My Cary amp - the story of a hum and a bug


Hi,
I have had a problem with my Cary SA200.2 power amp from the time i bought it 3 years ago. There's a hum from both speakers (doesn't increase when the volume is turned up). The hum is there irrespective of the connected preamp or power source and even if i take the amp to another city or location. I was told by the dealer that such a mild hum is normal in such a powerful amp. It was only later that I realized that a solid state amp with a toroidal transformer, however powerful, should not have any audible hum. By then, it was out of warranty.

With the help of the India dealer, I wrote to Cary in the US. From their delayed and intermittent responses, it appears that the hum is a known issue, inherent in the design of the amp, that needs a 'fix', which is taken care of in the newer model of the amp. The 'fix' consists of a cable with caps and a bridge rectifier. Shockingly, they expect that I should pay around $210 + duties for this. To me, it is not a question of money, but one of principle! Why should I pay for them to fix a bug, even if the amp is out of warranty? I even suggested that it will not cost me more than $30 to build the cable here in India if they can send the diagram and component values for this fix. But Cary is adamant that I either pay for the cable or trade in my amp for a new +1 model!! In desperation, I requested that they send me the service manual of the amp, hoping to address the bug with the help of the manual. Back comes the reply that it is proprietary and that they cannot share it with customers. The dealer has been unable to exert any real pressure on Cary to resolve this issue.

I would like to know, from fellow FMs:
1. Is Cary justified in it's stand?
2. Role of local distributors/dealers?
3. Does any other FM own a Cary SA 200.2 and how he has fixed this issue.
4. Can the electronic experts suggest the specs to filter out the hum?
5. Will adding this filter adversely affect the sound quality?

CUT TO CHINA:
I have a Chinese made integrated amp (Kinki Studio). It is no slouch, having been awarded the Blue Moon award by none other than Srajen of 6moons. I blew the amp some time ago by an incorrect connection. It was my fault. But within minutes of sending an email, the dealer in Singapore was on whatsapp chatting with me, asking for photographs, communicating with the manufacturer, suggesting diagnostic checks. Within 24 hours, they realized it could not be fixed via distance communication with a non-electronics-trained user like me. Within a week, a pair of new power amp boards arrived by DHL, shipped at the dealer's cost, with detailed instructions on how to replace the boards. The only cost I incurred was the cost of shipping the old boards back to them for diagnosis. So I guess Xi Jinping wins this round :) 

Thanks for reading
fiftyfifty
Was the amp itself humming?
i'd see if you can find a person with the updated amp and see if they are willing to take internal pictures, that may be an option abet not an ideal one. 

glen 
Was the amp itself humming?
No, only through the speakers at constant volume.

i'd see if you can find a person with the updated amp and see if they are willing to take internal pictures, that may be an option abet not an ideal one.
Thanks Glen, that'll be quite useful :)
Sounds more like a ground loop issue. 
Sounds more like a ground loop issue.
No, it's most likely a DC offset issue. Like this:
https://sound-au.com/articles/xfmr-dc.htm
Just to be clear, it is just the speakers and not the amp transformer humming. Because you have it written as if it is also the amp humming. This is an important clarification in a dc offset issue.
Just to be clear, it is just the speakers and not the amp transformer humming.

The source of the hum is the amp. The sound comes through the speakers. It is a very low volume.
(((Sounds more like a ground loop issue.)))
FYI its not a ground loop....This particular amp and MBs have had known design issues.His problem is Cary wants it back to fix and because he is far away this is difficult with shipping costs and all involved in my opinion should be split by selling dealer and Cary if he purchased it new or if possible Cary offers a local set up a repair solution.
((((I was told by the dealer that such a mild hum is normal in such a powerful amp.)))) that some tall grass their boy.
  

Yes, I understand that. Now, yes or no, is the amp itself making a humming noise? Not the speakers, is there a humming sound physically emanating from the amp?
What happens if you disconnect the preamp interconnects from the amp?  Does the buzz still persist?
@ fiftyfifty 

Your thread and posts to your thread are unclear. You say the hum is coming from the speakers and not mechanical hum/buzz/vibrating noise from the amp itself.
But then you post this.

fiftyfifty OP3 posts07-28-2019 6:51am
Sounds more like a ground loop issue.
No, it's most likely a DC offset issue. Like this:
https://sound-au.com/articles/xfmr-dc.htm

The article addresses DC offset on the AC mains. DC on the AC mains can cause large toroidal transformer, as found in a power amp to hum/buzz/vibrate, which produces an audible sound from the amp.  

