Polk SDA 2 A and Fosi amplifiers

modplod
modplod Posts: 10
in Vintage Speakers
I recently acquired a pair of S D A 2 A speakers. Really like the sound especially after getting an interconnect cable. At the moment I am using a Yamaha R-N500 to power the speakers but it does run out of steam. I was looking at a Fosi ZA3 or V3 as a replacement but cannot confirm if it is a “common ground” amplifier which is supposedly a deal breaker for the SDA. Does anyone know about this or can confirm a cheap power amp, under , $150 that would power the SDAs properly.

Thank you in advance
B&K ST 2020 power amp
Onkyo P3300 pre amp
MCS 6500 turntable
Magnavox CDP 500 CD Player
Polk SDA 2 speakers
Pioneer RT707 Reel to reel
Wiim Ultra streamer
· Share on FacebookShare on Twitter

Comments

  • xschop
    xschop Posts: 5,044
    edited November 12
    You have to build a Dreadnaught to be able to use TPA-3251/55 based amps with SDA's. BTDT
    Don't take experimental gene therapies from known eugenicists.
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 26,915
    The SDA 2a starts at 4 ohm and drops to the low 3 ohm area as well. That is why the receiver ran out of gas, those speakers will suck it dry faster than it can make power. Most receivers will struggle with a 3 ohm load.
    · Share on FacebookShare on Twitter
  • xschop
    xschop Posts: 5,044
    The V3 will handle the low ohm load, no problem.
    Don't take experimental gene therapies from known eugenicists.
    · Share on FacebookShare on Twitter
  • modplod
    modplod Posts: 10
    But is the V3 a common ground amp. Dont want to damage the speakers. Was also thinking about an older power amp like maybe an NAD. I do have a sonance 275 x3 but was told it is not a common ground amp
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • modplod
    modplod Posts: 10
    Pardon my ignorance but what is a dreadnaugt?
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 26,915
    Dreadnought is a audio grade torrid that allows you to use non-common ground amps, YOU cannot use it on 99% Blade/blade Polks and you cannot use it on the SDA2 a

    https://forum.polkaudio.com/search?domain=all_content&query=dreadnought&scope=site&source=community
    · Share on FacebookShare on Twitter
  • invalid
    invalid Posts: 1,438
    edited November 12
    I owned a pair of sda2a speakers since 1987 and they need a lot of current to shine. I blew up 3 different receivers with the sda2a, the fosi might drive them but it's not a good match for them. Save up some coin and get a used parasound. They love current, the best I've had them sound is with my Krell ksa 300s amplifier.
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 51,655
    can confirm a cheap power amp, under , $150 that would power the SDAs properly.
    That's a big Hell No!
    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

    · Share on FacebookShare on Twitter
  • xschop
    xschop Posts: 5,044
    edited November 12
    pitdogg2 wrote: »
    Dreadnought is a audio grade torrid that allows you to use non-common ground amps, YOU cannot use it on 99% Blade/blade Polks and you cannot use it on the SDA2 a

    https://forum.polkaudio.com/search?domain=all_content&query=dreadnought&scope=site&source=community

    Thanks for adding the blade/blade issue with isolation transformer.
    The OP could ohm out the neg- terminals on the V3 and find out quick if it is common ground. The Aiyimas and the 3E Audios are not CG.

    There's always the venerable smoke test lol...
    Don't take experimental gene therapies from known eugenicists.
    · Share on FacebookShare on Twitter
  • modplod
    modplod Posts: 10
    The SDA speakers I have do not have the blade/blade plug for the interconnect. The have
    blade/pin
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 26,915
    That sounds like SDA 2b. They are a much easier load on gear. 6 ohm IIRC
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 51,655
    There's always the venerable smoke test lol...
    🤣🤣🤣
    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

    · Share on FacebookShare on Twitter
  • odcics2
    odcics2 Posts: 371
    invalid wrote: »
    I owned a pair of sda2a speakers since 1987 and they need a lot of current to shine. I blew up 3 different receivers with the sda2a, the fosi might drive them but it's not a good match for them. Save up some coin and get a used parasound. They love current, the best I've had them sound is with my Krell ksa 300s amplifier.

    Parasound Halo A23+ at a minimum.
    · Share on FacebookShare on Twitter
  • modplod
    modplod Posts: 10
    tb7q7976n3dy.jpeg


    My speakers look like this and as I said they have the blade/pin plug for the interconnect
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 26,915
    SDA 2b all day.
    · Share on FacebookShare on Twitter
  • modplod
    modplod Posts: 10
    Is there a difference in amp requirements?
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 26,915
    modplod wrote: »
    Is there a difference in amp requirements?

    One thing about Polk Speakers is they love lots of current. The 2b will not be as demanding as the 2a. they can also use the dreadnought with non-common ground amps.
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,718
    Were these previously owned by MP?

    2B or not 2B but Matt's is the question.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
  • modplod
    modplod Posts: 10
    I don’t know who MP is but I am in N California and picked them up for $100
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • modplod
    modplod Posts: 10
    Is it possible to buy a dreadnought and how much would one cost. I have getting more online but have not been successful
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 26,915
    modplod wrote: »
    Is it possible to buy a dreadnought and how much would one cost. I have getting more online but have not been successful

    @VR3

    Most of us built our own. Maybe @VR3 can help you, I'll let him chime in.
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 51,655
    modplod wrote: »
    I don’t know who MP is but I am in N California and picked them up for $100

    MP is Matt Polk. His post was humor.
    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

    · Share on FacebookShare on Twitter
  • modplod
    modplod Posts: 10
    Ooops. Sorry
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • audioluvr
    audioluvr Posts: 5,861
    Do they say "SDA 2 A on the back of one? I wonder if those are my old ones.
    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
  • modplod
    modplod Posts: 10
    2oznspmrhy69.jpg


    I had a closer look at the label on the rear of the left speaker

    I also got hold got hold of a B&K ST2020 power amp and this is like night and day compared to the Yamaha I was using to power the Polks. The Yamaha would be running out of steam at higher volumes and the B&K is barely at a 1/3 volume.
    B&K ST 2020 power amp
    Onkyo P3300 pre amp
    MCS 6500 turntable
    Magnavox CDP 500 CD Player
    Polk SDA 2 speakers
    Pioneer RT707 Reel to reel
    Wiim Ultra streamer
    · Share on FacebookShare on Twitter
  • audioluvr
    audioluvr Posts: 5,861
    My old ones had that SDA 2 but then a square sticker with red background and a white A. But later found out they were actually B's
    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