Soundstream Continuum Modifications

Bias mods to a Continuum, absolutely necessary if the bias is to be set into Class A. The sensor now measures the output device temperature, not the heatsink, and therefore responds around 200 x faster to changes. Without this mod the outputs overheat.


Pile of switches from two 705′s and a Continuum. These were very low quality and I change them as a matter of course as they will fail at some point, it’s just a matter of when. Shafts get replaced with metal parts that fit properly.


Crappy OE switch on the left, quality branded part on the right. Price differential is around 8 times which is probably why SS went for the el cheapo option.



Main board now has new switches, uprated rail caps, upgraded preamp chips, bias adjusters, new control shafts, gain mods so it can be used with horns. More to follow next week.


The casing has a sheet of Polyamide / kapton to insulate the power devices but let the heat into the heatsink. When we increase the bias on the front channels we need a thermally better interface, so the Kapton sheet is removed where the 4 channel outputs go.


Board is now ready to fit into the chassis. Special Boron Nitride filled insulators are fitted to the 4ch outputs, and thermal compound to all the other parts.


Channels 3&4 set up for the horns. Sensitivity has been dropped so they don’t play too loud, and distortion is very low. With horns being so efficient 1 watt will be very loud, typically 105dB.




Distortion residual is clean.


As promised, this is a standard Continuum straight out of the box, just as it arrived. Distortion is ball park for a SS reference seriesĀ amp. Compare with the modified result though reduced by approx 92%


This shows the jagged distortion residual caused by underbiased outputs in the stock amp. The output stage biasing modifications detailed above all need to be done so this can be virtually eliminated. Picture taken at the same settings as above.


5 thoughts on “Soundstream Continuum Modifications

  1. Hello The Amp Doctor.
    Great work with Continuum.Can you explain a little bit more what did you change? Wich preamps,caps,bias adjusters and about Class A.
    Thank you,

    • Hi Viktor,
      Main upgrades:

      We upgraded the main rail caps from 1000uF to 3300uF

      Fitted bias adjusters to all channels and set with distortion analyser so crossover distortion was eliminated. We also pushed bias higher on the mid and tweeter channels so they ran in class A at low power.

      Preamp chips were upgraded to newer types, TL074 are OK for entry level amps but not really good enough for an amp of this quality.

  2. Hello again.

    Thanks for information.
    What is the name of preamps? Is it secret ?
    OPA4134 ? OPA2604 ?

  3. Hey Sarah.
    I have a S 705 amps,
    Are this amp same built as Continiuum?
    How much cost this upgrade ?

    Br //


    • Hi TJ

      I have passed your question on to one of our team and asked that they email you with a response. Sorry for the delay.

      Amp Dcotor