The 'fix' consists of a cable with caps and a bridge rectifier.

Sounds like an AC mains DC blocker circuit to me.



.
@jea48 , that's exactly what I'm trying to ask and not getting a clear answer. Did not think it was that hard a question.
Thank you all for responding. 

I would like to repeat there is no hum physically coming from the amp. It is coming through the speakers because of the amp. Please don't ask me to switch power source, preamps, etc. I've tried all this, even moved the amp to the dealer's store and other geographical locations. I  can very confidently state that the source of the hum is the amp and nothing else. Now whether it is a ground loop or a DC offset issue - that I do not know. But i do know that it is a design issue with the amp, for which Cary has a fix and they have fixed it in their newer version. Cary is not asking me to ship the amp back to them. They want to ship the harness/cable to me and they want me to pay for the cable. Alternatively, they want me to trade in my unit for the newer version. Considering that it is a design issue, I believe it is unfair and unethical that I should be asked to pay for them to fix a design issue. What is your opinion on this???

As for the hum, I guess I can identify an electronics expert who can fix it.

Cheers!
But i do know that it is a design issue with the amp, for which Cary has a fix and they have fixed it in their newer version. Cary is not asking me to ship the amp back to them. They want to ship the harness/cable to me and they want me to pay for the cable.

Cary should send the harness/cable to you free of charge. PERIOD!
The problem is a design flaw, which according to you, they admit.
Stupid move on Cary's part. You should try going higher up in the Cary company chain of command.


Thank you for the clarification. It is indeed unfair that you should be asked to pay for a repair if it is indeed a design flaw. That being said, I don't believe t is either a ground loop or dc offset issue. Dc offset issue would cause the transformer to hum, which you do not have. From my understanding,if you have an amp with a powerful toroidal transformer attached to high sensitivity speakers, you can hear a very soft hum coming from the woofer and can only be heard with your ear very close to the speaker. Some consider this harmless, and say it has no affect on sound quality.
if you have an amp with a powerful toroidal transformer attached to high sensitivity speakers, you can hear a very soft hum coming from the woofer and can only be heard with your ear very close to the speaker.
Thanks jea48 and thecarpathian! The hum is audible from the listening position. But it cannot be heard when the music starts to play. 
I know what I would do: send the amp to Cary to fix, when it is received back sell it, and never again buy a Cary product. There are plenty of other amps and amp companies out there, no need to settle for a poorly designed one from a company treating the owner of one of it's shoddy products with such disrespect, if not outright contempt.
fiftyfifty OP

You could have an earth loop.
Of all the equipment how many have earth pins on them?
If more than one, you should use cheater plugs to disconnect all the earth pins "except for the amp", it’s the only one that should be earthed.
It will then send it’s earth connection to all the other equipment via the interconnects. This will stop any earth loops happening if they were there.

Cheers George
If it is a design flaw, I think they should send you one for free, especially if you are the original purchaser, not that they have to. Seems like the good customer servicer thing to do. I don’t know what this wire thingy costs them to make, but I suspect one bad legitimate public complaint will end up costing more than many dozens of wire harness thingies. I have a lot of Cary gear, and they’ve generally been cool about stuff. This is disappointing to hear.

I’ve heard of this issue and the fix on the 200.2 from another person, too. I think that was actually mentioned in a seller’s classified that is was being sold without the "fix" in place.


I had an issue with hum on a new amp (not a 200.2)--both from a transformer and through speakers. Like you, tried everything (different locations/houses/cities, CMX2, isolation transformer, turn off the whole house except for the amp, etc. etc.). Nothing worked. Sent it back at my expense. Bench-tested to spec. Manufacturer’s service department noted that a cap came a little loose likely in shipment which might have somehow caused the issue. They fixed that and sent it back to me, and it was at least as bad as before, with an added higher frequency buzz (maybe a harmonic?). They wanted another shot. I was livid, sent it back again at my expense, and they ultimately did the right thing and sent what was represented as a new one. It also had a similar hum as the initial unit, but was significantly quieter and without the higher frequency buzz.

