Who has Caps on their AC lines ???

I have been playing around with caps on my AC line. After today, I don't think that I can live without them. Even with my dedicated AC lines, the one with the caps just has such a more natural sound no matter what AC power cord I place on it.

Unfortunately, I got them from a guy that I no longer speak to so I don't really know the value of the caps. Is there a way to determine the value?

I have been reading about a few members who use Auricaps, etc., and will try what they are using soon. I am also waiting on an isolation transformer to test in my system next.

I'd like to know what you are using to filter your AC lines and what you are hearing.

Thanks and Happy Listening.
Our friend an fellow Audiogon member Joe Sanders (Joe's tube lore over at AA) is a good friend and has a DIY version that is splendid. Perhaps he will post data here about values and how to construct. I think I have the data in an old email along with photo's.

The idea is the same as the Quiet Line devices that plug into your wall socket. It does work and the Quiet Line is great at less than $30.00. I have about a dozen Quiet Line's plugged in and around my audio system, having used them for more than a decade.

The DIY version uses better quality caps and higher value and should be a nice upgrade. I've never gotten around to ordering the plastic boxes and parts to build one, perhaps this will inspire me :^).
You can purchase a multimeter or dedicated capacitance reading meter to see what value they are. If you don't want to do this, and can live without them for a while, you can drop them in the mail to me. I can read the value and return them back to you. You might also be able to find a local repair shop that can read the value for you.

I have been using caps on my AC for quite some time. It is a simple tweak that i've discussed here more than a few times.

As far as Iso's go, they are not all created equally. Many people use too small of an iso, resulting in less than optimum results. They then base their opinion of how well an iso can work on this less than optimum installation, passing on the negative experience to others.

In order to avoid this, i've always recommended buying an iso that was rated for at least twice the draw of all of your components. On top of that, you want to find a model that uses a VERY large core. You can find iso's of identical KVA ratings with wildly varying core sizes. As a general rule, the larger the core, the less likely they are to saturate under heavy load or large dynamic swings. Sean

Very simple here.

5 Dedicated lines.

2 Dedicated separate grounds:
1 connecting the 5 duplexes
1 connecting the system components

No filters. No conditioners.
I used Auricaps in parallel on my AC, was a very nice tweek. Lowered the noise floor nicely. I removed them however, I wasn't comfortable having them on my AC due to the outside chance they could be a fire hazard. I have two kids and live in an apartment complex. While the chance something could happen seems to be minimal, based on my living situation it just wasn't worth it.
I use the Auricaps on all my outlets too, but couldn't tell you the ratings; although it may be on my system information in one of the upgrade notes I made. This is a very effective, inexpensive tweak to clean up noise. I still use an old Tice Powerblock One with Titan reserve power unit which was the orignal isolation transformer marketed and it does lower the noise floor. There are many newer and better models availble but if you can get a Tice cheap they work well.

I am interested in getting the info that Joe has. Please see if he can post or email me with the info.


I will see what I can find out or let you know if I have to send them to you. I will let youknow what the Iso units are before I do anything.


I use one in a DIY entension cord with an otlet on one end so I can unplug the unit when I want to, making it safer.

Thanks for the replies.


Go to the Magnan website. There is an example of this tweak that mentions the cap values even brands and sourcing for them.

Have a look and tell us what you think.

BTW Albert really liked your DC joke in another post....

Why don't you take a picture of the cap, upload it to your virtual system and post a reply here? Maybe someone can read its value for you.
Auricaps and the like are not AC rated! Be sure you are using 600v dc rated caps and even then they must be protected with a fuse to insure they do not start a fire when they fail. The best way to do this is to simply install them in your individual components, after the power switch and fuse and before the transformer. Thanks!
The ones I used were: Auricap .47 uF 600V

You can purchase the from VH Audio (no affiliation, etc.).
Are we having a cold war here? Pun intended...
I like my AC straight up no chaser.
There is quite a bit of discussion on this on the tweaks board over at audio asylum...start with a search on "auricap". The lack of AC rating is also discussed often. There are AC-rated caps that work well in this application.
I use 2 Auricaps .47 @ 600v in parallel on all my outlets as well (DIY Power Boxes) but I'm in the process of transfering them to inside the components. I also run 3 separate isolation transformers. one on my dac, one on my CDP, + and one on my preamp all on Dedicated lines. I also agree with Sean
do not get a small isolation tranformer, get one 2x3 times the size of the watts rated for the piece of gear pluged into it.

