new A21 same hummming!

[tboooe]

The title says it all. I got another A21 and I am still experiencing significant hummming/buzzzing throught the speakers. The only way to reduce it is to turn down the gain on the back of the amp. According to the manual, the gain should be turned all the way up if using a preamp which i am. With the gain turned down enough so that the hummm is not too audible, I cannot get the volume up beyond comfortalbe listening levels. I guess I will try a cheater plug tomorrow though I am certain that it is not a ground loop issue.

This has to be something to do with the halo product because I never had this problem with my rotel 1080 amp.

[bhuskins]

If it's resolved with a cheater plug, you may need it on all three devices.

That's one of the cool things about any of the PS Audio Power cables is that they have a removable ground pin:



Keeps it nice and clean.

Here's what they say about it:

Form their site:

"One of the coolest new innovations we came up with on the xStream and Power Punch power cables is a removable ground pin. The ground pin on a power cable is there to tie the ground of the AC receptacle to your equipment. However, in some cases, this ground pin can cause a ground loop and cause hum and buzz in your system.

Traditionally audio and theater enthusiasts have used what is known as a “cheater plug” to solve this problem and break the ground loop. A cheater plug is an inexpensive three prong to two prong adapter. Unfortunately, this adapter ruins many of the benefits of a high end power cable like the xStream or Power Punch.

PS engineers invented a better way: a screw in ground pin. Instead of using a cheezy cheater plug and runing all the benefits of the xStream's machined connectors, you simply unscrew the ground pin and voila! No more buzz. In practice, you would leave the cable grounded. Should your system have a ground loop problem that is causing hum or buzz in the loudspeakers, simply unscrew the ground pin of the xStream and the buzz is gone!

This just might be the solution you’ve been looking for!

Is it safe?

Generally yes. We recommend keeping the ground in place whenever possible. However, as mentioned, sometimes it's necessary to eliminate a ground loop by removing the ground pin. When you do this there's no difference between removing the ground pin and using a three prong to two prong adaptor like a 'cheater plug' except it will allow the cable to perform its best.

The ground on a power cable is generally used to tie the metal chassis of your equipment to a safety ground in the unlikely event that a wire inside the unit might break and make contact with the chassis. Many pieces of equipment use only a two prong plug with no ground and this is perfectly acceptable and safe for use in the home, even in the instance described above.

So, the safest way to operate your equipment is to leave it grounded. In the case where you need to break a ground loop to eliminate hum, the xStream and Power Punch cables with their removable ground pin might be the best thing to ever happen to your system."

Brent Huskins
Media Design
HTGuide Sponsor

[jonia]

I have read about this issue before, in a Norwegian magazine. They experienced the same hiss when A21 and P3 was connected. After having tried a lot of things to make the hiss go away, they decided to try another preamp. And the humming disappeared.

They received a new P3 from the dealer and this functioned perfectly, no hiss.

But perhaps you have tested the A21 with another pre-amp already?

[tboooe]

jonia, thanks for the response. I dont think its the preamp because i did try another one. the humming i am getting occurs when i connect any interconnect to the amp. the interconnect does not have to be connected to any source (preamp, cdp, etc), and I still get the buzz. i am still trying to sort this out.

[r100gs]

Did your B&W's buzz while using the Rotel? Are your speaker wires new? I guess what I'm saying is to check on the other side of the amp.

[tboooe]

Hi, with my rotel 1080, i had absolutely no hum or buzz. I am using the same speaker wires. What i noticed that as soon as I connect the interconnect to the amp, i get the buzz, even if there is no source attached. take away the ic and no buzz.

[bigburner]

Tommy, my hum is back too, and I'm dumbfounded.

[soundhound]

Sure does sound like a ground loop. Have you tried taking a wire and going from chasis to chasis on you're pre to power? Many times a good metal contact can be made on the bottom of the unit by loosening a screw and attaching a small guage wire. Just .02 more cents for the piggy bank.

[tboooe]

Nigel:

I share your anguish!!!

Soundhound, I will give your suggestion a try.

[mariachi]

Did you try the ground lift switch?

-Vic

[tboooe]

sure did...doing so had no affect.

btw, nice to see another OC'er here...

[ThomasW]

take away the ic and no buzz.

Are the IC's shielded cable?

[tboooe]

hi, i currently use nordost red dawn xlr ics but i have a bunch of different xlr and rca type cables...same result.

[bhuskins]

cheater plug results?