Here’s how I ultimately fixed it. I hooked it up to low-sensitivity sealed speakers (81.7dB(B)/2.83V/m) that were down at least 6db at the frequency of the hum. Added an active crossover with a sub to fill in the bottom. In a room with significant ambient noise that doesn’t get used for a ton of dedicated listening. With that, other than a slight hum from the unit that was usually inaudible with any music playing and the faintest hum with the ear nearly touching the mid-woofer, it sounded really, really good. Lemonade out of lemons.
@georgehifi Trust me, I've tried everything. It needs a fix and Cary Audio know about it.

@stfoth Very very interesting indeed. You have been patient. In my unit too, the hum is mild and not audible when music plays. It's just annoying to know that the hum is there, and it's very annoying to find Cary behave like this for a small sum of $200. I suppose legacy companies like Cary Audio that come with a big reputation tend to disregard customer experience and innovation, until one day they find that they have been edged out by smaller and more dynamic players. I own products from Kinki Studio, Denafrips and Jays Audio, all Chinese, all Bluemoon award winners from 6moons.com, all much talked about in other threads on this forum. These guys will bend backwards to make sure the customer remains satisfied.

Cheers!
Issue is Cary audio as a company should have atleast understood shipping an amp at buyers cost from India to USA is no joke.
Considering that ,and how niche market audio is worldwide, even more in india they should have agreed to sending the  parts needed to fix for free and requested fifty-fifty to consider paying only Shipping.

They flatly refused for that. If that's the response a person gets purchasing from authorized dealer in india, it will further make people buy gears from Singapore or elsewhere where it's cheaper then India.

Indirectly they they have even damaged the reputation of their India distributor

I am totally with bdp 24 on this one. There is no excuse. Sell it and never buy another. Tell the new owner about the hum and the fix and let him deal with it. You'll lose some money but Life is what happens while you are making other plans.
Did you attempt to contact Bill Wright (Cary CEO) directly?  IME, he is a very reasonable person.  I just googled " Cary SA200.2 hum issues" and did not get one hit, is this really a well known wide spread issue, or perhaps an isolated issue to your amp?  Something does not add up.
Trying powering up the amp with no interconnects connected to see if there is hum.  Sometimes unshielded cables can cause the noise.  If you are local to me New Jersey and can get the amp to me with their part to fix the issue, I will install it for you.
bigkidz   

1,928 posts  

07-29-2019 9:27am   

Trying powering up the amp with no interconnects connected to see if there is hum. Sometimes unshielded cables can cause the noise. If you are local to me New Jersey and can get the amp to me with their part to fix the issue, I will install it for you.

For a true test he would need to install shorting plugs on the input jacks of the amp for the test. Otherwise airborne RFI would enter through the unported inputs and cause a hum/buzz.
Trying powering up the amp with no interconnects connected to see if there is hum. Sometimes unshielded cables can cause the noise. If you are local to me New Jersey and can get the amp to me with their part to fix the issue, I will install it for you.
This would also confirm that the issue is not a ground loop problem
Perhaps this describes a different issue altogether.  I remembered fixable hum and thought it was the same.  This is text from an Audiogon ad on a 200.2 from about a year ago (no affiliation):


"Other notes: There is a low level hum
coming from the left channel, it isn’t very loud and depending upon your
listening room and seating arrangement, there’s a good chance you won’t hear
it. According to Steve at Cary Audio service, the problem is addressable,
please feel free to do your due diligence, my price reflects this minor issue,"
@fiftyfifty,
I am associated with a company that makes amplifiers. If this was one of our products, we would ship the fix for free with instructions of how to install it that could be executed by any competent technician.


No company is perfect; neither are the people that make the products or the product itself. That is what warranties are for!! In the the case were there is a defective part or design flaw, it is common to see the products repaired without charge well outside the warranty period. My Honda Insight was out of warranty when I realized it had excessive oil consumption. Honda knew about the problem and fixed it for free (oil rings- this required they take the engine apart!). During that time they lent me car to drive at no charge. Res ipsa loquitur.

Sorry but not too surprised to hear Cary isn't handling this better. Just because they know about something like this and fix it in a newer model however is pretty normal and hardly controversial. Hate to have to be the one to say it, everyone here should know this, but you buy a tube amp you are buying a tube amp. This is after all in the big scheme of things so minor a problem that doing a search for Cary hum problem gets zero hits. Now why would that be? "My amp makes a hum. I can't hear it when listening to music."

Guess what? Every single one of my components makes a noise I can't hear when playing music either.
Thanks everyone.

