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Experiment with VPI Turntable AC polarity...

Discussion in 'Audio Hardware' started by Todd Fredericks, Apr 1, 2002.

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  1. Todd Fredericks

    Todd Fredericks Senior Member Thread Starter

    Location:
    A New Yorker
    I did a little AC polarity experiment with my VPI HW-19 mk III this Sunday (why not?). I reversed the plug and listened carefully for any changes. I've done this experiment in the past (and settled on what I thought to be the correct AC polarity) but I felt like doing it again (again why not?). The VPI AC chord is not marked in any way for polarity (so it can be hit or miss). What did I notice? I listened to the Classic Records "Led Zep IV". Side one as is (making mental notes of different elements of the recording), side 2 was played with reversed plug. What did I hear/experience? The bass seemed to get a bit boomy (not tighter but bloated/not musical). I had an incredible loss of soundstage placement/detail. The space was still large but I couldn't precisly pinpoint where all the instruments were coming from. I could tell what was towards the left, center and right but it was kind of blurry. Everything was there but not distinct in the space. Robert Plants voice sounded kind of harsh/strained (not him but the recording of him) and not very pleasing to listen to (something was missing). Timing seemed way off. Notes were being hit but they seemed unnatural and just wrong with attack (sometimes like hesitation or almost there but not). These observations were extremely obvious because I was listening very carefully and tuning into these aspects. If the VPI was accidentally plugged in this way then maybe it would have taken a bit more time to realize that something major was wrong or off. So, after this quick experiment I turned the plug around and I was very aware of the improvement. I could've spent hours comparing side per side but I got a very good impression with this quick switch (also, I felt like enjoying some music in the afternoon and I wanted to relax). Give it a try...

    Todd
     
  2. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    Regrettably, AC plug polarity makes a difference on TTs, just as it does almost everywhere else. Also I have found TTs to be susceptible to power cord improvements.

    For the record, Neil Levenson was first to utter the truth about AC polarity and audio, shortly followed by Enid Lumley. That was 'way back in 1982! Look how far we've come today...

    To my knowledge, the next public mention was in my book The Wood Effect in 1988.

    Since then, I believe only Martin DeWulf, besides myself, has been banging the drum.

    clark
     
  3. Todd Fredericks

    Todd Fredericks Senior Member Thread Starter

    Location:
    A New Yorker
    Clark,

    I hope you and Martin keep banging the drum because the difference was there. I hope in the future more people start listening and also join in with the drumming...

    Todd
     
  4. Andy

    Andy New Member

    I never thought of trying any of this stuff until I started to hangout around this forum.
     
  5. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    ***I never thought of trying any of this stuff until I started to hang out around this forum.***

    Stick around, kid.

    But also let it be said, the reversal of *one* plug can be heard to greatest advantage, only after *all the rest* are properly set.

    Moreover, there is the occasional unit that is not susceptible. Don't let that stop you from trying others.

    clark
     
  6. Todd Fredericks

    Todd Fredericks Senior Member Thread Starter

    Location:
    A New Yorker
    Clark,

    What about my Dynaco ST-70? I read somewhere that AC polarity has no effect because of it's design. Any thoughts about this? I haven't had time to try it out yet...

    Thanks,
    Todd
     
  7. Ronald

    Ronald Forum Resident

    Location:
    Columbus, OH
    Interesting about the VPI.

    If you were to upgrade to SAMA, there is no directional preference to wire it to the switch. The SAMA itself is three pronged with a detachable power cord.
     
  8. FabFourFan

    FabFourFan Forum Resident

    Location:
    Philadelphia
    Neil Levenson? 1982? As if! :)

    C'mon, Clark, we were flipping plugs at Dynaco in the 70s - the Stereo 400 power switch actually has 2 ON positions, and that switch cost real money!

    But we certainly weren't the first ones to be doing it. I remember 'old-timers' telling me about flipping their home audio plugs back in the 50s!

    And no doubt they heard it from someone else when they were starting out.
     
