Questions RE: AC Power: Treatment, Dynamic Constriction (?), hum, amps, boxes, legs

[garyrc]

I would much appreciate some input from you technically minded folk on the following. Also, what kind of power treatment/protection/regulation do you have, and how do you like it?

I'm about to attempt to provide clean, adequate, steady power for the Music Room / Home Theatre, so I'm looking for the correct power treatment, perhaps including a UPS, at a less than astronomical price (under $1,000???). At the moment I just have Monster surge protectors (HTS 1000 mk II).

Power Treatment & Dynamics: I've heard that certain units interfere with dynamics, underpower transients, etc,. especially when power amps are plugged into them (I have 7 channels of amplification). Although I have very efficient speakers, eventually I will have a projector in the room, and perhaps some other big power draws. Since the room is large, the SPL, therefore power needs will be higher than some K-horn users need, and the surrounds are less efficient. On a few outrageous occasions I have put readable peaks of 25 wpc into the K-horns, with the briefest peaks presumably higher. What do you folks think of the notion that dynamics are interfered with by some of these devices? Do some brands/models limit dynamics, while others do not?

HUM To make matters worse, I have hum. The proximal source is the AV/tuner preamp (which has been checked out by the manufacturer), and the hum is independent of volume control settings (except at volume levels that would convert the house into a crater). The odd thing is that the hum level varies from time to time (time of day?). Sometimes I can just barely hear it when the equipment is on, with no music. Other times it is obvious (I would say 6 - 8 just noticeable differences louder than the "quiet" level mentioned above). Might this mean it is coming into the AV Tuner/preamp's vast circuitry through the air from some outside source? Or through the power line? I have tried everything the dealer and manufacturer have recommended, including checking lead dress, getting rid of potential ground loops, etc.

Amperage, separate legs, boxes, etc. Should I install all 20, or 30, or 45 amp circuits, including the wiring? Should the projector be on the same or a different leg? Should I install a separate power main just for audio? Should I feed the projector from this separate power box, or not?

[Spkrdctr]

If you have long speaker wire runs, 30 ft or more you can pick up garbage from the wires. If you have any long low level inputs/wiring (10ft) from unit to unit, you will automatically pick up trash. But, this noise is not noticeable when you are actually playing music. It is a super weak trash signal and not worth worrying about. I would think if you have a real hum, you can take it and hook it up to much less equipment, just the pre and amp with speakers to see if it goes away. Or hook it up at a friends house. If it is all the same all the time, you have a bad capacitor (or more) and an actual unit problem. Troubleshooting is a pain, but it is worth it sometimes.

As for power regulation, some of the guys on these boards have some good units they have used. Maybe they will post.

[IndyKlipschFan]

Look strongly at the APC line.. They have gone big time into audio..

Sometimes moving things around, especially cords will do the trick, or nothing that a good baseball bat will not correct.. hahahah J/K.

[WMcD]

This general subject or subjects come up from time to time.

I may not be a good one to speak on it. This because I've never had a problem with hum or suspected that the there is a power line issue. I've been running budget and old SS equipment, and budget VHS, and DVD in the settings of: Two apartments put up about 1930, one put up in 1960, and now a condo put up in 1975. All in Chicago.

I also now have a stack of old Mac s.s. equipment.

All use very elementry connectors. I.e. cheap.

None of these demand much power.

There are reports, generally, that the power lines have garbage. Maybe so. The odd thing is that the power supplies in our equipment filter, or integrate 60 Hz to D.C. If anything, they should be better at filtering out high frequency garbage.

It seems to me that you've become sensitive to the power line issue because of the hum problem.

It is my belief that you have a ground loop problem which can be solved and that the power line treatment units are not going to solve that. It is too bad that I'm not in your area. I'd love to help.

If I was doing this, as a first step for trouble shooting is as follows. It is taking everything apart to as little as possible to make it run, and then add to the complexity until the cause of the problem becomes clear:

Try running the AV receiver without any connections (DVD, CD, etc.) except for the speakers and the AC connection. Listen to silence with the volume at 1/4 for an hour or whatever period you think the hum is coming and going. I expect you will find no problem. But I'm guessing.

