CA5200 Hum noise

[Maverick71]

My newly arrived CA-5200 has a hum coming from the unit itself (not through the speakers). It is noticeable at quiet passages during the day and even more noticeable at night when listening to music at low levels.

Is this normal? The sound is originated by the toroidal transformer. My previous power amp had 5 toroidals and they didn't make noise that could be heard at the listening position but, on this case, the hum is distinctly heard at about 5 meters of distance from the power amp that sits on a stand.

Does anyone has any experience on this?

Thanks :T

Mav

[hifiguymi]

It sounds like it's either saging line voltage or someting wrong with the amp. If it's worse at night when more people are home and more electricity is being used it sounds like saging line voltage to me. Do you have a volt meter to check your incoming line voltage?

Eric

[Maverick71]

I've just measured and it reads 243 Volt which is within the operating range. It's worse at night because the ambient noise is lower and I also tend to listen to music and movies at lower levels.
It's a permanent hum that bothers me not much during the day (when music levels and ambient noise just about overcomes it) but, at night, IS a bit disturbing.
I was wondering if any CAx200 users had similar experiences..?

Mav

[RebelMan]

All of the Delta CA-XXXX amplifiers are dead quiet and so should your 5200 be.

[hifiguymi]

Since the voltage is OK I'd have your dealer look at it. As RebelMan said, that amp should be dead silent.

Eric

[Maverick71]

All of the Delta CA-XXXX amplifiers are dead quiet and so should your 5200 be.

That's very good news.
I was begining to think that there was some kind of trade off for this kind of power. Just last night I was getting crazy with the permanent huuuuuuuum the amp makes! Your brain just dials that sound and you almost seem to listen to anything but it!
I think it is normal that the transformer makes some noise but it only should be listenable when placing the ear against the unit, I guess.h

Thanks for the help, guys.

Mav

[Xavier]

Good luck!

[Maverick71]

I was sugested that the problem might be due to noise on the AC mains that causes the transformer to vibrate. Anyone suggests a line conditioner or some any means to measure and/or eliminate noise from AC lines?

Mav

[Glen B]

I was sugested that the problem might be due to noise on the AC mains that causes the transformer to vibrate. Anyone suggests a line conditioner or some any means to measure and/or eliminate noise from AC lines?

Mav

I suggest you first contact the Classé factory. If the hum in being caused by the AC supply, they may have a solution for you. With certain CA-XX0 model amps Classé added a noise filter modification to eliminate transformer hum. CAX01 models appear to have the noise filter included as stock. The Deltas may or may not have this noise filter on the input of the power transformer.

[Maverick71]

Thanks Glen. They suggested a line conditioner and I'll get my hands on a Shunyata Hydra 8 noise filter (http://www.shunyata.com/Content/prod...st.Hydra8.html) tomorrow for some testing. I'm a but sceptic, to say the least, but it can't hurt to try.

Mav

[Glen B]

Thanks Glen. They suggested a line conditioner and I'll get my hands on a Shunyata Hydra 8 noise filter (http://www.shunyata.com/Content/prod...st.Hydra8.html) tomorrow for some testing. I'm a but sceptic, to say the least, but it can't hurt to try.

Mav

I wish you good luck with the Hydra. If your hum is being caused by DC on the power line, the only solution is to either find and remove the source of the DC or block it, which a Hydra will not do. The PS Audio Humbuster blocks DC.

[Maverick71]

I wish you good luck with the Hydra. If your hum is being caused by DC on the power line, the only solution is to either find and remove the source of the DC or block it, which a Hydra will not do. The PS Audio Humbuster blocks DC.

Thanks for your sugestions. Are there any other DC blockers you know of? I think it'll be hard to get my hands on a Humbuster for testing.

Can I read if there's any DC on my AC with a multimeter?

Mav

[photoman]

My newly arrived CA-5200 has a hum coming from the unit itself (not through the speakers).
Is this normal? The sound is originated by the toroidal transformer.
Mav

Mav I have a 5200 dead silent. only way you should know it on is via the blue led's or feeling the heat sinks

[Maverick71]

Mav I have a 5200 dead silent. only way you should know it on is via the blue led's or feeling the heat sinks

I envey you . Mine hums and for example, at this time (it's 1am over here) my living room is dead silent and I can hear loud and clear the hum coming from the toroidal within the 5200. My previous power didn't do this and it had 5 smaller toroids.

I've just plugged the Hydra line conditioner and, as somehow predicted by Glen, it didn't work. It hums just as much. If it's in fact due to noise or DC at the AC mains I think I'm going to have a hard time (if ever) to solve this issue :cry: .

