it, but it's great for function checking a phono stage. I've got one on my bench and use it frequently.
I'll bet you can also find a suitable MP3 file online somewhere that you can use to feed directly in to your phono preamp. And if that doesn't exist it should and I'll see if I can make one.
... and you are not concerned about finite RIAA compliance, then just use a 1/8" stereo phone to 2 RCAs cable and use the headphone jack on an iPod with the volume very low. Start at zero and slowly increase the volume. This will tell you if the input works or not.
Prehistoric 4-Channel Lizard
You could buy or build a reverse RIAA EQ box with an input level control and run a line level signal through it. You could also do this on a PC if you have a sound card with RCA outputs and can install AudioMulch and a VST or two.
Rick R, Sony's legendary 2010 receiver has lower than normal audio from its' tape output jack. Around mike input level. Handy for testing vintage phono pre-amps. For a receiver touted as having sub-standard audio quality, 2010s were fairly robust via phono pre-amp or mike input(like on Sansui's 5000x & 9090 Receivers; several Kenwood-n-Pioneer receivers also had mike input capability). Too bad there aren't as many stations nowadaze which benefit from such aural improvement. 73s from Sactown!!!
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