Line Noise

[JjR]

I live in a older home and my tube amp seems to be picking up fan noise, noise from the iceboxes turning on and off etc. This has been driving me nuts!

I really thought that somthing was wrong with the amp and took it into a shop and it checked out ok. I did not believe the shop owner untill this morning.

The cooler weather is here and the ceiling and floor fans have been turned off and the noise has gone away. I still pick up a floresent light being turned on or a icebox kicking in but nothing like it was before.

Now what to do about it? I did a quick look online at some AC line conditioners,well forget that as they are very expensive. What other options do I have? Should I have the amp grounded? I do not use a turntable only a tube tuner and CD player. My patch cables are cheap ones . Would a better grade of cable possibly help? Somthing like monster cable.

I did have a tube receiver in the past but never noticed any line noise but I really can not remember. Also a ceiling fan was added the floor below me this year. It seems that I never had a problem with the Solid State Amps or receivers?

TIA

[JjR]

Thanks!

[maiz]

The best thing you could do is run balanced power to your equipment. This cancels out all noise and does away with the need for "filters" and "conditioners". As a matter of fact, this is what a lot of those expensive "conditioners" do. While also providing some surge protection and filtering. The balanced power can be done quite cheaply. As in under $100. Go to Jon Rischs' website for more info.

I was able to find and old suitable transformer for this application and would not run my equipment without it.

[JjR]

Back to the filter's I see that Monster Cable makes a few reasonable priced. My brother brought up this questiion??

My amp does not have a grounded cord nor does the electrical sockets in my bedroom have a three plug socket. So I guess the filter would not work correct?

What is I just ran a ground right to a raidator in my room going right to the amp's chassies just to do a test to see if that would help?

WOuld that do somthing?

BTW my amp is a Fisher x202

[Erik Mandaville]

In addition to what has been said above, perhaps I line isolation transformer (fairly easy to obtain). These will often have a common grounded three prong outlet on the body of the transformer, into which a sturdy but inexpensive power strip can be installed to handle the power cords of the components.

It also might not be a bad idea to get an AC supply tester. These are very, very inexpensive, and available at common home improvement/hardware stores. You simply plug the thing into the wall outlet, and coded indicators will show possible wiring errors -- reversed neutral and hot, an open ground, that sort of thing. DON'T CORRECT ANY ERRORS YOU MIGHT FIND THIS WAY UNLESS YOU HAVE SOME EXPERIENCE WITH THIS SORT THING -- AND IN ALL CASES BREAK THE CONNECTION TO THOSE OUTLETS BEFORE touching ANYTHING behind the plastic wall trim piece.

...and please pardon me for using caps above. I would just rather encourage caution in a very obvious way. I have been shocked a couple of times in the past, and it's not much fun -- definitely not something you would want to go back to for a second helping!

Erik

[JjR]

The lines are ok as we had a electrician go through the house last summer. He never made it up stairs to change out the sockets.

WOula you have any names of the device your talking about?

[Erik Mandaville]

Sure:

"Line isolation transformer"

A number of different companies make them. Check the link below:

www.tubesandmore.com

[Erik Mandaville]

Also:

www.mouser.com

Find this under the listing for Hammond (that's the name of the company)transformers. Sometimes you have to dig a bit to find what you want, since the catalog is very big. Detailed descriptions for what they carry is in PDF format with links provided.

[3dzapper]

On the cheap, you can take a 0.1uF 600V capacitor and an old two wire extension cord, solder the cap from one lead to the other and tape it up really well. Plug the stub with the cap into your outlet strip for your equipment. This should shunt the HF freq's ahead of your gear. It is similiar to what Mark was talking about a tech doing inside your amp with filter caps.

Rick

[Erik Mandaville]

Old timers and lots of new ones who learned from them would also often make home-made brute force line filters with a combination of hand wound coils and capacitors.

