As per subject line, I am looking for some help and advice with my whole house distribution system.

I think it may be better to deal by email or phone than on this forum to have things moving faster.  I can post final solution here if people are interested to know.

Wiring as per the Russound product manual.  See attached doc that represent the exact wiring in my house.

Quick description of issue:
Main amp overheats.  Connections were verified many times and look ok.  Jumpers on Impedance Matching Volume Control (IMVC) are properly set.

Possible solution   ?   : Removing the jumper pins from the PRE OUT/MAIN IN jacks to enable this unit to operate separately as a control amplifier and use a separate power amplifier.

Main Amp = Yamaha RX797: spec in attached doc


If you are qualified and/or experienced with whole house audio distribution system, please PM with either your email address or your phone number and timings when I can call you.

Much appreciated.


Chris

Well, if the amp is overheating and going into protect mode you have one of 2 problems.  

Seeing as this amp can drive High Current loads (down to 2 ohms), and looking at your diagram it looks as though you're pushing it down to the 2ohm level assuming all the speakers are a nominal 8ohms. (and assuming you have the wall controls setup correctly)  As long as everything is setup correctly, this shouldn't be the problem but you can measure the impedance of the whole circuit where you attach it to the amp with a DMM.  My guess is the actual reading will be under 2 ohms, as long as it's above say 1.5ohms you *should* be ok.  If you get anything lower than that, and something isn't wired right.

If all that checks out, the only other issue would be airflow around the amp.  If you've got it in any sort of cabinet, you're asking for trouble, especially when running a load that low.  Even running it out in the open @ 2ohms that thing will heat up like a SOB, so you can try putting a fan on it to see if that solves the problem.

I'd start there...  Hopefully the amp hasn't suffered any thermal damage.

D

Don't know if you've ever been there, but I would try posting your question here :

http://www.avsforum.com/avs-vb/forumdisplay.php?f=36

There are alot of guys there that are very helpful.

Quoted from Menace

As long as everything is setup correctly, this shouldn't be the problem but you can measure the impedance of the whole circuit where you attach it to the amp with a DMM.  My guess is the actual reading will be under 2 ohms, as long as it's above say 1.5ohms you *should* be ok.  If you get anything lower than that, and something isn't wired right.

I thought a DMM's Ohm setting was resistance only.   I didn't think a basic DMM could measure impedance (units also in ohms) ?

Quoted from Menace

Seeing as this amp can drive High Current loads (down to 2 ohms), and looking at your diagram it looks as though you're pushing it down to the 2ohm level assuming all the speakers are a nominal 8ohms. (and assuming you have the wall controls setup correctly)  As long as everything is setup correctly, this shouldn't be the problem but you can measure the impedance of the whole circuit where you attach it to the amp with a DMM.  My guess is the actual reading will be under 2 ohms, as long as it's above say 1.5ohms you *should* be ok.  If you get anything lower than that, and something isn't wired right.

If all that checks out, the only other issue would be airflow around the amp.  If you've got it in any sort of cabinet, you're asking for trouble, especially when running a load that low.  Even running it out in the open @ 2ohms that thing will heat up like a SOB, so you can try putting a fan on it to see if that solves the problem.

I'd start there...  Hopefully the amp hasn't suffered any thermal damage.

D

OK,
I followed your advice and not only did I measured the impedance at the amp, I also measured the impedance at the speakers.  Well, theory and real life are two things...  3 out of 4 pairs were not 8 ohms as it is written on the labels.  They are all less than 8 ohms: a pair at about 6, and two pairs close to 4 ohms...

What I did, still according to the volume control paperwork, I switch the jumpers to the maximum setting for all volume controls.  Impedance at amplifier is now 2.5 ohms.  

I then tested the setup: played a movie.  Before, if I had a fan blowing air into the casing of the amp (tried that long ago), the amp would run longer and not shut off.  Obviously, this is not the way I want to do it.  Without the fan, the amp would shut down in less than 10 minutes.  With volume controls setting changed, I was able to watch the movie until the end without a problem.  The amp is almost not producing heat.  It is, but very little, about as much as my digital cable box.

