CIA D200 mono amp... Humming birds?

Force of Nature · « **on:** 16 May 2008, 08:17 pm »

Dear All,

I hereby kindly would like to ask you a question. My hifi dealer has offered me a pair of CIA D200 mono amps for sale which he had used for demonstrations since he knew I was looking for some new amps.

On the Internet I have read rave reviews about the amps so I am sure the sound quality will be more than okay. However I am a bit worried about the fact that my dealer told me that these amps are softly humming but I should not be worried about that.

What are your experiences with the D200 amps. Do they indeed hum? If so, how loud do they hum? Do you hear them humming between the numbers on a CD or is it barely audible?

Last but not least: what can be done to stop/eliminate the humming?
I have read that the Nuforce digital amps also suffer from humming; could this be something that this generation of digital amps share in common?

Thanks in advance for your time!

Best regards,

Rainer

IronLion · « **Reply #1 on:** 16 May 2008, 08:35 pm »

Mine hummed a little bit due to my halogen lamp in my room, which uses a dimmer in it (dimmers cause humming in lots of toroidal power supplies). Easy fix, that Dusty from Channel Islands Audio makes- the XDC2. It only removed DC from the powerline, which is what causes humming of those toroids in the first place. Now they're silent. Read the Dagogo review of the D200's and the XDC2 for some more explanations, but the XDC2 will fix your humming issue, assuming you even have DC on your mains, which you very well might not.

biz97 · « **Reply #2 on:** 16 May 2008, 08:39 pm »

FYI,

I have the D100s and I also bought the XDC2. Mine are silent w/ and w/out the XDC2. But since I live in an apt I don't know what the next place will be like so I plan to use the XDC2 anyways.

mcullinan · « **Reply #3 on:** 16 May 2008, 08:44 pm »

I have Nuforce SE v2 and they dont hum.
hmmmm.
Mike

CSI · « **Reply #4 on:** 16 May 2008, 09:41 pm »

I have both CIA D100's and D200's and neither pair hum. It has nothing to do with the amp technology - it's the transformers. Any transformer can hum if there is residual DC on the line and toroid's are apparently more susceptible. If you get them home and they hum, the XDC2 will block the DC and solve the problem. If it doesn't, take them back or send them off to Dusty for a check up (you should have a full warranty on dealer demos). Enjoy your amps!

denjo · « **Reply #5 on:** 17 May 2008, 12:46 am »

My D*200s hummed and not even the XDC-2 could cure the hum!

DaveX · « **Reply #6 on:** 17 May 2008, 06:34 pm »

When I first had my D200's the hum was very obvious at times due to something else on the power line (not DC) adding it's own waveform to the sine wave. Somebody close must have chucked out their old freezer because the hum is hardly an issue now, although not totally eliminated. I do plan to use a (possibly PurePower) power re-generator at a later stage but have ruled out the PS Audio PPP because in design the Premier's DC power supply that feeds the power amplifier producing the sine wave to the output is actually riding on the AC line. the downside to this method is that if there's DC on the line, the DC is also riding on the AC and is therefore passed along by the Premier's output amplifier.

kkc · « **Reply #7 on:** 19 May 2008, 09:22 pm »

There are many possible causes of hum - I think psaudio have a pretty good summary on their website. Assuming you have eliminated ground loop, dc on the mains and any othere noisy electrical fixtures like dimmer switches, you may well have only two options left - either a saturated toroid because the electricity supply is "very good" or a distorted sine wave.

By the way the easiest check you can do is to go to the house fuse box and switch off all power circuits except for one and plug the amps into that line to see if they hum. Defacto you will have eliminated all internal noisy appliances.

DC on the mainsline can be measured by some, not all, multimeters. However using an XDC2 is not a bad thing it will remove any DC and you can place it upstream of D200s and components too.

If toroid is saturated: use a variac and bring the voltage going into the D200s down. I bought my voltage all the way from 240vac to 210vac and all my electronics worked just fine.

If the supply signal is clipped: use the more expensive option - a power regenerator. You can check the sine wave using an oscilloscope. I think these are very expensive though and then you also need to ensure that the unit can supply power bursts almost instantly when the amplifiers demand it.

The hum will not damage the amp and should not effect the music unless its really loud and you hear it during quiet moments, so if you can live with it it's really no problem. However I did notice that with the variac, the sound quality seemed to improve - this could be due to either the hum being eliminated i.e dead quiet during quiet moments in music or an improvememnt in the amplification and signal processing when the core is not saturated.

marcel · « **Reply #8 on:** 13 Jan 2009, 07:39 pm »

:cry:The sound of the D200 is very good, but they do humming, sometimes quiet but often loud. Between the numbers i hear at 4 meter distance the humming. I used a dx termiator of kemps electronics and it didn't work. It is not a dc problem but a shortcoming of the trafo. My dealer shall replace the trafo's by others ones whch don't hum. Apparently some models hum and other don't. Why i don't know.
I live in the Netherlands and our electiricty is 50hz, the D200 was made for 60hz (USA), proberbly this is a cause. When the other trafo's don't hum it is for me the perfect compact amplifierwith a very high sound level.

kkc · « **Reply #9 on:** 13 Jan 2009, 07:48 pm »

sorry but whats a trafo?

mattyturner · « **Reply #10 on:** 13 Jan 2009, 08:11 pm »

trafo - Transformer i believe.

