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GK MB800 & Carvin BX500

Discussion in 'Amps and Cabs [BG]' started by Jarrett, Jan 7, 2013.

  1. Jarrett


    Jan 19, 2004
    Waxahachie, Tx
    I thought I would start this thread just in case anyone is interested. I decided to buy a backup amp for my GK MB800. I'm a fan of Carvin gear and own a couple SB basses and a BRX10.2 Neo cab of theirs, so I thought the BX500 would make a good head to try as a backup. And it was on sale for $379 new, so I figured it was a good time to jump on it. (As I was typing this I just noticed they have them for $359 new on Ebay, grrrr)

    So I got the BX500 in today. Here's the pic:


    I had forgotten how much bigger the BX500 was than the MB800 immediately on pulling it out of the box. I also forgot how tonally flexible the amp is. I first plugged into the MB800 on my standard setting with everything mostly noon'ed up to get an idea of what I normally use then switched to the BX500.

    Immediately I realized that flat on the MB800 is anything but. I started with everything flat on the BX500, but the sound was no where close. I had to really dial in the Contour (scooping) knob on the BX500 from "Flat" to much closer to "Scoop" to get a tone similar to the "noon tone" of the MB800. Even then it was a little off.

    I looked around back on the BX500 and noticed the 12AX7 tube was engaged and went ahead and disengaged it since the MB800 doesn't have a tube. At that point, the BX500 tone was getting closer to the MB800, but still not quite there. I dialed the Drive knob on the BX down to zero. That got it closer. Still a little thick. I switched from active to passive and that made it a bit closer.

    Going back to the MB800, I found it was getting pretty close now. The only differences I could tell were in the high end and an overall compression feel that the MB800 had compared to the BX500. So I switched back to the BX500 and turned the treble knob up a bit trying to find that high end, but that wasn't the frequency I was hearing. I put it back to noon and engaged the graphic EQ on the BX. I made sure all of the other sliders were at noon and then went to the 5k slider and started edging it up a bit. I didn't think it would cover the right frequency either, but it was closer than the treble knob. I played and bumped it up a little more and that got really close to the MB800.

    At that point, I went back to the MB800 and A/B'ed them again and it was pretty close tonally at this point. The MB800 just has some sort of inherent "sweet" sounding compression on it. I went back to the BX500 and tried to dial in a little compressor using the onboard, but that didn't really do the trick. At this point there is a little bit of compression I can't quite match between the amps, but I'm still working on it.

    That said, I was surprised as how well the BX500 held its ground in the volume department and how close I could dial it in to sound like the MB800 in just a few minutes of fiddling around.

    From here I'm going to try it out with my fretless bass next and then take it on a gig this week and try to A/B them between sets to see how it works at a stage volume and in the mix.

    I can record clips directly to the computer, but the DI out on the BX500 is pre only, so really you would just be hearing my bass on that time of recording. I don't have anything high quality that I could use to do an in room recording. I guess I could mic it up if anyone is interested, but not sure I would really capture the differences or not.

    Let me know if you have any questions on the comparison of these two that I can answer.
    seansv likes this.
  2. jeff7bass


    Apr 9, 2009
    Try turning the LOW MID freq to 100 and boosting it to 6 with the LOW MID gain (just above). Try the same types of adjustments with the HIGH MIDS. Do this with the graphic eq off, because you wanna find your tone without it, then use the graphic for fine tuning onstage or when switching basses.
    I'm on my third Carvin bass amp and and the sweet spot is usually found in the low mids.

  3. Jim C

    Jim C I believe in the trilogy; Fender, Stingray, + G&L Supporting Member

    Nov 29, 2008
    Bethesda, MD
    I like this test a lot.
    Carvin has all the features, at a bargain price, made in America, yet I've never seen one locally to try.
    Rather than compare to flat settings and on so forth please try this:
    Work with each amp individually and twist the knobs until you found your sound; same with the other amp; compare the two at home and then at rehearsal or gig.
    I want to know which one works better and why.
  4. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    My current amp is the mb800 and I previously owned the bx1500 which, I believe, has the same preamp section as the bx500(minus a few knobs).

    I like both amps tonally. The carvin has better features and the mb800 is more hearty as the Carvin bx1500 has issues regarding cleaning the ribbon cable. I found the bx1500 clipped way too early (bridged at 8 ohms for 900w) with my fEARful 15/6.

    I would like to see Carvin put out a preamp section of the BX series as a standalone preamp. I'd seriously consider buying that.
  5. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Funny, everyone's experience is different. I owned the BX500 and liked it so much that I bought the BX1500. It has more EQ options than I will ever need, and I have never had problems with the ribbon cables. I run it bridged into 4 ohms, and barely get the master above 4. Clipping, I have observed, is more of an EQ issue, imho.
  6. 2milehighspike

    2milehighspike Supporting Member

    Nice review! Damn ya got me gassin for it, I really dug it when I tried it at carvin , I first got a taste at an open mike night last May , . I think It was running thru an Ampeg 6x10. I was very impressed!
  7. That's what I told'em too. Got a 4x12 with a their DCM1540L power amp, so it'd be "white on rice" for me. Also, I agree with them excelling in the LOW MID area. I own the BX250, and don't know if this is a factor too, but I don't use the bass knob on my bass pre, I just bumpo the mid sweep to LOW MIDs, and it pumps.
  8. Jarrett


    Jan 19, 2004
    Waxahachie, Tx
    I'm not playing any monster gigs anymore, so 500 watts is plenty for me. I find that Carvin's 4 ohm BRX10.2 and an amp that can pump at least 500 clean watts into it at that ohm load is plenty for any gig I'm doing these days.

