This sob story comes complete with Hollywood writers, Russian service people holding components more or less for random, and one weird performance problem. I tried to be brief but it didn't happen.

It is complicated by the fact that the client chose not to buy the equipment from us, actually paid us a reasonable consulting fee for the design, then bought it at a local A/V whorehouse. Where the client's bookkeeper has an account. Of course. I should have seen that coming.

I installed a Denon AVR-3802 in a two-zone system. The second zone has six pairs of speakers using impedance-matching volume controls, all set to X 8 (times eight).

All was wired and in place without Zone 2 being connected or turned on, and it all worked fine. Upon connecting and turning on Zone 2, the amp got warm for a few minutes, then it quit. It would not turn on again.

The client's cousin took it to service. I thought the service company I recommended did warranty service on Denon. They did not but the client agreed to pay. Turns out four output transistors blew, nothing else. The service person, not knowing I had installed the unit, said installation was probably the cause of the problem.

About eight weeks went by as they waited for Denon to send them the transistors. Meanwhile, I did some testing, like I used to do while in the Speaker Design department at Marantz, and found that the entire second zone wiring system hovered between 6 and 8 ohms, depending on the volume levels at the VCs. Denon said that unit did not have a problem if the impedance dropped really low at subaudible frequencies, so that should not be a problem. I built a Zobel for the subsequent connection anyway.
There are no connections between any of the speaker leads and ground, or between the two channels once the wires leave the chassis.

Anyway, we finally got the unit back. It played for about two minutes. It switched the Denon off, but it would come back on as long as Zone 2 was off.

I found that if I switched the power amp away from Zone 2 and use the Zone 2 line out, the Denon did not switch off. Bla bla bla, client out of country, delay, delay,

They decided not to send the thing back to service but to cut their time losses and use the zone 2 line out to a separate power amp. The separate amp is installed and works beautifully with a REC OUT from the main zone. I finally got back out there today, and NOW Zone 2 shuts down about three seconds after turning it on.

It did not do that earlier. The power amp is switched away from Zone 2, so it is not that. The client knows how to work the system the way it is now, so I am leaving it like that and seeking an answer to be able to make this damn thing work as two zones.

Any clues?

Possible it is same TYPE prob. surfacing two ways...now with the power amp,power out = watts? and what are the power ratings on the impedence match volume controls...could u just set all the vol. conts. to X1 (easily if audioplex type without changing jumpers in rear)Then us a niles ( or equiv.) resistive match speaker selector box...

I've seen output failure due to poor connections on the negative side, usually due to a bad wiring connection, but sometimes due to something else down line, like a volume control, a crossover, etc... As I recall, Julius Audire had trouble with this in his early amps. I'm thinking his M-1 and maybe the Forte?

One clue might come from Denon. It would be helpful to know what types of faults their "protect circuits" are designed to react to.

My description was way too long and I think this point got buried: right now, I have nothing connected to the Zone 2 outputs, and in the setup, I have switched the amp that had blown AWAY from Zone 2. So connections to that amp do not matter now.

At this point, I am attempting to just say the heck with the Zone 2 power amp inside the Denon and use an external amp. That means that the volume controls are out of the circuit.

In the setup, I have switched the Denon's internal Zone 2 amp away from Zone 2 use, I think to BACK speakers, and I have set BACK SPEAKERS to none. That places that power amp in connection with the main zone, I believe, and I have no problems with the main zone.

And now I have nothing at all connected to ANY Zone 2 connectors. When I power Zone 2 on, it comes on for about three seconds, then goes off.

Shorted the outputs again? Happens all the time. :)

Have you considered swapping the zone speaker outputs, as a temporary test, and powering zone 2 via the main outputs? See if the zone-2 out will drive the main speakers, also

Wait! Are you saying that turning on zone 2 will shut it down with NO speakers attached??? Maybe there's a wire strand on the terminals, or internally, or a damaged terminal is shorting to chassis.

Just some random thoughts. (I have a lot of them, but some aren't fit for print!)

