OK, What's the Final Verdict on Class D?

[johnk_10]

My Crest audio CD3000 draws only a little over 7 amps peak at it's max 3000 watt output. This keeps from tripping circuit breakers especially if rehearsing in a household living room which is usually wired to a 15 amp breaker. This leaves plenty of amperage in that circuit to run the other players equipment. A class A/B amp at this power level would exceed 20 amps or more to achieve the same wattage.

i don't know where you're getting those specs, unless its another model? http://pro-audio.musiciansfriend.com/product/Crest-Audio-CD-3000-3000W-Power-Amplifier?sku=481646
here's the specs that i found online for it:

"Crest Audio CD 3000 3000W Power Amplifier Specifications:

•Model: CD 3000
•Stereo Power 8 Ohms: 800 Watts
•Stereo Power 4 Ohms: 1500 Watts
•Stereo Power 2 Ohm: 1800 Watts
•Bridged Power 8 Ohm: 3000 Watts
•Maximum output voltage: 85V rms
•Frequency response 1W @ 8 ohms: 20Hz—20khz, +/-1db
•Power bw rated power @ 4 ohms, 1% THD+N: 20Hz—20khz, +/-1db
•THD + N: <0.2% rated power @ 4 ohms, 1khz power @ 8 ohms
•Imd; SMPTE/DIN 4:1 (60 Hz / 7 khz): <0.35% @ -3 db below rated
•Damping factor: 400:1 @ 8 ohms (20 Hz to 100 Hz)
•Input CMRR: >60db @ 1khz
•Gain / input sensitivity @ 4 ohms: Selectable: x20, x40, or .775 V for full rated output power
•Input impedance: >20kohms balanced, >10kohms unbalanced
•Hum and noise: > -100db, A-weighted below rated power @ 4 ohms
•Crosstalk: > -60db below max rated power (1khz)
•Class: D
•Power supply: Linear with toroid transformer
•Circuit breaker rating (120V/230V): 20A /12A
•Current draw (120VAC) 1/8 power, 4 ohms: 7.0A
•1/3 power, 4 ohms: 14.0A•At idle: 1.5A
•Thermal emissions 1/3 Power, 4 ohms BTU / hr: 1024
•Cooling: Back to front via variable speed DC fan
•input connectors: balanced female XLR, 1/4" TRS, unbalanced 1/4" TS on Neutrik combo connectors
•output connectors: Five-way "touch-proof" binding posts and Neutrik Speakon connectors (which presents
•both outputs on the A Speakon for bi-amplified applications)
•controls: front panel: twin recessed stepped attenuators, power switch
•rear panel: signal ground-lift, mode select, gain select, circuit breaker
•LED indicators: signal level (5 element bargraph), protect, active, ACL / IGM
•Construction: 16-gauge steel chassis, cast aluminum front panel - optional handles available
•Dimensions (W x H x D): 19" x 3.5" x 15.375" (483 x 89 x 391 mm)
•Weight: 41.4 lb (21 kg)"

 

[JimmyM]

That's not a technical reason.

there's no technical reason tube amps should exist in the face of all this technology but tube amps are probably selling more now than they ever have. sales makes quibbling over technology completely moot. if it sells, people will make it.

 

[crusie]

Of course you will, but they won't go home telling all their friends about the lack of a bass player, they'll go home telling all their friends the band sucked.

sorry I really have to comment on this too - I know it's off topic. I don't know if you play in a band with 3-4 guitarists or what. I play in 2 bands - one 3 piece band (bass drums guitar) and a 4 piece ( with 2 guitars). I never have the problem of people just "feeling" my bass. it's quite audible and sits well in the pocket. reason for this is that my guitarists know that they shouldn't use too much lower register (read hertz) in their tone since it muds up the overall sound. this has been done in recordings for ages.
if you all choose to play in the same frequency I can understand the bass being washed out of the mix.
I'm by no means an awesome bassist - medicore at best ( still better than pete wentz lol). I just think that there's alot of bad bassist out there hiding behind the guitarists - telling people they play good " you just can't hear it..."

as for the class D amps - I play a Markbass LMII exclusively - never let me down.
I don't get the " it has to be old to be good" concept - if that's really the truth why do amp/bass makers even need an R&D department? things evolve

 

[bmc]

IMO, anything should be able to stand up to a couple years of hard gigging, even the cheapest stuff. If it can't, it should've never made it on the shelf for sale.

