reliability of the KPA for live use (reg. powersupply/fuse)

  • hey guys,


    last week i had to have my kemper repaired (blank display upon power-up, no powerat all whatsoever). got it back yesterday (yay!), and have since talked back and forth
    with the uber-friendly technician @synthesizerservice (achim lenzge) about the reason for the defect. he told me that the culprit was
    the power supply (as was to be somewhat presumed). upon asking him about the not-self-servicable fuse (which i thought must be hidden
    somewhere inside the KPA, since it's nowhere to be seen at the back or front), he replied that there is no fuse, but that the power supply itself
    has an electronical safeguard against overcharge.


    i now ask you: what do you do if something like this happens directly before or even during the gig, on site?
    that's not far fetched at all, has happened to me before, and was quickly remedied by simply replacing the fuse in question. easy enough.
    but now, if you rely solely on your KPA, chances are that one of these days, you're going to be standing in the rain with no amp to use and no possibility of a quick,
    self-servicable solution. i truly think that this is a major design-flaw, and that kemper should urgently consider to have the devices's design redone in the manner
    which i have just described.


    clarification: i still love my kemper madly, it's just that from now on, i will always enter stage with that naggin' feeling that it might break on me
    JUST right before or even in the middle of the gig, with nothing that could be done about it other than replacing it with some other kind of gear (if you're lucky enough
    to be able to borrow some on the fly or have some kind of replacement ready just in case). in short, as it is right now, the KPA is to be considered unreliable for live usage.
    sorry to have to say it, but it's the truth (in my most humblest of opinions).


    what do you guys think? discuss! :)

  • Under normal conditions, as I understand it, the aforementioned electronical safeguard leaves the unit fully functionable when you plug the power and wait for a few minutes.
    That said, I always carry a backup rig but never had the profiler fail on me once.
    I'm not nervous at all.

  • well... what's "normal" conditions? will a sudden peak in power still blast the supply and leave you with nothing in hand?
    wouldn't you, in that kind of situation, be glad that instead of the PS, the (hypothetical) FUSE would have blown,
    and that you'd be able to simply change it and carry on as usual? i sure as hell would... all that being said,
    i must admit that i know jack shit, honestly absolutely nothing when it comes to electronics, electrics and such, so this might very
    well all be some kind of uneducated drivel. everybody is more than heartily invited to educate me on the matter
    and set the record straight, or explain to me why the existing solution is better than "the traditional way" with a fuse.
    i for one don't see any benefit to this, only the exact opposite... :(

  • I'm no expert either. Normal conditions means I have never heard of a damage done to a unit because of spikes like this before. (I'm in Europe).
    I've heard people in the US have these problems more often and use Power conditioners with surge protection.

  • while possibly true, that's not the issue at hand here ;)
    the issue is: should a device such as the KPA, for reasons of reliablity, be desinged in a way that allows the user to
    fix at least common kinds of problems like a blown fuse etc by himself, on the spot? and i surely and strongly think so :)
    on a sidenote: one important point for quite a bunch of people when deciding for the KPA is the considerable
    reduction of gear they have to haul around for each gig. which makes the point of "always having a replacement ready"
    a bit moot, to be honest. besides... if you'd still be lugging around that 'ol trusty marshall fullstack, and the head would all of a sudden stop working,
    would you really have had a second head readily available? always? in any case? or wouldn't you rather... gasp... CHANGE THE FUSE?
    THAT is point i'm making, and i'd appreciate if everybody stayed on topic.

  • I had a power tube fail at a gig, and it damaged the tube socket - without a spare amp, I would have been in trouble.


    So, yes, with a tube rig, you need more than a fuse to be readily available.


    If it is a casual enough rig for some downtime, you need a set of tubes and fuses. If there is no downtime option, you need a spare head (or two).


    With a fuse protected circuit, it takes just as long to unplug it, replace the fuse, plug it back in, let it warm up, as it does to unplug the Kemper to reset the protection circuit.

  • In my experience, if a fuse blows in a tube amp it means that the amp needs repairing. My AC30 has blown a fuse twice in its lifetime and both times has had to go in for a service; replacing the fuse just blew the new fuse. However, I'm in Europe and have never experienced a power surge (as far as Im aware, at least).


    An electrical relay, if it works as described by Ingolf, is a much better safeguard, in my opinion. I never seem to have spare fuses that fit, hahaha!


