Denon AVR-3808ci receiver & Rotel RMB-1075 amp 12V trigger problem

0 Members and 1 Guest are viewing this topic. Read 5094 times.

OakIris

  • Jr. Member
  • Posts: 14
I posted this on another web site but received no response.  I'm hoping someone here might be able to help.  :)

I would like to set up my receiver and amp so that the amp turns on when the receiver is turned on. (The amp has no IR remote capability.) I thought this would be an easy proposition - just attach the trigger out of the receiver to the trigger in connection on the amp with the 3.5 cable, turn the amp trigger toggle switch to "on," and voila....but.... When I try this, the amp goes into protection mode, all speaker LEDs flash red, and the amp sounds as if it is turning on and off, or at least some sort of relay is picking.

Is the Denon receiver sending the amp too much power? I can't find any specs for the Denon trigger out voltage, nor any way to adjust it; the Rotel amp is supposed to be able to handle voltage from 3V to 30V.

What am I doing wrong, or are the two components just not compatible power wise?

Holly

Bob in St. Louis

  • Facilitator
  • Posts: 13248
  • "Introverted Basement Dwelling Troll"
Hello Holly,
I'm not going to be much help past these ideas, but:

- One thing that comes to mind is the amp may be going into protection mode because there IS a protection issue.
With the trigger wire disconnected, will the amp work normal? (just making sure there aren't speaker wires shorted).

- If you have a volt meter, you could measure the Denon's output. Knowing the Denon's output voltage would be nice, but if nothing else you'll know if you're out of the Rotel's "happy zone".

- Is the trigger cable supposed to be a "trigger cable specific" cable, or will any 3.5mm cable work? (what comes to mind is that you may be using a typical stereo mini plug instead of a mono, or visa versa). I do not know the correct answer.  :?

- Also, check the troubleshooting section of the Rotel's manual. If you're lucky there might be something in there about "flashing LED" when activated by remote trigger.

Just a couple ideas I had Holly. I've not messed with triggers before.


Bob

OakIris

  • Jr. Member
  • Posts: 14
Thank you for your response, Bob.

The amp works fine when the trigger cable is not attached; no protection faults show, all speakers work.

The cable I am using is a 3.5 mini cable from Radio Shack which I have seen recommended elsewhere for the "trigger application."  It is a mono cable.  There doesn't seem to be any cable specified just for use with a 12V trigger, at least none that I have found with a google search or two.

Excuse my ignorance, but how would I use a voltage meter to find out what voltage the Denon is sending from the trigger output? 

I did check the troubleshooting section in the Rotel RMB-1075 manual but there is very little there, and nothing about problems with the trigger control.  Sigh.

Holly

Bob in St. Louis

  • Facilitator
  • Posts: 13248
  • "Introverted Basement Dwelling Troll"
Hi Holly,
Uh Oh, You've gone through my suggestions pretty fast.  :?

- Your speaker connections are good if the system plays normal until you connect the trigger wire.
This tells me it's something in the wire itself, the trigger output of the Denon, or the input of the Rotel.
This narrows down....well....all the easy stuff.

The only ones left are the trigger cable and voltage.

- Trigger cable: Does your Denon or Rotel manual (not a Google search) specify a "particular" type of cable be used? You may have a recommended trigger cable, but you may have one of those unusual situations where you are 0.01% of the population and need a "XYZ" cable instead of the "ABC" cable that is readily available and used by the vast majority of the populous. Just maybe. You know how these things can be. No solution is always 100% accurate. There's always an exception for one reason or another.

- Voltage: Do you have a meter that measures voltage? If not you could buy a cheapy for $10 at Walmart. The possibility remains I'm sending you on a wild goose chase and voltage isn't an issue, but........it could be. You never know until you rule it out. If nothing else, you'll have a voltmeter to check 'other stuff' in the future.

When you say, "how would I use a voltage meter to find out what voltage the Denon is sending from the trigger output?"
I'm not sure how much information I need to give here. Do you mean how do you physically USE a voltmeter, and how do you connect it to the output of the Denon to test the output voltage?
I can explain, and walk you through it Holly, but it'll take a bit of explanation on my part. I want to make sure where we're at before I type a book, only to find out I've not typed anything you didn't know already.
Where are we regarding your knowledge of voltmeters and testing voltage? On a scale of one to ten, as 'one' being, "you've never seen a voltmeter in your life".......?
The quick answer to your question would be:
#1 Stick the trigger cable in the Denon
#2 Use alligator clips to hold the meters positive and negative leads to the other end of the trigger wire. (in this case, polarity does not matter.)
#3 Turn on the Denon as you normally would, keeping an eye on the voltmeters screen.
#4 Record the reading.

