Bias amp 600w Hiss issue



  • Hello everyone,

    I am facing hiss issue with my bias amp 600W. When I turn on the amp without having my guitar connected there is already a hiss coming out which is not that loud but is still present no matter what.

    After trying several solutions suggested in other topics and from positive grid's support team. I have come to the conclusion that this might be typical amp noise and maybe with a really good noise gate pedal this can be resolved.

    I am thinking of buying ISP Decimator II G string pedal but before I do I wanted to ask if anyone had already tried that out and if it made any difference. I would appreciate the information :)

    Last, here is something I tried and that made me realise that the noise gate of the amp not only works but works big time even though it doesn't eliminate the noise of the amp.

    So try the following:

    1)Connect the head/rack through USB and open the app

    2)With Noise Gate on the app turned on, put all knobs besides the Output knob at 10, Tube stages 5 with full distortion, Power Amp to the Max and Custom to the Max as well and with the clean channel selected. Remember, OUTPUT knob is in zero/off position and N.G. on the app is ON.

    3)Turn on the output knob at any level. You hear the same little noise.

    4)Now, turn DOWN the OUTPUT knob and turn OFF the NOISE GATE on the app.

    5)SLOWLY! turn on the output knob. You will see that you won't be able to turn it more than level 2 because the amount of noise that will be coming out will be immerse.

    With the above being said I am curious in hearing the opinion from people who don't hear any noise at all and from people who have the same issue. Maybe all of us have the same noise and some are being simply bothered whereas others might don't even care :)
    And I am also curious in hearing how the Decimator II works if anyone tried that already!

    Thank you all for in advance . Keep healthy and safe during these crazy corona days we are going through.

    Cheers!!



  • @george-efstathiou-87 Eventually I tried the Boss NS 2 from a friend of mine. The hiss is still going on and nothing changes. This is just weird so I contacted the distributor this morning and I arranged to send it back so they can check it out/repair it. It is just a pity to be so happy with how the unit sounds but having such weird hiss.. I'll keep you guys posted.
    Meanwhile, if anyone managed to solve the issue any other way you are welcome to comment.

    P.S. Here you can find the links with the hiss noise in video. Also I made a video that shows there is a high frequency every time you turn a knob on the amp. That ain't areal issue though but I wonder if it is somehow related to the hiss.

    https://drive.google.com/file/d/1nFimdhvK21RfLM0pI0G0iIfAAlI9ucg8/view?usp=sharing

    https://drive.google.com/file/d/1nL14xHthHwPn5Z7Odig-Jb8KukZpf6xr/view?usp=sharing