Usually on an upstroke (well on my upstrokes) the pick is still angled so your thumb is closer to the string than the tip of the pick which follows behind, so it still slides over the string, which means the string is compressed against the pickup the same as a downstroke. If you manage to get the tip of the pick under the string and then pull it out so you're lifting the string away from the pickup then it'd be round the other way.
Certain picking styles (yours by the sound of it) may well be different, but the key to my original point was that the direction in the vertical plane isn't the waveform initial polarity determining factor but rather the direction towards or away from the pickup.
paulster wrote:Whichever way you pick, up or down, you initially press the string towards the pickup, so a note will always begin with the same polarity. The only likely exception to this would be popping, but that's really for the 4-stringers. Then it's just a question of which way your pickups are wound or which direction the magnets face.
Aside from possibly the polarity of the initial transient, wouldn't the rest of this be a bit of a red herring? The string doesn't even continue to vibrate in the same plane for very long...the sine wave along its length rotates around its own axis while the string rings.
I don't know...if the interaction between the string and the pickup is anywhere near as complex as that between a string and the top of an acoustic guitar, polarity in an absolute sense isn't going to make much sense.
talbany wrote:...The only explanation I can think of can be if the primary wires are wound opposite which is a strong possibility...
I doubt the OT was taken off the winding jig, then reversed 180 during manufacturing. It's more plausible to assume the start and finish (dot or no dots) are reversed on the primaries or were at least connect that way. Primaries are usually 2 coils wound in steps to increase coupling and efficiency. A simple case other than complex interleaving is: The 1st primary coil is wound, then the secondary coil is wound, then the 2nd primary coil is wound. The 2 primary coils are then connected together to form the CT. It makes more sense that the 2 primary winds were connected wrong during manufacturing not reverse wound. constructive eh?
Paul at MM mentioned that some Fender transformers they blue printed were opposite polarity with respect to the primary than others (Blue and Brown..does this make sense)..Don't know if this was due to a mistake or intentionally reversed it..Fender did some some strange things in the Silverface era bringing in the HiFi engineers (Big on reversing phase) after CBS..Is it also reasonable to believe that the north south polarity reading is related to the direction of the winds on the primary and be some kind of clue as to output polarity....... If they were using JBL's at the time wound them this way to compensate for the different polarity there as well...The 2 amps here are Silverface era and doubt both were mistakenly constructed.... Constructive right back..
Tony
OK, now thats beginning to make sense, since they planned on using JBLs. Didn't read the whole thread are the amps UL? if so, who knows how they wired the OTs or got the taps correct. Tony, the pickup magnet polarity tester isn't really telling you useful info, as least nothing that you can change with the present transformer. As you know, using a scope and function generator will tell all about the polarity of each winding, and allow you to wire correctly, even if the windings are truly reversed. I assume you already have fixed these amps are now working correctly.
Richie was the first guy I saw who said that one way is better than the other. Practically, that means you want a short inversion cable to test for the best tone...then you can set the wiring in the cab.
Here's from John Suhr about the EC tweed twins -- "...speakers wired out of phase to normal so it pulled on the first attack (not out of phase to each other) and were re-conned Oxfords done by Eric’s Keyboard tech (Tim Meyer) regardless whether they needed it or not. (I would recommend G12-65's now) "
BobW wrote:
I doubt the OT was taken off the winding jig, then reversed 180 during manufacturing. It's more plausible to assume the start and finish (dot or no dots) are reversed on the primaries or were at least connect that way. Primaries are usually 2 coils wound in steps to increase coupling and efficiency. A simple case other than complex interleaving is: The 1st primary coil is wound, then the secondary coil is wound, then the 2nd primary coil is wound. The 2 primary coils are then connected together to form the CT. It makes more sense that the 2 primary winds were connected wrong during manufacturing not reverse wound. constructive eh?
Paul at MM mentioned that some Fender transformers they blue printed were opposite polarity with respect to the primary than others (Blue and Brown..does this make sense)..Don't know if this was due to a mistake or intentionally reversed it..Fender did some some strange things in the Silverface era bringing in the HiFi engineers (Big on reversing phase) after CBS..Is it also reasonable to believe that the north south polarity reading is related to the direction of the winds on the primary and be some kind of clue as to output polarity....... If they were using JBL's at the time wound them this way to compensate for the different polarity there as well...The 2 amps here are Silverface era and doubt both were mistakenly constructed.... Constructive right back..
Tony
OK, now thats beginning to make sense, since they planned on using JBLs. Didn't read the whole thread are the amps UL? if so, who knows how they wired the OTs or got the taps correct. Tony, the pickup magnet polarity tester isn't really telling you useful info, as least nothing that you can change with the present transformer. As you know, using a scope and function generator will tell all about the polarity of each winding, and allow you to wire correctly, even if the windings are truly reversed. I assume you already have fixed these amps are now working correctly.
Gotcha!! Thanks...The Super Twin is UL...The Bassman is 50...Sorry I should of mentioned this to start...The amps were a Re-tube/ Cap job normal maintenance and seem to be operating normally....The thing was when I played them they sounded like every other Silverface of that era..Bright uneven breakup no warmth and thin... Scoping it out would confirm it however my ears are telling me out of phase no doubt there...If I get time I still may do this...
I wonder how many of these amps are out there with different speakers running out of phase... Pretty much everyone that comes across my bench sounds like this...It may be a good idea to keep it in mind when converting these amps to D-Style....It's obvious this is something totally different that the D-Lator test Scott did... Thanks again everyone...
Tony
Last edited by talbany on Fri Dec 04, 2009 12:12 am, edited 1 time in total.
