N(tm)AD VBA 400--The Beast Has Arrived

Discussion in 'Amps and Cabs [BG]' started by Wasnex, Oct 5, 2023.

  1. Wasnex

    Wasnex

    Dec 25, 2011
    My New (to me) VBA 400 came in today and I tested it through a pair of Genz Benz 1288T Uber Quads using my Yamaha TRB6P.

    This amps sounds fabulous, but I don’t think it sounds particularly British. To me, British voicing tends to be sort of brash and aggressive. Think classic Marshall, Hiwatt, or Vox.

    My first thought is the VBA reminds me a lot of my Mesa 400+. However the VBA is warmer overall, and the highs are fairly reserved in comparison. It’s sort of like someone applied a tilt EQ to a 400+ to favor the lows more and the highs less. The VBA does have similar smooth and sweet upper mids, with a little bit of glass and air up high. So the VBA has nice extended highs, just not a lot of them.

    The VBA’s low end is very full and dynamic. It has a nice woody resonance in the low mids and huge kick down low, like the 400+, only bigger. When you pluck a note, you really feel it; even at relatively low volume. I expected the low end to be a bit woolly, but it seems surprisingly centered and focused with clear pitch definition, similar to the low end of a Trace Elliot V6.

    As you might expect, the VBA has massive clean headroom, but I don’t think you need to push it into beast mode to get a nice warm tubey sound. If you crank up the preamp gain, there is a lot of sustain and the tone has a smooth vocal quality. But the sound is also thick, full, and sort of bloomy down low.

    I cranked the gain all the way up and the preamp stayed clean. I also tried maxing out the Master and running the gain low. This changed the tonal balance and shape of the note envelope fairly subtly. However, even with the gain dialed way down, the sound still seems fairly compressed and smooth to me. My point here, IMHO you don't necessarily have to push the amp to it's limit to get a nice tone...but YMMV.

    The dynamic envelope of the notes is somewhat of an enigma. The low end jumps out, but then the sound smooths out and has massive sustain. IMHO, it has a nice, rich singing quality like some pushed tube amps…even when you are barely tickling the output section. This reminds me of the dynamic envelope of a pushed Reeves 400...but the VBA does it without being pushed.

    The amp idles very quietly. It seems to produce less hum and hiss than many of my other amps.

    Unfortunately the VBA has a pretty obnoxious fan that rivals the vulgarity of the fans in my vintage SVTs. The fan has two speeds, but I found the low speed resulted in a very audible and IMHO irritating whirling sound. The whirling diminishes greatly when the fan is set to high, but of course you get more white noise. I prefer the high-speed setting.

    The tone controls are pretty limited. Plenty of low end, but adjusting the mids and highs produces subtle/subdued changes. The tone network resembles a Fender tone stack, with an added voicing network that changes the tone contour. The voicing network has three presets that seem mostly to modify the amp's baked-in mid-scoop.

    I no longer perform, so I won’t be able to test the amp in a band setting. My impression is it sounds fabulous in my basement and would probably record really well. I would describe it as huge, sweet, warm, clean, clear, smooth. I suspect the overall tone would be bit too dark for me in a live environment, but I tend to like what most would probably consider an overly bright and somewhat lean sound on stage. This allows me to hear better at a relatively low volume.

    If you like a nice warm sound on stage, the VBA would probably work really well as long as you like the basic voicing and don’t expect the amp to produce any sort of drive or gank. If you want to push the output tubes to the point where they start getting a bit ratty, you will blow the roof off the joint. At sane volume levels, the amp feels like it has infinite headroom: big, clean, and warm.
    upload_2023-10-5_22-10-24.png
    When I picked it up for the first time, it felt really big!
     
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  2. gtirard

    gtirard

    Feb 22, 2020
    Paris, France
    Congrats!

    Edit: from your description (the comparison with the Mesa 400+ in paricular), it seems that it's exactly the kind of tone and feel I would dream off, except that I really don't need such a massive 400W power (and the kilos that probably go with it)
     
    Last edited: Oct 6, 2023
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  3. S.F.Sorrow

    S.F.Sorrow

    Dec 6, 2014
    Congrats! :drool:

    I've only played a VBA400 on a couple of occasions but I was very impressed. My thoughts were more or less the same as yours. Definitely not as aggressive in the upper mids as a vintage Marshall Major or Superbass. My 70s JMP Superbass is actually one of my favourite bass amps (although I sometimes wish it had slightly more clean headroom...) but the VBA400 is a MONSTER and certainly more versatile.

