Don't forget to check whether either one of the amp channels you are using on a speaker is phase inverting.
Don't forget to check whether either one of the amp channels you are using on a speaker is phase inverting.
Ok - I will call you on this one.
How about an actual LIST of amplifiers / models that invert the signal from input to output.
I know of only ONE that does as an *exception* to the standard and it has a specific topology reason for doing so.
Forget the tweako tube amps and anything before 1960.
go
Why?Originally Posted by subwoof
That is what I had been using... and the SETs did invert phase.
I agree that most pedestrian amps do not invert phase, but you can run into those that do.
Widget
A forum favorite for bass splits, all the JBL/UREI 62xx amps connected with xlrs, unless special cables are made up:
I was specifically referring to amplifiers that invert which are rare..
The JBL's are not inverting. The stated positive input terminal ( pin 3 in this case ) will cause a positive output swing on the red binding post.
Same for crowns except they use pin 2.
BOTH use the tip on a TRS as positive....confusing nicht var?
Why this stupid industry keeps changing the so-called "hot" pin is beyond me. And JBL's use of an XLR for an unbalanced *output* on the 5235 is another joke. I am installing one in a few hours and I have to make up special cables...grrr...
How you wire / adapt the balanced input connections is specific to your other gear and system.
**HOWEVER** if you went and grabbed a QSC MX1500 amplifier, and plugged a 1/4 TS or TRS plug into it's input that will cause a *negative* output swing.
And that is the only manufacturer I know of ( pro ) that does this ( maybe the newer lines don't ?? ) and it's because of their use of a grounded can ( collector ) output device heatsink. Of course that means that ALL the output audio has to pass through the same large electrolytics that filter the raw DC.
Clear as mud...
Just wait till some clver guy says that pin 1 hot is the way to go.I was specifically referring to amplifiers that invert which are rare..
The JBL's are not inverting. The stated positive input terminal ( pin 3 in this case ) will cause a positive output swing on the red binding post.
I had this problem 25 years ago using a Quad 405 and a Phase Linear 700B
So I ran one high channel with the Quad and the other high channel with the 700B.
The out of phase stereo image quickly told us the Quad was inverting.
This is a simple way of determining phase continuity of the entire signal path without having to scew around.
Some years ago a clever person made up a jacket pin that had a rotating arrow that would point to the numbers 1, 2 or 3 and it was labeled what pin is XLR hot today.
I think it was at an early 80's NAMM show and I wish I had a picture of one..
sub
I just wish that folks would agree that it is polarity that is opposite, not phase. Both pin 2 and/or pin 3 are of the same phase, but opposite polarity referenced to pin 1.
Not gonna happen. The two words are used with multiple, overlapping referent groups. Context often helps distinguish what is meant, but not always, as has been adequately demonstrated in this thread. The best thing is to try and be as clear and specific as possible, even though it might seem like it takes a lot of extra words sometimes.
Here is a solution to the cat problem. It's fully adjustable too!Work! This is what we like to call "Hell Week" each month.
This is one project I don't want to leave half-way done. And I also hadn't considered the interaction between the virgin grilles and our two cats! They've learned no to bother the C37s but that's some tough grille cloth. These get only one shot at being perfect until a casual claw gets too close. Rabbit wire?
(not my hand!)
Sigh!
It looks like the handle is out of phase.Here is a solution to the cat problem. It's fully adjustable too!
Yea, it was probably built by a "novice"It looks like the handle is out of phase.
Great! I'm enjoying listening to lots of jazz, and blues, and horn music I'd put away years ago.
I even managed to get the hum out of the system. Received the Carvin sequencer/conditioner today, damaged by UPS. Amazing how you can drop a 13-lb. 1-rack-unit item and bend the thick aluminum faceplate at a 45º at the rack-mount holes without even breaking the box. Granted, on-line there are more than a few complaints about Carvin's packaging on this unit. I tried it out anyway and the sequencer works well but it still didn't kill all the hum from my ancient home wiring—still worth if for the sequencer feature. Carvin, to their credit, is giving me full credit and then sending me a new one at the current sale price ($10 less off their web site than what I paid from their Ebay store as of today) and not charging me shipping for my trouble.
So while I was messing around, I lifted the ground from the D150A-II which for some reason made it quiet. The DC300A-II is still quiet. Must have something to do with operating the amps in the same place though I was careful to run input cables separate from power. :dont-know Works fine now for whatever reason.
Swapped the polarity at the LF amp back to "in-phase", again, but didn't like it as much and put it back to "out-of-phase". I'll leave the reasons to anyone who'd like to mediate the inquest.
Be very careful about lifting grounds from equipment.
The consequences can be fatal.
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