What if you suspend your electronic analysis for a moment and consider that this could be partly a physical phenomenon. When the speaker is in the right phase for your physical position it is helping with the continued vibration of the guitar string by the mechanism of pushing and pulling on it (sound waves in the air coupling to the guitar) in the same directions that it is already vibrating. Change the speaker polarity and stand in the same position and you dampen the sympathetic vibration. Akin to playing under a ceiling fan....
heisthl wrote:What if you suspend your electronic analysis for a moment and consider that this could be partly a physical phenomenon. When the speaker is in the right phase for your physical position it is helping with the continued vibration of the guitar string by the mechanism of pushing and pulling on it (sound waves in the air coupling to the guitar) in the same directions that it is already vibrating. Change the speaker polarity and stand in the same position and you dampen the sympathetic vibration.
Henry
I did read your last post on this and agree room acoustics amplifies certain frequency's depending on where your standing and can create all kinds of sonic illusions especially in open back cabs placed in the corner or to close to a wall... Wooden rooms are the worst can get all sorts of phase issues...
Back in the 90's I had a small sound company and developed a pretty good ear for phase issues in PA's since half the PA was JBL the other half was EV..I enjoyed mixing but screw carrying around all that crap... sold it..Thanks for the tip i'll check it out
heisthl wrote:What if you suspend your electronic analysis for a moment and consider that this could be partly a physical phenomenon. When the speaker is in the right phase for your physical position it is helping with the continued vibration of the guitar string by the mechanism of pushing and pulling on it (sound waves in the air coupling to the guitar) in the same directions that it is already vibrating. Change the speaker polarity and stand in the same position and you dampen the sympathetic vibration. Akin to playing under a ceiling fan....
If you chase the argument of physical location, you need to consider the wavelength issues - the ceiling fan has a considerably longer wavelength than anything on the guitar and the active wavelength interacting with the guitar will be constantly changing presuming it is due to a non-constant pitch.
When two signals are out of phase with each other, we get what we call comb filtering.
But in a way we are comparing the two.
Because in my mind, when I strike a note on my electric guitar, I want the speaker cone first to move out, not suck in. (I think) I will test this later today.
So in a way that is comparing the phase of the output to the phase of the input.
Of course we know what polarity is,
Last edited by Structo on Fri Dec 04, 2009 6:04 pm, edited 1 time in total.
When two signals are out of phase with each other, we get what we call comb filtering.
But in a way we are comparing the two.
Because in my mind, when I strike a note on my electric guitar, I want the speaker cone first to move out, not suck in. (I think) I will test this later today.
So in a way that is comparing the phase of the output to the phase of the input.
With reference to the input phase has to do with the initial attack..This is where it becomes most noticeable..You can test it by pushing the string tword the magnet the speaker should move out (gives you a stronger attack)...Also most stock Teles are opposite polarity with respect to Strats so you know...after the string starts vibrating it's virtually invisible..
I noticed yesterday that when I struck a chord while plugged into my D'Lite with a Dumbleator loop in the chain that the speakers (2 x EVM 12L's) pulled in.
I never noticed that before.
So is this due to the Dumbleator reversing the phase?
That is, instead of pushing air it is pulling in?
Anyway, I reversed the wires on the speaker cab as that was the easiest way to flip the phase because it has those push on connectors on the jacks.
Not sure if I hear any difference.
The pick up coil generates voltage no matter which way you pick the string.....no difference.
Phase relationship between tranny primary and secondary..............one way is right, the other is out of phase. When in doubt, meter/scope to find which is which. People do goof up sometimes tying the tail wires out of the tranny. Oops, orange wire tied to the one that is supposed to be green.
Nobody has zero defects. And no wonder some of us have fits trying to solve a problem with a internally miswired component you can't see.
Speakers are generally designed for forward motion. If they suck in, they are wired wrong. If the speaker box is designed for reverse phase, the speaker is designed (some bandpass types for example) for this application. If not, great way to tear up a speaker. Suspensions are typically designed for positive forward motion. The over excursion in reverse will tear up the speaker faster than forward.
I have replaced a few speakers in my years, for trusting others in a new wire up of a box or replaced speaker incorrectly wired. A battery works wonders to test here. I do it myself to make sure it is right.
So if some of various "X" amps went out the door with speakers out of phase, there seems to be a quality control issue there. Some may argue of intention with this.
What if an assembly goof happens, and to prevent a mass return of amps to rewire...........marketing tells you "It is a proprietary engineering specially for this amp, (so don't be concerned that) it is wired out of phase".
Most amp companies find a basic response need for a speaker, then put in the cheapest they can muster. If it works for a while (in the store) cool. After all, it is about the profit. The ones that care about quality use good speakers, and wire them correctly.
I have always replaced every combo amp speaker as soon as it got home since the 70's. All my cabs are EVM loaded with the exception of a couple G12-75's and one JBL.
I would never run any conventional speaker out of phase ever.
Even if this was to allow for more cabinet tone, or lower SPL due to reverse phase (running the motor energy to the back) I like the speaker producing sound to me, and the box reinforcing it.
JBL's weren't backwards, they just made the black terminal the hot.
Newer ones have the red hot. You should always test your speaker box with a 9volt after loading, to check for correct polarity.
guitardude57 wrote:Speakers are generally designed for forward motion. If they suck in, they are wired wrong.
No such thing as only forward motion unless your feeding pulsed DC to it. Speaker by their very nature (reproducing audio frequencies) have to operate equally forward and back. The only purpose for + and - terminals is so you can wire more than one speaker to the same amplifier and maintain the same polarity, the speaker itself doesn't care about it.
