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

Fiftyfifty

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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 Pune dealer and the Bangalore distributor, 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, as shown in the attachments. 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 Rs. 2000 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. Both the Pune and Bangalore dealers have 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 take a look at the attachments and 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. 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 :)
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If there was a bug in the original design, I think it’s the responsibility of the manufacturer to fix it, irrespective of whether it’s in warranty or not.

You should bring this up in US audio forums. That’s when they might wake up to it. I don’t think they care about India market
 
Cary is absolutely not justified in it's stand.
When the company is accepting it's a design flaw.
Infact, they should understand you being in India they should send you free parts and request their dealer to get it done for you
Worst they can request you to pay for shipping.
When they can't let you have schematics this is the least they should be doing.
Even on Amazon for small items they just take your word and send replacement without asking for the item.
This is fault of company and they are even accepting it.
 
I am absolutely shocked about this from Cary Audio.
Prem is correct, this needs to be posted on AVS or some such forum.
 
Cary is absolutely not justified in it's stand.
When the company is accepting it's a design flaw.
Infact, they should understand you being in India they should send you free parts and request their dealer to get it done for you
Worst they can request you to pay for shipping.
When they can't let you have schematics this is the least they should be doing.
Even on Amazon for small items they just take your word and send replacement without asking for the item.
This is fault of company and they are even accepting it.

Well, they are not directly accepting that it is a flaw. 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.' Why then, did they sell it in India? And what is the dealer's role in such cases?
 
Sorry to hear about this fiftyfifty.
My responses to your query:
1. I have had issues in the past where the manufacturer refused to send boards, parts, tubes etc., even if the equipment was under warranty. Their stand was that there will be liability issue if I electrocuted myself etc. so they will only service the equipment if I send it to them or their dealer at my cost. So if they are willing to send the part, that is better than what I have faced.
2. My biggest issue in your situation is with the India dealer/dealers. It is the absolute/sole responsibility that the India dealer address this issue at no cost to you, if you purchased the equipment from them. However knowing the dealers in India, I am not surprised that they just shoved the issue under the rug and left you hanging. I have faced this numerous times as well.
Other points I cannot answer.
To resolve the situation, Yes you can try posting in international forums and hope they respond.
 
new amp is in exchange for the old amp and u have to pay the difference ? OR its just exchange

u never experienced this Hum during the warranty period ?

Posting in international forums will generate some more discussion ....not sure if that will lead to any solution
 
new amp is in exchange for the old amp and u have to pay the difference ? OR its just exchange

u never experienced this Hum during the warranty period ?

Posting in international forums will generate some more discussion ....not sure if that will lead to any solution

The hum has been there from Day 1. Of course I noticed it, but was told 'Itna to ayega Sir' and I believed that. Exchange FOC for the new amp? You must be joking :)
 
From the pics, the device looks like a DC blocking circuitry.

See Fig 8 here. One bridge rectifier and two 4700 uF electrolytic capacitors is the parts count. Shouldn't cost more than Rs 500 in parts cost.
 
From the pics, the device looks like a DC blocking circuitry.

See Fig 8 here. One bridge rectifier and two 4700 uF electrolytic capacitors is the parts count. Shouldn't cost more than Rs 500 in parts cost.
Great input Josh, i agree that this is what it appears to be. Don't understand why they are making a fuss.
I have identified a guy who is very confident of getting rid of the hum, but the real issue is that of Cary and the Indian dealers
 
Great input Josh, i agree that this is what it appears to be. Don't understand why they are making a fuss.
I have identified a guy who is very confident of getting rid of the hum, but the real issue is that of Cary and the Indian dealers

Ignore Cary and its dealers and just cure the problem.

PS: I installed this on one of my buffers and it completely cured hum issue I had.

The flipside of this is to figure out if DC is self generated in the amp, or coming from a pre or a DAC or other source.
 
Aren’t these solid state amps?
Yes, mine is solid state

If you wish, I can try connecting to Dennis Had who left Cary and still makes and sells his own amps. He may be willing to at least give you tips and a schematic to cure the problem.

The hum is a result of poorly designed PS or may be filament supply.

Some tube Gurus say that adding a separate and better filament supply transformer cures the hum and settles the problem.

There could be problem with auto bias circuit too.

Mine are all guesses but I can also connect you to someone in India who May be able to give tips and help you. He designs his own tube amps.

Good Luck.

Thanks yogibear. I have identified a guy who is confident of resolving the issue. Will surely reach you if that doesn't work.
 
Agreed yogibear. Solid state and hum in today’s world is unpardonable. Even the 1970s well designed SS amps had zero hum.
 
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