[phansson]

Tracking down a hum in a system is usually a pain in the behind. I finally found mine. I am also running two A21's and two A23's. My hum was from my projector to the DVD player via my DVI cable. I removed the ground plug from my PJ cord and NO HUM! Try eliminating certain components and you will eventually find the problem.

[tboooe]

Brent, I have not tried the cheater plug yet though I plan to soon. I am waiting for my speakers to arrive next week. I will let you know how it works and if it works well I will touch base with you about the ps audio stuff.

[bhuskins]

.99 at Home Depot...best test you've ever tried.

What speakers did you get?

Brent

[tboooe]

thanks brent..i ended up upgrading from my B&W 805S to 804S. This was mainly due to the fact that I got exiled from my study which is a smallish 12x15 room. Now I am in a space that is this slightly smaller but one side opens up to a large living room with vaulted ceilings. My 805S really struggled in this room.

[Chris D]

I too was going to ask about the ground lift. That had NO effect?

[bhuskins]

He hasn't tried it yet.

Brent Huskins
Media Design
HTGuide Sponsor

[Chris D]

Ah... tbooe posted above that he flipped the ground lift and it didn't have any effect, but hasn't tried the cheater plug yet. Did I misunderstand? The reason I ask is that I too had a little bit of speaker hum. I used the ground lift and about 95% of the hum went away, with the remainder so small that it's negligible. I think the reason it wasn't fully eliminated is what Peter posted in another thread, that it doesn't fully do the same thing as a cheater plug.

But if you tried the ground lift, I would have expected it to have at least a little effect of some sort.

[mariachi]

I moved to a new apartment 2 months ago and finally had the chance to set up my equipment a few weeks back. As soon as I plugged in my A52, there was a nasty hum, which I did not have at my previous apt. Anyways, I shut it down, switch the ground lift switch, turned it back on, and it killed the hum completely.

[bigburner]

Tommy, how's your hum problem these days?

Last week I got my electrician to install a new 20 amp mains cable directly from the switchboard in an effort to eliminate the hum I have been experiencing. The new cable has only two power points - 1 for my amp / preamp / CD etc, and 1 for my sub which is on the other side of the room. The hum hasn't gone completely but is much reduced. I'm now at the point where I can live with it. The next step (if I do anything else) is to sink a new earth for the new cable.

brucek, if you happen to read this, would you recommend a new earth?

[Holland]

If you attach nothing to your power amp, its not difficult to get a hum. I had it with my rotel amp, as soon I switch my preamp off but leave the power amp on it starts to hum. Altrough I didn't use balanced cables.

Good luck with solving the problem, it indeed can be quite hard to find a hum source.

[H.Donald]

Humms are funny...with no humor,that is.Recently I had to take my system apart....and now cannot get rid of the humm from my coming thru my speakers.
My Rotel 1095 has them buzzing....with the same setup I had before.
At one time I simply switched the outlets and it was very quiet....same outlets now and they buzz like crazy.

On another thread I had read about grounding the amp and processor together....and this has worked somewhat.Now the humm only comes from the mains as opposed to all five that the 1095 powered.Sooo,I am still working on it.....

I now plug the 1095 into a power filter....which does not help....I am wondering if using the Xstream removable pin cord might be the cure for me...and would it be safe to use with the power filter?

[RebelMan]

My Rotel 1095 has them buzzing....with the same setup I had before.
At one time I simply switched the outlets and it was very quiet....same outlets now and they buzz like crazy.

Donald, when my three prong power amplifier was plugged into the same outlet as my two prong preamplifier I experienced humming also. I moved the preamp to another outlet which eliminated the hum. I suspect mixing dissimilar prongs on the same outlet can wreak havock to any system. Keeping two prong power chords separate from three prong chords (yet sharing the same circuit) seems to work well. Have you tried this approach?

[tboooe]

Nigel:

sorry for not responding sooner...things are pretty hectic.

I am now on my 3rd A21 amp and the humming as substanially decreased, though I am not sure if this is due to my new speakers. One thing I did notice was that the A21 is very sensitive to how properly seated my XLR interconnects are to the preamp. If not properly connected, there is a lot of buzz. I have to really wiggle the XLR around and push in very hard in order to get rid of the buzz.

have you considered trying something like the PS Audio Power Plant? I am thinking about it.

[H.Donald]

Rebel Man,so far nothing has worked as before.The only three pronged is the 1095...and I have put that on an entirely different circuit and still it sizzles.
I think my next step will be to try the removeable pin cord.....