AMP Heat issue with sda srs? Anyone?

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  • inspiredsports
    inspiredsports Posts: 5,501
    edited April 2011
    Now the test would be to do some extended critical with and then without the interconnect in place.

    If you still can not detect an audible difference, I would suspect parts of the SDA circuitry and/or some/all of the dimensional drivers didn't survive the non-common ground onslaught.
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  • Hawkeye
    Hawkeye Posts: 1,313
    edited April 2011
    I'm a SDA newb so take what I say with a grain of salt:biggrin: Are you using the standard interconnect or A1-A (1) as an interface?

    I had to get the A1 to allow my speakers to work correctly. I didn't even try them until it was on hand.

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  • prsartist3
    prsartist3 Posts: 20
    edited April 2011
    inspiredsports wrote: »
    Now the test would be to do some extended critical with and then without the interconnect in place.

    If you still can not detect an audible difference, I would suspect parts of the SDA circuitry and/or some/all of the dimensional drivers didn't survive the non-common ground onslaught.

    Oh there is a difference with the cable in place, but
    I'm hesitant to say it sounds "better"? Different yes.

    I can definitely hear distinct stereo separation without the cable.
    With the cable it kind of smoothes out the distance L&R distinction, just not really sure if I like it better or not?

    My speakers are only about 6' apart
    And the seating position is center about 10' back.
    It's not ideal I know! But you can only work with the space you've got.
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  • F1nut
    F1nut Posts: 50,566
    edited April 2011
    With the cable it kind of smoothes out the distance L&R distinction, just not really sure if I like it better or not?

    That's what it is suppose to do. It's much closer to how you would hear sounds at a live event. Distinct left and right isn't natural.
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  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    inspiredsports wrote: »
    I would suspect parts of the SDA circuitry and/or some/all of the dimensional drivers didn't survive the non-common ground onslaught.
    The ouput stage of the amplifer would be whats most at risk.
    prsartist3 wrote: »
    Either are his old phase linear amps.
    The schem I seen of the original 400 indicates that it is.
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  • Schurkey
    Schurkey Posts: 2,102
    edited April 2011
    Instead of guessing and suspecting that the Flame Linear and/or the M500T are/aren't common ground, connect an ohmmeter to a negative terminal on each channel and measure the resistance.

    I will say from direct experience that 20 ohms of resistance between the two negative terminals will make SDA-1B speakers unlistenable; and connecting a ~$5 home-made jumper cable between the negative terminals is the best sound-quality "modification" I ever did. Of course, not all amps will tolerate a jumper cable connected across the negative terminals. I didn't have a problem with heating the amps, though. Other speakers, other amounts of resistance between the channels = potentially different results.

    I don't know what the "maximum" acceptable resistance between channels is...but 20 ohms is terrible and clearly "less is better".
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  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    Schurkey wrote: »
    I don't know what the "maximum" acceptable resistance between channels is...but 20 ohms is terrible and clearly "less is better".
    With the 20ohms the amp would not be truly common ground until the negative terminals were strapped together.It is likely that there is a 10ohm resistor connected from each of the negative terminals to power ground. This is done to provide some isolation of ground currents between the two channels.Failing to strap the negative terminals could also lead to failure of these resistors because of the higher ground currents they would encounter with the SDA connection.
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  • prsartist3
    prsartist3 Posts: 20
    edited April 2011
    FTGV wrote: »
    With the 20ohms the amp would not be truly common ground until the negative terminals were strapped together.It is likely that there is a 10ohm resistor connected from each of the negative terminals to power ground. This is done to provide some isolation of ground currents between the two channels.Failing to strap the negative terminals could also lead to failure of these resistors because of the higher ground currents they would encounter with the SDA connection.

    Wow! This is all WAY over my head!
    Thank God I have a few different amps to choose from.
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