    I played both of them a little more with my fretless last night and it was really hard to tell a difference between them at that point. Looking forward to using it on this week's gig.
  9. L. L. Elwood

    L. L. Elwood

    Jan 22, 2004

    I've just lately sold my Carvin B1500 to jump into GK land. I just tried the mb Fusion for a while and have decided to replace it with the MB800.. The fusion was a cool amp, but it seemed slightly anemic to me somehow. I can't really describe it.. I'm curious as to why you've settled on the MB800? What qualities does it have that have you liking it so much compared to the other amps you've owned of late?

    Thanks, Larry
  10. Jarrett


    Jan 19, 2004
    Waxahachie, Tx
    Larry, here are a few things that drew me to the MB800:

    GK Sound

    It's a pretty slick little amp. It's not the swiss army knife of sounds like I've found the BX500 to be with its various EQ. But if you like the slick, smooth, hi fi GK sounds that it puts out, its a pretty good amp. I have no complaints on it really. I guess the one thing about it is if you don't like, grow weary of the GK sound, or just want to hear something different now and then, there is no escaping it, its baked in there. Also, its not flexible enough to dial itself to a diff cab, so you kind of have to hunt for a cab that fits it. Thankfully a bunch of them do.

    It's interesting that you mention the anemic thing. When I first started A/Bing the MB800 to the BX500, I was trying to emulate the MB800 sound on the BX500 and found I had to come up with tricks to make it sound thinner. Like bypassing the tube, turning drive to zero, switching to active mode on BX500 even though the MB500 was in passive mode. Basically had to thin out the sound on the BX500 to match the sound of the MB800.

    Here's something I wrote back when I was A/Bing the MB800 to the TC Electronics RH750:

    One of the big reasons I kept the RH750 as long as I did was the ergonomics of the amp and the built in tuner. Now I'm using a Korg Pitchjack plugged into the tuner out on my amps and now every amp essentially has a built in tuner :)

    I playing a gig tonight and I've decided to take the BX500 just to see how it sits in the mix. I would take the MB800 as well, but I don't think I'll have much time to swap them out.
  11. Jarrett


    Jan 19, 2004
    Waxahachie, Tx
    One big thing I like about the MB800 is the controls are backlit and easy to see in the dark. Not true for the BX500. Also, I like the size, handles and portability of the MB800 better as well.
  12. L. L. Elwood

    L. L. Elwood

    Jan 22, 2004

    Thanks for the info. I'm really hoping I like it well enough to keep it around for a while. I just picked up a couple of the 112 Neo II cabs and am crossing my fingers that this combo will have a little of that magic tone that we all look for. One of the best amps i've ever come across i recently sold (Carvin B1500). I have a funny feeling if the MB800 doesn't work out.. I may go back to that big 'ol lead slead of an amp. One of the "warmest" solid state amps i've ever played. I'll chime back in once I get the MB800 and do a little review.. Thanks for being so generous with your tonal experiences!
  13. 2milehighspike

    2milehighspike Supporting Member

    I would be carefull running your MB800 thru the Neo 112 II cabs, the MB800 has SERIOUS power that may overload the single 12s, I run my MB800 thru the Neo 212s and they are a perfect match IMHO. Other than that I bet you will love the MB800.
  14. cableguy

    cableguy Supporting Member

    Jun 4, 2009
    North Bend, WA
    Funny, I said the same thing about the B2000 to them. I guess with these amps beibg so light a pre doesn't make sense.

    Thanks for comparing these amps Jarret. I've been gassing for both of them.
  15. L. L. Elwood

    L. L. Elwood

    Jan 22, 2004
    Thanks for the advice! I'll take it easy. Luckily i don't have any gigs that require big volume.
  16. B-string

    B-string Supporting Member

    BGM found out that with a 4 ohm load the MB800 puts out over 1000 watts burst power :eek:
    If it was LOUD-peg it would have been called the MB 1000 :D :bag:
  17. lfbassguy


    Jul 4, 2010
    west texas
    Endorsing Artist: Lakland
  18. Jarrett


    Jan 19, 2004
    Waxahachie, Tx
    I gigged with the BX500 last night and it sounded great. I wish I would have been able to A/B the MB800 on the gig, but just didn't have time. The one thing I noticed is the BX500 is much bigger than the MB800 and due to its size and lack of handles, its a little tougher to carry around than MB800. Really a minor deal, but the MB800 is so small, I usually just hook a single finger through one of its handles and carry around like a set of keys or something, very easy.
  19. WoodyG3


    May 6, 2003
    Colorado, USA
    I wish the BX500 had a pre/post switch for the direct out. With the places I usually play, I really want that feature.

    Thanks for the review, Jarrett!
  20. Jarrett


    Jan 19, 2004
    Waxahachie, Tx
    You know, that's actually something I consider a plus for the BX500. In all cases, I like to send the board my straight bass signal since I feel like my Carvin SB5000 sounds great straight in.

    On my MB800, I always worry that the post EQ button got pressed in accidentally and it ends up being one more think I have to check when setting up. With the BX500, I don't have to worry about that, I know that its a pre signal going to the board every time.
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    Primary TB Assistant

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