Help!

markeddie

Ok all you experienced equipment guys, I am a newbie, green and have questions. Because of all of you, I have been accumulating equipment. I now have the disease, thanks a lot!

Anyway, I just got an Adcom 5802 and an Audible Illusions L1. As I understand it, the 5802 is not common ground. So to use it with SDA 2B's, I will have to connect the negative terminals on the amp, creating a common ground.

As to the L1, I have been told that it reverses the polarity. This creates the need to reverse the polarity at the speakers.

Now for my dumb question or series thereof. If the polarity of the speakers are reversed, do I now have to connect the positive outputs of the amp to create the common ground? How does all this affect the SDA effect? Have I gone absolutely bat sh.. crazy to get into 2-channel Hi-Fi?

Any advice, thoughts, or calming excercises would be appreciated.

Sax

well, I don't have experience with the above problem so...

breath in... breath out... breath in... breath out...

heiney9

Perhaps this will help.

Polarity
In electronics, two points that have opposite electric potentials (one is positive, the other negative). This is not the same as being 180 degrees out of phase (although the results can be similar). Phase implies a relationship with time, polarity does not. What most engineers, consoles and preamps refer to as a "phase" switch is actually a switch reversing signal polarity.

Polarity is important when interfacing equipment, particularly speakers - you don't want one cone moving in while the other moves out. Some designers feel that maintaining "absolute polarity" (no polarity reversal in a signal chain) throughout a signal path is important.

While tests don't indicate that the ear can hear which polarity is correct, they do show that it may be possible to detect a difference between normal and inverted polarity signals. (Try it for yourself in a critical listening environment: Play a signal though a single speaker, then reverse the speaker wires and play the same signal again - remember to switch the wires back when you are finished!)

You are on track with the Adcom....there is a specific thread on the forum somewhere about the 5802 and SDA's.

As far as the polarity on your AI-L1, I have no idea why it would permanetly reverse polarity. Many componets are switchable. If it were me I'd hook things up as normal until you have more info. Do you have the owners manual? If so, there should be something in there.

H9

P.s. When I say normal I mean as you would hook up a non-common ground amp by tying the grounds together.

heiney9

Just to clarify further. Here's a thread that might be of some help.

http://www.polkaudio.com/forums/showthread.php?t=28633&highlight=adcom+5802

There is still another thread out there too.

markeddie

Thanks for the advice, I have read most of the threads which cover the 5802. Raife seems to know a lot about this issue. The AI L1 is causing me the questions, and I don't have an owners manual for it. George has one, he stated the manual indicated you needed to reverse the connections at the speakers. From what I have read, a crash course over the last 2 months, some pre-amps reverse and some amps reverse. I don't really understand why they do.

markeddie

I know there are some experienced techies in here who can help with these questions. In the meantime I will follow Sax's advice, breath in... breath out, and scream!

heiney9

Here's why

Phase Invert
A switch found in the input sections of mixing consoles and mic preamps. The term "phase invert" is actually a misnomer, since what the switch really does is invert the polarity of the signal in that input (correct usage would be "polarity invert"). Its intended use is to correct for balanced lines and mics that are wired backwards.(usually during recording and mixing) In some cases toggling the phase invert switch may make a sonic difference if signals are out of phase, but doing so will also put that signal out of polarity with the others.

Sounds like you've got a handle on the common ground thing. Raife would be the expert in common ground/SDA issues, including your polarity issue.

Good luck

H9

heiney9

Mark, If all else fails talk to Ken at Polk CS. He is a great guy and can most likely shed some light on your situation. Call him and pick his brain.

H9

markeddie

Thank you very much! Talking to Ken or Raife sounds like a good idea, and getting an owners manual for the AI L1. For now I'm hooking my Adcom 545 back up and chilling out.

heiney9

markeddie wrote:

For now I'm hooking my Adcom 545 back up and chilling out.

This means you can stop the breathing exercises............................for now .