2. amps-preamps
  3. 164955-27965

Speaker terminal polarity

I just unpacked my Cary 300B-SE mono blocks after being in storage for over 15 years.  Both speaker outputs (on each amp) look identical (not color coded) and neither is labeled + or -. I tried a continuity test against the amp chassis and both terminals read the same. How do I determine + from -?  Does it matter as long as I have each amp wired to its corresponding speaker the same way?

I must have asked this question when I got the amps 17 years ago, but can't locate the thread.  Standing by with red and black sharpie pens if necessary.

jamesddurkin
twoleftears's avatar
twoleftears
5,318 posts
 
Didn't Dennis H. use a subtly colored piece of perspex under (behind) the output connectors?  Try looking at the back of the unit from slightly different angles and see if you can see a hint of red.
jamesddurkin OP
4 posts
 
Thank you all for the input.  Negative toward outside edge of chassis, positive toward middle.  Just leaving this hear for the next 15 years!

oldhvymec
5,101 posts
 
ALL of his stuff is the same way that I have. Smart actually. Yea warm those up and give them a good listen... 15 years is a long time, ay..
Keep a close eye for a FEW days ay.. Sniff and look for oil leaks, not kidding, Carys are like old Harleys, they will leak oil, LOL twice for me.
They use that same 560uf  X ??? VAC for the filter caps..

I got mad at the dog at first.. Got a quick pat on the head.. oil, no dog piss, heart attack time.. 

Enjoy..
speakermaster
738 posts
 
On an old cary amp the base of the post is colored red or black it is not marked in the usual fashion look closely you will see it.
ecscott482's avatar
ecscott482
44 posts
 
Place a 1.5 volt battery across the speaker inputs. 
If the speaker cone moves out, label the positive battery side connected to the speaker +   

If it move in, then label it - 

Do the same for the other speaker.


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