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Seeking your real world class D amp head comparison and experience

Here's what I found.

Class D Tube Hybrid
The NEXUS-SL’s power amplifier section combines the power and portability of cutting-edge Class D technology with the natural warmth, compression and dynamic range that only a tube can give: A high voltage ECC83 tube sits between the preamplifier and the 1000W RMS power section. A pioneering design solution to give the very best of both worlds.

"Best of both worlds." Reminds me of an interview with an amplifier designer who was talking about a new amp he'd designed with jazz guitarists in mind. Among other features, the amp included both solid-state and tube preamps. The interviewer asked about the differences in the voicing of the two preamps, and the amp designer replied that the two were very similarly voiced. He'd originally used an all-solid-state design for the amp, and was very happy with how that had sounded, but several guitarists told him that they'd never buy an amp that didn't have at least one tube, so he added the tube preamp.
 
"Best of both worlds." Reminds me of an interview with an amplifier designer who was talking about a new amp he'd designed with jazz guitarists in mind. Among other features, the amp included both solid-state and tube preamps. The interviewer asked about the differences in the voicing of the two preamps, and the amp designer replied that the two were very similarly voiced. He'd originally used an all-solid-state design for the amp, and was very happy with how that had sounded, but several guitarists told him that they'd never buy an amp that didn't have at least one tube, so he added the tube preamp.
That is hilarious and believable. Too many of us listen with our eyes.

Now David may say something different, I don’t know. However, when I had a WT 400 I really liked the sound of that little Eden amp. However, one day I had an issue with the input jack or something right around that stage and I plugged my bass into the effects return. I knew enough to do that because the return was pre-equalization. It worked fine, and not only that, the head sounded almost exactly the same. The interesting part was, the effects return input was after the tube stage. After that, I was wondering just what the heck the tube was actually doing.
 
That is hilarious and believable. Too many of us listen with our eyes.

Now David may say something different, I don’t know. However, when I had a WT 400 I really liked the sound of that little Eden amp. However, one day I had an issue with the input jack or something right around that stage and I plugged my bass into the effects return. I knew enough to do that because the return was pre-equalization. It worked fine, and not only that, the head sounded almost exactly the same. The interesting part was, the effects return input was after the tube stage. After that, I was wondering just what the heck the tube was actually doing.
That’s interesting! I’ve always been curious about those amps as a longtime Mesa Walkabout user (the Walkabout control design was clearly inspired by the WT-400!). I never really heard Eden amps as being particularly tubelike (not a bad thing!), but the tubes in the Walkabout are probably the most integral to any hybrid amp I’ve used from my experience (though the Mesa TT800 seems to function similar in this regard).
 
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I Am actually band-less at the moment. Those initials have me drawing a blank
"2U" means 2 unit. Each 'unit' is 1.75" of height in a rack. Most rack gear would be 1, 2 or 4 units tall. If you go look at a catalog page of rack mount gear, it will all make sense. Remember, always define an acronym on the first usage. Cheers!
 
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I just bought a walkabout scout 12” and I’m recording using that and a Quilter bass block 800 with a 2x10 Ampeg Pf cab and man my ears tell me the tubes def do something in the Mesa but who knows lol


That’s interesting! I’ve always been curious about those amps as a longtime Mesa Walkabout user (the Walkabout control design was clearly inspired by the WT-400!). I never really heard Eden amps as being particularly tubelike (not a bad thing!), but the tubes in the Walkabout are probably the most integral to any hybrid amp I’ve used from my experience (though the Mesa TT800 seems to function similar in this regard).
 

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I just bought a walkabout scout 12” and I’m recording using that and a Quilter bass block 800 with a 2x10 Ampeg Pf cab and man my ears tell me the tubes def do something in the Mesa but who knows lol
They definitely do! My Walkabout is one of my favorite sounding recording DIs for that reason!
 
I’m laughing as I write this because I used to be the co-moderator of this forum years ago and I may be breaking several of my rules for posting.

I haven’t followed recent events with the new ultra small ultralight ultra portable class D amplifier heads that have become quite popular lately. I’ve only been peripherally aware of them. However, I am interested in getting one for practices and smaller gigs. I’ve got no intention of replacing my main rig and I’m quite aware that it’s unfair to compare them directly against one another.

