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Is my receiver clipping? Shutting down when volume is high.

Hi, I have a Bang & Olufsen Beocenter 7700 system. It is an "all in one" center with turntable, FM tuner, and tape deck. It is rated at

40w x 2. It has hookups for 2 sets of speakers.

I bought this thing called a Quatravox Synthesizer, which is some kind of 70's surround sound/quadraphonic processor. It is supposed to turn a 2 channel system into a 4 channel. I hooked it up to my system to 2 sets of bookshelf speakers, one set is a Baby Advent II, and the other set came from a Mitsubishi bookshelf system. The latter set handles 80 watts. When I turn my stereo up past around 36 for a length of time (it goes to 60 I think) the receiver will power itself down.

I remember hearing about amplifier clipping and I am wondering if this is what is going on? That the receiver is not putting out enough power to drive the speakers. The Beocenter does have a set of what looks like RCA plugs on the back labeled "Preamp Left/Right Out". I am not sure exactly what these do. Can anybody shed any light on my situation?

thanks CTV

Reply to
Cartrivision1
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Have you tried it without the Q box? Just hook up the speakers to the speaker terminals and see if it behaves the same. My guess is it is just overheating the amp and shutting itself down.

The preamp out jacks were probably intended to be used with an equalizer or other signal processor. Are there preamp in jacks as well, connected with a metal jumper on the back?

Reply to
Michael Ware 

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money"  ;-P
Reply to
**THE-RFI-EMI-GUY**

Preamp outputs are just what it says... preamp outputs... the signal before it goes through the power amp.

I have no idea what Quatravox does... but I'm quessing the Beocenter is shutting down for its own protection. Are both sets of speakers at least nominally 8 ohms? You might be presenting to low an impedance to the amp. Try hooking one set of speakers straight to the B&O and see if it still shuts down. Then the other. Then both. If it only shuts down with both...its most likely because one pair or the other or both are less than 8 ohms. I'd yank the Quatra thing anyway and see how stereo sounds.

ScottW

Reply to
ScottW

I have been running the Advents with the Beocenter for a a couple years now with no problems. And the other set of speakers are definetly 8 ohms, I just checked. I wanted the Quatravox processor because it is supposed to do a good job of decoding both surround and Quad sources. And it also gives me an excuse to hook up 2 sets of speakers in my living room! I could just hook up the other set straight to the Beocenter as it has 2 sets of speaker connections, but it uses special speaker cables which I don't have right now.

thanks, CTV

Reply to
Cartrivision1

I checked and it seems that my particular Bang & Olufsen stereo uses 4 ohm speakers:

Power output RMS DIN: 2 x 40 W / 4 ohms Harmonic distortion:

Reply to
Cartrivision1

I think that is what you need to try to see which piece is at fault. Try just one set of speakers. Does it still fault..then it is has to be the B&O or the speakers... most likely the B&O. If that works add the second pair of speakers. If that works its obviously the Quadrovox.

Good luck.

ScottW

Reply to
ScottW

No... it you hook up both sets of 8 ohms speakers to the B&O you have 2 speakers in parallel on each channel which should be ~4 ohms. It could be one of your speakers isn't really 8 ohms or that Quad box presents a less than 4 ohm load and the B&O is just protecting itself.

If you have 8 ohm speakers, hooking up both pairs to the B&O should not be a problem.

ScottW

Reply to
ScottW 

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money"  ;-P
Reply to
**THE-RFI-EMI-GUY**

Some receivers become unstable using the Quatravox. When Dynaco released the original version back in the 70s, we would get in receivers with blown up power amps from using this device. Chuck

Reply to
Chuck

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