Powerhead cutting out at high volume?

  • At rehearsal last night my Powerhead was cutting out intermittently at high volume. I was running it with the master at -7db to -9db with power amp boost on 12db into an 8 ohm Marshall 4x12 and then tried it through an oversized mesa rectifier 4x12 with power amp boost on 7 and still it would cut out for a couple seconds on the higher db transients. I was also pushing the front end with a boost pedal and there was some intermittent orange on the input light, but no noticeable input clipping. Does this happen to anyone else? Is there something wrong with it? In the past I've run the Kemper with the master at -3db and power boost on 12db for hours with no problems, but the rig I was using last night had a lot more bass percussiveness and low mids which I know takes more power for an amp. I was really digging the sounds, liked it better than my 100w plexi, and was excited to use it live, but until I get this figured out I'l need to use the Marshall.

  • Something si wrong. I have a Powerhead (taster) run it thru a Recto 4x2 (oversize)..Crushing. Othe rguitar player uses a 50 w Marshall..no prob keeping up or being too loud. Get a service ticket and get the power section fixed. (ALso try master reset to make sure something weird didn't happen,.)

  • Check the speaker cable.

    Check if the power amp is overheating. Sufficient air circulation?

    Check if the cabs really have 8 Ohm. The power amp has a power limiter at 600 Watt, which could theoretically exceeded at 4 Ohm.

    Master Volume itself has no dB scale. Relevant is the level of the MONITOR OUTPUT also feeding the internal power amp. MONITOR OUTPUT could be linked to Master Volume or not.

    Given your information you seem to run everything at full throttle. I'm wondering if you are perhaps exceeding the 600 Watt even at 8 Ohm.

  • Thanks for your input. I think I know what happened. I blew two of the speakers and I think the speakers were shorting and dropping the impedance which kicked the overload protection in. It seems to work totally fine otherwise. I upgraded the OS and did a global reset anyway. I guess the question I have now is how loud can I run the Kemper without destroying my speakers? The cab is rated for about 240 watts. What combination of main output/ monitor output and power amp boost will be safe? Would it be ok to run it at -3db with the power amp boost off without destroying my speakers?

  • steinweiner what levels of output and power amp boost are you running at?


    It was significantly louder than my Marshall 100w that I switched to when I was having problems.

    Honestly, I don't know..I just plug in and go..Only have adjusted the master volume (global on the front)...as well as eq and gain...I'm not "hip" to all of the different /additional poeramp settings..sorry

  • Thanks for your input. I think I know what happened. I blew two of the speakers and I think the speakers were shorting and dropping the impedance which kicked the overload protection in. It seems to work totally fine otherwise. I upgraded the OS and did a global reset anyway. I guess the question I have now is how loud can I run the Kemper without destroying my speakers? The cab is rated for about 240 watts. What combination of main output/ monitor output and power amp boost will be safe? Would it be ok to run it at -3db with the power amp boost off without destroying my speakers?

    Sorry to read that! I guess, you found a way to run your 8 Ohm cabinet at 4 Ohm.;(


    I would say, normally, if the four chassis are ok, the cabinet should stand it. But you used it over a long period, you ran Power Amp Boost at maximum, the Input LED was orange because of your external boost pedal, your signal had more bass, your output volume was probably at - 3 dB. It appears, you ran the unit really at maximum throttle over a longer period and cooked the chassis.