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I've been going in circles in respect to power management. I guess it basically boils down to diagnosing which approach would benefit me most...any help?
I live in a VERY highly populated area, in an apartment building, with new electrical wiring and 2 dedicated power lines for my stereo, composed of a McIntosh MC275, a Lamm LL2, a Rotel CD player and a REL subwoofer. I hear no hiss from the speakers. What am I trying to fix, you might ask? Nothing! I'm "just" trying to improve the sound.
I've looked into filtering, regeneration, etc, etc. Many options. Recently I came by isolation transformers and balanced AC power. Very intriguing. Balanced AC seems to be rather expensive. How can I tell if I'll benefit from isolation transformers or balanced AC? No chance to in-home audition.
Will more than welcome your thoughts!
Follow Ups:
Iff'n you'd like to try individual isolation transformers for each of your source components, < 100va, here is an inexpensive way to try, and it includes both hardwired input(plug) and output(IEC) cords.
4 individual units for $32!
The seller sells a single for $8, or 2 for $15, but as its $15 shipping for 1, 2, or 4 via UPS or Priority Mail, be a big spender and collect all 4 and trade with your friends.
These units are based on a split bobbin Signal Transformer unit, and can easily be rewired as a 65va balancing isolation transformer
Not my cuppa, constrained by the attached cordage, lacking caps to work with the transformer for improved performance, etc... but definitely Cheap 'n Cheerful.
...is to re-establish a close coupling of neutral and ground on a circuit where a lot of neutral current causes an offset, or induction generates noise. These situations are typically found in industrial or medical facilities, not homes.
Such transformers can improve performance of audio gear by absorbing RF noise, but with the possible introduction of mechanical hum or limitation of current to demanding components. In other words, you need a very large, and very well-made, transformer to fully avoid the problems and provide the benefits. The Acrolink isolation transformer is one such.
The other tweaks mentioned by bartc absorb the noise without having the possible transformer problems. They can introduce their own sonic signatures, and it is possible to over-do them.
I don't have an isolation transformer. If I did, I would still experiment with the other methods of reducing noise. No single approach is likely to be completely successful.
Yeah.. I' buy several.... (I know I am being snotty)
I like Barts list but would insist on adding a used PS Audio P-300 for your sources (preamp, CDP ,phono etc.). I would run it at the 120hz sine wave setting. It, unklike the new power plants outputs balanced power. I see them on Audiogon for 300-600 depending on what features and how upgraded it is.
ET
I thought it was time to change my signature line
Edits: 08/02/10
Can you elaborate more why you recommend this vs. the list by Bartc? You made your point about a P300 vs. new PS models, but do you think a P300 would be better than the sum of the options suggested by Bartc, or rather you are suggesting a P300 instead of the iso transformer?
I am saying use Barts list AND a P-300 for sources only.
ET
I thought it was time to change my signature line
I don't have experience with that kind of power regeneration plant. I eschewed that due to expense and reports of dynamic loss from others, but that doesn't mean that this particular one won't work for you.
FWIW, the tweaks I'm suggesting work on other factors in the equation. There is probably no single tweak that solves all the AC issues.
The key is to understand that there are several AC issues in probably all of our systems, and then experiment with what resolves them.
Bart wrote: " I don't have experience with that kind of power regeneration plant. I eschewed that due to expense and reports of dynamic loss from others, but that doesn't mean that this particular one won't work for you."
The dynamics issue only comes up when you use the full potential of the power plants (p300,500,600 etc.) They have protection limiters. When using a PS Audio power plant its best to only use half or two thirds of its potential leaving it plenty of headroom as it works like an amplifier. This is easily done when using a P-300 for sources only.
You can get one for 300-400 used on A'gon, that's not expensive.
ET
I thought it was time to change my signature line
Sorry my answers came out without order. They were supposed to be answers to specific posts.
Anyway, thanks all for the great feedback. This is very helpful.
So I'm taking away I need to use a combination of approaches and I need to experiment to figure out what will work. Fair enough.
Some approaches are more expensive and more complicated, especially considering I now live in Argentina where voltage is 220V and getting stuff shipped here is possible but cumbersome.
So the first two things I want to try are RC filters and isolation/balanced power transformers. For the latter I need to speak with a local transformer manufacturer tomorrow. So that leaves me with the RC filters. Did some reading online and I gather we are talking about low pass filters. I'm fully aware the capacitor and resistor values in a filter designed for 110V will not work for 220V, but it would be very helpful if someone could point me to a schematic of a RC filter designed for AC power, and some reference info such as metal foil capacitors are to be avoided or what I should look to find as far as components. Also is the 50 vs. 60 Hz going to be an issue?
This should be fun!
Capacitors made for AC noise suppression are designed to not generate resistive leaks when exposed to power line spikes. Other capacitors may have much higher DC voltage ratings, but may not withstand repeated power line spikes without degrading and catching fire.
Noise suppression caps these days are all rated at 225 volts AC or higher, as it is too expensive to maintain separate stocks for different countries. Any of these would be safe to use with your mains.
The dielectrics in noise suppression caps do affect the audio performance, even if the filters are used on other branch circuits. The ones I've found to give the best sonic performance are Wima MP-3 metallized paper.
