Class D amps like Acoustic Image?...

[8strings0hair]

So from what I understand my AI Clarus is a Class D amp which is supposed to give it its nice warm tone.
I see a whole bevvy of new portable amps like the new Ampeg Portaflex, the Markbass, the GKs, etc...
Are all those Class D, and is that what makes the amp sound "warm"?...
Thanks for any input.

[GrowlerBox]

The pre-amp. The Class D refers to the power section, which has minimal impact on tone (some people disagree, but they're wrong ). They are small and light, and run relatively cool, meaning you don't need lots of cooling fins and fans and such to keep them running.

[kai_ski]

I would suggest looking at the EA iAmp series. They have been my preferred class-D amplifiers, because I like a very non-colored sound, with good eq options. Also they use class-D power, but toroidal power supplies in their larger offerings, so you get really full even response out of the power section. Their micro line is ~500W @ 4 ohms and weighs between 3-5lbs IIRC.

[Alexander Eddy]

[quote=8strings0hair;10357686]So from what I understand my AI Clarus is a Class D amp which is supposed to give it its nice warm tone.
QUOTE]

IIRC Acoustic Image says on their website that their amps are not "voiced" and provide a neutral tone, basically reproducing what you instrument puts out, not coloring it. I have an AI Focus, and absolutely love it, because I can get the sound of my bass accurately reproduced, in a hifi sense.

[KJung]

Originally Posted by 8strings0hair

So from what I understand my AI Clarus is a Class D amp which is supposed to give it its nice warm tone.
I see a whole bevvy of new portable amps like the new Ampeg Portaflex, the Markbass, the GKs, etc...
Are all those Class D, and is that what makes the amp sound "warm"?...
Thanks for any input.

The 'class of amp' has relatively little impact on the tone. 'Warmth' and other tonal characteristics typically come from preamp voicing.

Class D does affect efficiency (i.e., they don't generate a lot of heat and they don't draw a lot of power from the wall) and size (for example, the Markbass LMII/III is a class A/B amp and the F1/F500 is a class D amp with the same wattage output. The F1/F500 is significantly smaller than the LMII/III).

The real thing that makes 'micro amps' micro is the SMPS (the switch mode power supply that eliminates a typically large and heavy transformer). All micro's have these sort of power supplies.

So, IMO and IME, do not use 'type of amp' when making a purchase decision. The micro's (most of which are class D) all sound and perform quite differently regarding tone, frequency range and absolute volume.

[KJung]

Originally Posted by Alexander Eddy

IIRC Acoustic Image says on their website that their amps are not "voiced" and provide a neutral tone, basically reproducing what you instrument puts out, not coloring it. I have an AI Focus, and absolutely love it, because I can get the sound of my bass accurately reproduced, in a hifi sense.

I am a fan of the AI amps, but they are not any less voiced than any other amp. EVERY amp (i.e., integrated bass head) has its own internal voicing (frequency range, distortion level, inherent voicing, etc.), and I've yet the hear any two amps (or cabs for that matter) that are advertised as being 'flat and transparent' sounding anything like each other.

For example, many fans of AI and fans of Walter Woods and fans of the EA amps each describe their amps as 'transparent', 'uncolored', and 'you get out what you put in'. These three amps sound TOTALLY different from one another... so which one is the 'transparent one'

Better off to leave 'flat' and 'transparent' at home when deciding on an amp

[KJung]

Originally Posted by kai_ski

I would suggest looking at the EA iAmp series. They have been my preferred class-D amplifiers, because I like a very non-colored sound, with good eq options. Also they use class-D power, but toroidal power supplies in their larger offerings, so you get really full even response out of the power section. Their micro line is ~500W @ 4 ohms and weighs between 3-5lbs IIRC.

EA has switched to SMPS even in the larger offering now, since there is really no downside to SMPS (switch mode power supply) any more.

However, I always found the iAmp500/800 and Epifani 502 a 'clever compromise' back when they were developed. Many of us always felt that the Walter Woods amps (the first production class D/SMPS bass heads, as far as I know) gave up quite a bit of low end meat and girth when really pushed, and many felt it was a power supply issue with those very early SMPS designs.

EA and Epifani did a kind of hybrid design in the early days of more mainstream companies offering 'lightweight amps' by using a class D amp to reduce size, weight and to increase efficiency, but still using a toroidal power supply to provide low end meat and girth. Whether you like those amps or not (like anything else, they have their own inherent tone profile like any other), they both HAMMERED down low, and were smaller and lighter than the typical full sized Eden or SWR amp of their day.

Things have come a long way in the 10 years or so since those models were introduced, but again, a clever 'bridge' sort of design between the 'old heavy ss amps' and the new class of ultra light SMPS offerings.

[KJung]

As you can tell, I love this topic. I've been using class D and/or SMPS amps for 20 years now (since my first Walter Woods), and even owned the infamous GK1200 combo, which was one of the first 'non Walter Woods' class D/SMPS designs, in the 80's I think. (Edit: I think it was called the 1200... it was the single 15" driver in a metal box with the horrible 'pink and blue' graphics!. It sounded good for its day, and was WAY ahead of things... lightweight, small, class D/SMPS, built in tilt back stand... same pre as the 400/800 series GK).

[Type-55]

I never thought the AI Clarus had a very warm sound.
Very uncolored and neutral. Warm to me is Mesa, Alembic F1 and Aggie
to name a few. I agree the tone is in the design of the pre.

