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No voltage across power out terminals and speaker playing

Hello!

I have a Marantz SR4600 receiver.I wanted to measure it's approximated performance with an excellent quality sound card and RightMark AudioAnalyzer.

I have a neccessary voltage divider for speaker-to-line levels conversion. My other amp, Technics SU-V4X works ok.No problems at all.

With Marantz, I have no voltage reported across speaker terminals when measuring with a multimeter and playing a sine tone through speaker.

Still the speaker is playing very loud.

To be assured, I also connected the receiver to pc's line in. Here a signal is not sensed too, although I've fiddled with volume. So, I doubt it is a multimeter's fault.

I don't have much experience with various exotic amp designs... So possibly I'm missing something.

Maybe, this has something to do that (perhaps) Marantz used switching mode discrete amps?

With sincere greetings, Daniel K.

Reply to
gijoe
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Switch your multimeter to AC VOLTS.
Reply to
John Fields

It is on AC... I said I have measured Technics amp with no problem. I only have problem with the receiver.

Reply to
gijoe

Measure across the active speaker terminals. Expect to see less than one volt AC.

Reply to
Homer J Simpson

I do it all the time.There is 0 ac volts across active speaker terminals.

Reply to
gijoe

You're saying that you have a speaker output with no voltage being applied to the speaker. There's something wrong with your measurements. Period. Can't have a speaker output without voltage.

Try measuring another voltage source with your DMM on AC volts, and see if your meter is working. Try measuring another voltage source with your sound card and voltage divider, and see if it's working, too.

Own the problem. Use your head.

Good luck Chris

Reply to
Chris

The DMM is working.I've tested it again with a line out signal from cd player. And about your statement "You're saying that you have a speaker output with no voltage being applied..." I think we got misunderstood that time. What I meant was, that I read 0 volts across active speaker terminals, with DMM. All the time.Even when there is sound in the speaker. I always try to use my head first, before I post. But this time, I got owned by physics. This is very mysterious problem for me.

Reply to
gijoe

Pay attention to what Chris told you - You cannot measure zero Volts AC AND have sound from the speaker. If your meter is ok, your test is faulty.

Reply to
Don Bowey
[snip]

AND

Or the meter is insensitive to audio frequencies.

Reply to
Greg Neill

Or it's a crappy connection with the meter probes.

Reply to
Lord Garth

How can it all be, if I play *exact* same signal (calibration signal from RightMark AA) and on every device, but the Marantz, it all works! Should I assume my receiver is damaged? (Irony warning)

Reply to
gijoe

Hook it to a scope and see for yourself. If you think there is 0 volts, there should be no vertical deflection.

Reply to
Lord Garth

Disconnect the supply connections to the speaker, first one, then the other and see what happens to the sound. Connect the meter across the amplifier outputs without the speaker connected and see what happens. Connect up everything and measure the voltage between each speaker input and ground.

R >
Reply to
Roger Dewhurst

--- Think about it for a minute. If you have sound coming out of the speaker then you _must_ have current in its voice coil, and in order to drive current through the voice coil there _must_ be a voltage across it.

So either there's something you're not telling us, something you're telling us which is wrong, something you're doing in your measurement which is wrong, or you've just discovered a source of perpetual motion.

Why not post a schematic of your test setup so we can see what's _really_ going on?

-- JF

Reply to
John Fields

Most Likely he's using a DC volt meter, the Marantz being the most likely device that is generating a perfect AC sine through out and nulling it. just a thought! :)

--
"I\'m never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5
Reply to
Jamie 

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So, by thinking that you had made an error, but hadn\'t, you were
wrong in thinking that and have made at least one error, no? ;)
Reply to
John Fields

Ahh! Of course, that makes the most sense. It never occurred to me that one might read the output with DC set on the meter.

Reply to
Lord Garth

What was it that Kirk said.... oh yes, "Jackson Roy Kirk, your creator is dead! You have mistaken me for him.... You have made an error! You are flawed and imperfect...You did not detect your mistake, YOU have made two errors...and you did not correct by sterilization, you have made three errors!"

"Execute your primary function"

(excerpt from 'The Changeling')

Reply to
Lord Garth

Of course, if it's a bridged output amplifier, then that will short out part of the output stage.

I don't have a clue how common bridged output amplifiers are in home stere amplifiers.

Michael

Reply to
Michael Black

Object lesson, get an isolation transformer...

Reply to
Lord Garth

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