    Marshall's bass amps don't get the credit they deserve IMO. They've made some real classics, like the 60s/70s JMP-versions of the Superbass and the Major. Of course, they've also made some less impressive ones, like that later, awful, dull sounding JCM800-style Superbass...:vomit:
     
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  4. @Wasnex thanks for posting this! Funny, my fan only has one speed, on high. My drummer loves it in the winter, not so much in the summer months! LOL
    Running mine through an NV610, I have to agree about the lows. My HPF comes in really handy with this amp.
    Hitting the "bright" switch might get you more of the glassy highs.
    Here's a thread with some more info in case you haven't come across it yet.
    https://www.talkbass.com/threads/marshall-vba-400.1014968/
    I get a bit more wool out of the amp by using the passive input with my active bass. Set the gain to 3:00 and I find the amp jumps up and sings.
    Looking forward to more of your thoughts as you get more time with it.
    Fishheadjoe
     
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  5. Wasnex

    Wasnex

    Dec 25, 2011

    The output of the TRB6P is not particularly hot, so I am using the passive input. The only time I use an active input is when my bass causes unintended distortion in the front end of an amp.

    So far I prefer Contour preset 3. The manual says this provides a gentle mid-boost. Preset 1 and 2 are different mid scoop contours. Haven't really explored those yet.

    I tried the bright switch. It seems to reach well down into the mids and bring out a bit more grind. Takes away some of the sweetness from the highs, but should help cut through a bit better on stage.

    I also tried rolling the bass off. Even with the control fully off, the tone is relatively full and seems to have sort of a warm, woody focus in the low mids. My bass control appears to be a bit glitchy, so this may not be representative of how it should work.

    The overall sound does have sort of a looseness. But the low end seems to stay focused rather than getting sloppy and blurry to the point where it's hard to discern the pitch center.

    To me the lows on this amp are totally over the top, but they are also exceptional. IMHO it's rare to find an amp that does huge lows this well.
     
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  6. Killing Floor

    Killing Floor Supporting Member

    Feb 7, 2020
    Austin, TX
    Nice!
     
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  7. Wasnex

    Wasnex

    Dec 25, 2011
    Do you mean low speed doesn't work, or there is no switch to select the fan speed?

    The fan runs off 100V AC tapped off the primary of the power transformer. For low speed, a 47 ohm resistor and capacitor is switched into the circuit in series with the fan. The resistor may be fried or the may be disconnected.

    So probably something that can be easily fixed the next time the amp is in the shop.
     
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  8. Aussie Player

    Aussie Player

    Apr 20, 2011
    There is no such thing as too much power. I have played gigs on a setting of "1" with the master full up and always, the bass players come forward and ask questions.
    Plug in a quality bass guitar and you are at a place many spend a life time searching for.
    EB3 and Marshalls.jpg
     
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  9. Aussie Player

    Aussie Player

    Apr 20, 2011
    Congrats on a great bass amp.
    I use mine live with Alembic, Warwick, Fender and Gibson basses and it always sounds wonderful.
    Have never felt like I need to keep looking. This amp will see me out regardless of the venue size.
     
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  10. callofcthulhu

    callofcthulhu

    Oct 16, 2012
    Always wanted to try one of these.

    I've got two of the 4x12 cabs. FWIW their voicing is very shy in the lows, with a wicked snarl in the mids - it's a killer, grinding, aggressive sound that makes an 810 sound like a muffled fart. They pair great with my SVTCL.

    Likely the tonestack was optimized with the cab voicing in mind (or vice versa).
     
  11. Aussie Player

    Aussie Player

    Apr 20, 2011
    The matching VBC 4x12 cab sounds terrific. Never been able to find a second cab but the single cab works fine for the venues I play.
     
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  12. Wasnex

    Wasnex

    Dec 25, 2011

    I bet a pair of the VBC412s would be insane :eek:. So why do I want to try it :roflmao:.
     
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  13. callofcthulhu

    callofcthulhu

    Oct 16, 2012
    Brothers, let me tell you.

    It is great.

    Total overkill but I played with a guitarist who used a full stack and insisted I do the same for the aesthetic, so I sought out a second.

    These days I just use the one live. Still nice to have a spare to leave at the practice space.
     
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  14. Congrats.
    Would love to have a residency at a club where it was my amp!

    What cabs are you using it with?
     
  15. Wasnex

    Wasnex

    Dec 25, 2011
    I have only played the VBA through a pair of Genz Benz 1288T Uber Quads so far. Eventually I will try it through a pair of EV TL405s and a Greenboy Dually loaded with Faital 15PR400.