[KJung]

Originally Posted by Type-55

I never thought the AI Clarus had a very warm sound.
Very uncolored and neutral. Warm to me is Mesa, Alembic F1 and Aggie
to name a few. I agree the tone is in the design of the pre.

'Warm' is one of those terms that is hard to exactly define, and everyone has their own definition. My definition of 'warm' is that bit of midrange distortion (the good kind), and typically a bit of bump in the lower mids, and also a bit of softening of the upper mids.

Again, if the AI is uncolored and neutral, than literally every other amp made is extremely colored and not neutral, since the AI 'sounds like an AI' and sounds different from other amps marketed as 'neutral and uncolored (AI, Walter Woods, etc., etc.).

If you directly compare a Walter Woods (very bright, very open down low, very clean in the midrange, and a full dose of upper treble extension and lower treble/upper mids) with an AI amp (higher low mid to deep bass ratio, a bit more 'character/distortion' to my ear in the mids, and a much less 'bright' upper mid voicing with a more attenuated/lo passed top end), you will hear what I'm describing.

IMO and IME!

As I always post, every amp seems to sound 'neutral' transparent' to a user who likes that particular amp!

[8strings0hair]

Thanks for all the great info guys!

My main reason for asking is that I tap on an 8 string guitar (tuned to low E) and had to find an amp that was portable (I gig in NY) but had more "warmth" than most solid state guitar amps.
I have been using my Clarus extensively for the past 7 years, and absolutely love it.
But I'm always looking for an alternative and/or backup, and with all the new lightweight amps coming out I was curious about what Class D really meant. Thanks again for enlightening me!

On a side note, I'm definitely intrigued by the new Ampeg Portaflex (especially at its price point), but since my requirements are somewhat unique compared to a bass player's perspective, I might just have to pull the trigger and try it out for myself.

[GrowlerBox]

Originally Posted by 8strings0hair

On a side note, I'm definitely intrigued by the new Ampeg Portaflex (especially at its price point), but since my requirements are somewhat unique compared to a bass player's perspective, I might just have to pull the trigger and try it out for myself.

You should definitely give it a try. I would just encourage you to try as many as you can, and not be put off by myths concerning power stages. "Warmth" is at best a difficult quality to describe, and you'll only know what you like when you hear it.

On a slightly different, but related, note, I've always been puzzled by demands that an amp "sound like my bass". What does your bass sound like when it's not played through an amplifier? Acoustic uprights notwithstanding, surely your bass "sounds like" your entire signal chain. N'est ce pas?

[Alexander Eddy]

Originally Posted by GrowlerBox

You should definitely give it a try. I would just encourage you to try as many as you can, and not be put off by myths concerning power stages. "Warmth" is at best a difficult quality to describe, and you'll only know what you like when you hear it.

On a slightly different, but related, note, I've always been puzzled by demands that an amp "sound like my bass". What does your bass sound like when it's not played through an amplifier? Acoustic uprights notwithstanding, surely your bass "sounds like" your entire signal chain. N'est ce pas?

It also applies when you play a large hollowbody with a piezo bridge, like I do

[GrowlerBox]

Originally Posted by Alexander Eddy

It also applies when you play a large hollowbody with a piezo bridge, like I do

Fair enough, but this demand comes most often from slab players, at least on this side of TalkBass. I'm certainly not saying that all solid-body basses sound the same, but they're all plugged into something. The most "hi-fi" sounding amp available (whatever that may be) is not going to sound like your bass unplugged, and if it did, you probably wouldn't like it.

[Type-55]

I guess the terms used to describe audio circuits are some what personal.
When I tried the AI line of stuff years ago with an electric bass the AI amp compared to
Eden, Mesa, Ampeg, Ashdown, Alembic, Aguilar and SWR sounded cold and sterile. TOO NEUTRAL. Not my definition of warm at all. I tend do like warmer stuff though.
Pick the flavor you like.

[KJung]

Originally Posted by Type-55

I guess the terms used to describe audio circuits are some what personal.
When I tried the AI line of stuff years ago with an electric bass the AI amp compared to
Eden, Mesa, Ampeg, Ashdown, Alembic, Aguilar and SWR sounded cold and sterile. TOO NEUTRAL. Not my definition of warm at all. I tend do like warmer stuff though.
Pick the flavor you like.

I would agree there.... I think we are using the term the same, but just differing in the level that we are talking about. I agree, compared to your list above, the AI's are clean, 'hi fi' machines. Compared to Walter Woods and EA, not so much.

It's amazing how the 'jazz guitar' guys have adopted the AI bass heads... that 'warm but still clean and accurate' sort of tone profile works will with those hollow-body jazz guitars. I play with a guy on occasion who uses one of the old NY heads (I think that was the name... that 'mini Clarus') and one of the little Raezor's Edge speakers (or whatever they were called). That has become a classic jazz guitar rig.

As reported by a few above, something about the voicing and design of that AI preamp is really special with piezo loaded instruments, which I guess makes sense given their design goals of being focused on DB amplification.

[Swift713]

I love my Clarus and I agree that it's quite "warm" compared to my PJB Bass Buddy or a mixing board but much more transparent or neutral than most Fender, Ampeg, GK, etc. amps. Through my fEarful 12/6 the Clarus is really super sweet, the warm side of super clean.

[plangentmusic]

I love my AI, it just was a tad underpowered so I went to a MarkIII. Both have a nice flat, clear, pure response. I still use the AI for upright amping.

One very cool feature of the AI is that the cable is inserted on TOP of the head. In that way, it doesn't pull out. And you can see your controls when standing over your amp. Very smart.