nonstandard power cord on 970?

I was curious if anyone knew of a reason the Outlaws decided to use a nonstandard 2-pin power cord for the 970? It seems much easier that they could have used the more prevalent IEC-style. Was there a technical reason for this?

I was under the impression that the connector was an IEC but without the ground pin, but I could be mistaken. The main reason I'm aware of for the two-prong approach is that it reduces the likelihood of ground loops causing trouble.

I've always thought of the standard IEC plug being 3-pin. It could just be that I've never seen a 2-pin before.

Interesting... so they compensate for the possibility of improper house wiring by using a lesser connection on their piece of equipment. I'm not sure that makes sense to me. It's not a major issue, more of a curiousity.

In the same way that orange juice is a lesser juice than tomato juice. Some equipment is designed to run with a ground, some is not.

The use of an IEC type power cord with only two spades on the plug is not uncommon on consumer audio gear. A number of other products and brands use it.

HOWEVER: Don't simply use these to substitute for a "three to three" type power cord. WHen a manufacturer uses the "three to two", it is because the unit was designed for that type of cord.

The 950 also only has the 2 prong without the ground prong. I connected a MIT Z-Cord2 cable without any problem.
The MIT Z-Cord2 does have 3 prongs that plug into the power and 3 holes on the other side that plug into the audio device.
Sicnce the 950 only has 2, the 3rd hole isn't used.

I've had no problems using it at all.

I come from a ee/aerospace background so maybe the consume electronics world is completely different, however outside of poor house wiring is there any technical reason you would not want to use a grounded plug?

I would think most of the people interested in Outlaw gear are fairly serious and have taken the time to sure their electrical is in good order or upgraded so the ground loop "problem" should be a non-issue.

I guess I should note, I'm not NOT going to use the outlaw gear because it only uses a two-prong plug, I was/am just curious as to the logic behind that decision.

As an EE, the following will make sense to you.

The house wiring system in a typical US home has two conductors at ground potential. One is a non-current carrying conduct which is called the grounding conductor, the other is a grounded current carrying conductor called the grounded conductor, or neutral. Both these conductors are connected to earth at the distribution panel OR, in case of mobile homes and such, at the service entrance.

Outside sourced signals over copper, such as the telco and cable signals, are generally not earth grounded at the same grounding electrode as the home distribution system. They are, rather, earthed at a remote location.

This sets up a situation where stray current can (and often will) travel in a circuit from the outside sourced system (say, down the cable wire) and out on the grounding conductor rather than the grounded conductor, and then (perhaps) also back to the remote system earth grounding electrode.

This is a bad thing. Bad house wiring isn't a factor, really.

Makes sense, but I'm sure you're aware of all issues with a standard 2 conductor line. Most modern homes have been built with 3 conductors inbound and three conductors to every outlet. As I mentioned I would think most of the niche Outlaw customer base would have upgraded to a similiar scheme at least for their home theater/listening room.

If everything is grounded/filtered correctly I really don't see how low voltage signal will bleed over onto AC.

The two-prong power connector found on a fair bit of Outlaw's gear (the big amps being an exception in general, as I recall) is pretty common for the industry. How many DVD players have you owned with three-prong plugs? How many cable or satellite receivers? Heck, my TV doesn't even have a three-prong plug.
It is probably very common for Outlaw components to be plugged into outlets whose wiring hasn't been touched since the house was built 50, 60, or even 80 years ago. Having grown up in a house from 1927 and owned two houses from the 1950's, I can vouch for the cost and challenges involved in updating to a three-conductor dedicated circuit for home theater. I suspect that far fewer Outlaw owners have made improvements to their wiring than you might think.

If your oustside sourced signals aren't grounded at the same place as your incoming electricity to your dwelling you should insit it be done by the installler or signal provider!!! It's a fairly inexpensive procedure. Jim

Imagine a long coax, both ends of the shield earth grounded. Now send a current through the center conductor, through a load, and back up the shield. Notice that there are two 'return' paths for current, one along the shield, one in the earth.

Gounding/filtering won't really help.

That's not what you were explaining above. What you said previously, as I understood it, was a low voltage signal (like cable TV) coming in, hitting a component and somehow finding its way into the AC line. If the LV and HV "parts" are properly isolated then the signals should not interfere/bleed.

It's actually precisely the same thing, with more focus on a specific single case the second time. Try this:

"Imagine a long coax, both ends of the shield earth grounded. Now send a current through the center conductor, through a load, and back up the shield. Notice that there are two 'return' paths for current, one along the shield, one in the earth."

Now imagine that instead of directly grounding our end of the shield, we instead connect it to our cable box. The shield is now connected to chassis ground via the threaded shell connector. Next, we run a signal connector from the cable box to our Pre/Pro, say, an audio left channel RCA connection. That connector may or may not be shielded, but it won't matter, because it's a single ended connection, meaning one of the signal wires is connected to the "shell" connector at each end, and on most devices the shell is chassis grounded.