    The 1288Ts tends to sound really even and controlled with pretty much every amp I have played through them. The TL405s sound great with some tube amps, and not so good with others. The Dually is designed to sound loose and bloomy, so I think it sounds best with a big solid state amp. The best tube amp I have tried with the Dually is the Reeves 400.
     
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  16. Wasnex

    Wasnex

    Dec 25, 2011
    Decided to study and experiment with the tone stack and Contour switch. Not 100% sure exactly how the tone is changing. My impressions follow.

    Preset:
    1. is the brightest and most mid scooped. Also I think the mid scoop is centered at a lower frequency.
    2. seems to be sort of intermediate. Similar in brightness to 1., but slightly narrower mid-scoop.
    3. is the warmest and darkest. I think the mid scoop is even narrower, but perhaps shifted up into the high-mids.

    My perceptions may be slightly off because of how the controls interact with the Contour circuit.

    There is definitely some brightness in this amp especially with preset 1. and 2. The trick for me is the Treble control needs to be pretty high to bring it out. With the Treble control around 10:00 the Contour switch does not seem to have much impact on the highs, but I think I can still hear the size and center of the mid-scoop changing. I believe the Contour circuit should have some impact on how far the Treble control reaches down into the high-mids.

    My impression is the low-mids fill in as the presets advance from 1. to 3. Switching from 1. to 2. seems pretty subtle and switching from 2. to 3. seems more noticeable. Although the switch seems to impact the low-mids, it seems to relate more to the operation of the Bass control. If the Bass control is turned all the way down, the Contour switch has little, to no effect on the low-mids, unless the Treble control is also turned all the way down. Then there is a subtle impact.

    This is the tone stack and Contour circuit for the VBA

    upload_2023-10-7_13-2-10.png

    This is the basic Fender tone stack it is based on:

    5F6-A Bassman circuit
    upload_2023-10-7_13-15-8.png
    Ref: TMB Tone Stack (robrobinette.com)

    Trace Elliot and Ashown tube amps use a later version of the Fender tone stack as their foundation:

    AB763 circuit
    upload_2023-10-7_13-15-56.png

    The difference is in the way the Mid control is connected. Per the webpage referenced above, the AB763 connection causes the controls to interact a bit more.

    The Contour switch basically adds some extra capacitors and resistors that are switched in parallel with the treble capacitor and mid capacitor. The resistors are 1 meg for the treble circuit and 2 meg for the mid circuit. I think the resistors have no impact on tone and they are intended to eliminate switching noise.

    The lower part of the Contour circuit seems to function similar to the Mid Shift circuit in Trace Elliot and Ashdown tube amps, despite the differences in how the Mid controls are connected.
     
  17. beans-on-toast

    beans-on-toast

    Aug 7, 2008
    If you want to amp to truly sound british, some swear by using a frequency converter to change the 60 Hz line frequency to 50 Hz. Bands do this with converters that also set the line voltage just right. Some Marshall tube amps sound best at 234VAC.

    See 9:30 in this video, 235VAC @60hz



    A quieter fan can be sourced. Well worth the cost.
     
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  18. Wasnex

    Wasnex

    Dec 25, 2011
    Spent some time running the VBA through the EV TL405s and Greenboy Dually over the past two days. The amp's defining qualities shine through both pairings, so it does not seem overly picky about cabs.

    The TL405 gets along well with some of my tube amps, but not so well with others, as the low ends can be peaky/uneven. With some amp cab pairings I prefer the TL405s to the GB 1288T...but not in this instance. The 1288T is my favorite by a fairly small margin. The TL405s accentuates the attack of notes; almost makes fingerstyle sound like your playing with a pick. It also seems to have more character/texture in the mids.

    The Dually tends to be more vintagey than I like, especially with tube amps. But it pairs well with the VBA--some of the sweetest highs I have heard from this cab. The Dually seemed to accentuate the VBA's singing quality a bit more than the other two cabs...but the amp sings through all of them.

    I prefer Contour preset #3 with the 1288Ts. This preset seems to make these cabs sound a bit more resonant and musical, and also produces the most focused tone. I prefer running the bass control between about 9:00 and 11:00.

    With the TL405s and Dually I preferred the bigger mid scoop of preset #2. To my ears this results in the most pleasing tonal balance and also the most clarity and focus. Preset #1 seems a bit too mid-scooped and preset #3 seems a bit to bloated in the low mids. I prefer the bass control between 9:00 and all the way down with these two cabs.
     
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