  9. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    "Neil Levenson? 1982? As if!"

    Yes! In Fanfare. Want chapter and verse?

    "C'mon, Clark, we were flipping plugs at Dynaco in the 70s - the Stereo 400 power switch actually has 2 ON positions, and that switch cost real money!"

    Oh, I see what you're getting at... Read on...

    "But we certainly weren't the first ones to be doing it. I remember 'old-timers' telling me about flipping their home audio plugs back in the 50s!

    "And no doubt they heard it from someone else when they were starting out."

    OK, here we go.

    When I wrote "utter" I meant *in print*. As opposed to old-timers trading vest-pocket information.

    More importantly, the earlier switches were installed -- to the best of my knowledge -- as hum-reduction devices! What Neil, Enid and I were discussing was *sonic improvement*, distinct from hum. Perhaps the earlier switches had caused some people to notice this effect too, but never had it been researched, codified or put into print.

    I happily await contradiction on this point.

    clark
     
  10. Todd Fredericks

    Todd Fredericks Senior Member Thread Starter

    Location:
    A New Yorker
    Clark,

    Good points about the difference of a concept as "vest-information" and being put in "print". The latter attempts to seriously address the concept and moves the ball further...

    Any ideas on the AC polarity on the old Dynaco ST-70's?

    Todd
     
  11. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    "Any ideas on the AC polarity on the old Dynaco ST-70's?"

    Just one. Friggin' TRY IT!

    But not to forget my cautionary notes...

    clark
     
  12. Todd Fredericks

    Todd Fredericks Senior Member Thread Starter

    Location:
    A New Yorker
    Thanks Clark... I'll try it this weekend. I'm just kind of tired this week when I get home and my ears just want to relax. I'll post my findings. Now back to my coffee...

    Todd

    P.S. "Friggin' TRY IT!"? But I was expecting you to do all the work for me... :)
     
  13. kim kerwin

    kim kerwin New Member

    Location:
    Agoura Hills, Ca
    polarity

    If you have a three pronged plug you need a cheater plug so you can reverse it. You probably need to file the widest prong so you can reverse it but it gives you the chance to test it and believe me there are a lot of componets that are out of polarity. Another thing with cheaters are that your're removing the ground which will also give you a huge improvement in sound.
     
  14. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    "If you have a three pronged plug you need a cheater plug so you can reverse it."

    Quite so! I go for Eagle. Quality tells.

    "You probably need to file the widest prong so you can reverse it but it gives you the chance to test it and believe me there are a lot of componets that are out of polarity."

    Again, quite so! With one proviso:

    "Out" or "In" is a function of *two* parameters: The piece of gear itself, and the wiring at your location. Which leads to this IMPORTANT CAUTIONARY NOTE:

    If juice enters your domain at 240v and is split down into two 120v legs, those two are *out of phase* wrt each other! You must make all your tests, and all your connections, on one leg only.

    Are you surprised?

    "Another thing with cheaters is that your're removing the ground which will also give you a huge improvement in sound."

    Here I gotta say, maybe yes, maybe no.

    But you are, Sir, a very advanced practitioner of the art. Care to e-mail me?

    clark
     
  15. Todd Fredericks

    Todd Fredericks Senior Member Thread Starter

    Location:
    A New Yorker
    Thanks Kim! I've used cheater plug many times before (especially when doing some sound recording jobs). My vintage Dynaco ST-70 (pre-1964) has a 2-prong plug (none are wider/before that time). I'll do some experiments this weekend and post my findings. I'm enjoying all these posts about polarity because I've been aware of this for a long, long time. I used to do these experiments (and others) and heard differences but without knowing why. A few years ago I started hearing different ideas about "why" and it's great to hear more. We're all a strange lot!

    Todd
     
  16. Humorem

    Humorem New Member

    Location:
    LOS ANGELES
    Clark is deadly right about the two legs being out of phase. The first time I had dedicated wiring installed for my stereo I used both legs and the sound was terrible! The house wiring sounded better.

