I read it somewhere and even if I don't understand why somebody would do so as the sound should not be affected at all, I am curious to know if that's true.
And therefore, are there chances that Robben Ford's cab is out of phase (with its polatiry reversed)?
[img:720:960]http://i273.photobucket.com/albums/jj23 ... 5ODS04.jpg[/img]
Did Dumble reverse polarities in his cabs?
Moderators: pompeiisneaks, Colossal
Re: Did Dumble reverse polarities in his cabs?
That picture shows positive to positive on both speakers.
Re: Did Dumble reverse polarities in his cabs?
I mean that the global polarity is inverted. No one speaker to the other. They are wired in parallel in the pic
Once you've got both speakers wired, there is one + and one -. If you connect the current from the amp the opposite way, the speakers will vibrate the opposite way too. You can google a lot of literature about this.
It is presumed that the sound will not be altered but some people says it does. Dumble used to wire his cabs this way. (that's what I have read....)
[img:768:480]http://forums.audioholics.com/forums/at ... -phase.jpg[/img]
Once you've got both speakers wired, there is one + and one -. If you connect the current from the amp the opposite way, the speakers will vibrate the opposite way too. You can google a lot of literature about this.
It is presumed that the sound will not be altered but some people says it does. Dumble used to wire his cabs this way. (that's what I have read....)
[img:768:480]http://forums.audioholics.com/forums/at ... -phase.jpg[/img]
Last edited by rufes on Fri Jan 17, 2014 10:40 pm, edited 1 time in total.
Re: Did Dumble reverse polarities in his cabs?
I think what the OP is talking about is the phasing of the output transformer/ speaker.
In other words, when you strike a string, the cone should move outwards.
I remember Scott Lerner going on about this and I did check my amp.
Due to the stages in a Dumble amp, if I recall correctly, the phase is reversed from other standard amp builds.
So if you are able to, observe the speaker cone when you strike a note.
Like palm mute your strings with the amp up loud and strike the strings.
I forget what I did about my speaker phasing but I believe I addressed the issue years ago.
Easy enough to check out.
In other words, when you strike a string, the cone should move outwards.
I remember Scott Lerner going on about this and I did check my amp.
Due to the stages in a Dumble amp, if I recall correctly, the phase is reversed from other standard amp builds.
So if you are able to, observe the speaker cone when you strike a note.
Like palm mute your strings with the amp up loud and strike the strings.
I forget what I did about my speaker phasing but I believe I addressed the issue years ago.
Easy enough to check out.
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: Did Dumble reverse polarities in his cabs?
Speaker phasing really boils down to if the initial attack of the strings is outward or inward..After the speaker returns to 0 (center) it really does not matter.. Some can hear the difference others cannot tell!!. (you might notice it a bit more on attack in a closed back cab..thump ,thump)
All of this is " also"determined by the input phasing,which can change when you use certain pedals,guitars (pickups) and yes the Dumbleator..where you have to be most concerned about speaker phasing is when you use more than one amp and cab at a time where certain frequencies can cancel (moving in opposite directions) and can be somewhat noticeable in certain rooms..Since the color standard on speaker wire is Blk =common (Gnd) and red is + flow.. His looks to be tip + Blk - (normal polarity) (BTW.Most older JBL's were opposite than that of EV or Celestion)
..The Red Speaker is an Eminence..Robben was working with them around this time to try and do a G-1265 replica speaker..AFAIK Eminence didn't get it up to Robben's standards so he discontinued using them..
Bottom line if you are using 1 amp..I wouldn't be too concerned..Unless you have really sensitive ears then carry a reversed speaker cable!!
Tony
All of this is " also"determined by the input phasing,which can change when you use certain pedals,guitars (pickups) and yes the Dumbleator..where you have to be most concerned about speaker phasing is when you use more than one amp and cab at a time where certain frequencies can cancel (moving in opposite directions) and can be somewhat noticeable in certain rooms..Since the color standard on speaker wire is Blk =common (Gnd) and red is + flow.. His looks to be tip + Blk - (normal polarity) (BTW.Most older JBL's were opposite than that of EV or Celestion)
..The Red Speaker is an Eminence..Robben was working with them around this time to try and do a G-1265 replica speaker..AFAIK Eminence didn't get it up to Robben's standards so he discontinued using them..
Bottom line if you are using 1 amp..I wouldn't be too concerned..Unless you have really sensitive ears then carry a reversed speaker cable!!
Tony
Last edited by talbany on Sat Jan 18, 2014 6:44 am, edited 5 times in total.
" The psychics on my bench is the same as Dumble'"
Re: Did Dumble reverse polarities in his cabs?
Just to be clear.
The picture shows correct polarity of the two speakers connected.
But what I am talking about is how the speakers are connected to the amp.
We are talking about the wave form phasing.
Which means, when you first hit the amp with a signal, the speaker cone should move outward.