Then add a primitive FM antenna or just a piece of wire to one of the antenna terminals so you can pick up FM. Try cranking the system as you please with the cleanest station you have out there. My guess is that the system will be okay.

Then add connection to the other units, like the CD player, etc.

My guess is that you'll find something added that causes your problem.

Best,

Gil

[Guest " "]

Garyrc

In response to your specifc question about power treatments....

Since you have a surge protector with RMI filters in it, and have been down the trouble shooting road, my recomedation would be to do a search on this forum for balanced power or isolated balanced power.

Sellers of these devices report it is a growing solution used in recording studio's to reduce the noise floor and as a result, increase dynamic range.

The concept involes the principals of isolated ground outlets , split power supply, isolation transformers, TVSS's. It bascilly transfers into a balck box, an idea electrical environment that becomes independent of any issues your electircal wiring may have. Grounds leads are terminated at a central point, neutral blades on the out let are isolated from the ground system, transformers isolate the box from the house system, a center tapped secondary winding creates a split power supply that results in out of phase 60 - 0 - 60 (net 120), which cancels out imperfections. The toroidal transformers used are quieter than traditional plate transformers used in ISOTAP devices and capacitor loaded brown out devices, both of which include isolation transformers, but do not split the power to 60-0-60 thru the use of a secondary winding.

There are off the shelf black box versions, DIY articles to construct one, and if you are running a sub panel, opportunities to hard wire one.

The DIY black box version is about 150 for 800VA's and 350 for 1600VA's.

I ordered the parts to build 2 of these devices, one for my home office, the other for my hT room.

I would not rule out issues independent of the power system such as your inter connects, and some of the items suggested here on this forum.

Take the amp and preamp to someone else's house and see if it hum's there. If it does'nt, have someone check your AC outlets for proper installation configuration.

[Duke Spinner]

at a minimum, I would run a SubFeed box to the area....

#6 aluminum ( "SEU Cable" ), will give you 50 amps, 220v, for very little cost...

maybe $60 for a 6 space panel/ breakers, and $60, or so for the cable

you'll need a 50 amp breaker for you Service Panel , also

this will give you a Neutral isolated from the Ground, at that panel

[Guest " "]

at a minimum, I would run a SubFeed box to the area....

#6 aluminum ( "SEU Cable" ), will give you 50 amps, 220v, for very little cost...

maybe $60 for a 6 space panel/ breakers, and $60, or so for the cable

you'll need a 50 amp breaker for you Service Panel , also

this will give you a Neutral isolated from the Ground, at that panel

Duke, have you been sneaking around my house?

Thats what i have, using a 60 amp run to a sub-panel and have 6 local breakers to a room addition. The run brings 220 to the sub panel and there are 3 breakers on each phase. The balanced isolation transformer is the next step.

When doing something like this (a 2 phase run), size the wire need using the nuetral wire. Most recomendations is 160% above what you come up with for the red and black leads.

For most folks, running additional runs and installing sub panels may not be an option, so the block box approach is worth considering.

[Duke Spinner]

Whoops, S.F. .....

You didn't catch my mistake .....

shoulda said "SER" cable... that's w/ the insulated neutral.....

SEU... just has the un-insulated neutral/ground wire ......[:$]...[:$].....[:$]

[JohnA]

I have a similar sounding system. I, too, have a hum. My

pre/pro and power amps are made by the same company so they should be

as compatable as they will be. My hum is a ground loop caused by

my DVD player(s). All 3 have done it. My only solution has

been to lift the grounds with cheater plugs,

[BiggerIsBetter]

Another easy idea. If you have a cable TV cable connect anywhere in the same "system". Disconnect the cable....they can be a huge source of noice and be intermittent. If the hum goes away when you disconnect it's obviously the souce....only take a few seconds to try it....

[D-MAN]

I've found that AC power filters definitely compress dynamics. However, they also definitely clean up the "hash".

I do not run my power amp (I have separates) through the filter for this reason.

I do, however filter the pre-amp and especially the cd player.

DM