As far as not caring what the audience hears, that can be dangerous. I totally understand wanting yourself to sound the best you can and we do all this intricate bass tone stuff to please ourselves mostly but we're not the ones paying our bills, they are. Not to demean audiences in general too much, they certainly can tell the difference between what's good and what's not, they just don't know why. I can take all this technical stuff I've learned here and apply it and the 3 people in the audience who actually realize there is a bass player will say, man, you sound great, that's some mean bass playin', etc. but they still don't know why.

Face it, you're a bass player. Unless you look good, move around, get into it, have some stage antic or persona gimmick you're know for, you're a ways down the list, man.

Audiences pay attention to

1. Lead singer

2. Guitar player(s)

3. Horns if you have 'em, or the keys or the drummer.

4. Any other instrument that might be thrown into the mix.

5. Bass player but only if he sings at least backup. Otherwise you're number 6 behind the lights, the merchandise booth, or the hot chick begging for tips, unless you're a hot chick bass player, then you move up the list a notch or two. Maybe even close to the top if you're a hot chick bass player playing a Sadowsky in a band with relatively unattractive guys.

There. I fixed it for you.

 

[Munjibunga]

My Crest audio CD3000 draws only a little over 7 amps peak at it's max 3000 watt output.

A little aritmetic:

power = voltage times current, or P=IE.

So you're saying 3000 watts = 7 amps times X volts.

Solving for X, we get X = E = 429 volts.

So you've got 430V at your outlets?

So let's solve for current, assuming 120V at the outlet.

3000W = I x 120V, and I = 25A.

Now, that's if the amp is 100 percent efficient, and it's not. So you'd better have that thing on at least a 30-amp circuit if you're going to run at full power.

 

[KJung]

They're remarkably light and the manufacturers must be saving a fortune on production costs relative to retail, but now that the novelty is wearing off some and the amp mavens have had a chance to mess with them for a couple of years...has Class D really replaced the "conventional" bass amps we've all been playing for years? Are those forty-pound heads just boat anchors?

I've searched around and haven't really found anyone address this question head-on.

Thanks for any serious analysis.

I think you are confusing class D power amps with the power supply (SMPS). The power supply is what makes these lightweight amps really lightweight. Many of the micro amps are class D (I've been playing these SMPS/class D amps for 15 years as my primary amplification), but some are class A/B (Markbass LMII/LMIII), some are class G (GK I think), etc.

There was an issue with some of the early SMPS amps years ago sounding a bit thin down low (i.e. some of the Walter Woods models 10 years ago, etc.). This was such an issue that a couple of companies actually used an 'interim' design of combining an efficient and small class D amp with a toriodal power supply for more 'current' (I think that's the right term) and hence a nice combination of heft down low, but still relatively light weight (under 15 pounds... AE iAmp800, Epifani 502). However, these issues are a thing of the past, and even these companies are now using SMPS.

There is zero issue at this point with these small amps. Of course, there are some executions that are better (fatter, ballsier, etc.) than others, but this is the case with traditional, heavier amps also.

Amps like the TC Electronics RH450, the Markbass stuff, the TecAmp stuff, etc. are IMO among the best amps ever made. They all sound different though, so again, like any class of gear, there will be some that sound harsh to you, some that sound underpowered, and some that sound perfect

I would not buy an amp because it was a class D/SMPS design. I would also not eliminate any amp from consideration if it was class D/SMPS.

 

[cassanova]

there's no technical reason tube amps should exist in the face of all this technology but tube amps are probably selling more now than they ever have. sales makes quibbling over technology completely moot. if it sells, people will make it.

