Keep or trade SDA 1C's?

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MLampen
MLampen Posts: 8
in Speakers
Hi all,

Been reading through some of the content here and am grateful for it. I just recently picked up a pair of SDA 1C's while on a road trip for $200. I was originally thinking I'd use my Pioneer SX-1250 to drive these speakers. I was pretty excited to upgrade from my Monitor 5's but after speaking with DHS Speaker Service (discussing upgrade options) I've learned that these speakers need a preamp or power amp to drive them correctly. I'm sort of at a loss of what to do from here so thought I'd solicit some feedback from the friendly folks here.

I love my 1250 and have invested prob $1,500 over the past 2/3 years in refurbishing it including the purchase price. I want to stick with it. DHS suggested either switching to Monitor 7's or I could just use the 1C's without the interconnect but that without the interconnect, they're just regular speakers. So I'm wondering, will the 1C's still be better than the 7's without the interconnect? Or should I just try to sell the 1C's for what I can and try to find some 7's?

My goal is to put together the highest quality system I can using the 1250 I already have and that has been fully refurbished. Are there other speaker recommendations or options I should consider? I'm open to any thoughts. I would like to keep my speaker budget under or around $1,000. I do like the way Polk speakers sound. I love the 5's but just feel like they're a bit small for the 1250.

I listen to Classic Rock, Country, House, Electronic, Big Band, Jazz. Room is about 25x17. Willing to put in some effort on upgrading crossovers, etc.

Would appreciate and wisdom you folks could share.
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  • Gardenstater
    Gardenstater Posts: 4,187
    edited November 2020
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    Here are the specs from SDA Manual. They are stated to be 6 Ohm nom. Impedance and your receiver is rated for 200WPC into 4 Ohms. Rec. amplifier power is 50W - 500WPC. Efficiency 90dB. Your receiver has a damping factor rating of 30.

    nlnejup9bcey.png

    This requires a common ground amplifier or receiver, but since virtually all receivers are common ground you should be OK. From the manual https://polksda.com/pdfs/SDA1C.pdf

    edikfcp5wa6j.png

    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
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  • gyosa
    gyosa Posts: 699
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    dunno why the 1250 wouldn't work.
    give it a try .

    way back in 1988 or so when I got my 1C's I used a Yamaha R9 receiver (125w 8 ohms) with them for about a year until I got a B&K ex-442 amp (200w 8ohms) - worked fine !

    bk
    Dayens Ampino , Yamaha wxc-50 , Polk SDA 1c’s ( my first love .. ) , Kimber Kable 4TC, Sony 42” - BEDROOM

    B&K EX-442 ( it will go in my casket when I die ... ) , PS Audio 4.6 preamp ( old school , but it still jams on ... ) , Eversolo DMP-A6 , Boston Acoustic voyager 7’s - POOL

    Parasound A21, Eversolo DMP-A8 , Yamaha wxc-50 , Kimber Kable 4vs , Salk Supercharged Song towers ( difficult choice between these and my family if I had to choose ... 😩 ) , Sony XBR-A8F 65” OLED - DEN , MAIN RIG

    PS Audio S300 - sitting in the closet for now …

    Onkyo TX-nr609 , Polk atrium 7 , Boston acoustic sound ware (4) , Boston acoustic sub , B&W center , Sharp 65” TV - PATIO
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  • F1nut
    F1nut Posts: 49,802
    edited November 2020
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    It appears your receiver may be dual mono and may not share a common ground.
    Pioneer developed the now legendary power section of the SX-1250 with completely independent power supplies, including separate power supply windings, rectifiers and smoothing capacitors for each channel

    You can test this by checking the resistance between the negative outputs of the left and right channels. Do this with it unplugged.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • Gardenstater
    Gardenstater Posts: 4,187
    edited November 2020
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    Definitely good to check. Schematic shows a common ground.

    https://www.hifiengine.com/manual_library/pioneer/sx-1250.shtml

    vefb5e806tda.png

    There is a review of your speakers ($200 wow!) on p. 41. You will have to go over them and people here will help you with that (Post some pics!), but you probably have struck gold:

    https://worldradiohistory.com/Archive-All-Audio/Archive-HiFI-Stereo/80s/HiFi-Stereo-Review-1987-11.pdf
    Post edited by Gardenstater on
    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
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  • audioluvr
    audioluvr Posts: 5,437
    edited December 2020
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    I love my 1C's! If your vintage receiver has been refreshed properly, it should work fine. You can always upgrade to better components later in life.
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • MLampen
    MLampen Posts: 8
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    Thank you all for the feedback. I also just read the below on another post from a while back.