Use resistors in series with the caps to provide electrical damping. Placing the caps directly across the AC line will result in ringing, as the caps do not absorb noise energy. Use resistors that are flame-proof, or mount them in such a way that if the cap fails to a short-circuit, the brief flame resulting from the resistor burning out (about as much as a kitchen match) will not create a fire hazard. You are responsible to make these things safe: I'm just telling you the possible sources of hazard.
Each size of capacitor needs a different value of resistance to achieve optimum performance. I'm not ready to share the values I've found by experimentation, but you can make some experiments and find combinations that sound best to you. Start in the range of hundreds of ohms.
A couple years ago I was working on a friends amp that wasn't quite working right. I was bending over the circuit with a scope probe and was about to touch a wire (hadn't actually touched it yet!) when a resistor next to the probe burst into flame. It was about a 6" pure white flame that lasted quite a while, right below my face. I WAS wearing safety glasses so there was no eye damage.
I checked with the manufacturer and it was a flameproof resistor. I've never seen one give off a flame like that before, even when TRYING to get that effect! (what can I say, high school electronics class)
I still have that scope probe, with a black charred tip. Its hung on the wall of my lab to remind me to ALWAYS wear eye protection when working on live circuits.
I don't believe in "flameproof" any more.
John S.
Thanks all for the input. Very helpful. And thanks for that iso tranny schematic!!
Anybody able to share a schematic of an RC filter for AC power? Been reading some more and found the Jensen 4-pole caps to be very well liked (also Blackgates), but can't get a schematic.
Thanks!
Try the archives.
In any rate, for the R-C filters you need caps that are properly safety rated for your voltage. I have no idea what those might be, but Al might.
The Rs are matched to the cap values too. Again, I don't have the knowledge to tell you what to use in your situation.
So be safe first and get satisfactory answers from those in the know!
I don't think these are intended as low pass filters, though. These are parallel filtering schemes.
Jon Risch's recommendations for a Signal DU-2 will give you both balanced and isolation which in my opinion does wonders for a system.
How you got a dedicated line in an apartment is really intriguing and I hope it does well for you.
Meantime, I can't answer all your questions, but I have some experience with some kinds of non-problematic AC filtering. What works for me (besides good PCs and outlets) is: Jon Risch's Iso Tranny for digital, Al Sekela's R-C filters, and Alan Maher's CBF line of passive piezoelectric filtering. All work well, all are cumulative and positively synergistic, and they really do make a difference that's appreciable.
Of all of them, the easiest and cheapest to try (other than the DIYing I do) are the Maher CBFs, especially best with his Signature versions. Seriously, these little gizmos do the most remarkable things with your sound and it's really great once broken in.
Just to warn you, transformers do buzz/hum. While it's controllable to some extent, I gather that it's not fully erasable. The Risch design is a back to back set of matched EI transformers and it works very well. But it does hum in my case. Some would not like that aspect of transformers; I can lower it and live with it in my case.
The R-C filter arrays have no downside I can detect and do a great job without damping the dynamics - a problem with other kinds of active filtering systems I'm told.
The iso tranny is only on your digital components. Depending upon the secondary volt-amps, one can drive a CDP and in my case an outboard DAC as well, but that's about the limit of one of them. Other trannies may do better on that count, but how many digital items do you really have?
The others can be used in many places in your household you might not realize contribute what you get as noise in your audio system, so you use more than one if you can. I've got the R-C filters all over my system and in other places in the house. Same with the Maher CBFs and these go right back to my electrical breaker panel!
a Hammond 193L choke. Fairly inexpensive and easy to use with positive improvements in sound.There are also a couple non-audiophile companies (read reasonably priced) like Hammond and Kleen Line that offer isolation transformers read to go.
Medical grade transformers are also manufactured with low EMF radiation.
http://www.isobox.com/medical_transformer_C-Serie.htm
Cogito Ergo Credo
Edits: 07/31/10
i dont think many audiophiles appreciate how much performance is to be gained via treating the other circuits in the house w/ R-C networks to prevent them from polluting your audio AC.
likely room targets that need R-C networks: room w/ computers / routers, fluorescent lights, the fridge, dimmer switches (!) on fans.
cheap, easy, effective. no downside.
Before moving into the apartment I had the electricians put 2 dedicated lines from the breaker panel in my apartment to the outlets for my stereo, which is 45 feet away. Yes, walls needed to be broken (brick construction), but I guess that's the benefit of doing it before moving in.
Thanks for your suggestions. I will look into them here in the forum. If you know of other websites, please let me know. I can't find the Jon Risch design for iso trannies here on AA. Do you know where I can get it?
Bartc,
Thanks for all the links. Unfortunately this one isn't working for me ("the webpage cannot be found").
Jon is a moderator at Cables Asylum. Try pinging him there.
His old website o Geocities was demolished some time ago, but it was archived somewhere on the Web and maybe the FAQs page can help you find it. Or try Googling it and following the links. It is reproduced somewhere for sure!
Here's someone else's posts elsewhere that may help:
Link...
Thanks for this link. It does work, but all the pages archived here have the room treatment designs only. Nothing about electrical designs.
I looked through some of those pages. At least one of them has a "home page" link, this will take you through the front door of the site, and will allow access to his DIY page. This page had the filtering and balanced power page linke.
try this
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