Loud Hiss using Monitor Out to Poweramp/Cab

  • Anybody else getting a loud high pitched hiss on some high gain patches. I'm using monitor out cabs off to either a matrix gt800fx or Mesa 2:100 and it happens on both. Tried all combinations of ground/lift switches, nothing is clipping, no common effects(happens with all effects off or on). Tried system reset, didn't help. Turned noise gate on/off, up/down, no difference. Firmware 1.6 but this happened on previous firmware as well. Tried different pickup combos. Different cables didn't help.
    *edit* This happens on all outputs when using a power amp/cab. When using the master out and other outputs, this only happened when I disengaged the cabs.


    Any help is GREATLY appreciated!

  • Hello all! First post here.
    I have the exact same problem. A high frequency noise on high gain profiles when using a power amp and a 412 cab.
    I have the Kemper rack without the power amp. I usually use a 6505 with double 412 cabs ( we rehearse pretty loud ...) but, now I decided to sell the 6505 head and one of the cabs and give the Kemper a try. So, I have a ISP stealth power amp and a 412 Peavey cab with Jensen speakers, disabling the cab in monitor output and get this high frequency hiss on the high gain profiles. Why? I'm on the latest firmware (2.5.0).
    I tried to go FRFR with a EV ZLX112 but none of us could hear it so that one ships back on Monday. I will try a DXR15 instead. But that's another topic!

    Edited once, last by Danne69 ().

  • I would try to work with the ZLX a bit more to see if what you're lacking is eq or presence related and not just power. Remember this is FOH sound not a 412 stage sound, it is a bit different but if you can adjust to it the benefits are huge, you hear what you're audience hears. If it's more bottom end you need that's easily fixed, at 1000 watts hearing the ZLX shouldn't be a problem. I have 2 ZLX's and it's rare I use both live and my band is loud as hell. I can't speak about the DXR15 but I tried a few 15" setups and the crossover point was not ideal for guitar at all and it annoyed the heck out of me.

  • Check to see if you have a lot of Clarity in the Stack section, you can turn that down to bring the gain to the forefront and then use less actual Gain to achieve the same sound, this might quiet things if the problem is Gain related. Worked for me with my Mesa profiles when I switch to single coils.

  • Anybody else getting a loud high pitched hiss on some high gain patches. I'm using monitor out cabs off to either a matrix gt800fx or Mesa 2:100 and it happens on both. Tried all combinations of ground/lift switches, nothing is clipping, no common effects(happens with all effects off or on). Tried system reset, didn't help. Turned noise gate on/off, up/down, no difference. Firmware 1.6 but this happened on previous firmware as well. Tried different pickup combos. Different cables didn't help.
    *edit* This happens on all outputs when using a power amp/cab. When using the master out and other outputs, this only happened when I disengaged the cabs.


    Any help is GREATLY appreciated!


    I, at least, have run into some profiles where that high frequency content is on account of strange profiling. It's not on account of your device, in this case, the profiles themselves are "defective".

  • I, at least, have run into some profiles where that high frequency content is on account of strange profiling. It's not on account of your device, in this case, the profiles themselves are "defective".


    Yes. that seems to be the problem! I came back from our rehearsal studio just now and tried different profiles and a few of them had this artifact.

  • The problem with the ZLX is that we can't hear it when we rehearse. It will probably work just fine as a wedge on stage for me to hear myself, but will not work for us when we rehearse.
    The reason that i want to go FRFR is that I want to hear what the audience hear. My sound that i have with my stack is awesome, but that's only in the rehearsal studio so the only one to benefit from it is me and my bandmates. I tried to explain that to them when they said: "But, but you have a great sound with your gear!" "Yes." I said, "But we are the only ones hearing it."


    I want some low end to my sound and i think the DXR15 will do the trick.


    BTW, thanks for all the replies! This is a great and a very helpful forum.

  • I would try to work with the ZLX a bit more to see if what you're lacking is eq or presence related and not just power. Remember this is FOH sound not a 412 stage sound, it is a bit different but if you can adjust to it the benefits are huge, you hear what you're audience hears. If it's more bottom end you need that's easily fixed, at 1000 watts hearing the ZLX shouldn't be a problem. I have 2 ZLX's and it's rare I use both live and my band is loud as hell. I can't speak about the DXR15 but I tried a few 15" setups and the crossover point was not ideal for guitar at all and it annoyed the heck out of me.


    + 1 to what Booyah said. I cannot imagine the ZLX112P being not loud enough. There must be something else going wrong here.
    As for the DXR15, it has been checked against the 10 and the 12 by several users and the overall estimation is that the 10 is the leader of the gang.

  • + 1 to what Booyah said. I cannot imagine the ZLX112P being not loud enough. There must be something else going wrong here.
    As for the DXR15, it has been checked against the 10 and the 12 by several users and the overall estimation is that the 10 is the leader of the gang.


    As I said, the ZLX112P would probably work perfect on stage but we are much louder in rehearsal. I don't know why? Loud drummer perhaps. The sound guys always goes: "Turn down your amps!" when we're soundchecking... I once let a sound guy hear our rehearsal volume and he gets that strange look on his face... ;( Haha.


    We are all using earplugs btw.


    Regarding DXR10, 12 and 15 i've read some great things about them here on the forum. One that said: DXR10 is the winner, but if you like some flapping pants bottom end, go for the DXR15.


    We have been doing this for over 20 years now and I think it take some time to get used to FRFR, and that the other guitarist, using his Randall V2 with Mesa oversized cab maybe should turn down a little or go FRFR as well?

  • The ZLX has a sub option in it's menu's, I don't use it for my guitar but have it on when my other one is used as a vocal monitor. You can set the sub a 80hz 100hz and 120hz, no clue what the 4th option is lol.