Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
In Reply to: RE: SET headphone amp without hum? posted by aarocks on August 07, 2016 at 08:01:16
What "Frihed89" said. While DNA amps have vanishingly low self-noise, "ground loop" noise issues can affect any chain of amplification.
So you need to get rid of those ground loop issues no matter what.
How can I figure out whether I have ground loop issues or not? The Opera Consonance SET headphone amp I have now hums but it has a reputation for humming so I don't know if it's a ground loop issue or not.
Some amps have a reputation for being "noisy" and/or more sensitive to ground loop issues than others. Humming can also be cause by things like internal wires or parts that are loosely attached.
A few years back and seemingly out of nowhere, my tube phono preamp developed a hum. When I opened up the case, I discovered that one of the input cable terminal nuts had loosened up. After I untwisted the wire and tightened the internal nut, the hum disappeared. Another time, I discovered that the phono section in an integrated amp that I had bought on the used market had a terrible hum. I looked inside and noticed that the casing internal ground wire attachment was painted metal rather than bare metal. After I scraped the black paint residue away and re-tightened the terminal nut, no more hum...
So, sometimes it's worth opening up the case and checking things out. Or if the amp is new and/or still under warranty, consider sending it back for a checkup.
If all else fails try contacting the manufacturer for advice on how to deal with hums and/or ground loop issues.
Thanks, I will do that. As far as SET amps that are less prone to hum due to ground loops, are those the ones that are said to be less noisy?
Some amps have better power-supply filtration, better internal layout, and better internal grounding schemes than others do. These amps should generate the least amount of self-noise and should also filter out the most external noise, but I would guess that ALL components will perform better when potential ground loop problems are simply non-existent.
An easy way to eliminate (or check for) ground loops is to install two-prong "cheater plugs" on all components in your system that currently use three-prong plugs. If ground loop problems are solved this way, remove one cheater plug at a time until the offending component(s) have been identified. If humming disappears only when all components have cheater plugs, it might be best to have a certified electrician examine your house wiring so that the use of stock three-prong plugs might be resumed.
Simply making sure that all components are plugged into one single wall outlet often cures ground loop hum. Using too many outlets for the same system increases the chances of ground loop problems.
Sometimes too, simply reversing the orientation of one or more two-prong plugs (only some two-prong plugs are designed to allow for such a thing) in your system can uncover or eliminate humming issues and/or improve the quality of the sound. My old Rega CD player came with a reversible two-prong cord and in some instances it sounded slightly better with prong orientation one certain way.
Also, make sure that all interconnecting cables between components are firmly pushed into their respective sockets. Once you've checked all cable for tightness, slide your hands along the entire length of each cable while bending them back and forth slightly. A loose or broken wire and/or little bit of looseness anywhere can sometimes cause humming, so if the humming increases or stops when you test your cables this way the "problem" will have been solved...
This system is made up of a computer and DAC and headphone amp and the computer and DAC are battery-powered. I've tried unplugging the battery chargers and using a cheater plug on the amp but the hum remains. This amp is said to hum generally so I guess I still might have ground loop issues. My subwoofer has a low hum that I can't hear from my listening position and one of the built-in lights here hums.
I'm trying to avoid buying a nice headphone SET amp that I can't listen to because I have a ground loop that I don't want to fix since I'm renting.
Consider one of the Donald North Audio headphone amps if you want a quiet unit. They are not exactly cheap though - especially now that the old $1000 - $1200 "entry-level" Sonett is no longer being made by DNA. DNA's new entry level model, the Stratus, will cost you a cool $2700, but it truly is a versatile and great sounding SET headphone amp.
Look for a used DNA Sonett or DNA Stratus if you're on a budget. Or, shop around for another SET amp that has a similar reputation for low background noise. Decware also makes very nice headphone amps, check them out too.
Installing cheater plugs on all the gear is a good way to get killed. VERY bad advice here.
Buy Chinese. Bury freedom.
I just can't believe some of the bad/dangerous advice that is being posted lately on the AA and other forums. Especially with tube gear! It gets even more dangerous as you go up past 500Vdc.
Some need to read the Safety rules on High Voltage equipment and how properly work with it.
"Cheater plugs" can be used to find out what and/or where problems are. I'm not recommending them for long term use.
It only takes a split-second to get electrocuted. Cheater plugs aren't necessary. One of us should be able to walk him through the process; this problem might not even be a ground loop.
Buy Chinese. Bury freedom.
Maybe, but that's what wives are for...
Post a Followup:
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: