Just got these RTA 12B’s.

1246

Comments

  • CH46E wrote: »
    No matter how you slice it, they are a huge improvement over 30 year old electrolytics.

    You will very much enjoy the 12b.

    Looking forward to it.

    John
  • Gardenstater
    Gardenstater Posts: 1,999
    xschop wrote: »
    Ducati makes caps?

    0 to 60 in 3 secs
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • xschop
    xschop Posts: 2,020
    edited October 2020
    Harv2002 wrote: »
    xschop wrote: »
    Ducati makes caps?
    Yes but they are attached to a gas tank that feeds 90° Of Desmodronic bliss. If I was really a motorcycle guy, I’d have one just to listen to it!

    John

    Maybe that's why they were prone to auto-combustion on the track.
  • Harv2002
    Harv2002 Posts: 56
    edited October 2020
    Desmodronic.

    Cam open cam close.

    Lots of shims.

    Jingly cam chain sounds.

    John
  • Ok. So I got my new MT-4115 Peerless repos. They look very nice.

    Now, +/-

    My original tweeter has the hf out (White wire) going to the unlabeled terminal on the tweeter and the ground (Black wire) going to the red terminal. The new tweeter only has one terminal denoted as red. In my mind that’s + no?

    Help!

    John

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    k9gi48grv643.jpeg
  • Gardenstater
    Gardenstater Posts: 1,999
    On your Polk (Peerless) tweeters, the black wire is positive and the white wire is negative. Red on the tweeter terminal denotes positive. I sincerely doubt that in that Peerless Replica speaker you bought they would have undone that convention, although who knows? They seem to have had no problem with reversing the side that has the red terminal.

    There is a way to check. If you connect a AA battery momentarily to the tweeter with a strip of tissue paper on the dome you should see the dome move outward if you have the polarity correct.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • pitdogg2
    pitdogg2 Posts: 19,266
    edited October 2020
    Tweeters on the RTA12's are connected out of phase to correct the phase reversal in the crossover. Black should go to negative and white to positive... UNLESS the wires were desoldered from the board to "correct" what Polk had originally.


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  • CH46E
    CH46E Posts: 3,339
    Thanks guys. I can never remember the way they are.
  • Harv2002
    Harv2002 Posts: 56
    edited October 2020
    pitdogg2 wrote: »
    Tweeters on the RTA12's are connected out of phase to correct the phase reversal in the crossover. Black should go to negative and white to positive... UNLESS the wires were desoldered from the board to "correct" what Polk had originally.

    Interesting.

    John
  • CH46E
    CH46E Posts: 3,339
    Harv2002 wrote: »
    pitdogg2 wrote: »
    Tweeters on the RTA12's are connected out of phase to correct the phase reversal in the crossover. Black should go to negative and white to positive... UNLESS the wires were desoldered from the board to "correct" what Polk had originally.

    Interesting.

    John

    Yes, a PITA everytime I work on them.
  • Gardenstater
    Gardenstater Posts: 1,999
    edited October 2020
    More than likely Polk maintained the convention of connecting a black wire to the + terminal on the tweeter but at some point on the XO a white wire effectively connects to a black wire. Just my guess. On the binding post you probably still have black to red binding post (+) and white to black binding post (-).
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • pitdogg2
    pitdogg2 Posts: 19,266
    edited October 2020
    More than likely Polk maintained the convention of connecting a black wire to the + terminal on the tweeter but at some point on the XO a white wire effectively connects to a black wire. Just my guess. On the binding post you probably still have black to red binding post (+) and white to black binding post (-).

    Look at the schematic it plainly shows what I'm referring to.
    Black wire goes to negative on the tweeter and white to positive.

    The correct way to hook up tweeters on the RTA 12's is as I just described.

    Yes the binding posts are correct black to positive white to negative, the signal gets reversed 180° in the XO to correct that you hook the tweeter out of phase to correct the shift.
  • CH46E
    CH46E Posts: 3,339
    Question.... why would all the caps be on the negative side anyways?
  • Gardenstater
    Gardenstater Posts: 1,999
    Yeah I know but clearly Polk soldered the black wire to the + (Red) terminal on the Peerless. He needs to trace those wires on the tweet back to the XO and make sure that it is correct as per the schematic. That way he will determine if anything is amiss.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • Harv2002
    Harv2002 Posts: 56
    edited October 2020
    8co2znf39h7o.jpeg

    Here you can see the white wire coming from the high out and the black coming from the high ground.

    John
  • Gardenstater
    Gardenstater Posts: 1,999
    "Look at the schematic it plainly shows what I'm referring to.
    Black wire goes to negative on the tweeter and white to positive."

    Actually the schematic doesn't designate wire colors after the XO, only between the connector and the XO. So what I am saying could very well be true, specifically that effectively a white wire from the connector could effectively be connected to a black wire between the XO and the tweet.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • I think I understand.

    John
  • VSAT88
    VSAT88 Posts: 1,035
    edited October 2020
    Hook them both up the same way on each side and listen. Try it the other way around. What way did you like em best ? That is the way they should be my man !! If you can tell the difference I will send you a dollar. Just joking.
    Where in Alabama ?
  • CH46E
    CH46E Posts: 3,339
    Nice man. You are going to like them a lot.
  • VSAT88
    VSAT88 Posts: 1,035
    Nice, very nice.
    Where in Alabama ?
  • xschop
    xschop Posts: 2,020
    Nice, like someone said, ANYTHING film is better than old factory heat sinks. Are the Clarity SA's worth a try on the tweeter circuit? Or just get the CSA's that a lot of members are using?
  • We'll find out eventually. I have to go to work next week or so. I’ll tackle it when I get back. Need to order some of that low temp solder and some solder braid. Maybe some flux. While I’m at it maybe some new binding posts.
  • CH46E
    CH46E Posts: 3,339
    They look oddly familiar :);)
  • VSAT88 wrote: »
    I always thought having that crossover on the outside, on the very top of those speakers was just about bad @ss as all get out.

    Me too but wait! There’s more inside!

    John