Are you talking about tube power amps, preamps, or both?

With the way tube emulation has evolved I don't see a technical need for all tube amps/preamps either. I've played through all tube amps that sounded brittle and sterile as well as solid state that sounded rich, fat, and warm. It's all in how the manufacture designs it to sound.

I don't like using the blind tests as examples but this is one where I bet you could take all tube compared to ss and class D type amps and most bassist wouldn't be able to tell which the all tube amp is. Toss in the fact that many bassists use some sort of effect to help fatten up their tone a bit and the challenge becomes even harder.

But like you said (only differently) manufacturers will continue to produce something as long as they know they will continue to turn a profit on it.

 

[cassanova]

A little aritmetic:

power = voltage times current, or P=IE.

So you're saying 3000 watts = 7 amps times X volts.

Solving for X, we get X = E = 429 volts.

So you've got 430V at your outlets?

So let's solve for current, assuming 120V at the outlet.

3000W = I x 120V, and I = 25A.

You lost me where I made it bold. What I mean is, I get the arithmetic behind it all, what I don't understand is the correlation of the volts/amps and how they apply to each other.

 

[wateroftyne]

I didn't have many great experiences with Class D amps up until I tried the RH450. My opinion changed overnight.

Finally, a Class D head with punch and girth. Love it.

 

[Boombass76]

I think that Class D is definitely here to stay. After having used a GK RB2000 and an Aguilar DB750 for years, which are both very heavy, I tried the Aguilar AG500, which weighted much less 8around 17 lbs.), and I liked the tone just as much.

So, I got a taste for lightness in amplification, which caused me to check out these ‘new’ Class D amps. Today, I use a MB F500 (I need the semi-parametric EQ on the mid bands for double bass), which weighs less than 5 lbs., and it spits out 500 great sounding watts.

I am not switching back

I may try out some of the other Class D amps on the market, but to me, weight has become a major issue when checking out amps. And that goes for cabinets as well – as lightness had become the new black in my world, I decided to check out some light cabs as well. So, now I use my F500 with one or two Epifani cabs, and it sounds just as great as the much heavier rigs I have been using in the past!

 

[mongo2]

has Class D really replaced the "conventional" bass amps we've all been playing for years?

It has in my stable.

 

[MikeBass]

RH450 = yes, and it's light. Personally I would not haul a heavy amp around at this point in time regardless of minor perceived differences in tone.

Thank you....I couldn't have said it better.

I LOVE the DB750 (and would slap your mother for a SA200), but the trade off in weight has me in the "4 pounds 900 watts" catagory for years to come!

That's 225 watts/pound with my GB 9.0.
Or with an SVT- 4.285714285 watts/pound.
Can the hot chick at the end of the bar tell the difference?
No, but loading out, you can attend to her MUCH quicker with a featherweight rig!

 

[will33]

Maybe I'm just old-fashioned or behind the times or something. Heck, I play an SM400S with a pair of homebrew 112 cabs and consider that my light, easily portable small club rig. I also thought it was cool when I got the poweramps in my PA rack down to 2 rackspaces each. There's also a Classic400 sitting here that needs an octet of power tubes, whenever one of my bass amps does go down, I'll be putting 4lbs. of tubes in that thing instead of buying a new 4lb. amp.

I have played the LMII, Shuttle and MB500 and liked the sound of all of them, just don't "need" one. Now if I lived in NYcity and took the subway to gigs or flew to gigs or had back surgery or something you can bet there'd be one in the pocket of my gig bag.

 

[jnewmark]

At age 61, I've pretty much been on the lightweight hunt for amps that can cut the gig for me in two different bands. I have tried a few and the one so far that does the job is the MarkBass F1. I don't know if it's a " D " , or "A", but at 4.5 lbs, it's a no brainer. I've yet to try one though that sounds like my '67 B15N ! Nothing I've tried in 40 years of playing sounds quite like that little baby.