The portable head that it has to beat is an old SWR electric blue had which is 14” x 14” x 5” and tips the scale at 14 pounds. The rated wattage of that unit is 150 into four and 120 into eight.

A disclaimer about wattage: I’ve been around long enough and done enough A/B comparisons to know that there is the wattage that the manufacturer claims for their amplifier, and then there is what you actually experience. I’m less interested in what the amplifier says on the package, I’m a lot more interested in what you have actually experienced. Especially if you have put two or three or more of these little heads up against one another and found out which ones are actually louder than the others. I won’t bore you with the war stories but I have certainly seen “standard” amplifiers blow other “standard” amplifiers out of the water that were rated at four times the wattage. (I’m not going to mention that these might have been the old Trace Elliot amplifiers and the Aguilar DB 750). If one amp is significantly louder than another, let me know.

Tone itself is of course subjective. However I would be interested in your thoughts here as well, especially if you have had the opportunity to do direct comparisons.

otherwise, portability is certainly a factor, otherwise I would not be writing this. It seems like they are all the same ballpark in terms of weight being somewhere around 3 to 5 pounds give or take. I’m a little more interested in actual outside dimensions and if they fit in something like a gig bag. Being able to carry a gig bag and a small cabinet and be done with it is kind of a holy Grail.

in the future I might inquire about how the small and light cabinet scene is these days. I’m not about to give up my bag and cabinets, and anybody who has been around a long time those that I was quite a champion for them. However, despite being compact they are on the heavy side. I do miss my GS 112 but I know that there are quite a few cabinets that have popped up in the last 10 years or so.

Anyhow, let me know your experiences. How they stacked up to one another in terms of volume and tone. How well you’re able to fit it in a gig bag or something like that. If you experienced problems, what were they? If you picked one over the others after doing comparisons, why?

Just to be clear, if you have opinions without experience I’m really not interested in that. And comments that little class the amplifiers are no good or will never be as good as regular class A or class B amplifiers are exactly helpful either. Remember, I’m not looking to replace anything, just for another option. Edit: “class D amps are great” without letting me know which one you like and why isn’t super helpful either.

thanks a lot in advance ~ Ivan


I put my old SVT 4pro on the shelf and replaced it with a PF 500. I'm using schroeder cabs and I'm very pleased with the sound. Here's a pic of my "small" rig. I have a 310/212 schroeder cab too. This one is a 1212.
 

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There is no clear winner. They are like two really good ice cream flavors. View attachment 4208488
So, I bought a WD about a year ago. Didn't play it first and had never really played a Walkabout.

Anyway, I am familiar with my WD now. What would you said the difference is or what the WD "lacks"
or can't do that the D+ brings to the table IYHO, please :)

What I've heard was, the Deep switch on the D+ may bring more low end than the WD, and the voicing knob and the simplified tone controls makes it easier to find one's sound and the D seems quicker than the WD.
Don't get me wrong, I love my WD!

giphy.gif
 
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Gigged, indoors and out, the Quilter Bass Block, Markbass Big Bang, Markbass LM 800 and GK MB 500. Still have the GKs.

They are all capable of far more volume than I can use.

The Quilter had an unacceptable EQ setup and DI situation. The new one addresses the EQ but not the DI. The universal voltage is a true bonus. The amp is extremely loud.

Markbass has the Markbass sound. Not what I wanted but still gigged them for two years. Both very, very loud. The 800 had a truly terrifying amount of power on tap.

The GK had the tone I’ve been looking for; like my old SWR but way louder. The MB series heads would disappoint anyone looking for that OG GK tone, but in my book that was a plus. Mine have been loud enough for any gig I’ve done, but I will say these are the only heads I’ve managed to come close to the power limit on. I always use the protect switch, more for the sake of the speakers than anything else. I understand with it off, it increases perceived headroom. Don’t need that.

Both the Markbass and the GK heads have EXCELLENT DI setups; really well done.

One day I’m going to find a good MB 800. Tried one out, just like my 500 but with this sensation of bottomless power, don’t know a better way to describe it.

Hope this helps.
 
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So, I bought a WD about a year ago. Didn't play it first and had never really played a Walkabout.

