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Flat response Class D amp?

Rob22315

Rob22315

Oct 23, 2010
1,750
466
Alexandria Virginia
#1
I recently fixed my Ibanez Promethean P500H 500W amp so I'm quite pleased to have it working again with my Promethean 210 cab. Compared to my GK MB500, I really like the uncolored response of the P500H vs the MB500 and prefer the tweakability of the P500H. The P500H has three separate tone controls - a 6 band EQ, high/low controls, and a Vibe control. I'm not looking for these specific controls in a new amp but, since the family of amps similar to the P500H (e.g. the Harley Benton BA500H and the Redsub/Beta Aivin BT500H) are somewhat unreliable, I may need a new head in the future.

What currently available Class D heads provide a similarly flat response and decent tweakability?
 
#8
Glockenklang Blue sky. There is a a button to bypass the preamp. Having this option really helps you dial in a flat response. It is very tweakable too.

I've read somewhere that the Kustom KXb500 ( Not sure of the exact model name) is a very flat amp that can be tweaked very effectively.

Besides a flat response what other controls /options are you looking for? What is your price range? The Blue Sky isn't cheap!!! However the Kxb can be found used fairly cheap.
 
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#9
Markbass amps were, I believe, found to 'scope pretty close to flat in a Bass Gear Magazine test. (You'd have to doublecheck, but I'm pretty sure that's the case - @tombowlus might know.) LM2 and LM3 amps can be found used at decent prices. F500, with semi-parametric mid bands (if you want tweakability), more rarely so, but it happens. (If I ever sell mine, I'll let you know! ;)) To my ear, the LMs are a little warmer with more texture/detail in the mids than the F500. The F500 is quicker and chords have a bit better note separation/slightly more 3D quality.

I have a KXB500/and have A/Bed it with the f500 a few times. It doesn't sound "flat" to my ears, but any voicing it has is fairly mild and doesn't seem to get in the way or necessitate any weird EQ. I haven't 'scoped it - will have to see if there's an easy way to do that with a laptop and an Audio interface - maybe it really is flat or close to it. Compared to the F500, mids are a bit rougher (in a good way), lows slightly more extended and present. Through my MAS Flex cab, it's a bit more aggressive/forward in a mix than the F500 but doesn't sound wanky at all. The F500 is more smooth and full in the upper mids - upper register chords, again, sound more full and consistent with the lower register, but I'm being picky. EQ on the F500 is more flexible.

Never owned a Euphonic Audio amp but I played through an EA Doubler once or twice and thought it sounded more clean-and-clear than any of the aforementioned. I liked it, though I've heard they're a bit underpowered.

If you look through the KXB500 thread, I posted short, comparative clips of it, the F500, and a Mesa Walkabout - not with the EQ flat, though, I'm afraid.
 
#10
Just about all class-d "amps" are flat in a head. The pre-amp part of a "head" is not. The maker of the "head" will make the signature sound weighted. It's going to be a sound with knobs at noon that make the amp part sound like what the maker wants you to hear first. Many times it subtle and can be tweaked to get to flat. A simple RT app for a smart phone or PC can help you set it flat. You may find you like the signature sound better.
 
#13
BigBobbyBass said:
I find MarkBass amps to be pretty flat to my ears
Click to expand...

They have a reputation for being mid-present, but I think that is partly because a lot of amps (like GK which you noted) tend to be scooped. MB will be much stronger on mids compared to those.

I had a guy at the store tell me an MB is flat when the VLE and VPF filters are at noon. That's not true but it sounds like a lot of other scoopy amps when you do that.
 
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#14
Downunderwonder said:
GK amps flatten with a little bass and treble cut and a little boost to both mids. Contour off.
Click to expand...

Absolutely that was my experience too. Of course. most any amp can be made flat-ish in some EQ position but the OCD among us often like to have flat = noon on the EQ controls.
 
#15
Filters at noon on Markbass amps (which is how I often see them at Guitar Center) is both filters *heavily* engaged. Completely wrecks the sound, IMO, and I'd never run the amp like that. Filters are disengaged when run fully counter-clockwise. Markbass needs to make sure its dealers are educated on that. Even a little sticker on top of the amp or a hang-tag wouldn't hurt.
 
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#16
Or are you looking for a head with flat response with the tone knobs at noon? Passive vs active tone stacks can be confusing.

I have one head that is measured flat with bass:minimum, mid:maximum, treb:minimum.
I have another that is flat with bass:noon, mid:maximum, treb:noon.

Does that mean one head is flatter than another? No.
With both set to flat, do they sound the same? No.

All heads color the sound to the designer/engineers taste, or the brands tone goals.
In the Hi-Fi world, flat response is pretty dull @ lifeless to most.
 
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