I will keep on monitoring the situation.  I also noticed that I need to pump the volume on the amp at a fairly high level to get a decent level of sound in the speakers...  A bigger amp would probably produce more sound.?.  Can I use a power amp in PRE OUT/MAIN IN jacks to enable this unit to operate separately as a control amplifier and use a separate power amplifier?

Thanks for helping.  Really.


Chris

Quoted from underachiever

Don't know if you've ever been there, but I would try posting your question here :

http://www.avsforum.com/avs-vb/forumdisplay.php?f=36

There are alot of guys there that are very helpful.

Tried to register there before you posted because there seems to be a lot of info and good knowledge.  System is supposed to send a confirmation email back and you need to follow the link on the email to activate account.  Never got that email...

Quoted from Tuborg

I thought a DMM's Ohm setting was resistance only.   I didn't think a basic DMM could measure impedance (units also in ohms) ?

Resistance is a concept used for DC (direct currents) whereas impedance is the AC (alternating current) equivalent


Hey, I am not taking credit for that.  It's all there: http://www.physlink.com/education/AskExperts/ae517.cfm

Quoted from Tuborg

I thought a DMM's Ohm setting was resistance only.   I didn't think a basic DMM could measure impedance (units also in ohms) ?

Imdedance = resistance = ohms.  I think you're thinking of inductance, which would require a totally different kind of meter to measure. (inductance is resistance and capacitance)

D

Quoted from RedFive

OK,
I followed your advice and not only did I measured the impedance at the amp, I also measured the impedance at the speakers.  Well, theory and real life are two things...  3 out of 4 pairs were not 8 ohms as it is written on the labels.  They are all less than 8 ohms: a pair at about 6, and two pairs close to 4 ohms...

What I did, still according to the volume control paperwork, I switch the jumpers to the maximum setting for all volume controls.  Impedance at amplifier is now 2.5 ohms.  

I then tested the setup: played a movie.  Before, if I had a fan blowing air into the casing of the amp (tried that long ago), the amp would run longer and not shut off.  Obviously, this is not the way I want to do it.  Without the fan, the amp would shut down in less than 10 minutes.  With volume controls setting changed, I was able to watch the movie until the end without a problem.  The amp is almost not producing heat.  It is, but very little, about as much as my digital cable box.

I will keep on monitoring the situation.  I also noticed that I need to pump the volume on the amp at a fairly high level to get a decent level of sound in the speakers...  A bigger amp would probably produce more sound.?.  Can I use a power amp in PRE OUT/MAIN IN jacks to enable this unit to operate separately as a control amplifier and use a separate power amplifier?

Thanks for helping.  Really.


Chris

Glad I was able to help, sounds like the amp was being over driven by too low an impedance which can easily happen in a muti-room/muti-speaker setup like yours.

Now to answer your question about the volume, 2 things...  Because you're running multiple speakers, the power is divided across all speakers equally (as long as they are all the same impedance).  Now the reason it's nice to have a high current amp is so you can load it down to 2 ohms and suck as much power out of it without issue.  But if you increase the total impedance the amp "sees", the output power will drop. (the higher the impedance the lower the power output).  So now that you've increased the impedance to 2.5ohms (approx) it's higher than it was before so the amp isn't working as hard and you're not getting as much power output.  Make sense?

The other factor to consider is the fact you're using an integrated pre-amp / power amp.  In order for this setup to work at it's peak performance you really don't need the volume control in the pre-amp section for all the speakers that have their own wall control. (you only need a source switcher and a power amp)  All you need for those speakers is max power, as you're controlling the volume from the wall controls.  So the only way you'll get decent volume from those speakers with wall control is to basically run the amp volume at 3/4 full.  Most consumer amps can handle full volume, but I usually find the last 1/4 turn to to do nothing but add distortion.  This also depends on the quality of the amp design so you'll have to play around with it to find your amp's distortion limit. (where yours is a high-current model it will probably handle more than 3/4 turn, but not full volume)

And to answer your question about the impedance of each speaker, even though your 8 ohm speakers were measuring at around 6 or even 4, that's normal.  It's all about component tolerances.

Anyway, hope you don't run into any more issues and enjoy your setup!

Doug