 

[MikeBass]

I don't like using the blind tests as examples but this is one where I bet you could take all tube compared to ss and class D type amps and most bassist wouldn't be able to tell which the all tube amp is. Toss in the fact that many bassists use some sort of effect to help fatten up their tone a bit and the challenge becomes even harder.

I'm in the middle of finishing my bands CD.
This is the gear used thus far:
Genz Benz 9.0/AccuGroove Tri110 mic'd (Sennheiser 421 and/or AKG D112)
API "LunchBox" DI/mic-pre thingy
70's Jazz
Valenti J/MM 5
Warwick Streamer (with EMG's)
Roscoe SKB-3006
Roscoe LG-3000 (not yet, but will be trying it on Monday)
AND!!!!!! Roland V-Bass- modeling various basses and amps.
My bet is that pretty much no one here would be able to tell me which is a "real" bass/amp and one of the modeled basses/amp from the V-Bass.

I crapped my pants the first time I heard playback with the Jazz Bass model in the track.

What my post has to do with the OP...I dunno!

One of these days some manufacture is going to put DSP in the amp to replicate a big ol' SVT type tube amp.
Then, all bets are off IMO.
Technology is getting so good these days, it's getting REAL hard to tell the difference, if you can at all.

 

[MikeBass]

..... I'll be putting 4lbs. of tubes in that thing instead of buying a new 4lb. amp.

Awesome line right there!!!!!!

 

[Doc Halo]

As with most things nowdays from computers to appliances to even cars. They're all "disposable" as in, screw maintainence or repair, just throw it away and get another one.

As pertains to amps, this is a major deal-breaker for me. I really began to re-think my desire for a LMII when I read (here on TB) it's designed in such a way that if a certain chip fails the entire motherboard has to be replaced, thus making it cheaper to throw the amp away and buy a new one than to repair it.

Of course, this has more to do with keeping production costs down than it does with amp topology. When my EA iAmp 800 failed shortly after I bought it--it was part of the run that inadvertently used some counterfeit caps from China--Gary sent me a small snap-in replacement board, and I fixed it myself in about five minutes. I guess that's the difference between a $500 amp and a $1100 amp.

At the same time, I also wonder about the opposite extreme: If I understand correctly, Walter Woods amps are made in very small batches by hand, using the highest quality parts. But what happens when the reclusive Mr. Woods dies? Does anyone else understand his amps well enough to fix one when it fails? Does anyone else know where to get the parts? These aren't rhetorical questions; I'd really like to know.

Somewhere in this world there has to be giant junk mountains of computers, electronics or whatever all of them needing a 38 cent parts but it was easier to throw it away and get another one.

There are many such "somewheres," most of which are in underdeveloped or developing nations, and none of which are very pretty. PBS did a short documentary on the subject a few months ago, which can be found here.

 

[will33]

Another point of contention with these switching amps. Some of these things are so tiny, where the hell are you supposed to set your drink? They should come with one of those cupholders you clip on your mic stand.

 

[Lync]

i actually like the smaller amps better than the bigger solid state and hybrids. never really did get used to the sound of solid state amps. but the small class ab's and d's rock tonally as well as sizewise for me.

I agree...I am digging my Carvin BX500 more so every time I play it.

 

[Implosion]

You lost me where I made it bold. What I mean is, I get the arithmetic behind it all, what I don't understand is the correlation of the volts/amps and how they apply to each other.

Good ol' Wikipedia is always useful when science is involved.

The watt (pronounced /w&#594;t/) is a derived unit of power in the International System of Units (SI), named after the Scottish engineer James Watt (1736–1819). Its unit symbol is W. The unit measures the rate of energy conversion.

*One watt is equal to 1 joule (J) of energy per second.

*In terms of mechanical energy, one watt is the rate at which work is done when an object is moved at a speed of one meter per second against a force of one newton.
1W = 1Js-1 = 1kgm2s-3 = 1Nms-1

*By the definitions of the units for measuring electric potential (volt) and current (ampere), work is done at a rate of one watt when one ampere flows through a potential difference of one volt.
1W=1V×1A