Before starting this thread, I had tried all the permutations and combinations to isolate the problem - powering up the amp without any other components connected, installing the amp in a different room, friend's house, dealer's listening room, different city, etc. The hum remains. There is no hum coming physically from the Cary or its transformer. The hum comes from the speakers connected to the Cary, with or without and preamp or source connected!

But anyway, I now have a fresh response from Cary as detailed in my next post.

Thanks for all your suggestions and offers to help :)
 
To put things in perspective, let me elaborate on Cary Audio's response and position:

When first contacted about the issue, Cary Audio responded with requests for pictures of the inside of the amp. After reviewing these, their initial advice was to make an incision in the trace at the rear of the input terminal. However, this did not resolve the issue, leading to further discussions and sharing of pictures. After a more detailed review of the issue, Cary informed me that the issue could be addressed by a cable harness which they could build for me at a cost. They also sent me a picture of the harness installed in another machine. As this appeared to be a known fix that had been implemented by Cary in other machines, my contention was that this was a known issue and, hence, a defect or bug in the design. Accordingly, I suggested that Cary should ship me the harness free of cost or, alternatively, send me the specs of the harness so that I could build it locally in India. Cary Audio was not willing to ship me the harness unless I paid for its cost plus shipping. As an option, they suggested that I could trade in my old unit and purchase the upgraded version on their website. They were also unwilling to mail me the schematics or the service manual.

Cary Audio does not agree that it is a design fault. In their words, "Some countries have issues with grounding and some with hum. In order to help with these countries and our product we design in more filtering. It’s not always the case in every country, but we have come across some which need our help resolving  issues with their power infrastructure." 

I had already tried the amp in different cities in India. Wanted to check if the issue was a result of the kind of power we get here. So I carried the unit with me on my trip to Singapore and tried it there. The same hum in that country too! 

I do grant that Cary Audio has responded to all my mails and have been reaching out to help resolve the issue. But on their terms, which are not acceptable to me. In their latest mail received yesterday, they have now agreed to build the harness at their cost provided I pay for the shipping. I suppose this is a fair proposal and will take it forward with them. 

I'll post an update after installing the fix.

Thanks for reading.


I actually owned the "newer" model of this amp that had the bridge rectifier installed. It still had low level hum in one channel, so the issue is inherent in the design of the amp. I know this because I called Cary and discussed it with them. To be fair, the hum was tolerable, but I felt unacceptable for an amp otherwise of this level of overall quality and associated cost, so I eventually traded it in to a Cary dealer on another amplifier. Two more comments. First, as SS amps go, I thought it sound really good, more musical than many I have owned. Second, having once owned many pieces of Cary gear and having had several upgraded or modded by Cary, they charge a lot for the parts they provide and their service, but they do really good work and are honest people. It’s really a matter of caveat emptor.
the hum was tolerable, but I felt unacceptable for an amp otherwise of this level of overall quality and associated cost
I thought so too. I also agree that the amp sounds good. I'm just very surprised on 2 counts.
  • Why isn't a company of Cary's stature unable to overcome this design issue?
  • Why do they have such a high handed attitude towards customer service?
Unfortunately, I was unable to amicably resolve the issue with Cary. They refused to acknowledge the issue of inherent hum. They pointed out the possibility of power conditions in India, the possibility of misuse, the fact that the unit was out of warranty, age of the unit, etc., etc. But that they would still do me a big favor by sending me the cable harness at their cost. Understandable, but I am unable to deal with such attitude. I have therefore informed them that I do not need their harness, that I will scrap this amp and buy another brand.

