New power source is bad?

Carlman · « **on:** 21 Aug 2003, 07:19 pm »

I moved into a new house with a bigger room for audio pleasure... I intend to run dedicated lines but have not yet. After this week's experimentation, that has moved up the 'to-do' list.

In any case, I played my system which is configured exactly as it was in the old house (which had a dedicated line) and the AKSA is really sucking in the upper volume ranges. I crank it to the level I used to and it just gets glary, distorted, and weak like a lower powered amp. It sounds like it's clipping. Please understand that this is really loud levels and I normally wouldn't listen at this level but, it's on the edge of where I'd listen to certain music sometimes. It's the same amp but, sounds very different.

I plugged the amp into a different outlet and I got better results immediately. (not perfect, just better) Once I run good outlets with dedicated lines, I think the amp will be back to where it was.

However, I was wondering if anyone had noticed this phenomenon with the AKSA... that it needs a good clean power source to sound great. It sounds good at lower levels but, I know my dirty power is introducing a lot of bad things. For instance, the preamp picks up FM radio but, I have no tuner....

The design of the amp seems to me that it would depend on power delivery speed from the outlet for optimal sound quality.

heathkehoe · « **Reply #1 on:** 21 Aug 2003, 08:48 pm »

I don't have an AKSA (yet), but I've seen this effect even on my mid-level japanese receiver. Moving to a dedicated outlet made for a big improvement in sound.

The reason is simple, IMHO: the loop resistance of the branch circuit causes a drop in line voltage proportional to the amount of current being drawn. In other words, as the amp draws more current, it sees a lower voltage. So you want as low of a loop resistance as possible to minimize this voltage drop.

Most electrical branches are chained from one outlet to another, which can result in a fairly long run. Longer runs of wire = more resistance. Further, each outlet junction is going to add even more resistance, and finally the wire is probably 14-gauge wire which is the minimum size required for a 15A circuit.

So a dedicated outlet, i.e., a single outlet that is connected with a direct run to the service panel, minimizes the length of the run and has no intermediate junctions; which minimizes the loop resistance of the circuit.

When you install your dedicated outlet, use a larger wire gauge, like 12 or 10. Also, choose a high-quality heavy-duty outlet (I'm thinking of the ones that cost $3-$5 as opposed to the ones that cost $0.50). You also might consider a 20A circuit (with 10 or 8 gauge wire), because the slightly higher current capacity of the breaker and outlet means slightly lower resistances of those components.

Carlman · « **Reply #2 on:** 21 Aug 2003, 09:09 pm »

Heath, you nailed it. I just didn't realize how big of a difference that it would make. I used commercial 'Eagle' brand outlets in my last place that appeared to have good contact area with standard 14/3 Romex.

This time, I'll be using Belden cable and Hubbell outlets since I'll be here a lot longer.

I think the long chain you described also acts as an antenna which is what (I think) is causing some of the FM I'm picking up in the preamp.

Also, I'm out of empty slots on my service panel so, I'm thinking of having a separate service panel just for the audio. But, I'm not sure how to break off from the main panel/main power supply. I would think I'd need the power shutoff to my house to do this properly but, I will probably look at the main supply again and see where it goes. I've bought a book and will be doing some reading before I touch anything.

heathkehoe · « **Reply #3 on:** 21 Aug 2003, 09:41 pm »

Quote from: Carlman

Also, I'm out of empty slots on my service panel so, I'm thinking of having a separate service panel just for the audio. But, I'm not sure how to break off from the main panel/main power supply. I would think I'd need the power shutoff to my house to do this properly but, I will probably look at the main supply again and see where it goes. I've bought a book and will be doing some reading before I touch anything.

Disclaimer: I'm not a licensed electrician

Whenever I've seen a sub-panel, it is always connected via a breaker in the main panel. So you don't have to shut off your electrical service entrance to install a sub-panel. But you can shut off your "main" breaker if you're not comfortable pulling or installing breakers "live". You will have to move a couple of branches out of your main panel to make room for the breaker for the sub-panel. So if you are installing a 50A sub-panel, you'd put a 50A 2-pole breaker in your main panel, and run the appropriate gauge wire from that to the main breaker of your new sub-panel.

stvnharr · « **Reply #4 on:** 22 Aug 2003, 01:37 am »

Installing a sub panel box off the main box is NOT beginner's home electronics 101 stuff. You have to know what you are doing!!!
If your box is already full, you have to be sure that you are not exceeding your electrical service.
Guidelines in home electrical wiring are thus:
14 ga. wire is 15 amp MAX
12 ga. wire is 20 amp MAX

12 gauge wire will handle more than enough current for a single dedicated audio circuit of normal capacity. Unless you are installing a full fledged home theatre using a lot of current, there's not much to be gained in using 10 ga wire and a 30 amp breaker. Also, 10 ga. wire is extremely stiff and difficult to install.

Carlman · « **Reply #5 on:** 22 Aug 2003, 12:49 pm »

I have run a subpanel before off of a breaker but, that was when the panel had room for a 50A breaker, that could go to a utility shed. I've never had to deal with a full panel before so, I may have to call in some outside advice on this one. Luckily, I have a great location for the outlets and easy access underneath the house to run wire. So, other than the slightly complex wiring at the panel, things won't be too bad.

Sorry this is so AKSA unrelated at this point... but, I couldn't believe the difference. This whole ordeal has really strengthened my opinion on expensive power cords.... If you don't have a dedicated circuit (or close to it), there's no way a fancy power cord can really be effective. It'd be the only strong link in the chain.

-Carl

stvnharr · « **Reply #6 on:** 22 Aug 2003, 02:09 pm »

As long as you still have enough available service, there are a couple options on a full box. One is to use slim line breakers, if they are not already in use, to free up some space in the box. Another is to run the sub off the main line before the box, if you can turn the power off before the box. If you've run a sub before, then you know it's not all that difficult.
Good outlets are always a good idea as the typical American outlet is incredible for its cheap construction and parts.
The best power cord you'll ever need can be made yourself. DHLabs has some new 12/3 cable and it's all you'll need. Get it from Parts Connexion for $5.40/ft. Use connectors of choice, I like Marinco. Even a hospital grade plug isn't much. Cover with tech flex if you like. I made one of these and got more power to my amp than my expensive Shunyata Mojave could provide. An amp power cord is all about current delivery.