Anyway, I am familiar with my WD now. What would you said the difference is or what the WD "lacks"
or can't do that the D+ brings to the table IYHO, please :)

What I've heard was, the Deep switch on the D+ may bring more low end than the WD, and the voicing knob and the simplified tone controls makes it easier to find one's sound and the D seems quicker than the WD.
Don't get me wrong, I love my WD!

View attachment 4208514
Well take everything I say with a grain of salt because literally this is based upon a day or less of playing in my living room no band no gig.

I have the WD 800 and the D 800+ plugged into identical side-by-side stacks. So I’m able to do pretty quick comparisons. I also ran the tuner out of one amp into the input of the other amp and they sound really good together driving that stereo rig but I know there is a small effect upon tone of the second amp when you do this so I did my comparisons straight into the input jack of each.

The WD is very responsive to the instrument. That is, it sounded quite different with my Valenti 5 than it did with my Tobias 4. Despite the WD having what I consider more of a signature sound, the character of the instrument seems to shine through. The Valenti has a pretty aggressive top and it’s not shy in the lows but it likes them to be bumped a bit. My 1986 Tobias is a low end monster. It has a different voicing in the top end.

When I play the Valenti and compare the amplifiers the WD definitely sounds brighter even with the bright switch engaged on the plus. When I play the Tobias, the WD sounds darker than the plus as long as the plus has the bright switch engaged.

You can mess around with the tone controls on each amplifier to make them sound pretty similar in any given situation but it’s only ballpark. You can definitely hear the different voice of each amp even when they’re set to where your ears they sound pretty similar. This often requires different settings on each amplifier. ~ To be honest, I ran into the phenomenon of every time I switched amplifiers I decided that the one I just plugged into sounded better! This was with identical volume set by ear not by eye. Although the middle damping setting is my favorite on the WD, I tried to do most of my comparison with it set to high to mimic the hardwired damping in the plus.

The voicing control on the plus is a lot more musical and a lot more subtle than similar controls. I am accustomed to the dramatic enhance knob on the Eden amp or the Aural enhancer on the SWR. The voicing on the plus is really usable throughout its entire range. It depends upon the bass What kind of effect this ends up adding. With the Valenti it had the instant effect of sounding great but also made the amp sound quieter than the WD. Have no fear, I could turn it up and shake the house and it got every bit as loud as it normally does. But I was taking out some of the mid range that helped that bass cut through. With the Tobias it seemed to have no appreciable affect upon the perceived volume of the amplifier.

The deep switch on the plus is very useful depending upon the bass guitar. It was a bit too much with the Tobias, and that was the bass that I originally tried the D 800 with in the store where I mentioned that the deep switch was a bit boomy. With the Valenti the deep switch sounds magnificent. It’s one of those things where you cannot replicate it with the bass control. Speaking of, the bright switch is one of those things that you cannot replicate with the treble control. I tried. It sounded fantastic with both basses. Even though the Valenti is aggressive up top The bright switch emphasizes a different range which just makes it sparkle without being unpleasant, while it really made the Tobias sound fantastic. I should mention that it is time to change the strings on the Tobias. Well... probably overdue. The bright switch really makes the plus a different amplifier than the D 800. Of course the semi parametric mid range and bypass filter are also great features over the original 800 but if I had to choose just one feature it would be the bright switch. It would be neat to see deep and bright switches on the WD, but they are not deal breakers. While you can’t get quite the same “bright” vibe with the tone controls and passive mid on the WD, the amplifier has more than enough presence. It’s also got more than enough low end when needed.

What can the 800+ do that the WD can’t? It sounds like the 800+. Mic drop.

The plus is not exactly a thick sounding amplifier (smooth is a better descriptor) but the WD sounds a lot more complex and open. They both sound really refined. It’s literally like different flavors. The 800+ Sounds like butter, the WD has this raw thing going on. I would not hesitate to bring either one on any gig. I am suitably impressed.

TT is on 4-6 week back order.
 
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First Class D amps were all tube and built back in the 1930s as I recall from my radio classes. They are not useful for anything audio - I gather the switching rate is far too slow, as one would expect. But it can and has been done.
The switching speed is plenty fast, but the impedance, size, weight and efficiency limit the viability IMO.

Class C radio transmitters are an example of the potential switching speed.
 
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