    Finally got it straightened out, just by desperately trying something different, because nobody seemed to know anything about this stuff that I could talk to.

    As Steve, Kim and others remember well, I had a big switch that would cut the neutral and the hot (you have to do both) to the whole house except for the stereo. It was never less than a dramatic demonstration of how all the other devices plugged into your circuits screw up the stereo, as well as the effect of the wiring itself acting like a big antenna.

    I would guess that 80+% of the members of this forum have at least one component out of electrical polarity. If you want to make your stereo sound better, it's free to fix it. Just takes time and some critical listening skills. Use vocals, not classical or other "spacious" recordings. Spacious recordings can sound better out of polarity, I've found. When people sing with giant heads, that's wrong. (Dipole speakers give kind of the same effect: great on openness, bad on focus, because when that rear out of phase wave arrives, it arrives out of phase, the Bose effect.)

    And cheaters don't always make an improvement, so do them one at a time and in various combinations before you settle on the final setup.

    And most importantly, go back and check your stuff from time to time. Things get hooked up wrong by accident, and improvements to the sound can show you that the way you liked before isn't always the best way to hear it now.

    TP
     
  17. Bobbit

    Bobbit Forum Resident

    Location:
    Topanga
    Hey Kim, Could you explain the use of a volt meter to get correct polarity?
     
  18. kim kerwin

    kim kerwin New Member

    Location:
    Agoura Hills, Ca
    volt meter

    It's been so long since I've used mine the battery is dead and I can't remember which setting I use. I listen to determine which way is correct but the way to do it with the volt meter is to hold one of the probes in your fingers and put the other on one of the screws on the chassis of whatever you're testing. Check the reading, then reverse your plug and check it again. The lowest reading is the correct position for the plug. You should also make sure the rest of your componets are unplugged and your interconnects are disconnected from the piece that's being tested. The first time I did this, along with removing all the grounds I was blown away. It's a free tweak that's bound to put a very large smile on your face.
     
  19. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    Humorem wrote: "Nobody seemed to know anything about this stuff that I could talk to."

    My child, you can talk to *me*.

    clark
     
  20. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    kim kerwin wrote: "It's a free tweak that's bound to put a very large smile on your face."

    O yay!

    Say, you don't suppose, that just because it's *free*, that's why the stereo mags never mention it?

    clark
     
  21. Steve Hoffman

    Steve Hoffman Mastering Engineer Your Host

    Re: volt meter

    Just to repeat, this is the cheapest and most amazing free tweek there is! (Well, it's not exactly free, 'cause you have to buy a cheap voltmeter), but when you do, and you check out all of your components to see if their polarity is correct or not, WOW, are you going to be in for a shock!

    I was.
     
  22. Todd Fredericks

    Todd Fredericks Senior Member Thread Starter

    Location:
    A New Yorker
    I'll try it this weekend with my trusty voltmeter. Thanks for "tweak" info!

    Todd
     
  23. Clark Johnsen

    Clark Johnsen New Member

    Location:
    Boston MA
    Master Steven wrote:

    "Just to repeat, this is the cheapest and most amazing free tweek there is! When... you check out all of your components to see if their polarity is correct or not, WOW, are you going to be in for a shock!"

    It's so good to be in a forum where people will actually listen to you! I've been touting this stuff for twenty years, with most readers standing on the sidelines sniggering. Boy are they a spectacle!

    But, Steve: Have you ascertained that your mastering chain is duly corrected? If so, notice any differences?

    clark
     
  24. Steve Hoffman

    Steve Hoffman Mastering Engineer Your Host

    Clark,

    My mastering chain is correct, but most of the master tapes I play sure aren't. I have a polarity switch that I use though...

    Folks, buy your little voltmeter at Radio Shack and go to it, the way Kim Kerwin describes. You're gonna be happy you did!
     
  25. Bobbit

    Bobbit Forum Resident

    Location:
    Topanga
    volt meter test

    I think the meter needs to be in the AC mode. B
     
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