I'll keep talking to my dealer and Classé to see if they can help me out.

Mav

[Glen B]

I envey you . Mine hums and for example, at this time (it's 1am over here) my living room is dead silent and I can hear loud and clear the hum coming from the toroidal within the 5200. My previous power didn't do this and it had 5 smaller toroids.

I've just plugged the Hydra line conditioner and, as somehow predicted by Glen, it didn't work. It hums just as much. If it's in fact due to noise or DC at the AC mains I think I'm going to have a hard time (if ever) to solve this issue :cry: .

I'll keep talking to my dealer and Classé to see if they can help me out.

Mav

How good are you with DIY ? Here's a common DC blocking circuit you can try that will let you know if such a device will solve your hum problem. It employs four caps and 1,000V diodes. The parts are not more than about $25-$30. You can connect the circuit in the hot line between the AC supply and amp. Exercise caution as the cans of the electrolytic caps will be energized. If this circuit does not work you're not out much money.

[photoman]

I envey you . Mine hums and for example, at this time (it's 1am over here) my living room is dead silent and I can hear loud and clear the hum coming from the toroidal within the 5200. My previous power didn't do this and it had 5 smaller toroids.

I've just plugged the Hydra line conditioner and, as somehow predicted by Glen, it didn't work. It hums just as much. If it's in fact due to noise or DC at the AC mains I think I'm going to have a hard time (if ever) to solve this issue :cry: .

I'll keep talking to my dealer and Classé to see if they can help me out.

Mav

Just out of curiosity - can you bring the amp say to a friends house to see if you have the same problem there - to rule out your mains or the amp ?

[Maverick71]

How good are you with DIY ? Here's a common DC blocking circuit you can try that will let you know if such a device will solve your hum problem. It employs four caps and 1,000V diodes. The parts are not more than about $25-$30. You can connect the circuit in the hot line between the AC supply and amp. Exercise caution as the cans of the electrolytic caps will be energized. If this circuit does not work you're not out much money.

Thanks Glen! I've been doing some research and these circuits usually work and I'm able to put my hands on it (I did many circuits so no problem there). The diodes are just 1,000v spectd? Do you have any 1Nxxx or 2Nxxx reference for them?

Thanks :T

Just out of curiosity - can you bring the amp say to a friends house to see if you have the same problem there - to rule out your mains or the amp ?

My dealer suggested that if the Hydra didn't work, I'd try a line conditioner they sell (Belkin ??). After that I was thinking of taking the amp to their demo room (which is quite silent) to see if it hums, but I was avoiding this last option because, as you know, this s not a 'portable' item...

So, after the Belkin I'll either make the DC blocker suggested by Glen or take the amp to the dealer.
I am hoping that Classé might suggest a solution of their own for this cases. If the hums are a possibility at the costumers home, it would be wise to implement a DC block on their amps. They obviously don't do it therefore I suspect that there might be some reason for that...

Mv

[Glen B]

Thanks Glen! I've been doing some research and these circuits usually work and I'm able to put my hands on it (I did many circuits so no problem there). The diodes are just 1,000v spectd? Do you have any 1Nxxx or 2Nxxx reference for them?

Thanks :T
Mv

1N4007.

I am hoping that Classé might suggest a solution of their own for this cases. If the hums are a possibility at the costumers home, it would be wise to implement a DC block on their amps. They obviously don't do it therefore I suspect that there might be some reason for that...
Mv

It could be possible that Classé is using Plitron LO-NO transformers in their amps. They have also used Toroid Tech (another Canadian transformer manufacturer) products in the past. The LO-NOs are generally quieter and more tolerant of DC than ordinary toroids, however no toroid, even the LO-NOs or Equi=Tech's similar Q type are totally immune from saturation by DC. If Plitron LO-NO trannys or some other equivalent are being used, my guess is the Classé designers may feel that DC blocking circuitry is not necessary.

[Maverick71]

1N4007.


It could be possible that Classé is using Plitron LO-NO transformers in their amps. They have also used Toroid Tech (another Canadian transformer manufacturer) products in the past. The LO-NOs are generally quieter and more tolerant of DC than ordinary toroids, however no toroid, even the LO-NOs or Equi=Tech's similar Q type are totally immune from saturation by DC. If Plitron LO-NO trannys or some other equivalent are being used, my guess is the Classé designers may feel that DC blocking circuitry is not necessary.

Thanks!

This is the first time I have problems with transformer hums hence my questions. All the power amps I had previously didn't show any issues with the AC mains but none were as big and powerful as the Classé's...

