Posts by ucnick

    I play a Powerhead through various cabs, usually a 1X12 loaded with a Beyma 12GA50 for rehearsals, and use an FCB1010 with the Uno4Kemper EEPROM. I had loaded the Marshall 72 100W profile from the Rig Exchange (posted by Janne) a few days ago and auditioned it (sans FCB1010) and liked it a lot, particularly after tweaking, so kept it to use for Duane Allman-esque "Live At Fillmore East" sound (I play in an ABB trib band, among others). Put it into a performance slot for quick access.


    Last night at rehearsal I plugged in the FCB1010, set performance mode, selected the rig, and discovered that the volume pedal, with pedal in heel down position, didn't put the KPA into tuner mode on the KPA screen, as it did with all the other profiles. FCB1010 didn't go into tuning mode either. Didn't have time to debug it, as it ended late and had to get up early for work (ugh! curse of the drinking class!).


    Tonight I plan to recheck and do some debug if I get a chance, but it was not obvious to me exactly what is occurring. I figure I did or am doing something stupid and am overlooking something obvious, but I looked through the manuals (RTFM!) and didn't see anything helpful except perhaps the volume pedal range setting, perhaps something to do with the heel down position setting in that profile, which I thought was global but may not be global in Performance mode. Remember, all the other profiles I have set up in performances do not have this issue, and I never had this occur prior to last night on any profile. I will check the behavior of the profile in Browser mode and see what happens as well, but thought I would bring t up in case (a) there are any suggestions of what to check and (b) anyone else should have the issue. The profile is really really good for DA at the Fillmore type sound and I would like to use it. Thanks folks.

    Has anyone heard definitively that it is the LEDs themselves? It may not be the LEDs, they can theoretically last over 100 years if not mistreated. It could also be that the LED driver chips being used are failing or having issues. I haven't the foggiest notion of what the Kemper uses to drive the LEDs, but I'd say some sort of pulse width modulation to control brightness (and color for the multicolor LEDs). Just saying.


    Update - saw the post from one of the moderators (Burkhardt?) that said it was a bad batch of LEDs. So never mind the drivers comment...


    BTW, are there any unit S/Ns that are known to be from that time frame so that the owners can be aware of this potential issue? I purchased my Kemper last December from a distributor here in the States (American Musical Supply) and would like to know if there is the potential for LED failure in my unit. As a cautionary measure, I have turned my LEDs down to try to lower the probability, and will only turn them up for use in sunlight.

    Can anyone tell me definitely for sure 100% which Ice1000 is in the Powerhead? The bandwidth of the Ice1000A is only about 3 kHz into 8 ohms, whereas the Ice1000ASP has a BW of around 30 kHz into 8 ohms (check the data sheets) which seems to me to be what is needed forFRFR capability. Seems to me the Ice1000A 3 kHz BW is just too low.

    Beyma 12GA50 and an old Lopoline 1X12 cab.


    Also found that an old Carvin V212 2x12 cab I had lying around, with the older GS-75 speakers, sounds great with the Powerhead. Will be gigging with it tonight with the louder of my two bands, using my IEMs in addition to maintain clarity, the bassist is loud as hell.

    Received the replacement and it is just fine, sounds great! First one must have been damaged in transit, cannot imagine shipping bad product. Will be using it next Monday at rehearsal. Us Speakers, and you guys, rock!

    Some info from the datasheet for the Icepower 1000A amplifier, for information only:


    PO Output power @ 0.1%THD+N
    10Hz < f < 1kHz (AES17 measurement filter):
    1000W RL=4Ω, Vp =120V
    800W RL=6Ω, Vp =120V
    600W R =8Ω, Vp =120V

    f Frequency response 20 – 1kHz, all loads ±0.5 ±1 dB
    fu Upper bandwidth limit (-3dB), RL = 4Ω: 3 kHz
    fl Lower bandwidth limit (-3dB), RL = 4Ω: 4 Hz
    Zo Output impedance f = 1kHz : 5 typ/10 max mΩ
    ZL Load impedance range 2 Ω min /4 Ω typ
    D Dynamic range A-weighted 120 dB


    And a VERY important caveat:


    Warning! The balanced speaker outputs are both “hot” with a common-mode DC level equal to Vp/2. Always
    use balanced probes for monitoring and measurements. Shorting one of the terminals to ground results in an
    over current situation. As the module has no internal current limiter even a brief short circuit (phase-to-phase or
    phase-to-GND) will damage the device beyond repair. Current limiting circuitry must be connected externally.


    CK says that the protection doesn't work properly at 4 ohms. So it would be wise to avoid going below 8 ohms. Caveat emptor. :-0

    Never mind, I found the answer... from ck himself...


    You are right, I said that.
    The protection circuits do not act properly at 4 Ohm, that's why we do not recommend it.
    Still it's possible, but do not run too high volumes, otherwise you will break the power amp.

    I take that back, 250A data sheet says 210W @ 4 ohms. Must be the 1000A, says 600W AES @ 8 ohms, and 1000W @ 4 ohms! Wow! I guess 4 ohms not recommended due to heat?

    I recall having seen a link somewhere to another site that links to the manufacturer's site of the actual amp used in the Powerhead, but darned if I can find it. Couldn't find it in the Wiki either. There were some posts that mention a B&O amp but I seem to recall it was something else. Anyone know where it is? Thanks!