Tony knows his stuff.
Thanks for a better analysis Tony!
The picture shows correct polarity of the two speakers connected.
But what I am talking about is how the speakers are connected to the amp.
We are talking about the wave form phasing.
Which means, when you first hit the amp with a signal, the speaker cone should move outward.
Tony knows his stuff.
Thanks for a better analysis Tony!
Tom
Don't let that smoke out!
Don't let that smoke out!
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groovtubin
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Re: Did Dumble reverse polarities in his cabs?
U BETTER BLV IT! Try this on a PV classic 30 with a VTG 30 in it, n AMAZED at what it does!rufes wrote:I mean that the global polarity is inverted. No one speaker to the other. They are wired in parallel in the pic
Once you've got both speakers wired, there is one + and one -. If you connect the current from the amp the opposite way, the speakers will vibrate the opposite way too. You can google a lot of literature about this.
It is presumed that the sound will not be altered but some people says it does. Dumble used to wire his cabs this way. (that's what I have read....)
[img:768:480]http://forums.audioholics.com/forums/at ... -phase.jpg[/img]
Re: Did Dumble reverse polarities in his cabs?
I have a speaker cable with 2 banana connectors in the middle to flip phase when setting up my amps. Many times I can hear/feel a preferred phase relationship and wire the permanent cable in the phase that pleases my ears/pant leg. If I ever put a new or different effect in the loop - I will repeat the test. Distance from the amp, size of the room - all these things come into play. If it feels good do it. I keep the cable in my gig bag in case I am not "feelin' it" at set up. 2 seconds and I can make a decision as to whether it's worth flipping.
This is such an easy thing to try with your amp, I don't know why more people just don't do it. If you notice a difference for the better - fine. If you don't - fine, too. No disrespect intended to any one.
This is such an easy thing to try with your amp, I don't know why more people just don't do it. If you notice a difference for the better - fine. If you don't - fine, too. No disrespect intended to any one.
Re: Did Dumble reverse polarities in his cabs?
@stelligan: Do you have two sets of speaker cables then, in and out of phase, to use once you tried it/ Or do you just use the banana plug cable?
Re: Did Dumble reverse polarities in his cabs?
I've been known to use the banana cables with super cool duct tape as insulation and security. They are 2 short cables with 1/4" on one end and banana on the other. It's only now I realize what a dumb ass I've been, and could've got by with lugging one well marked crossed cable. Thanks, Tony. 
Volume seems to be the other big variable in this and with a head & bigger cab setup. With a combo I would only consider messing with this if there was something new introduced in the signal path somewhere. At the SPL most indoor venues are now, you usually don't move enough air to feel the difference or give a shit. I miss the good old days.....
Volume seems to be the other big variable in this and with a head & bigger cab setup. With a combo I would only consider messing with this if there was something new introduced in the signal path somewhere. At the SPL most indoor venues are now, you usually don't move enough air to feel the difference or give a shit. I miss the good old days.....
Re: Did Dumble reverse polarities in his cabs?
you usually don't move enough air to feel the difference or give a shit. I miss the good old days.....
... Funny..I used to carry around different reversed cables and different length D-lator cables ....I even built an amp that displayed bias current (digital read out) on each tube on the back and adjusted it with a variac ..Now I have better things to do with my time as soon as I get set up..... Go to the BAR!! Tony
" The psychics on my bench is the same as Dumble'"
Re: Did Dumble reverse polarities in his cabs?
You got your bidness straight now!
Re: Did Dumble reverse polarities in his cabs?
When reversing polarity I do it at the speaker jack not the speakers, so RF's cab could be reversed. When you reverse one cab you need to also do the other if you are playing in stereo. I wonder if RF or his tech would have reversed all the different cabs each night, rental twins etc.
Re: Did Dumble reverse polarities in his cabs?
Good question.
Probably most folks would not obsess about these things that we do.
Basically, if an amp has a uneven number of stages then the output will be a different phase than other amps.
As mentioned, some stomp boxes also mess with this.
It's pretty easy to check out.
Power up the amp with Dumbleator, and with your favorite effect engaged, see if on the first attack on the strings causes the cone(s) move out or suck in.
I think with this simple observation, that you will see what everybody is talking about.
In most cases it won't matter but if you are anal obsessive, then yes, it does matte.r
Probably most folks would not obsess about these things that we do.
Basically, if an amp has a uneven number of stages then the output will be a different phase than other amps.
As mentioned, some stomp boxes also mess with this.
It's pretty easy to check out.
Power up the amp with Dumbleator, and with your favorite effect engaged, see if on the first attack on the strings causes the cone(s) move out or suck in.
I think with this simple observation, that you will see what everybody is talking about.
In most cases it won't matter but if you are anal obsessive, then yes, it does matte.r
Tom
Don't let that smoke out!
Don't let that smoke out!
