Will this affect the SDA effect?

GlennDog
GlennDog Posts: 3,121
edited October 2012 in Basic Hookup/Wiring Questions
If the preamp signal is inverted and the manufacturer sez connect speakers out-of-phase, will this cause SDA issues?

Thanks as always,

G
AC Regenerator PS Audio PerfectWave Power Plant 10
Source Lumin U1 Mini into Lampizator Baltic 4 DAC
Pre Cary SLP-05
Power Rogue M180 Dark monos
Mains Salk HT2-TL
Rythmik F12
Post edited by GlennDog on
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Comments

  • ambiophonics
    ambiophonics Posts: 726
    edited September 2012
    Yes - you cannot connect your SDA speakers out of phase as requested by your preamp because that would short one side of your the poweramp to ground when the IC is used. I've never heard of a preamp inverting the signal at its output... are you sure it isn't the poweramp that is doing the inverting - common with many carver amps.
    2 Channel - Polk SDA-2BTL, Carver TFM-35, Peachtree iDAC, Qobuz streamed via Episode Lynk using bubble UPnP server
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  • GlennDog
    GlennDog Posts: 3,121
    edited September 2012
    ambiophonics wrote: »
    I've never heard of a preamp inverting the signal at its output... are you sure it isn't the poweramp that is doing the inverting - common with many carver amps.

    Positive, just read in the manual. Is there a way around this issue?

    If you are correct, sir. I may have an excuse to go speaker shopping! . . . There may be some Polks on the market soon.

    G

    ps Thanks for the quick reply!
    AC Regenerator PS Audio PerfectWave Power Plant 10
    Source Lumin U1 Mini into Lampizator Baltic 4 DAC
    Pre Cary SLP-05
    Power Rogue M180 Dark monos
    Mains Salk HT2-TL
    Rythmik F12
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  • nspindel
    nspindel Posts: 5,343
    edited September 2012
    What about inverting the poles of the interconnects between the pre and the power amp?
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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  • pitdogg2
    pitdogg2 Posts: 25,575
    edited September 2012
    ambiophonics wrote: »
    Yes - you cannot connect your SDA speakers out of phase as requested by your preamp because that would short one side of your the poweramp to ground when the IC is used. I've never heard of a preamp inverting the signal at its output... are you sure it isn't the poweramp that is doing the inverting - common with many carver amps.


    WHOA hold on here....
    I'd like to know which Carvers you are talking about? I know the 500 and 500t are NOT common ground but as far as inverting....none i know of.

    I think you jumping to quickly here on this inverted thing. I remember a member selling some gear that did the same pretty sure i was told it would be no problem with SDA's as he used them with his SDA's.

    F1, Mark, Brock care to chime in? or a quick call to Kim or Mark(Doro) at customer service will settle it quickly
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  • ambiophonics
    ambiophonics Posts: 726
    edited September 2012
    http://www.polkaudio.com/forums/archive/index.php/t-121454.html

    similar issue
    2 Channel - Polk SDA-2BTL, Carver TFM-35, Peachtree iDAC, Qobuz streamed via Episode Lynk using bubble UPnP server
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  • pitdogg2
    pitdogg2 Posts: 25,575
    edited September 2012
    ambiophonics wrote: »
    http://www.polkaudio.com/forums/archive/index.php/t-121454.html

    similar issue

    yep forgot about the coffee can amp...
    Glenndog needs to give us the amp so we can give a good answer that would help.

    I remember an amp that inverted and was told to just switch at the speaker and all would be good.
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  • ambiophonics
    ambiophonics Posts: 726
    edited September 2012
    Yea - inverting the speaker connection would work, just not with SDA's. Maybe the OP needs to couple his inverting preamp with an inverting carver cube!
    2 Channel - Polk SDA-2BTL, Carver TFM-35, Peachtree iDAC, Qobuz streamed via Episode Lynk using bubble UPnP server
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  • GlennDog
    GlennDog Posts: 3,121
    edited September 2012
    I think I need to clarify . . . It's my preamp that's inverting the signal

    The thread got derailed at #2

    G
    AC Regenerator PS Audio PerfectWave Power Plant 10
    Source Lumin U1 Mini into Lampizator Baltic 4 DAC
    Pre Cary SLP-05
    Power Rogue M180 Dark monos
    Mains Salk HT2-TL
    Rythmik F12
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  • ambiophonics
    ambiophonics Posts: 726
    edited September 2012
    It doesn't really matter where the inversion is happening - be it in the preamp section, power amp, or even the source. The end result is an inverted signal at one speaker, which can usually be remedied by reversing the wiring of one speaker. Unfortunately that is not possible with most SDA's when the IC is being used as that would short one side of the power amp to ground. I don't know much about the AI? interface but perhaps that provides the isolation needed to accomplish this?
    2 Channel - Polk SDA-2BTL, Carver TFM-35, Peachtree iDAC, Qobuz streamed via Episode Lynk using bubble UPnP server
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  • ambiophonics
    ambiophonics Posts: 726
    edited September 2012
    What about inverting the poles of the interconnects between the pre and the power amp?
    Most pre-amps, poweramps, and sources use a shared ground for the Left and Right inputs/outputs. If you tried to invert one side you would end up shorting it to ground.
    2 Channel - Polk SDA-2BTL, Carver TFM-35, Peachtree iDAC, Qobuz streamed via Episode Lynk using bubble UPnP server
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  • ambiophonics
    ambiophonics Posts: 726
    edited September 2012
    I feel like an idiot now - for some reason I was thinking the OP meant one channel only was being inverted. I'll let someone else chime in about absolute phase and how to safely connect the SDA's in the situation. Sorry GlennDog!
    2 Channel - Polk SDA-2BTL, Carver TFM-35, Peachtree iDAC, Qobuz streamed via Episode Lynk using bubble UPnP server
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  • gimpod
    gimpod Posts: 1,793
    edited September 2012
    GlennDog, This should clear up the inverted signal issue & SDA's for you.

    From the SDA Quick Troubleshooting Guide and I quote:

    "With some amplifiers, the common inter-channel connection is made through the positive terminals, rather than the negative terminals. In this case, the speakers behave as though both units were connected in reverse phase, and the dimensional drivers will not work; this can be corrected by wiring BOTH units in reverse phase."

    Note: "units" in the above quote refers to the speakers.

    So when you hook them up like your suppose to (red to red, black to black) and the dimensional drivers don't work along with a lack of bass, just reverse the wires on BOTH speakers (red to black, black to red) and you should be good to go. Now on the other hand if the dimensional drivers work and the bass is good when hooked up like your suppose to (red to red, black to black) you should be good to go.

    Hope this helps.
    “The two most important days in your life are the day you are born and the day you find out why.” ~ Mark Twain
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  • GlennDog
    GlennDog Posts: 3,121
    edited September 2012
    bump
    AC Regenerator PS Audio PerfectWave Power Plant 10
    Source Lumin U1 Mini into Lampizator Baltic 4 DAC
    Pre Cary SLP-05
    Power Rogue M180 Dark monos
    Mains Salk HT2-TL
    Rythmik F12
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  • drgalexo
    drgalexo Posts: 159
    edited October 2012
    Did you ever resolve the out of phase issue?
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  • GlennDog
    GlennDog Posts: 3,121
    edited October 2012
    Yes (pretty sure), it appears that there is no issue at all . . . I spoke to Kim at Polk HQ, who was very knowledgeable and sounded very confident in his recommendations . . . .

    He said he had a so&so amp (dont remember make/model) very similar and that I should just connect it as is. . . . just connect it without changing the speaker polarity . . . I cannot technically explain the reasons why. I do recall him saying "do not, under any circumstances, invert the wiring at the SDAs" or something to that affect,

    sorry for being so vague

    But I have always wondered, why the inverted polarity option on the Adcom GCD 600/GCD 700?

    G
    AC Regenerator PS Audio PerfectWave Power Plant 10
    Source Lumin U1 Mini into Lampizator Baltic 4 DAC
    Pre Cary SLP-05
    Power Rogue M180 Dark monos
    Mains Salk HT2-TL
    Rythmik F12
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  • drgalexo
    drgalexo Posts: 159
    edited October 2012
    I blew three drivers because I used non common ground amps with the interconnect cable. It was ear shattering the sound that came out. Not related to the volume at all. I know you connect the negatives together on your amps. I think these SDA SRS 2's are particularly difficult with mono blocks.
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