Now the chassis of our pre/pro is grounded thru (yes, indeed!) the ground wire of its' power cord.

Thus, current will flow along the cable signal wire, down the chassis grounded signal wire of the
low level signals, and out back to the cable ground rod via the devices grounding conductor and thus to the house grounding system to earth.

EDIT:

I'd like to know what the supposed benefits of grounding would be in a case like this, as per the assertion that Outlaw was "using a lesser connection"; I see it as more of a design choice.

Charlie, is it really worth rehashing a discussion that I'm sure you're read a million times at places like audioasylum, avsforum, etc on 2 vs 3 prong connections? i think not. Both sides of the argument are pretty common knowledge. If you really need a unbiased explanation, here ya go: http://www.gov.ns.ca/enla/electricalsafety/esbadapterplugs.asp

Your argument on the RCA cable is moot when you consider the existence of single-ground cables that are only grounded on one side which are fairly prevalent in many analog audio (over RCA) designs. In addition, even in the case of a dual grounded RCA cable, the resistance should be significantly higher over the aluminum chassis versus the copper conductor and since current follows the path of least resistance, it will never enter. Current only takes one path at a time through any given circuit. High relative resistance effectively equals isolation in circuit design, excepting field dynamics which aren't really at issue here.

I think we'll just have to agree to disagree. Design choices always have compromises. I see this as one of them. I simply would have liked to see the logic behind the decision. You've given a lot of "maybe" scenarios, but none of it relates to what the outlaws might have been thinking when they made the decision. Gonk's explanation that, in his experience, many homes to outlaw equipment are older and have old-spec wiring seems the best possible explanation. However, I would have liked to see the Outlaws err on opposite side and allow a three-to-two adapter with a grounding lug for 2-conductor systems.

Here's what my perspective has been: a great many homes and apartments have either older wiring, mild to severe issues with grounding on cable TV wiring, or both situations and even then some. In an ideal world, none of that would be the case, but we clearly aren't dealing with ideals - the large number of complaints relating to ground loop hum and noise generated by light dimmers makes that abundantly (almost frighteningly) clear. When components can be reasonably designed to rely on a two-prong electrical connection, the gremlins derived from that old wiring and those grounding issues are less likely to cause people grief. In those cases, I have a difficult time finding fault with the companies or their designers for electing to take that approach.

A discussion of cheater plugs isn't germane to a discussion of a UL approved device.

As I explained already, this is a non-issue. In a single ended connection such as an RCA type, ou have a pin and a shell. Even on the cables you describe, the "shell" HAS to have a conductor associated at each end.

For example:

Shell->Shield->(No Connection)
Shell->grounded signal wire->Shell
Pin->Floating conductor->Pin

Is a fairly typical construction. Note that there is and MUST BE a path from shell to shell for the interface to work. The connection of the SHIELD is not really of interest.

Perhaps I didn't understand you before, but I thought you said you were an EE? I assumed that was Electrical Engineer?

If this little "fact" were remotely true then only one device on each distribution grid would get power at once. Your neighbor turning on their TV would turn off your water heater. Indeed, taken to it's extreme conclusion electrical devices as we know them would be impossible. This is, to put it plainly, wrong.

Current follows all available paths. This is a basic electrical fact. The small current flowing in the path I described proves (using basic algebra and Ohms' law) that there is a voltage also present. The presence of a ground-loop induced current therefore causes noise.

But none of that is primary to the discussion. The main thing is that Outlaw designed this unit to not use a grounding conductor and had the realization of that design UL approved. The device is safe, and furthermore, not intrinsically inferior due to this design choice.

I appreciate that you want to bow out of this gracefully, and I applaud your intentions to do so, but I'm not going to let you present fiction as fact to further that aim.

Where's Soundhound when you need him, anyway? Jeez.

"Makes sense, but I'm sure you're aware of all issues with a standard 2 conductor line. Most modern homes have been built with 3 conductors inbound and three conductors to every outlet"

This statement is a little misleading. Yes, a modern home's electric service has three conductors inbound - one ground, two hot wires (different phases). Each outlet has three conductors, but not the same as the three inbound. A single phase hot wire, plus a neutral and ground, which are tied together at the distribution box. So in reality, only two of the three wires from your electrical service are present at an outlet.

And being an EE (electrical engineer) has little to do with being an electrician.. I'm an MSEE, but wiring my basement addition took a whole bunch of different skills.

dave

Very true, but that basic failure to understand basic theory sort of makes me think someone needs a refresher course.

openhelix, i think you're whole argument is a moot point. you're paranoid about a piece of equipment not being grounded, while the rest of us are simply enjoying our equipment. just DON'T buy it !!!