    Cheers,
    Sam

  • while possibly true, that's not the issue at hand here ;)
    the issue is: should a device such as the KPA, for reasons of reliablity, be desinged in a way that allows the user to
    fix at least common kinds of problems like a blown fuse etc by himself, on the spot? and i surely and strongly think so :)


    I agree that Kemper should make their devices as easy to service as they can, within whatever other design constraints might apply. In this case, I could be wrong, but it sounds to me like instead of a user-replaceable fuse they opted to go with a circuit breaker that automatically resets itself without the need for a fuse replacement. All you have to do is wait a bit and power it back up.


    Quote

    on a sidenote: one important point for quite a bunch of people when deciding for the KPA is the considerable
    reduction of gear they have to haul around for each gig. which makes the point of "always having a replacement ready"
    a bit moot, to be honest. besides... if you'd still be lugging around that 'ol trusty marshall fullstack, and the head would all of a sudden stop working,
    would you really have had a second head readily available? always? in any case? or wouldn't you rather... gasp... CHANGE THE FUSE?
    THAT is point i'm making, and i'd appreciate if everybody stayed on topic.


    In your tube amp hypothetical you're assuming that (1) you will be able to quickly troubleshoot the issue in the heat of the moment and (2) the issue will be solveable with an easily replaced part. I once had a power tube blow out in my Bruno UG30 combo during soundcheck. (I later found out it also took out a screen resistor.) Swapping in new tubes did nothing and the fuse was fine, so after a panicked scramble I eventually managed to get a hold of someone else's amp in time for the set. After that incident, I always brought a spare head to plug into the speakers of the UG30. Then I switched to modeling and my primary and backup gig units became a lot more manageable.

  • I definitely recommend getting a good power conditioner and a backup unit for live use, it may save your unit someday from a power spike and often it will help filter out noise/hum problems from poor power at venues. I do over 200 shows a year with my Kemper and like Ingolf and am not worried in the least but I do have a GSP1101 as a backup and I use some of it's effects as well from time to time, though I pray I never have to use it for tone!!

  • Btw... a fuse doesn't blow for no reason. So "user replaceable" fuses are not really a big benefit. Just don't gig without a backup. A Zoom G3 doesn't cost very much and sounds more than ok. And it fits in a gigbag :)

    MJT Strats / PRS Guitars / Many DIY Guitars -- Kemper Profiler Rack / Kemper Remote / InEar

  • Im surprised people don't make a larger deal about pure Line Interactive sine wave UPS's. This means your Kemper runs off a nice sine wave power supply with battery. I have had mine running on such a unit since I bought it more than 2 years ago and guess what, not a single problem.

  • Hi,


    As mentioned before, a backup KPA is nice, and you can do more things with 2 of them 8o An uninterruptible power supply (UPS) is the best, cheapest bet, however.~50 bucks for something that comes with a surge protector, insurance for what you plug in--typically up to $10,000 should have you sorted. UPS means there is a battery in it, typically a 12 volt, with a power inverter to 120, 240v, etc. depending where you live. Many have built in breakers, essentially a resettable fuse, that doesnt need changing (lightning strikes aside :) just a button you push. a non powered KPA should last a while, and if power has issues where you are, other gear may be affected.
    The only downside are many UPS approximate alternating current differently, what Mikeb was referring to. You can actually hear different kinds of hum in these with a tube amp, and I am not entirely sure if it is good for them. UPS were designed for digital devices, with a "normal" power supply. Few have tubes of any sort in mind, more PC's, servers etc. It would indeed be a niche market to have a UPS/ surge/power conditioner for tube amps as "dirty power" can cause damage. Would not be surprised if they are out there in some capacity.
    The KPA is a digital device, and should work well with any decent UPS/surge/conditoiner. There may be exceptions, feel free to correct me if im wrong--I have not researched this very much, just relating what I know offhand about these devices. I use them at for PC, Mac, home audio, video, even plug a KPA into it with no issues fwiw. If power is cut at a house for example, I can see stove clock needing reset, but other things are fine, if it is not prolonged... Do a google/ amazon etc. search, there are tons of them on the market, just a matter of finding one that does exactly what you want, some have extras others not, so impossible to recommend for you.


    Hope this helps :)

  • If I decide to use the Kemper live (not used it live yet) I will bring a backup - either my Boss ME 80 or a 2nd Kemper (no money for second option at the moment).


    The Boss will not sound as good as the Kemper but it is just the emergency option.


    If you play live you should always have a backup solution (we normally have one spare amp - for 2 guitar players). In the unlikely event that both main amps burn we are screwed I guess (-;

  • We have a number of reports from heavily touring pros, that the Profiler is appearingly much more reliable than a tube rig with adjaced pedal board etc.


    While ten thousands of units have been sold already, we can tell only a handful of stories where a unit failed on stage. Unfortunately you have experienced it too.
    A UPS is a good safety device in this sense for sure.