In addition to what Rick Suggested:

High voltage (I K-volt, or so) .01 ceramic or film capacitors can be installed between each AC leg (hot/neutral) and ground, which can help with the high frequency line transient/RFI issues. If you have a solid state rectifier with large capacitance associated with it, it's possible to install .1uf (approx)of similarly high voltage capacitors between the AC inputs to the bridge rectifier and ground -- this is on the secondary of the power transformer, which is still AC, rather than on the DC side after it. Another way of shunting high frequency noise/buzz artifacts before they get into every part of the circuit. While you're at it, if you have a tech do something like this, you could have him/her install one of those 1K volt .01 capacitors across the switch in your preamp (if you use one). It will snub the 'pop' one hears through the speakers when the power switch is hit and the amps are already powered up.

But, an isolation transformer, IMO, might be a very good way to go, and as Mark suggests, a 4A transformer should be fine. However, you know better than any of us if your situation might requires it -- I can't know since I'm not there. I have friends who use isolation transformers as a common practice. Another way to deal with this is to install a dedicated 'audio system' supply from the equipment back to the breaker box -- installed on it's own breaker. However, this can be expensive and complicated, and one is still at the mercy of what 'dirty' electricity is fed to one's particular area.

The problem with any of these internal mods to the equipment is that they would probably cost you more to pay someone to do the work than it would to buy a decent line isolation device, which is more of a cure for the problem - IMO. If the wiring/RFI in your house and/or neighborhood is a problem, I think you might be more at ease with your system, as well as enjoy listening to it more, to pay a little extra for some line isolation and protection. A pair of interconnects could easily cost much more than what we are talking about. I personally would opt for some line treatment first.

[maiz]

I would really investigate balanced power. It isn't hard to do and IMO should be done before any of the above suggestions. The problem is, that the above solutions are filtering (or trying to) the AC noise right at your equipment. Balanced power eliminates all of this noise at the balanced power transformer. The noise doesn't have to get near your equipment.

I use a transformer very similar to this one:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4665&item=3841823666&rd=1

I have mine sitting on the floor next to the dryer.

Apparently you can hook your tv up to this also and get a clearer picture. However, if you want to hook up too much equipment, you need a bigger transformer. Something around 5 kVA. 3 kVA is plenty to run your stereo equipment. My transformer is 2 kVA and I run the same amp as you and a cd player and a turntable and a small turntable light off of it.

Here's what you do:

1. Get the above transformer or ask your local electrical contractor if they have an old one laying around which would probably make it cheaper. No shipping. I found my transformer in an old outbuilding here on the farm. It hadn't been used in 40 years. Except for having to clean out mouse****, it works fine.

2. Go to Home Depot and get at least a 16 guage three prong extension cord and get a plug that will plug into the 220 volt outlet of your dryer or oven or hot water heater. This part cost me $13.

3. You cut the extension cord and wire it to the transformer and discard the plug end and install the dryer/oven/220v plug so that you will have 220v going into the transformer and 120v coming out of the outlet end of your extension cord. You run this to your equipment and plug it in. What you get it 2 legs of 60v coming out of your plug. These two legs are out of phase and you get common mode cancellation of the noise on your AC line. Instead of a 120v leg and a neutral leg which your normal household outlet is giving you.

4. This way you can try it and if you like it, then move the transformer or run 220v to the living room (this is what I am going to do). I can almost guarantee it will astound you. I too, live in an old 2 prong outlet house. The place where you have a ground is the 3 prong outlet of your dryer or oven or heater.

Feel free to contact me if you would like to go this way. It is cheaper and a lot less hassle than soldering in stuff to your amp.

I used to hardly ever listen to my cd's. They just sounded terrible next to the vinyl. Now the cd's sound pretty darn good and I find myself listening to them a lot more. It makes the vinyl sound even better. I highly recommend it!

[Rickieheinz]

Try a 3 to two ground plug and plug your amp into that.It works on ground loops if that is the problem.