What I'm not sure about (but assume), is the trigger signal is just that. A trigger. Like a gun. It's sends a quick "zap" of a signal, just enough to wake up the piece of equipment downstream. OR, is it a longer, slower build up, stabilization, and drop off of voltage. Nice easy and slow. I'm not sure. But either way, keep a close eye on the meter, as the signal might be a very quick (milliseconds?) 'snap' of signal.
Again, if I were the person doing the testing in this situation, I might prefer to have an analog voltmeter as opposed to a digital one. My digital meter isn't quick enough to see 'snap' changes. An analog jobby would have a sweep needle you'd see go from the left side of the spectrum - full right - and back to left in a split second.
So, again Holly, do you have a meter of any sort?

Do you have a Radio Shack part number for the cable? Seeing it would help me know what we're dealing with.

With the exception of the actualy testing, I'd avoid playing too much with the trigger wire installed. It sounds like your Rotel is getting a wee bit pissed with the situation. I wouldn't press my luck playing with it. Only for testing purposes only. Know what I mean?

I'll do some digging for you, but I work tomorrow (Saturday) and have prior engagements Saturday evening and Sunday morning. If my reply time is a day or so, I'll be back, don't worry.

Bob

OakIris

  • Jr. Member
  • Posts: 14
Hi Bob,

I spent my weekend outside instead of checking back here, so didn't see your post until today.

I can't seem to locate the cable I am using on the Radio Shack site.  Sigh.  I will have to check for the part number when I get home. 

I do have a cheapo volt meter at home, but have almost never used it, thus my request for instruction!!  Thank you - now I know how to use the meter in this instance.

I couldn't find anything in either manual that specified what trigger cable should be used.  I'll check again to make sure I didn't stuff it into my 'miscellaneous cable" drawer, but as I recall, no trigger cable came with either the amp or the receiver.

Thank you for your continued assistance.  I will also check for a 12V transformer.  I am beginning to feel that all of this fuss may not be worth it - it really isn't a monumental task to walk 10 feet to turn the amp on or off manually.  :D

Holly

Bob in St. Louis

  • Facilitator
  • Posts: 13248
  • "Introverted Basement Dwelling Troll"
I spent my weekend outside instead of checking back here, so didn't see your post until today.
What just a minute......You mean you have a LIFE:dunno:

I doubt a trigger cable came with either unit. I've never bought from either brand, but have never seen a trigger cable come with....well....any type of unit.

Is there a setting in the receiver to send a signal? Or maybe a setting to adjust the voltage?

I succumbed to Google searching myself (found your 'other' thread too by the way :wink:), and found another thread you may find interesting.
It doesn't spell it out, but has some thought provoking points:
http://www.avforums.com/forums/archive/index.php/t-120721.html

I see on the Denon site, there's a spec of "assignable 2x150mA triggers". I assume there's two (quantity) trigger outputs? If so, did you try the other one? You *may* have to shut the unit down to allow it to "see" the cable in the other jack. Also, Denon says the trigger is assignable. This may be a clue there's some setting buried deep down in a menu that allows that output to be turned on.

I kinda doubt this too, but you may need a firmware update. *Maybe* your version of receiver wasn't compatable with the Rotel,but a firmware update may have fixed that.

The Denon site is very informative. A wealth of information there. But alas, nothing regarding triggers.  :roll: They don't even sell trigger cables in the "Denon store". That right there tells me the cable probably isn't proprietary.

Have you tried Denon/Rotel tech support?

Denon:
Tech and Operational Support hours of operation:
*New extended hours M-W (April '08)
9:00 AM to 7:00 PM ET, M-W
9:00 AM to 5:00 PM ET, TH-F
Tel:  201-762-6665

Rotel:
http://www.rotel.com/NA/Contact.htm


Regarding 'making a fuss', you betcha it's worth it.  :lol:  :wink:

Bob