    "The twin/blade speakers would short out the non-common ground amplifier. The pin/blade speakers don't short the amplifier, there just isn't anything coming from the SDA components." - I have the pin/blade interconnect cable.

    Also pulling from another post: "You can touch the a probe from a VOM to each negative speaker terminal with the meter set to the lowest range, usually 200 ohms. If it's common ground the reading will be 0 or close to, like 0.5 ohms."

    I'll check this this afternoon. Unfortunately, 1C's are not very wife friendly speakers. I may need to find a new home for them. I'm in Charleston, SC if anyone is interested let me know.
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  • MLampen
    MLampen Posts: 8
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    So I took the reading and tried two different VOM settings for Ohms. The first was at 200kOmega and it read 0. The second with the VOM set on 200Omega and it read .6 and .8. So unless someone says otherwise, I'd say the receiver is common ground and it is safe to use the interconnect cable. I shouldn't have any trouble with my receiver or cause any damage and the SDA effect should function properly?

    xz03kmnquqyw.jpg
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  • Gardenstater
    Gardenstater Posts: 4,187
    edited December 2020
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    Yes. And the schematic I posted above for your receiver clearly shows that it is a common ground. If you touch the probes of your DVOM together when it is on the lowest setting of 200, what do you get?
    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
    · Share on FacebookShare on Twitter
  • MLampen
    MLampen Posts: 8
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    Thanks Gardenstater. I get .5 or .3 depending on which setting I have it on.
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  • Gardenstater
    Gardenstater Posts: 4,187
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    Should be the same reading as you got when touching the probes to the Neg binding posts on amp, but, as they say, close enough for govt work! :D
    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
    · Share on FacebookShare on Twitter
  • MLampen
    MLampen Posts: 8
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    Haha. Thanks again all.

    Now I just need to figure out how to get the wife on board with these monsters. She certainly does not like the look and size of them.
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  • Gardenstater
    Gardenstater Posts: 4,187
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    Maybe a doilie and a vase with a rose on the top of each one? :#
    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
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  • dromunds
    dromunds Posts: 9,984
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    Stuff on top of the speakers? Never! 😈
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  • F1nut
    F1nut Posts: 49,802
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    "The twin/blade speakers would short out the non-common ground amplifier. The pin/blade speakers don't short the amplifier, there just isn't anything coming from the SDA components."

    Say what!?!
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • Gardenstater
    Gardenstater Posts: 4,187
    edited December 2020
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    dromunds......it was a joke. :)

    MLampen.....perhaps you can sell them to PolkFanVA so that he can use them as his garage speakers and move the RTA12B's into his office. :D
    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
    · Share on FacebookShare on Twitter
  • dromunds
    dromunds Posts: 9,984
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    Gardenstater wrote: »
    dromunds......it was a joke. :)

    MLampen.....perhaps you can sell them to PolkFanVA so that he can use them as his garage speakers and move the RTA12B's into his office. :D
    Gardenstater wrote: »
    dromunds......it was a joke. :)

    MLampen.....perhaps you can sell them to PolkFanVA so that he can use them as his garage speakers and move the RTA12B's into his office. :D

    I realize it was a joke. That’s why the emoji. Although I must say every time I see things on top of speakers I involuntarily cringe.
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  • audioluvr
    audioluvr Posts: 5,437
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    MLampen wrote: »
    She certainly does not like the look and size of them.

    Slap her on the a$$ and tell her to get over it...
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
    · Share on FacebookShare on Twitter