[jtwrace]

Total realistic time for us the consumer? 

[brother love]

One more question.  Does the sub hum with input cabling disconnected?  I know that this is simplistic and I'm sure that you've done this, but I have to ask.  When tracing down hums, I always start with the just the sub amp hooked to the wall - no input cabling.  Then I would hook it up to the receiver with all of the receiver inputs unplugged, plug one set of component cables into the receiver at a time with the component turned on and see if you can't isolated the problem that way.  I would imagine that you have already done this.  Another thing to consider is the unseen hum inducers, like in-wall wiring in proximity and in parallel to any signal wiring or to the plate amp in the sub.  I've seen this happen all too frequently.  You may want to pop the top off of the Denon and see if it is properly grounded internally.  In other words, make sure that the chassis ground and the neutral are common.  Same with the plate amp.

Concerning the sub amp being on the same phase as the 'fridge:  First, make sure that all of the above is OK.  Then you have to ask yourself some questions.  What are the trade-offs involved in the opposite phase going to be?  Plug the subamp into Phase 1 and listen to determine if it is superior in sound that way.  Since electricians spend time balancing current demands in the panel there is going to be downside/upside considerations both ways.  Generally speaking audio should ALWAYS be on the same phase.

As a diagnostic tool, destroy a 3-prong adapter by removing the ground pin and file the left hand (wide = neutral) blade until it is the same width as the right hand one.  Check each piece of gear by using this plug to try input AC polarity both wys to that piece of gear.  Odds are you will find one offending piece and then we can figure out how to do this properly.  DON"T USE THAT PLUG UNDER NORMAL USE! 

Dave

Dave,

One of the downsides about posts is you can’t provide enough details without writing a darn book. If you try not to hog (or derail) the thread, then you leave out pertinent stuff.

Anyways, back many months ago when I was trouble-shooting servo sub hum, I did try different scenarios to pinpoint problem as much as possible.  I did disconnect rca single cable from avr, & hum persisted.  I did try different outlets, move sub to other room/ different circuit & hum persisted. I unplugged all A/V equipment & hum persisted. I tried different cables & well, you get the picture.

So I assumed that eliminated everything except for servo sub internals and/or residential wiring. Fast forward to the here & now, & your comments re: noise sources & proper phase layout caused me to revisit my existing problem for possible fix.

Not sure if I’m any closer to resolving issues, but I’m learning a heckuva lot in the process.  Thanks ! 

[dBe]

Dave,

One of the downsides about posts is you can’t provide enough details without writing a darn book. If you try not to hog (or derail) the thread, then you leave out pertinent stuff.

Anyways, back many months ago when I was trouble-shooting servo sub hum, I did try different scenarios to pinpoint problem as much as possible.  I did disconnect rca single cable from avr, & hum persisted.  I did try different outlets, move sub to other room/ different circuit & hum persisted. I unplugged all A/V equipment & hum persisted. I tried different cables & well, you get the picture.

So I assumed that eliminated everything except for servo sub internals and/or residential wiring. Fast forward to the here & now, & your comments re: noise sources & proper phase layout caused me to revisit my existing problem for possible fix.

Not sure if I’m any closer to resolving issues, but I’m learning a heckuva lot in the process.  Thanks ! 

Hunting down hums is especially painful.  They are insidious and a pain in the butt.

Does your servo amp IEC power inlet have 2 prong slots or 3?  Seems to me that the first amps had 2 slots, i.c. no groundpin.  Have you talked to Danny or the guys at Rythmik?

One of the great things about the 'net is all of the different realms of experience to draw from to solve propblems.

Dave

[werd]

Dave,

One of the downsides about posts is you can’t provide enough details without writing a darn book. If you try not to hog (or derail) the thread, then you leave out pertinent stuff.

Anyways, back many months ago when I was trouble-shooting servo sub hum, I did try different scenarios to pinpoint problem as much as possible.  I did disconnect rca single cable from avr, & hum persisted.  I did try different outlets, move sub to other room/ different circuit & hum persisted. I unplugged all A/V equipment & hum persisted. I tried different cables & well, you get the picture.

So I assumed that eliminated everything except for servo sub internals and/or residential wiring. Fast forward to the here & now, & your comments re: noise sources & proper phase layout caused me to revisit my existing problem for possible fix.

Not sure if I’m any closer to resolving issues, but I’m learning a heckuva lot in the process.  Thanks ! 

Hi

I had a servo sub that buzzed, not so much as a hum. Anyways after doing all the stuff you did, i looked inside. It ended up being the servo lead from the amp to the driver was off. It was busted so i got a new servo wire and it fixed it.....