Larry
www.fineelectricco.com

YOU CANNOT PUT MORE THAN ONE PAIR ON ZONE 2...

If you call denons tech # they will tell you that zone 2 is for one pair of speakers only.

You risk and did risk blowing that zone2 amp...

you might get away with 2 pairs on it but denon will not warranty it if you knowingly over taxed that Z2 amp...

How do I know this....because one of my stupid employees tried doing the same thing with his freinds denon 2803 amp...he kept blowing the amp...

it would get hot and shut off...so dont do it...

DONT BE CHEAP... tell him HE HAS TO BUY AN additional amp to drive the other speakers...

I garuntee that amp is now bad...

easy as that...



hope that helps...

primo

I have to go with “primos” answer. The second zone amp is not designed to drive anything substantial irregardless of impedance impedances of 6-8 ohms is technical called 8 ohms nominal so that is not an issue. What is an issue is the minimum amount of power required to drive 12 speakers. Lets imagine that each speaker requires 15 watts minimum to fill the room it is mounted in with a listen able amount of sound, which of course is 90 watts per channel. Now look at it this way, most of the time the second zones volume is fixed at 0 db or manually set to about 0db which should be about 10 millivolts output to the internal amp. 10 millivolts is usually what is required to drive a power amp to full volume before detectable distortion is reached. As we all know, the volume is usually set to this point, so that the customer can just crank up the V/C as desired and enjoy. So maybe you can see where I am going with this. If the volume on the amp is set to full power before distortion and the well that needs to be filled is deeper than the supply line can keep up with. There should be a little light on the front of the receiver that comes on under such circumstances, that says- thank you for opting to buy our optional external amplifier.

Oh I am sorry, I just noticed you said it does this with nothing connected to zone 2, I had a Denon receiver do this before, it was the weirdest thing, turned out to be a bad video output cable, I don’t know why it was freaking out on second zone, go figure. Replaced the cable and the problem went away.

What is this word?

regardless

this is waht most people mean to use when they use the double-negative non-word irregardless

That is one of those forbidden-by-teachers words, like ain't.

A college girlfriend, an English major, had a dream one night where God assembled all the English teachers across the countryside, then God speaks the word "Irregardless" and they all go straight to hell.


I'll vote for weird! I was about to ask you which cable when I actually paid attention to what you wrote, being video output. I will disconnect the video outputs (composite and component) and report back.

Many thanks for all the suggestions. No, no short on the outputs, maybe a loose wire inside, and I will inspect it; now that the Russian Mafia has worked on it, who knows?

I talked to a Denon tech early on and described what I was doing. He was not at all bothered by the idea of six pairs on that amp. If this is true, then that fact, the three zones of output, the output trigger and the RS232 computerized setup and the auto-EQ are LOTS of reason to buy Yamaha instead of Denon. Of course, I am talking about a new Yam and an older Denon, so ? ? ?

I recently did a Denon 3805 with 2 pair of speakers on Zone two with impedance matching volume comtrols and they crank pretty good. At some point they distort a bit indicating some clipping. I do not think those channels would survive 6 pairs of speakers. BTW, this receiver rocks, sounds great for a receiver, has all the bells and whistles and the discrete IR codes are extensive. My only complaint is the 1/8 inch phone jack for the calibration mic.

I have a client with a Denon 1803. The second zone goes to 2 pair of Kef outdoor speakers via two Russound impedence matching volume controls hooked up through a Russound EZB-1 terminal strip.

The speakers crank. Who did your customer buy this receiver from? Was it B-stock? I think you've got a bad receiver, Should have pushed for a replacement.

Notwithstanding, the Anglo slang of the aforementioned first part, by the founder of this thread, my remark may have been a bit obtuse but for a moral remedy indeed. Wherefore, it was not intended to be as a prank or insult by nature, but more as a conduit to congeal an end to a diminutive selection of words.


Actually I suck at language arts, I have just seen to many old episodes of Star Trek, (Spock was my hero)..


I am voting for a short in one of the A/V cables.