Are you using balanced interconnects? When I had a Meridian amp, if I used balanced IC's, I had to put in shortening plugs in the RCA jacks or else I would get a hum. |
You have a ground feedback loop or are picking up hash from adjacent power cords, etc. First have a look and make sure you have hooked up OK, make sure all connections are good and tight and correct. Then (with power still off) disconnect the source interconnect, power up and see if you still have the hum. If not, then the hum loop is from the source side, if yes then you have to look at the output side. This means you are picking up thru the cables unwanted signal from adjacent power cords or transformers (large ones powering tube amp..???) and therefore you will have to "dress" the cables (get them away from power cords and sources, etc) and avoid unneccessary loops in the cable. Keep the cables at 90 degrees when they have to cross other cords and make sure they go straight out and away from the amp before they head off in the direction of your speakers. Hope this helps you, regards Richard |
Hi Brian, The quickest and easiest thing to try in addressing the ground loop problem would be to inatall "cheater plugs" on the amp's AC cords so as to float the ground pin. You can pick them up for a couple of dollars if you don't have them on hand. I had the same problem with the SE 100s and the "cheater plugs" cured it instantly. Good Luck! |
Plato, the Meridian amp I owned came with the "shortening plugs". |
Hey Brian, If you only have one AC adapter plug you could try it on the Cary AC cord first, because that could cure the hum as well. |
Plato, you have me confussed with the original poster. Brian |
Brian, sorry--I got you mixed up with the fellow who first posted the question. Anyway, I was referring to AC plug adapters, not RCA jack shorting plugs. Sorry for my confusion. |
Thank you for the quick responses. One think I forgot to mention is that the cary preamp has been working with my Hafler DH200 with the same equiptment in the same setup for over a year. This may not change you respective advices but i thought i should mention it. Cheater Plugs, where can i pick them up? and are these used to fix polarity problems? Thanks again all. Cheater |
Brianmgrarcom, I am using RCA's as my Preamp doesn't have Balanced outs |
Yo Commodore, You can pick up the 3-prong AC adapter plugs ("cheaters") at any electronics store, even Radio Shack. Some supermarkets, drug stores, discount stores like Wal-Mart, Home Depot, or any hardware store--really just about anywhere! These things are very common. :) |
Brianmgrarcom, I am using RCA's as my Preamp doesn't have Balanced outs |
Cheater Plugs?, you guys talking about those grey 3 to 2 prong adapters? Thus eliminating the ground? |
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Thanks again all. Just talked to Mr. Poon at Monarchy Audio. By the By, super nice and helpful. He agreed that Cheater plugs would fix the problem and that my Hafler didn't have the problem because it has a two prong plug. Can't wait to get out of work and give it a listen |
A quick way to see if your hum is from a ground loop is to plug everything into the same outlet(via an outlet strip, if you need). If it disappears, it was a ground loop problem, nothing wrong with the equipment. Then you can go to work on attacking the problem |
I heard of a case recently where a guy touched the chassis of a power amp that had a cheater plug. He ended up wearing his beer after the jolt he got. Okay, there may have been a problem somewhere, but beware of cheaters...the ground prong is there for a purpose....so the chassis does not float. |
Hey, Ralph Nader, thanks for that hair-raising anecdote. I think we can agree that it's certainly tragic when good beer goes to waste. :) I guess I'll just have to install a dedicated earth ground for all my audio gear. If your heads-up prevents just one more drop of beer from being spilled then... Sniffle... I'm sorry, I just can't go on... Thank you and may God bless! Seriously though, you raise a valid issue. People do get struck by lightning, win the lottery, and get shocked with the potential to be badly injured from touching improperly grounded gear during major malfunctions when current shunts to the chassis. |
Not meaning to beat around the Busch, but are you sure this guy didn't spill a little beer into the powered-up amp before he touched it? How many did he chug down anyway. I have to apologize for my indefensible flippancy, but I've always held that drinking and critical listening don't mix--and this is just another classic example to support my case. :) |
ah? well, it's the next day, and all is well Cheaters worked, sweat gone, can't wait to crank it when i get home |
Commodore, I'm glad that the cheater plugs worked for you! Now if you ever suspect that an ungrounded amp is on the verge of melt-down (major failure) don't touch the amp, pull the rubberized plug out of the AC outlet instead and let it cool before handling. Enjoy your Music. :) |
Plato (aka the fountain of wisdom): I'm unsure about how many beers this guy had chugged before, or whether he intended to share his beer with the amp. Needless to say, had you been in his position, the jolt would have done nasty things to your toga, O Wise One ! BTW, I agree that drinking and critical listening do not mix, but this guy was at a party, and his critical faculties were no doubt not at their best. The correct way to fix a ground loop is to interrupt the loop, but not at the chassis ground. Sorry, but I am cautious and do not believe in cheaters, even if they work. |