I have heard that some people have put the caps in the isolation transformer as well. Maybe I'll try that but with my other ones will that be to much of a good thing??

Benie: You want to place the caps near the input side of the iso's for greatest results. This reduces the amount of "muck" that the iso has to deal with.

After that, all you'll have to worry about is keeping the AC "clean" from behind the iso up to the component. This means running low impedance power cabling that is RFI / EMI resistant.

One could take further steps to improve the internal power supply of the components by adding increased filtering, snubbers on the rectifiers, etc...

Paying attention to system grounds and how they are implimented component by component can also help lower the noise floor. There are a couple of different grounding schemes that manufacturers use, some being more effective than others.

Obviously, one can go as "crazy" on this as they can afford to and / or spend the time on. If done in reasonable fashion and with some form of consistency though, the benefits are quite additive and beneficial in nature. Sean
"running low impedance power cabling that is RFI / EMI resistant"

Any Belden number for this from the top of your mind?

I am currently looking through Belden's online catalogue for something like this that also meets some other specific criteria. So far, i haven't been able to find anything that i'd recommend. Sean
I've implemented the Auricap tweak in several DIY mods to digital players and DAC's. In each case I've always put them AFTER the fuse, just in case there is a blow out. You really don't want a short, no matter how well the caps are rated. It could cause you your house, since you are volurantarily implementing a hazardous situation, and the insurance company could invalidate any claims.

Basically it isn't worth the downside to get a little better resolution, unless you implement it with a proper failsafe, or use X rated caps (which is what is inside the Quiet Lines).

Thanks Sean. I plan on ordering some raw wire again from VH Audio soon and put a better Power cord on the isolation Transformers, I think this will be a good time to install the caps in the input.

My Transformers are in an ajoining room with a pass through in the wall to place my DIY power strips through. They are of the twisted design from VH Audio but unshielded, maybe I'll use some of thier shielded wire for 2 of the Power strips.

It for sure is additive, from the first time I used an isolation tranny, to caps across the line, to even making a tweeked out Power strip box with no caps and hearing an improvement.

I Don't have a problem with the Auricaps in my line but my inlaws want me to build them a Power strip for their HT setup as they noticed a difference when I demoed it to them. I feel better with an X rated cap if for someone else. Any recommended X caps of the quailty of Auricap?

Thanks for your comments Sean
I know people are speaking DIY but are there any commercial iso transformers that are recommended by this group ... sorry i'm not a diy guy
Gordus above is right. The 120V power lines actually have a peak to peak value of 340V. 600V rating would suffice. Fuses also a good idea.
I should have clarified that the 250 volt rating that i previously mentioned was for the working AC voltage, which is different from the DC working voltage quoted for most capacitors. I agree that a higher voltage rating is better, as the 120 volt ( nominal ) rating of U.S. based AC systems is an RMS rating, not a peak rating. AC peaks will typically run at somewhere around 160 volts during normal use. Having said that, the peaks can be measurably higher than this, especially if one is talking about heavily distorted AC or spontaneous spikes and surges. As such, it is better to be safe than sorry.

As a general rule, a cap rated at 400 volts DC will typically spec at appr 250 volts AC. Going to a cap that is rated for 600 volts DC offers even more headroom, but at increased cost. For as much money as we spend on some of these other ludicrous and far less beneficial "tweaks", splurging for higher rated caps can buy a lot of peace of mind for not that much more money.

Musicfile: I've used Xentek and Topaz "ultra-isolation" units in the past. These are superior to their standard "isolation" transformers, as they typically offer appr 20 more dB's of common mode noise rejection. Having said that, even their standard models are typically far superior to a toroidal design, as they typically offer appr 30 - 40 dB's more common mode rejection. Just make sure that you choose a unit that is rated for well above the intended draw and that it has a "gonzo" sized core. The actual core size may be more important than the actual rating, so long as one is not trying to run the transformer at or very near rated capacity. Sean
I guess the first time I tried this was the Van Evers. Since then I have tried at least two others. In my system all it does is to hurt the sound. Removing them gave me a big improvement.