Comparing sound of GK MB-150S and MB-150E combos

[tornadobass]

Sometime in the past week or so, this forum started up a bit of discussion about sonic differences between the GK MB-150 S vs E model combos. I'd mentioned that the GK manual says that both are voiced the same when the variable mids are straight up. It was countered that several players swear they sound different, with the S better for double bass.

Okay...time for a test

I had a friend bring over his MB-150S to compare to my MB-150E. They're both from the early '90s. Mine, the E version, had the power supply upgraded at the factory recently because the original power supply wasn't working correctly. I imagine it's more like the series iii in that respect.

So...we set the two amps side-by-side, both EQ'd flat, both with master gain at noon and input gain at 10 o'clock. I turned down the Boost on mine all the way – the S doesn't have a Boost control. Limiter was turned off on both, too.

Unfortunately for this forum, the test instrument was a G&L L-1000 electric bass...I thought it would eliminate feedback potential and stuff like that to keep our comparison more manageable.

Surprise #1: the E model was much quieter and darker than the S. Then I turned up the boost half way and their volume and tone got much closer.

Surpise #2: Without the Boost turned up, the E has a rounder, smoother tone than the S. I guess that's just the nature of what the boost does...it adds growl, grind, whatever.

Surprise #3: the E model had noticeably more bottom. I wonder if that has to do with the redesigned power supply. It would be helpful to do a comparison on the two models where they both had the same power supply.

P.S. When we were all done with the comparison, we hooked up my Wizzy 12 to the S combo (with internal speaker turned off). More volume, more top, more bottom! Going back to the internal speaker was disappointing...a small, dark, boxy sound in comparison. And then we got used to it again after a few minutes and it was okay.

[Jaromir]

According to my experience, the 90's models sound way better than the series III, which I also found very noisy.
From the two (MBS or MBE) I like the MBE better. It sounds somehow more natural, less boxy. I like the sound a lot with double bass.

[R Sturm]

Both comments jive with my experience - I have a 90s E and my default setting was to have the boost turned down. I never needed much volume, so having boost down was not a constraint. Maybe with boost in the middle the S and E are really voiced identically, at least if they are the same vintage.

I've seen some posts with S being better than E for upright, that's puzzling and doesn't make sense given that GK built them the same way and the E has only additional options. I would guess that came from comparing different vintages. An older S might sound better for upright than a new E. When I got my amp, every upright player seemed to have an MB150 (I was particularly influenced to buy one by Charlie Haden), it was the first choice amp for upright then. But designs change and maybe GK went back its roots to appeal more to electric basses - after all, that's a much bigger market. Always was a fine amp for BG, but making it more appealing for BG would make it less attractive for DB.

[Marc Piane]

I don't know. I had a older MB150S that I sold cause it developed a rattle that I never could isolate. I loved the sound though so I bought a series III MB150S. I notice no difference in sound. I use the same eq I always did. The series III run way cooler too. The only thing is that a speaker needs to break in a bit. One right out of the box it might sound a little more rigid and cold which is not good in a metal box. After a little use it warms up IMO.