Got my GK MB Fusion and 410MBE 8 ohm cab today. It's the time for very subjective and first impression review. I need to point out to the fact I'm not an experienced bassist, and I only could test this one rig with one bass guitar, compared to my experiences to HA3500 amp with very old ferrite-speaker based 410 Hartke cab.
I will be able to do some A/B tests only on Saturday next week the earliest, since my rig has been left at the rehearsal room and I'm not back there before next weekend. I will certainly verify my impressions as the time passes by.
First unpacking the cab. Lightweight as promised (50 lb), unluckily only with a carrying strap at the top. I'd be happy with handles at sides, so a bandmate could help me carrying the cab. Anyway, I could easily bring it upstairs to the room where I practice myself.
Unpacking the amp. First impression: solid, rugged piece of gear. Feeling somewhat heavy for such a small box, but it is only an impression (the weight is 1.9 kg). I've connected the amp with the cab by a separately bought speakon cable. First small confusion: the box contained a jack cable too, but I correctly guessed it belonged to the included footswitch. The foot-switch is a small aluminium box, simple but rugged; I like it very much. So, foot-switch connected too. Great thing about the MB Fusion is very clear marking of all vital points on the case. You do not need to look at the rear panel of the amp to find right sockets/switches -- the descriptions at the rear of the top panel guide you when you look at the amp from the top.
I inserted the power cord. One con quickly spotted: I think that the IEC power socket here has loose machine tolerance. It happened twice the amp turned itself off due to poor contact of the IEC socket/power plug. I have to investigate it more closely though to make sure.
Pots were behaving very well. You need exactly as much force as expected to turn them and they stay in position during the transport (I was using the original styrofoam to carry the amp to the rehearsal room later). Of course, noiseless.
The switches used for e.g. Presence, Deep, Limiter etc., located at the top panel were as perfect as the pots. You need exactly the expected amount of force to switch them, they stay in their position and seem to be completely flawless.
The amp as powered on looks very sexy. Pushing the Power button makes a small ring of LED go continuously from red to blue as the amp starts and the preamp tubes heat up. This is a very fast process taking only several seconds. As expected, all of this is totally silent with respect to the speakers. Whenever a special function is activated (-14 dB pad, Tuner Mute, manual switching to Channel B), tiny push buttons go red and it just looks fantastic!
If I would like to say something negative: I miss small dots around pot knobs. Yes, you can visually tell the o'clock position of a knob, but I'd prefer dots with digits. Minor thing anyway at cost of attractive visual design. One can get used to that.
Now, I will describe my aural impressions. I must say now that I know my Sandberg 4 tonal capabilities very well. I've played with the Hartke gear described above for couple of weeks (using presets of its owner and his setting of internal compressor). So I know the wonderful snarl of E-F-G played on the E string, I know growl of power-chords F (strings A and D) and B (strings E and A). I know how my songs SHOULD sound when I play them. I say this because...
...my very first impression with the GK gear could be described as "disappointing".
My bass guitar has active preamp and MM-style pickup. I play d'Addario Half Rounds. I always set tone knobs on the Sandberg in neutral positions, only tweaking the tone slightly when really needed. I mostly play with the pick, and only in slow, bluesy songs based on walking I play fingerstyle. With my bass at neutral EQ settings and these settings of MB Fusion:
Treble, Hi-Mid, Lo-Mid, Bass at noon, Contour off, Presence off, Deep off, Gain A at 9 o'clock, Master A at 10 o'clock, the amp/cab were playing mostly mids and highs. The horn in the 410MBE when on was producing highs of my bass with hi fidelity. So, noise of fingers moving up the frets, pick noise, basically everything I would not like to hear. I guess this kind of fidelity would be perfect in slap, but it is not my kettle of fish. So, I have turned the horn off as soon as possible and here the matters improved.
The tube-based EQ works as GK promises. Even slight movement of a knob significantly affects the tone, and the EQ knobs interact with one another. I could easily make a dry tone by rolling off the low mids (11 o'clock) or make it fuller by only turning to 1 o'clock. Similarly, slight turning of hi-mid affected the punch dramatically. I could roll off the highs easily when needed. But my problem was I could never get meaty lows. Either not bassy enough or yes, lows but of unpleasant type. Nothing like sweet blues bass. Yes, the lows could be deep but not the kind I would expect, no roundness.