[brother love]

Dave, It's a 3 prong @ the amp. I used a cheater plug on the outlet end w/ no change.  I did talk to Brian Ding @ Rythmik & he said they have never had problems reported like mine for the A300SE amp. Can't remember if I discussed w/ Danny or not.

Werd, I've checked the driver/ amp connections before when I put in No-Rez, but I need to inspect things again.

I don't want to monopolize the thread any further. At worst the hum is just barely heard from 5' away when all is dead quiet. Shoot, when the fridge kicks on from 15' away it drowns it out. 

I'll delve into the sub guts when I feel a little more frisky.

[dBe]

Dave, It's a 3 prong @ the amp. I used a cheater plug on the outlet end w/ no change.  I did talk to Brian Ding @ Rythmik & he said they have never had problems reported like mine for the A300SE amp. Can't remember if I discussed w/ Danny or not.

Werd, I've checked the driver/ amp connections before when I put in No-Rez, but I need to inspect things again.

I don't want to monopolize the thread any further. At worst the hum is just barely heard from 5' away when all is dead quiet. Shoot, when the fridge kicks on from 15' away it drowns it out. 

I'll delve into the sub guts when I feel a little more frisky.

When someone comes out with a dead silent refrigerator we'll have to draw straws to see who goes and kisses them square on the mouth    Oh, yeah, I can't do it.  Gayle would get a wee bit ticked!  Who's single around here?  Guys?  Ladies?

I bet when you do find it (and eventually, you will) it'll be a DOH! moment.  Always seems to happen that way...................

Dave

[srb]

There's an idea I should run with.  If someone will pay $1K for a power cord, there should be no problem selling a $20K standard size refrigerator.  I wonder how many years before thermoelectric cooling modules could be efficient enough, large enough and cost effective for full size home refrigeration and freezing?
 
The Soni-Cool SSD audiophile refrigerator.  And of course it's power cord would have a Techflex covering.
 
Steve

[HAL]

The Igloo Peltier solid state 56qt coolers are very nice.  Problem is the cooling fan for the module which has to run continuously while it is cooling.  The can run off DC as well as AC, so a quiet power supply is possible.   They also do not have regulated thermostats.  That would help to keep them off for periods of time.

They are great for storing beer! 



   

[Wayner]

Just saw this thread and read it. I will have to jump in here as there has been mentioned several times about "phase" coming from the breaker box.

It is true, that homes have 2 120 volt lines and a neutral coming in from a branch transformer from the wonderful utilities, however, the use of the term phase may be misleading. Both 120 volt lines are IN PHASE with each other. That is how we get 240 volt, by putting these 2 branch circuits in series.

Since the power comes from a single transformer, the 2 lines are "connected" as well  as the neutral, relative to each other, so trying to isolate the noise from one set of 120 to the other is pretty much futile. A voltage surge, such as one the may come from a capacitor started furnace motor, may end up in both branch circuits.

The best was to determine if there is an offending appliance, is to shut off every breaker in the house, except for the main, and the circuit your system is on. If the hum is there right away, it's in your system. If it's not, began to turn each breaker back on, one at a time and check to hum with each new additional breaker activation.

Wayner

[dBe]

Just saw this thread and read it. I will have to jump in here as there has been mentioned several times about "phase" coming from the breaker box.

It is true, that homes have 2 120 volt lines and a neutral coming in from a branch transformer from the wonderful utilities, however, the use of the term phase may be misleading. Both 120 volt lines are IN PHASE with each other. That is how we get 240 volt, by putting these 2 branch circuits in series.

Since the power comes from a single transformer, the 2 lines are "connected" as well  as the neutral, relative to each other, so trying to isolate the noise from one set of 120 to the other is pretty much futile. A voltage surge, such as one the may come from a capacitor started furnace motor, may end up in both branch circuits.

The best was to determine if there is an offending appliance, is to shut off every breaker in the house, except for the main, and the circuit your system is on. If the hum is there right away, it's in your system. If it's not, began to turn each breaker back on, one at a time and check to hum with each new additional breaker activation.

Wayner

Wayne, thanks for the clarification of the term.  You are exactly correct.  We (I) have used the perm 'phase' to indicate the relative value of the AC in an audio specific context as it relates to noise in the audio system. We are trying to discuss the situation in an audio friendly manner.  In this context they are in phase electrically, but (more precisely) 'antiphase' as regards hum and noise discussions in audio.

Here is New Mexico we are kind of a backwards lot, anyway.  Branch circuits is not a term that is used very often.  We tend to talk about power as single phase (120V) and 3 phase (208V, 240V, 377V, 480V etc.).  We often use the term "2 legs of single phase power" or simply "phases" when discussing 120V AC.  Certainly not textbook correct and colloquial in meaning.

Thanks for your input.  Keep it coming.

Dave