Mav

[Maverick71]

Well, I've just tried this http://catalog.belkin.com/PureAV_det...duct_Id=178914 from Belkin with no practical results. The hum's still there. It's a cool gadget, though. It shows permanently the voltage and the amperage that's being used (the 5200 shows 240v and 1,6A which is accordingly with Classé's specs).

Back to square one, I'm afraid.

I'll give the DC blocker a try and, if that fails, take the 5200 to my dealers room to see if it hums there.

Mav

[Maverick71]

Just finished building the DC blocker and test it. Unfortunately (or fortunately, I don't know) the hum's still there.
So, neither Shunyata, Belkin or the DC blocker made any difference so I guess I'll have to take the 5200 to my dealer demo room and see if it hums there. If it's an AC mains problem, then I guess it'll be quite hard to solve it.

Mav

[RebelMan]

Interesting Mav. I am eager to see how this pans out for you. I am not sure what side to root for though. I would hate to see the amp be the problem but given your circumstances it might be your best (easiest to fix) alternative. Keep us posted.

[Maverick71]

Well, today I was finally able to take my 5200 to the dealer and see if the problem still occurs.
To my despair (in some way) although the amp has some noise, it is barely audible and only when placing the ear near the amp. At my home it's audible and disturbing at about 3m away from it...

Therefore, I think I've just run out of options and possiblilities... . With this results the obvious conclusion is that the problem is at the mains, but no other power amp showed it and none of the filters I tested did anything in order to minimize the hum! What to do :roll: :huh: :banghead: ...

Any suggestions / advice?

Mav

[Glen B]

Well, today I was finally able to take my 5200 to the dealer and see if the problem still occurs.
To my despair (in some way) although the amp has some noise, it is barely audible and only when placing the ear near the amp. At my home it's audible and disturbing at about 3m away from it...

Therefore, I think I've just run out of options and possiblilities... . With this results the obvious conclusion is that the problem is at the mains, but no other power amp showed it and none of the filters I tested did anything in order to minimize the hum! What to do :roll: :huh: :banghead: ...

Any suggestions / advice?

Mav

I would contact Classé and explain that I've tried everything, including the line conditioner they recommended, DC blocking circuit, taken the amp to the dealer and it still hums. The amp is still under warranty, let them deal with the problem.

[Maverick71]

I would contact Classé and explain that I've tried everything, including the line conditioner they recommended, DC blocking circuit, taken the amp to the dealer and it still hums. The amp is still under warranty, let them deal with the problem.

Thank you Glen :T . The problem is that the amp does not hum (at least it's not audible at 1 foot away) at the dealer so the logical conclusion would be that the problem is within my mains and not the amp (although other amps never showed this problem). Dead's end, so it seems .

One thing I noticed is that the voltage at the dealer is 230V and at my home 240V. Could this have an impact?

Mav

[Glen B]

Thank you Glen :T . The problem is that the amp does not hum (at least it's not audible at 1 foot away) at the dealer so the logical conclusion would be that the problem is within my mains and not the amp (although other amps never showed this problem). Dead's end, so it seems .

One thing I noticed is that the voltage at the dealer is 230V and at my home 240V. Could this have an impact?

Mav

The voltage should not make a difference. Have you tried shutting off all circuits except the one the amp is on to see if the noise goes away ? Going back and re-reading you previous posts, you did not mention trying that. What surface does the amp sit on at home ? Anything that can resonate and make the hum louder ?

[Maverick71]

I haven't tried that... After getting back from the dealer I thought about what more could I do and decided for a few more tests. Tomorrow I'll get the amp back in my house (it's at the dealer now) and try it on other AC outlets in my house. If that does not make different results I'll do just what you suggested. I thought about shutting off all circuits except the one that serves the outlet where the amp is connected.

The amp sits on an thick acrilic base that has 4 legs with soundcare superspikes at the end. One thing I forgot to mention: when humming, if I press the top plate of the amp, the hum slightly reduces (or changes frequency).

Mav

[Glen B]

One thing I forgot to mention: when humming, if I press the top plate of the amp, the hum slightly reduces (or changes frequency).

Mav

Check the transformer mounting bolt for tightness. There are vibration damping products you can apply to the inside of the top cover.

http://www.musicdirect.com/products/detail.asp?sku=AAAPANEL

http://www.partsexpress.com/webpage.cfm?DID=7&WebPage_ID=3&Start=1&searchorderby=1&ObjectGroup_ID=37&sm=1&so=1

[yannparis]

Hello,

Sometimes mechanical hum coming from the transformer is caused by a DC component on you line.

Regards

Yann

[Glen B]

Hello,

Sometimes mechanical hum coming from the transformer is caused by a DC component on you line.

Regards

Yann

He has already tried a DC blocker (post #21).