2. amps-preamps
  3. 159522-19072

Phase inverted preamps and Rel Subwoofers.

I have come to realize that my preamp is a “phase inverted” preamp.  This basically means that most recordings will sound better when you reverse the positive and negative wires on the back of your speaker terminals.  Since doing this my amp is getting hot.  I have Rel subs hooked to the terminals of the amp the normal way.  Could this cause the heat? Should or (can I) reverse the subs positive and negative positions on the (amp) along with the the speaker wires as well?  In this case the speakers positive and negative would be changed back the traditional way. 
puffbojie
17 responses Add your response
noromance's avatar
noromance
9,769 posts
 
You've got to test by a process of elimination. Put the connections back the way they were. No swapping. Is the amp getting hot now? If not, you are back to where you were.
Disconnect the RELs from the amp. Now swap the speaker wires. Does it get hot now? If not, reconnect the RELs. Now what's happening?
(Check to see if the RELs have a phase control.)
turnbowm
353 posts
 
If the speakers are passive and isolated from everything else, there should be no problem in reversing the +lead and -lead going to the speaker(s). As for the Rel sub, connect it in the normal manner and use the Rel's 0/180 phase switch to reverse the phase. The correct position for the phase switch is the one that provides the most bass, which means that the speaker woofer is in phase with the sub driver.
helomech
1,673 posts
 
First question that needs asked: did the bass of your main speakers improve when you reversed polarity of the cables?
millercarbon's avatar
millercarbon
12,531 posts
 
I have Rel subs hooked to the terminals of the amp the normal way.  Could this cause the heat?

No. 


puffbojie OP
115 posts
 
@helomech 
Yes.  (Overall) I definitely felt their was a noticeable improvement in bass response.
pjr801's avatar
pjr801
192 posts
 
As long as your speakers are identically wired.
erik_squires
16,055 posts
 
 Could this cause the heat?

No, BUT you could have a minor short, especially if using bare copper ends. Double check you don't have a stray conductor strand.
jjss49's avatar
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jjss49
6,612 posts
 
rel subs should have a phase switch (or setting)

read the rel manual - it is carefully written FOR YOU - the user  :)

they are very clear on how to manage phase 
puffbojie OP
115 posts
 
@jjss49 

I know how to phase my subwoofers.  This is in regards to the mains.  The subwoofer set up was  in question due to the heat I am experiencing -which is likely not the cause based on some of this feedback.  I switched the speaker polarity back and am still experiencing heat so not sure at this point.  
puffbojie OP
115 posts
 
@erik_squires Thanks Eric.  I checked and they are in place.  I will just need to disconnect the subs for a period of time and check that next.  
helomech
1,673 posts
 
Sub inputs should be too high an impedance to cause the amp additional stress. 
noromance's avatar
noromance
9,769 posts
 
What’s your amp? Is it running in Class A? Is the bias set too high?
puffbojie OP
115 posts
 
It’s a Modwright KWA SE.  It has a high bias and low bias switch.  I have it set on high bias.  
puffbojie OP
115 posts
 
*KWA 150SE
noromance's avatar
noromance
9,769 posts
 
High bias can cause the unit to run hot. If it's new, you may need to run it on low for a period. Check with Dan Wright in case there's an issue with the thermal sensor etc.
Post removed 
puffbojie OP
115 posts
 
Talked to Dan. I’m getting the bias adjusted.  
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