Moderators- please close this thread.
Why not take Cary up on their offer to send you the “fix” if you pay shipping?  Sounds like you rather bash a manufacture than getting your issue resolved. As an alternative, why not purchase an amp designed and made in India that is compatible with their power grid.
my personal experience with Cary repair has been pretty bad.  They replaced a single tube on a mono block and it cost me $700.  I would never send them an amp for repair again and I would never buy another Cary product.  (too bad, they are beautiful and sound great).  It's just not the same company it used to be.  
It is a design issue flaw. Potentially in the power supply. A well designed S/S amp should have no hum either from the amp itself or at the speakers. I have experienced both. My bugaboo is usually when the amp itself has some hum. This can be because of not using a power transformer that is over spec’ed for the needs of the amp. In way older amps or even tuners or other equipment using the older type trannies the plates can vibrate because of the potting material no longer in good condition. I have a Sony 80’s tuner that is for sale that has been restored. It had hum which is a bit unusual for a tuner. Granted , this was not hum at the speaker. I certainly empathize with you on the type of hum you are dealing with. The transformer was re-potted which eliminated the hum. In your case as I mentioned this is a design flaw in the power supply creating a hum that exhibits at the speaker. My Pass amp which operates in class A which  could as well be a set up for having hum either at the speaker or at the amp itself and it has neither and runs dead quiet. This is a well designed amp.. period. If Cary was a stand up company they would at the least cover the repair and pay for at least half of the shipping although it would seem that footing the entire bill would be the responsible thing to do as this is not a fault in your system but in their design of the amp.
Post removed 
I had a poor experience with Cary Audio in the late 90s and no longer use their products. We purchased their popular 300B monoblocks and accompanying preamplifier for trade show use (CES and Stereophile shows) and worked quite well with our speakers.
A couple of years later Cary Audio requested that we ship a pair of our speakers to them free of charge and shipping on my dime. The speakers were disassembled in order to reverse engineer them and they did a poor job of putting them back together—that’s how I knew they were disassembled, and our proprietary wiring, crossover and solder were taken apart.
Cary Audio released a speaker line very similar to my speakers a year later. I was in my 20s and disappointed in their actions and never used their products again. 
Even I use an amp probably deisgned in Germany, made in USA but don't have any issues.
Odyssey stratos and the owner of the company would go absolutely out of way to solve any issues a customer would have 
Power supply in India is not so bad that it would need a special design to make it work.
I have Cary equipment and so do several friends.   We have had great support and modifications done by them.   I admit I love the sound and overall build quality.  We are all tube.    I would fualt your dealer on this and go after them to cover all shipping costs.  They sold you a bunch of BS on the hum and had you wait until warranty has expired.  Their bad and dishonesty.
Thanks for the responses.

I realize now that there are others like me who have not had too great an experience with Cary Audio. Some of you have had to deal with worse situations as compared to my hum issue. I realize that the dealer too is to be held accountable. But as a customer, I see the company and its dealer as a single entity. It is for them to communicate and sort it out with each other to resolve my issue. 
I've been able to find a technician who is confident of eliminating the hum. I don't know at this stage whether it will cost me more or less than what i would have to pay to Cary. But, like I said earlier, it was never a matter of money.
Cheers!
@fiftyfifty wrote....... I do grant that Cary Audio has responded to all my mails and have been reaching out to help resolve the issue. But on their terms, which are not acceptable to me. In their latest mail received yesterday, they have now agreed to build the harness at their cost provided I pay for the shipping. I suppose this is a fair proposal and will take it forward with them.

Why didn’t you take up Cary’s offer to send you a harness at their cost if you pay shipping?

Why didn’t you take up Cary’s offer to send you a harness at their cost if you pay shipping?
Because as soon as I softened my stand and agreed to their proposal they completely denied that there was any inherent problem with the amp, alleged possible misuse, denied having ever sold the amp to an Indian distributor (the distributor says he has now taken this up with the Cary CEO), wanted me to, in a way, reverse my position on this thread and generally accept on this AG thread how 'helpful' Cary had been! Interestingly, Cary's offer of replacement came only after I started this thread. So, thank you Audiogon :).
All this without any guarantee that the issue would be resolved. I'd rather go to a technician who is confident of getting rid of the hum. 
I wish to repeat that Cary products are excellent, but history has shown how legacy companies slip into this kind of complacency on service and innovation fronts.
Cheers!
I owned that same amp.  I had the same problem as you.  I emailed them and got the following response:

"If you look at the picture, this is the inside of the SA-200.2 looking at (1) amp module. You will see I have circle (3) wires connected to the PCB board in pink. Disregard the circle in red because it doesn't apply. We have learned the manufacture of these connectors used oil film coating on them for storage

When the connector are plugged into the board sometimes the metal doesn't make a good connection. To make a better connection we would pull the connectors off and push back on once or twice. By pulling off the connector and pushing back on the (2) metal pieces scrape and dig into each other making a very good connection.

There are (2) amp modules. So one would have to do this for both channels."

I did what they suggested.  It did not resolve the problem.  I ended up selling the amp.  Cary Audio is not the company it used to be.  While I still use a Cary SLP-98P preamp, I certainly would not buy a new product from them.
I owned that same amp. I had the same problem as you
What a pity!