CSI · « **Reply #11 on:** 13 Jan 2009, 09:11 pm »

I have a pair of D200's and had a pair of D100's. Neither hummed at all, even with my ear almost on the case. Interestingly, class A/B, tube and another brand of Class D amp did hum a little but not enough to be a problem. In my house, CIA's were the only completely "clean" ones in this regard.

A person from Richard Gray's Power Company (they make isolation transformers) told me that they have trouble with 50Hz power (European) sometimes and the solution is to use a large enough transformer. Apparently, the smaller the transformer the more likely it is to hum (assuming the transformer is meant for 60Hz mains but used on 50Hz). This is on the isolation transformers only. The regular Richard Gray device has no problem.

koiman · « **Reply #12 on:** 13 Jan 2009, 10:44 pm »

I have had my Channel Island D-200 for 3 years and have never experience hum of any kind.

NewBuyer · « **Reply #13 on:** 14 Jan 2009, 03:07 am »

I wonder what approximate percentage of users experience hum with the D-100's or D-200's. I wonder, aren't there other types of transformers that don't hum and could be used instead of toroids?

IronLion · « **Reply #14 on:** 14 Jan 2009, 03:31 am »

I used to have D200's; they hummed. I got a CIA XDC-2 filter. They stopped humming. I still have the XDC-2 although I sold the D200's because I clearly had some DC on my lines.

designdude · « **Reply #15 on:** 16 Jan 2009, 02:48 am »

I have a pair of D-100's. When I plug them into a wall socket using a cheap power cord they are quiet, even when I daisy chain them with a cheap Home Depot unshielded extension cord.

When I plug them into an Audio Power Industries Power Wedge Ultra 116 power conditioner they have a very slight hum, noticeable at about 3 ft.

When I plug them into a PS Audio Quintessence Power Conditioner they hum so loud it scares my cats.

Needless to say they are now hooked up using the cheap extension cord. I am not happy with this solution, and will probably be selling them once I find a suitable replacement amp.

Charles Calkins · « **Reply #16 on:** 16 Jan 2009, 03:48 am »

designdude:

You're kidding!! You gonna shit can your D-200's because they hum when you plug them into an expensive P.S. audio gizmo and they don't hum when plugged into a wall socket or with a Home Depot extension cord? I don't get it??? You kidding?

Cheers
Charlie

designdude · « **Reply #17 on:** 17 Jan 2009, 05:46 am »

Charlie,

Your note is a breath of fresh air in a hobby that is often filled with gobble-dy gook.

Let me expand upon my earlier statement.

I have multiple systems and about $20,000 of audio gear. I have invested approx $4,000 in source components (including a $1,000 CD player, a $1,000 DVD player, a $1,000 turntable, and a $1,000 digital music server), $5,000 in speakers (including a pair of Gallo Ref 3.1, among others), $3,000 in preamps (including a McCormack MAP-1 and a Dared SL-2000-A), $3,000 in amps (including the Channel Islands D-100 monos, and an Onix SP3 with lots of NOS tubes), $1,000 in power conditioners (PS-Audio Quintessence and the API Power Wedge), and over $2,000 in cables and power cords. I also have a Sony high-definition direct view TV (a tube TV with a high def tuner - described by many experts as the best TV ever made).

Every piece of gear that I have I enjoy. Collectively they provide sweet, beautiful music, even when I plug any of them - or all of them - into a wall socket using generic power cords. But when I start making tweaks, and I swap out the generic power cords and replace them with aftermarket power cords, and use power distribution devices that are engineered for audio excellence, I end up listening to music that takes my breath away - except when my speakers are connected to these little amps made by Channel Islands. As I wrote, the D-100's sound OK connected to the wall socket using a Home Depot power cord. Hell, everything I own sounds OK in that regard. But when I tweak everything else I own the sound goes from OK to FANTASTIC, whereas the sound of the D-100's goes from OK to OUCH!

Does this explanation help you get it?

I spent $1500 on these little boxes. I expect much more than OK. For that price I expect - hell I demand - something that sounds fantastic. Not a block of vibrating metal that makes the 15 year old refrigerator in my basement sound quiet.

Don't get me wrong, I think CI makes a decent product that fills a small niche in the audio world. They are small, they are light, they produce decent sound for the price - but from my experience they will only work in certain situations. In some situations they will hum like hummingbirds. And you don't have to have Ray Charles' hearing to experience that hum.

Personally, I have hard time understanding how they ever got the awards they got.

wilsynet · « **Reply #18 on:** 17 Jan 2009, 06:24 pm »

The solution may lie in a previous post on this thread.

Quote from: kkc on 19 May 2008, 09:22 pm

There are many possible causes of hum - I think psaudio have a pretty good summary on their website. Assuming you have eliminated ground loop, dc on the mains and any othere noisy electrical fixtures like dimmer switches, you may well have only two options left - either a saturated toroid because the electricity supply is "very good" or a distorted sine wave.

[...]

If toroid is saturated: use a variac and bring the voltage going into the D200s down. I bought my voltage all the way from 240vac to 210vac and all my electronics worked just fine.

You should probably talk to Dusty, but anyway, if you want a variac, here are some:

http://variac.com/staco_3PN10_20.htm

Looks like the cheapest one here is $323.

There are also a number of auctions on EBay:

http://shop.ebay.com/?_from=R40&_trksid=m38.l1313&_nkw=variac&_sacat=See-All-Categories

Charles Calkins · « **Reply #19 on:** 17 Jan 2009, 06:38 pm »

designdude:
Very interesting. I mean very interesting!!. If you can figure out the hum problem let us know. I'm sure the hum problem must be taking away some of the sound quality from your d-100's.

Cheers
Charlie