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Thread: RW/RP... Is there a tonal difference?

  1. #11
    Axellent Member Jammin'John's Avatar
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    The hum cancelling trumps any possible tone improvements for me.
    I play in some places with rheostats & fluorescent lights.

    JJ
    Tele's & Tweeds.Yes sir.

  2. #12
    Axe-honerated spellcaster's Avatar
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    I don't think I've ever owned a three pickup guitar with a middle pickup that wasn't RWRP, other than a Univox I had briefly.....but it was the 60's, and my memories of tone nuances are not great, lol.

    One thing I've seen claimed is that the RWRP aspect of the middle pickup is in-part or completely responsible for quack in Strats. It would be interesting to hear from somebody who owns a Strat with no RWRP on the middle pickup, but does have a five-way switch. Do switch positions 2 and 4 still quack?
    "I know just enough to be dangerous....."

  3. #13
    Axellent Member Mreilander's Avatar
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    Both quack... but they quack differently. It's more to do with how you set the heights than the polarity, BUT... properly set up, a non rw/rp mid gives a very unmistakable, classic strat quack.

    I think a lot of this 'rw/rp is better for quack' came from people misunderstanding the use of the term 'phase'
    A lot of people confuse sonic phase (vibration of string, sound output) with electrical phase. A rw/rp pickup is electrically out of phase with its counter part, but sonicly in phase.

    Quack is caused by the two pickups, which are sonicly in phase, picking up different points of the vibration of the string. For example, the neck pickup may be sensing string on the up cycle of the vibration, where as the mid pickup may be sensing the transition from up cycle to down cycle. This will put some of the harmonics out of phase, cancelling or partially cancelling each other out.

    When discussed, these fine details are often left out, and the conversation goes something like...
    - What causes quack?
    - It happens when harmonics are out of phase

    New discussion
    - Why do we have RW/RP pickups
    - It puts the mid pup out of phase electrically with the others to cancel hum

    Assumption, or deductive reasoning
    -Out of phase = quack
    -rw/rp = out of phase
    -rw/rp = quack
    The key words that make them not like terms (electrically and sonicly) are left out.


    FYI, the classic Quack in Clapton's lay down sally and Knopflers Sultans are from non RW/RP pickups

  4. #14
    Axellent Member Mreilander's Avatar
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    Here's a new graph with a field density overlay.

    RW/RP



    non RW/RP

  5. #15
    Axetastic doublewah's Avatar
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    Quote Originally Posted by Mreilander View Post
    ...FYI, the classic Quack in Clapton's lay down sally and Knopflers Sultans are from non RW/RP pickups
    All very interesting stuff, Mike.

    As for the last bit, it makes sense. That's before there were any 5-way switches, right? Back when they had to jam a piece of a match or something in there to get the 2 or 4 position. But they were just after the quack - it seems the RW/RP hum-cancelling perk came later.

    By the way, I rely on the hum-cancelling of RW/RP middle pickups, as does JJ. I also use series wiring for the same reason (plus the faux humbucker tone it gives).
    I bought a relic'd guitar because I liked the way it sounded. Then I refinished it because I didn't like the way it looked.

  6. #16
    Axellent Member Mreilander's Avatar
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    Quote Originally Posted by doublewah View Post
    That's before there were any 5-way switches, right? Back when they had to jam a piece of a match or something in there to get the 2 or 4 position. But they were just after the quack - it seems the RW/RP hum-cancelling perk came later.
    The 5 ways became standard in the mid 70's. RW/RP didn't become standard until the early-mid 80's I think.



    I spent the afternoon yesterday dusting off and setting up my spectrum analyzer.
    With the spectrum analyzer, I don't actually need to put the pickguard in the guitar until it's time to do an audible A/B comparison. I will be using a set of our 65 pickups because this is a non calibrated set, meaning the bridge, neck, and mid pickup should have the same frequency response and output.

    So here's the procedure:

    1) Magnetically charge pickups and allow 24 hrs for pole pieces to stabilize.

    2) Measure the frequency response of each individual pickup, isolated from adjacent magnetic fields. (no other pickups close by)

    3) Load pickups into Strat pickguard and measure frequency response of each individual pickup.
    -Looking for a measurable difference from this step and step 2

    4) Reverse polarity of mid pickup and re-charge neck and bridge pickup. Allow to stabilize for 24 hours.

    5) Measure Frequency response of each individual pickup
    - Looking for a measurable difference from this step and step 2 and 3

  7. #17
    Axe-honerated spellcaster's Avatar
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    This all sounds like good science, Mike, and it's nice to see somebody actually doing the work and being able to offer empirical evidence instead of the subjective bs that's so common on the net. I'm looking forward to hearing how this goes.

    I didn't intend to sidetrack the thread by bringing up the Strat quack issue. It just seemed that it might be related. Obviously, the RWRP thing figures into some of Fender's two-pickup designs too, so the implications are a lot more widespread than just three-pickup Strats.
    "I know just enough to be dangerous....."

  8. #18
    Axetastic doublewah's Avatar
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    Spell, I for one think that the strat quack issue belongs in this conversation.
    I bought a relic'd guitar because I liked the way it sounded. Then I refinished it because I didn't like the way it looked.

  9. #19
    Axellent Member Dan Martian's Avatar
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    I have an old Hondo Strat-o-copy. I discovered after owning it for fifteen years that it's bridge pickup is RW/RP. Very odd, but it works and it quacks just fine. Great for the tele twang sound, if you wire it up right.

  10. #20
    Axellent Member Mreilander's Avatar
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    Ok Guys,
    I spent the better part of last Saturday morning working the experiment...



    This is a transmitter coil, or exciter coil. It is a humbucker bobbin with approx 100 turns of 36 awg. You can use any coil for this, so long as it has a wider frequency response than the coil you are measuring.



    The exciter coil is coupled to the pickup, and a signal sweep is run through the exciter. This induces a signal through your pickup. If you were to connect the exciter to a speaker terminal, you could hear your favorite song through your guitar amp, colored by the characteristics of your pickup.



    Now we measure the pickup on the scope against a known capacitance. This will give you info needed to do the math for inductance.


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