    I have a Beyma 12GA50 that I want to mount into my 1X12 cab. The terminals on the speaker are larger than those found on all the speakers I have used to date (such as Eminence, Celestion, Weber, Jensen, ...). The quick-fit terminals look like this (dimension not certain):


    http://www.keyelco.com/product…-Fit/4470/product_id/1141


    The Beyma terminals on the speaker are wider than on the Eminences, etc, and the quick-fits I have do not fit. While I can directly solder the wires to the speaker terminals, I'd rather obtain the correct size mating quick-fits and solder them to the speaker wires, rather than the terminals, so that I can slip on the connection, rather than directly solder the wires to the speaker. More pro that way. Anyone know offhand what size the Beyma terminals are, and what the correct size quick-fit would be? They may be some European standard, with which I am not familiar, as it is manufactured in Spain, and I am in the U.S. Thanks.

    I'm fairly certain I understand what it means... are you saying that, by increasing the boost level, you decrease the volume?


    From the Basic Manual, page 27:


    "Power Amp Booster
    As mentioned, the power amp is connected to the Monitor Output, which provides enough headroom to
    support even loud attacks and transients of clean guitars. However, this comfortable headroom will naturally
    lower the signal volume for the power amp, so you might not achieve the desired loudness. Turning
    up the Power Amp Booster will increase the loudness by up to 12dB.
    Although this will shrink the headroom,
    this is no bad thing, as this happens in tube amps as well. Very loud signals and transients will then
    be compressed by a nice, organic-sounding soft-clipping circuit."


    I understand this to mean that, as the Power Boost level is increased, the continuous power delivered to the speaker increases and the headroom (the remaining available volume before clipping) decreases. When the amp hits the ceiling, it soft clips, as it states. As pointed out in the manual, it is the same as in tube amps, you can turn it up but as you do so you lose clean headroom. A tradeoff, as usual. Increasing the Power Boost level increases the continuous power delivered to the speaker. Hence my concern at cranking it up.


    The Power Boost level is nominally set to allow maximum clean headroom (0 dB, as I recall) and if you turn up the Power Boost level the loudness increases, at the expense of clean headroom. I have verified this personally wth my Powerhead. It says it can provide up to 12 dB of loudness, going by power increases by 3 dB for every doubling of loudness, that works out to 8 times as loud. I know I turned it up to 6 dB and it was considerably louder, I didn't measure it with my level meter but it certainly could have been 4X as loud.

    Hm.


    FWIW I'm currently using a Weber Vintage 12F 100W RMS 16 ohm speaker in a 1X12 cab with my Powerhead (although hope to move to a Beyma 12GA50 soon).


    The reference manual spec says 300W for 16 ohm load and 600W for 8 ohm. No mention of type (AES, RMS, peak, or otherwise), so not certain exactly what the power is, however since it is half the value with twice the impedance, suspect it may be RMS (look at the definition of RMS power and you'll see what I mean, for same peak voltage twice the resistance yields half the power). ANYWAY I am really paranoid about blowing the speaker, so I don't use any power boost at all, keep the monitor output level below -2 or -3dB, and keep the front panel level less than about 5/8 and I haven't had any issues with the speaker, and it seems to have plenty of power. Ran it for three 1 hr sets the other night and no issues with the speaker. The little 1X12 (with a closed back, no less) was clearly heard above my quite-loud band (my FOH connection had some problems, so was running on cab itself plus a K10 monitor for myself driven from the main out). And that is with a 16 ohm speaker.


    Not sure if it may have contributed, but - was the cab sim on? I do have my cab sims off. I noticed that the sound is sort of thicker and louder in some rigs with the cab sim on and currently don't use them with my 1X12. However, if you had them on, perhaps some of the transients may have been enhanced and over time overheated the coil. Just throwing out an idea.

    Used my Powerhead and FCB1010 (with Uno4Kemper EPROM) last Sat night for a party gig, maiden voyage, overall extremely pleased, tones were great, however had a single glitch occurrence, not certain of cause. thought I should report it.


    I was running in Performance mode and at the time was in Perf #2 slot 4 (which was FB1010 button 9) for next to last song ("White Wedding") and wanted to switch to slot 5 (FCB1010 switch 10/0) in same performance for final tune ("Rebel Yell"), which has some different settings (I put them next to each other for this reason). Not important. What is important is that, when I pressed the footswitch button for slot 5, nothing happened, the footswitch LED didn't light, the slot 4 switch LED stayed lit, and the slot stayed right where it was, on slot 4. So, I'm playing my parts and trying to figure out what to do at the same time. Tried it a few times, no good. Finally, during a hiatus, hit the footswitch button for slot 2 (FCB1010 button 7) and then hit the slot 5 button again (FCB1010 button 10/0) and it came on and slot 5 was selected. It only happened the one time, and at the end of the gig.


    Not certain of the cause, whether it is related to the FCB1010 or something in the Kemper, but I think most likely suspects are likely the FCB1010 or the EPROM, as I don't see how the Kemper could affect slot selection, only if the MIDI engine malfunctioned somehow. Never had this problem switching from front panel, but again MIDI is not involved using the front panel controls.


    Has anyone else run into this? Other than this single glitch occurrence, the rig operated flawlessly. Wish I could say the same about my playing. :)


    As an aside - in terms of switching delay between slots or performances using the FCB1010, had no issues whatsoever, seemed plenty quick to me, much less than a second. On the same order as switching pedals in and out on my analog pedalboard.