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  • Re: SDA-SRS 3.1TL - Need Assistance with Feedback Problem

    Everyone I've discussed this with at Emotiva, including this tech, asks somebody else whether this amp is common ground and consistently have the same answer, but if they're asking the same person, or getting information from the same source, then that explains why.
    Its the definition of common ground that's confusing things. Emo's tech is defining it as the negative binding posts of each channel being at ground potential,and he is correct. However the channels grounds are isolated from each other with a small amount of resistance. Polk defines common ground as having no resistance(other than that of the wire) between the negative binding posts to avoid the kind of issue you are experiencing. Others with similarly configured amplifiers have reported having similar issues to yours that were fixed by simple strapping.

  • Re: SDA-SRS 3.1TL - Need Assistance with Feedback Problem

    The Emo tech gave you great advice and the correct procedure to track down and eliminate ground loop issues. However I believe earlier you measured 14 ohms across the two negative binding posts with the ground lift switches in the ground position. If so the amp is not truly common ground. That small amount of resistance is likely to cause issue. The simple fix is strapping the negative outputs together. Since the amp is not a bridged/ balanced output design you can safely do so.
  • Re: Bi Amp? what is it and how explained?

    mikeyb128 wrote: »
    Bridging an amp will also increases distortion.
    Like any balanced/differential circuit it depends on the amplifier and how well matched it's two channels are.Some of the very best sounding (and measuring)amplifiers in existance use bridged output stages.(Pass Labs,Bryston) In fact the Bryston 7B is basically a 4B internally hard wired into bridge mode. The power supply voltage rails have also been lowered to reduce thermal issues.
    For curiosity due you have the spec sheets for the Bryston pieces in your sig. It should have actual numbers measured for distortion and noise in bridged and individual modes.
  • Re: Common ground amps

    analogluvr wrote: »
    So 3BSST is out? It is a dual mono design. Does that always precluded it from having a common ground? If it is dual mono does that mean you cannot strap the negatives?
    The 3SST is common ground already connected internally.

    Its the configuration of the amplifiers output stage that determines if it can have its negative terminals strapped together.Amplifiers that have bridged/ balanced output stages cannot be strapped because their negative terminals are not at ground potenial,they are active like the positive side,just opposite in phase. By connecting the negative terminals together you would be creating a direct short between two "live" outputs.This ofcourse could cause damage to the amp depending upon how forgiving it is of having its outputs shorted.

    Amplifiers, be they dual mono or otherwise that have their negative terminals at ground potential can have their negative terminals strapped together without risking damage. Many of these type have small value resistors that isolate the grounds of each channel from the other and safety ground.(So not quite common ground).Strapping the negative binding posts bypasses the resistors making the amp common ground.There will still be a connection to chassis safety ground.
  • Re: Which capacitor brands, and why...???

    lightman1 wrote: »

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