Power Rack volume levels

    Hi guys,


    New Kemper owner here just trying to suss everything out. I'm sure many of you are running exactly the same setup as I am planning and was wondering if you could help me out?


    Could somebody with a power rack, a 16 ohm guitar cab and a generous spirit let me know roughly what db output you get from your cab on the Gundy Nile Rodgers profile?


    Mine maxes out at around 100-102 db which seems a bit on the low side for a "300w" power amp. I've unlinked the main output and set that at -18db which seems to be the general advice on here and left the monitor output linked to control it from the front. Cab is a 100w eminence 1x12 and guitar is a Kotzen telecaster. Can you think of anything i've likely missed or is that about right?


    Thanks everyone!


    David

    Have you tried the power amp boost? I've got a Powerhead into a 16ohm cab. I definitely have to run it louder than in my old 4ohm 2x12 but don't have any trouble in a band. The only issue is the psychological 'it's almost at full volume' thoughts!

    Not tried the power amp boost yet, I just thought it sounded a bit lower than I expected from a power amp of that rating. It doesn't seem to add up, as the speaker is rated at 100w RMS, running a 300w power amp at the max should be well into "blowing the speaker" territory and it's not even close (having said that, I haven't run the power amp boost yet. This could well be the key)


    If anyone fancies downloading a db meter app to their phone and giving me an idea of what volumes others are kicking out then that'd be aces!


    Or even what settings you hit around 100db if you aren't in a position to really crank it ;)

    I've owned 100 watt Marshalls and understand where you're coming from. Part of the issue is comparing 100 watts of valve power which compresses and distorts the transient peaks pleasantly, at quite reasonable levels. In comparison, a 300 watt D-Class amp doesn't and the headroom required is much greater to stop the amp compromising tone. I was initially disappointed only to stop caring once I realised that it was loud enough for every scenario I require it to; I've never run out of volume in my band but I have gotten used to running it at a few dbs from flat out (without boost) which isn't something I've ever done with valve amps. Also, most valve amps I've owned show most volume up to 50% on the master, the final 50% does comparatively little; again, unlike with the Kemper.


    It's much like with a bass amp. Ever wondered why the bass player needs 800 watts and 4x10s to keep pace with a 100 watt guitar amp?


    Have you tried increasing the volume in the stack section? Maybe the profile is already a little conservative.


    As for chucking a db meter in front of it, I can't crank it at home and next band practice is in a few weeks....

    Edited once, last by chu ().

    Like 1

    Excellent,
    it sounds like I'm just being a little conservative about running it at the levels it needs.


    I'd still like to have a comparison if anybody could help me out though :)

    Without using "power amp boost" I can't imagine that your rig will sound loud enough for live performance.
    With a 8ohm cab I turned Power Boost up to + 6db with a single Celestion v30 , on the stage I compared loudness with a ENGL sovereign 100w valve-amp with the same speaker.

    Yep, the Boost is not something that will give you more power than what the power section is designed for... IOW, you can only get the power amp's maximum output by engaging it.


    Also, as Ingolf said, if your loudspeaker's sensitivity is low you'll get lower SPL Vs. a more sensitive one.

    Yes I've experienced the same thing Chu.


    Running into a 2X12 at 16 ohm loaded with Celestion G12-75T I have had to turn up full on the monitor out at some gigs to try and match the other guitarists 100 watt Engl Powerball 2 running into a Marshall 1960AV 4X12 running Celestion V30's.


    Straight away I'm competing again 3 things:

    • Other guitar player has correctly matched impedance 16ohm into 16 ohm (I'm running 8 ohm into 16 reducing the Kemper to 300 watt)
    • V30 are a more efficient speaker than the G12-75T's I'm running. The 3db difference which is very noticeable in its own
    • His 4 speakers vs my 2


    Power amp boost is usually set to stock +6db, however sometimes I have to turn this up. This is enough to match is levels, so I wouldn't worry, it is just sometimes the psychological factor that you are running a "600 watt" amp and you have to use it up full sometimes to match overly loud guitar players haha.

    Ok, by now im sure you have hopefully solved the issue but in your clean sense can raise the volume of your clean sound and disortion sense changes the parameters on how it disorts that globally through all profiles. Hope this helps. Rock on!!

    That must be blistering on stage!!! 😲