Sounds like a 60 cycle hum - a grounding problem most likely. Try floating the ground at your amp and see what happens. Usually it will go away. This is usually not tube noise but tubes do have a residual noise typically heard as a hiss sound. If your amp has a high input sensitivity and your speakers are very effieient you could well be hearing tube noise. If so, be careful buying NOS tubes, many are not all that quiet. |
Newbee (time to change your name, dude) is most likely right. In addition to poor ground at outlet, could also be a bad IC ground, or induced hum from an IC or speaker cable near the power cord. |
I had a 60Hz hum in my system due to an antenna/cable connection, when the TV was connected to my Jolida amp. The TV cable had a ground that is different from the electrical ground thus resulting in a ground loop.
Best way to find out is to disconnect all ICs from your amp but leave the speakers connected. If you still hear hum then it might be a problem with the amp. Then slowly start connecting one piece at a time, so that you find the faulty piece.
Good luck. |
I love the Golden Dragon 6922's. They are great for the money or for any value. I've been using GD 6922's for about 5 years now and love them. The 12ax7's are quite good also. Very reliable, clean and unbiased sound. |
Also, Steve designs his amps to be passive pre-amp friendly, i.e. high input sensitiviy. It may be something you'll have to live with. |
Helo Eagleman -
The noise is most likely caused by a ground loop created by more than one piece of equipment with a 3-wire AC cord. This problem may also be caused by a cable TV connection if you have any audio signal cable connected from the TV (or any associated equipment) to your audio rig. Here is a link to a good explanation of ground loops and how to fix them: http://www.altavistaaudio.com/hum.html
If you ever want to know what the noise contribution of the amplifier is by itself, just unplug the interconnect cables and replace them with RCA shorting plugs in the amp's inputs. Shorting plugs are so-named because they make a connection from the center-pin (hot) to the outer ring (ground), thus "shorting" the input to ground. This will tell you what the intrinsic noise level of your amplifier is, and this can be useful information when you are troubleshooting system noise. A properly operating amplifier should be fairly quiet - there should be only a tiny amount of noise (or none at all) with your ear close to the speaker.
Beyond that, you should keep in mind that the DNA amplifiers run at slightly higher voltage gain than is typical. This means that the noise floor of your preamp may be more noticeable than it used to be, depending on what amp you have replaced. This is not usually an issue, but I have seen cases where a small amount of preamp noise that had previously gone unnoticed became audible (right at the speaker) with a DNA amp.
I hope this helps. Please call me at 760-732-0352, 10-6, M-F PST (California) if you would like to discuss this further.
Best regards,
Steve McCormack
www.SMcAudio.com |
Well,
I changed preamps from the ARC to the TAD-150. The hum or buzz was fairly low and not audible unless I got right near the speakers. When I hooked up the TAD-150 I could hear the hum and buzz from across the room. I unhooked the IC's and it seems to appear when the preamp IC is connected. Sounds like the 60HZ that newbee was talking about. Any other Ideas. This pre sounds fabulous but, I can't block out the noise.....
Eagleman |
Did you try putting a cheater plug on the amp PC. Only costs a couple of bucks at the local hardware store and is usually quite effective. That is what I meant by "floating the ground" as the cheater plug removes the ground from the circuit. This is not really a major safety issue if the pre amp has its ground intact, and even then...... Try it. |
Thanks Newbee, i will give that a shot.... |
Well newbee, that didn't work. ny other ideas are welcome. |
If the input sensitivity of the McCormack is higher than the B&K it is quite possible that, as Steve Mc said, you are now hearing the noise floor of your pre-amp a bit more than before, although usually this is more hiss than buzz. See what happens when you change tubes, I suspect you will like the tone of the Amperex's much more (assuming that they are low noise tubes.) At least you can't hear it from more than 3ft away...........:-) |
I just switched out my B & K M200's to Rogue M120's. I had the same problem "the 60HZ" hum. I tried everything, and it was driving me crazy. I had the amps going through an Adcom Ace 515, took out it's ground still nothing, then as a last resort, I eliminated the Ace and went direct to the outlet with no gound (Took it off in the box and insulated it)I have the Pre and CDP on another line... the hum is almost gone, all but some very minor residual amp/tube noise. Good luck I know what your going through. |
Well guys, I tried everthing that i could think of and finally took the TAD-150 to a local hi-fi outlet to see if the buzz and hum was present on their systems. Turned out that the same noise was present there so i will be sending back to Bizzy-Bee to repair. Meanwhile i will run my ARC P9 MK2 with the Amperex tubes and wait for the TAD. The only noise I get with this combo is a slight hiss or buzz when i put my ear right next to the speaker. Seems minor. Anyway, thanks for the advice.... |