The Channel B gives you quite plenty of growl when you turn gain B more than 12 o'clock. Quite pleasant overtones with power-chords at middle strings, tragedy at low strings.
I tried Presence -- this makes mids present, but I had had enough of mids without Presence. I had tried Deep -- a lot of bass but again not the lows I like. Contour does very little and I would say it only spoils the tone. With 500 Hz setting you can get somewhat darker tone, but overall Contour was a mistake so I switched it off.
Of course, my bad impression could be caused by the room's tonal quality or perhaps this was just how this 410MBE cab is or I cannot EQ at all.
Great thing however is -- and please read it carefully -- that the Channel A/Channel B switching worked instantly! There was no slightest delay. If I needed to go from, for example, louder clean to quieter growl -- I needed that -- I just pushed the foot-switch and got immediate channel change, as I would expect from a guitar effect. So at least in MB Fusion the report of small delay on channel switching I read on non-Fusion MBs proved false. MB Fusion does not have this problem at all!
So I took the gear to the rehearsal room for 3 hour practice with my band. We are a guitar rock band and we play LOUD because of our energetic drummer, double-kick lover. There, the 410MBE stood on a pedestal, good 10 feet from me and the vocalist and more from the guitarist and the drummer.
This MB Fusion thing with 410MBE (8 ohm!) is loud as hell and that's very good! With 8 ohm, maximum rated power is 350 W. I had Channel A with Gain at 9 o'clock and Master at 3 o'clock. Gain B was at 3 o'clock, and Master B was at 9 o'clock. I had the horn off at the cab until last 2 songs. During the rehearsal, I was continually tweaking the amp settings, very delicately until I found quite satisfactory EQ. The bass and treble ended up almost at noon, the mids
slightly tweaked (I do not remember which way each, but it was 11:30 for one of them and 12:30 for the other). Presence on or off (it almost did not matter), Contour off, Limiter off. I have also found that in the band's mix, the horn even helped for greater clarity.
This little devil has tons and tons of presence. Our band is single-electric-guitar, so I need to replace the rhythm guitar, too. When we practiced new songs and I dropped a note, the room instantly became "empty", even if the guitarist plays full rich tone and not quietly

So, the MB Fusion/410MBE with almost standard EQ settings allowed my electric bass occupy the right tonal space, and I liked this very much. (With Hartke and the settings of its owner, my tonal space was far closer to the guitar).
With slow songs and dominating walking bass (Channel A, clean setting), I had to tweak the bass knob on my guitar to quickly add the missing (rounder) lows.
Playing chords on Channel B and middle/upper strings was fun, very good response from my new gear. Chords on low strings were terribly bad... I have to think what to do with that.
As for me, it was still something missing. I feel I lost that snarl on low strings. On the other hand, the chords on A/D were fantastic, as if I played bass "electric guitar". The E string was significantly louder than other strings, I have no idea why.
The Hartke gear did the work tonally better for my ears. Perhaps this could be the internal compressor, which GK does not have.
The band however praised the tone from the new gear. They described the tone as "fat". At the same time they LOL'led at the size of the amp
Don't be baffled by my first impressions. This gear is very new to me. Next week I will A/B the Hartke rig with the GK rig, then I will do cross-checking with the Hartke cab/GK cab, MB Fusion/Hartke cab, and two basses, the second one being my Epiphone Viola Bass.
Ah, before I forget. The thing has tubes inside. Cranking up the Gain B near to the limit causes audible noise. Not only the AC mains noise (the guitar has a humbucker), but some white noise, and that is strange. And the fan, strange thing. I am not sure if it went off during the rehearsal at all. However, when I was playing around with EQ and similar stuff at home and the amp was even not that loud, suddenly the fan went off and
it was not quiet. So no, at least in my amp the fan if it needs to spin is
not quiet. Hartke's is audible but not that much. Strange, strange
