McIntosh Transformer causing noise in speakers while disconnected.

[Golf]

Update**
A couple of new observations: I am noticing a couple of minor cosmetic things that could mean absolutely nothing, or could be indicitive of improper handling or missed in the QA.

The power knob is warped, or crooked, and not level with the face of the amp. I notice that the feet are not 100% level either; the back left foot was actually not making any contact with my cabinet, and is still imbalanced on the new Salamander Archetype stand I am now using. It's making contact now, but it's still imbalanced. All feet have a noticeable gap on the inside of each foot, supported by the outside portion of the feet.

Lastly and most of all, the noise to the speakers when wired and fully connected (not talking about the disconnected noise) has increased noticeably over the last couple days. It was originally very quiet, but now even the Right Speaker on the other side of the room has a bad noise when connected, and the amp is now much farther away from it (far enough where the non- wired noise is barely noticeable, like i have to really strain to hear it but it's still there 10ft away), with the entire cabinet between amp and Right Speaker. It is the same distorted tone as the startup surge, the tone I hear within the Transformer, and the noise that it sends to disconnected speakers. It can now be heard through audio playback.

Is it wise to put this away until the exchange at risk of damaging my speakers? I worry about the B&W tweeters.... but the amp still makes them sound so good with movies and such, so I am just sad to put it away if I don't have to......... :*(

All that is really really awful. QC failed badly, obviously

I wonder if QC at McIntosh can be traced back from a certain device to a certain employee.

 

[Doodski]

Regarding the Fluke 87 Series handheld multimeter. Here is the lowest prices 87 Series model @ the Fluke USA website. It's a lot of buckeroos <$> for a meter that a casual user is going to purchase. I reallly like it but...

 

[NiagaraPete]

QC at McIntosh can be traced back from a certain device to a certain employee.

Most certainly

 

[restorer-john]

agree, but a Fluke 87 is about $500.

Sure, but you will never need another meter if you buy a Fluke.

For most of my younger electronic life, I pissed around with very good but not excellent meters of various sorts. Not even sure how many DMMs I own, too many for sure. You gotta remove the batteries for all the 'spare' and 'emergency' DMMs in the cupboard, lest the batteries leak... I love them all, but the Flukes are on my lab bench and I trust them implicitly. Just forget the cheap ones and buy a Fluke- you'll never regret it. (I sound like an ad)

Here's my old 87 III

And an even older Fluke 183 (Actually a Tektronix TX1 from circa 2000)- my favourite meter by far.

Flukes can save your life because they don't lie.

Even a little 11x series true RMS Fluke (Chinese made) is decent, but bandwidth is limited. The older Agilent DMMs are great too- 24 bit A/D converters and are SO fast compared to the Flukes.

 

[Doodski]

maybe just listening to the disconnected speaker is dead simple, costs nothing and accomplishes what is needed.

I think this is the best route. We know it works and it is a reference that is repeatable with reliability. I went through researching several brands of handheld multi meters and all of them are probably not up to the task of such fine metering capability. So I say use the speaker too.

 

[Blumlein 88]

I did some searching and what a person gets in the Klein MM325 for USD <$45 online pricing it is very good value although it has minimum 200 V AC scale @ 0.1 ±(1.0% + 3 digits) Volt accuracy. Not enough resolution and accuracy for what it needs to do.
Additonally the frequency range for metering AC V is 50 to 60 Hz. Very limiting in it's application.
So... One need a better meter....
View attachment 358887
View attachment 358888

You are correct. This meter will not do. I saw a different list of specs and it listed voltage resolution as .1 millivolt. That is not for AC however which was deceptive as they didn't mention it in the list I saw.

I have a MM700 Klein I keep in my car. A couple models up the line. It has specs in the same manner. .1 mv resolution DC and 1 mv resolution AC. So I connected it to a small speaker I had (Radio Shack Linaeum). I found if I hummed really loud it would show a couple three millivolts. Using my other brand meter which has .1 mv resolution it would pick this up with just minor humming by me next to the speaker. And by me humming I just mean drawing in some air and humming through my mouth.

I found a better way. My MM700 can do current in microamps. I found the moderate humming was easily detected this way, and loud humming was picked up even on the milli-amp setting. So the MM325 will still not do even though it does microamps. It only does that with DC while the MM700 does it with AC and DC. That is a True RMS meter and costs around $90.

I would think if moderate humming creates enough current to be seen, and the McIntosh is causing the audible movement of the speaker the OP has then it would generate a few dozen microamps of current to do this. Again, maybe we are complicating the issue too far. I feel better about an MM700 measuring the amperage for this purpose.

 

[Doodski]

MM700 Klein

Hot Momma! That Klein MM700 has some really nice current metering capability.

 

[Blumlein 88]

Sure, but you will never need another meter if you buy a Fluke.

For most of my younger electronic life, I pissed around with very good but not excellent meters of various sorts. Not even sure how many DMMs I own, too many for sure. You gotta remove the batteries for all the 'spare' and 'emergency' DMMs in the cupboard, lest the batteries leak... I love them all, but the Flukes are on my lab bench and I trust them implicitly. Just forget the cheap ones and buy a Fluke- you'll never regret it. (I sound like an ad)

Here's my old 87 III
View attachment 358894

And an even older Fluke 183 (Actually a Tektronix TX1 from circa 2000)- my favourite meter by far.
View attachment 358895

Flukes can save your life because they don't lie.

Even a little 11x series true RMS Fluke (Chinese made) is decent, but bandwidth is limited. The older Agilent DMMs are great too- 24 bit A/D converters and are SO fast compared to the Flukes.

I don't necessarily disagree with you, but it nevertheless can be overkill. The reason I keep the MM700 in my car is it is tough, reliable, safe at higher voltage and suited for many purposes I might happen upon, but I'm not toting around a $500 meter just in case. The OP can make up his own mind. If the speaker works and he has no familiarity with meters I'd say skip it altogether.

 

[restorer-john]

I don't necessarily disagree with you, but it nevertheless can be overkill.

I agree for sure. For most people.

That is, until he gets all "ASR" and wanting to level match at 1kHz for ABXing (LOL) and we tell him to connect his DMM to the speaker terminals and trim it to a few mV...

I'm going to bed.

 

[radix]

Update**
A couple of new observations: I am noticing a couple of minor cosmetic things that could mean absolutely nothing, or could be indicitive of improper handling or missed in the QA.

The power knob is warped, or crooked, and not level with the face of the amp. I notice that the feet are not 100% level either; the back left foot was actually not making any contact with my cabinet, and is still imbalanced on the new Salamander Archetype stand I am now using. It's making contact now, but it's still imbalanced. All feet have a noticeable gap on the inside of each foot, supported by the outside portion of the feet.

Lastly and most of all, the noise to the speakers when wired and fully connected (not talking about the disconnected noise) has increased noticeably over the last couple days. It was originally very quiet, but now even the Right Speaker on the other side of the room has a bad noise when connected, and the amp is now much farther away from it (far enough where the non- wired noise is barely noticeable, like i have to really strain to hear it but it's still there 10ft away), with the entire cabinet between amp and Right Speaker. It is the same distorted tone as the startup surge, the tone I hear within the Transformer, and the noise that it sends to disconnected speakers. It can now be heard through audio playback.

Is it wise to put this away until the exchange at risk of damaging my speakers? I worry about the B&W tweeters.... but the amp still makes them sound so good with movies and such, so I am just sad to put it away if I don't have to......... :*(

I think a few people -- many pages back -- suggested that there might have been handling damage (i.e. dropped) and that caused something to loosen inside that's causing this high EMF emission. The bent knob does point towards this direction.

I would personally have your dealer deliver and install the amp replacement. This completely avoids any issue with you mishandling the replacement. I'm not saying you did this before, just that with the warranty replacement, I'd let them assume all the risk. Once they have installed it and you have all seen it work perfectly, then you can hand-off the responsibility.

If the problem is changing and getting worse, I agree, don't do it any more. I'd just leave it off, and definitely not wire it to the speakers. Doing the inductive coupling tests is likely low risk, if you want to measure it in the name of science. Although it's fused and tested to not go up in flames for an internal short, no reason to risk it.

How did you get the original amp, was it shipped or did you pick it up? I'm wondering if it was shipped freight on a small pallet or by a regular carrier or just picked up at the dealer.

 

[mhardy6647]

Is it wise to put this away until the exchange at risk of damaging my speakers? I worry about the B&W tweeters.... but the amp still makes them sound so good with movies and such, so I am just sad to put it away if I don't have to......... :*(

I would (stop using the amp, that is).

 

[Golf]

How did you get the original amp, was it shipped or did you pick it up? I'm wondering if it was shipped freight on a small pallet or by a regular carrier or just picked up at the dealer.

Btw, I wonder if by any chance @ClassG33 has been supplied with a »reworked« MC255 unit from the start. And I wonder even more what will happen to this very unit after it has been sent back to McIntosh.

 

[Doodski]

Btw, I wonder if by any chance @ClassG33 has been supplied with a »reworked« MC255 unit from the start. And I wonder even more what will happen to this very unit after it has been sent back to McIntosh.

It depends on the policy of the respective company à la McIntosh and others.
I have heard like Sony of Canada would collect all the gear like this bad boy for the end of year, put it on the parking lot asphalt and have a payloader demolish the stuff so it becomes a tax write off. (I was told this by a friend.) Others will service it, determine it as fit for use and sell it as refurbished.

 

[RKV1]

It depends on the policy of the respective company à la McIntosh and others.
I have heard like Sony of Canada would collect all the gear like this bad boy for the end of year, put it on the parking lot asphalt and have a payloader demolish the stuff so it becomes a tax write off. (I was told this by a friend.) Others will service it, determine it as fit for use and sell it as refurbished.

Yamaha of the US would also demolish problem child units. That way they couldn't be resold and potentially sully the brand name.

 

[pma]

Fluke is an overkill in case he needs to make sporadic measurements of several mV induced. Any general purpose multimeter would do the job.

 

[mhardy6647]

Fluke is an overkill in case he needs to make sporadic measurements of several mV induced. Any general purpose multimeter would do the job.

Yeah bit... if one wants resolution (mV), accuracy (!!!), true RMS AC (with reasonable frequency response)... well... one gets what one pays for. One might want longevity and even support, too.

 

[pma]

If you are a regular or professional user, then it makes sense. If you want to measure one-time something you do not understand, then it makes no sense to buy Fluke at almost $500.

 

[Doodski]

If you are a regular or professional user, then it makes sense. If you want to measure one-time something you do not understand, then it makes no sense to buy Fluke at almost $500.

I think a proper bench meter at >better than 6 digits might suffice. At the least and with a time measurement over a extended time frame for repeatability.

 

[Golf]

@ClassG33 could try to charge McIntosh for the costs. After all, it is not his fault being in some need of a multimeter now.

 

[Doodski]

@ClassG33 could try to charge McIntosh for the costs. After all, it is not his fault being in some need of a multimeter now.

North America is not accustomed to such dedicated and personalized service. We simply do not expect it nor demand it.