Which power amp for bass?

[BassmanPaul]

If weight is not a factor for you have a look at Carvin's older DCM series power amps. I loved the DCM1000 and the DCM1500 almost as much. They were still selling off these older amps quite cheaply.

Paul

 

[Gwardar]

Thanks for the info.

All I really care about in a power amp is the uncoloured sound, lowest distortion at given power output and reliability. And hiss of course (for hiss they have, at least some).

I'll check some deals on Crest and QSC. Prefer to stay away from Yamaha, got a PA and the tone just sucks. Hissy and lifeless albeit it was really cheap.

Price-wise I'm not too worried. As someone pointed out in this part of the world you get caned no matter what you buy. So I'll have to splash out anyway, might as well get good stuff. Crowns have switchable voltage, so I hoped to get one from US, but I'm a bit worried about quality.

BTW - can you guys believe that a Vietnamese made Ampeg SVT CL in local shop is 5000 AUD (that's about 4100 USD only because AU buck dived down, used to be like 4700). That's a real bargain

 

[sawzalot]

I'm using a Crown XTi 1000 in my rig now and it's pretty decent. The best I think I had was a QSC MX-1500 driving 2 Eden 4x10's--that amp/cab combination was KILLER! The problem was the QSC weighed in at almost 50 pounds by itself, which got to be just too much. The XTi doesn't seem to have as much "slam" as the QSC did, but it's also only 18.5 pounds.

I also really like the digital signal processor built in to the XTi--I have it programmed with a high-pass filter around 20 Hz to prevent any big low-end spikes getting through to the speakers. Other power amps have fixed-frequency HPF's built in also, but at the time the XTi was the one I went with. And yes, it had a bad display board and it had to go back for warranty service. Right now it's doing fine though, and I don't have any plans to change it out.

As far as tone goes--I rely on my preamp section for that. What I want out of a power amp is volume, speaker control, speaker protection, etc. I always split it up this way: I spend lots of $$ on a good preamp to get the sound I want, and I get a good power amp to reproduce it without at high volume without damaging my speakers or the power amp itself. Usually any of the usual suspects (Crown, QSC, Crest, lab.gruppen, etc) will do just fine.

True story: Years ago I had a gig where I was biamping my rig for the first time. I was using my SWR SM-400 for the preamp and to power the highs and a Crown DC-300 to power the lows. I was in a hurry and somehow I managed to hook up the speaker output of the Crown to the speaker output of the SWR. When I turned on the power to the rig, the SWR smoked while the Crown sat there wondering what all the fuss was about. I wound up finishing the gig going direct into the Crown. Now THAT'S what I call a solid power amp.

Tom

 

[Rockit]

I've used 3 different power amps, QSC RMX850, Peavey PV900 and a Stewart World 1.2 since I started playing again 10 years ago. The QSC sounded great, was fairly cheap (200 bucks used) and plenty of power when I bridged it, 830 watts. If weight isn't a consideration because that thing weighs a ton, its a great amp for bass.

The PV900 is more suited to PA applications so forget that one.

The Stewart 1.2 which is what I'm using now is the balls. 1000 watts @ 4 ohms bridged, 1 rack space and 11 lbs. Very clean sounding and I've run it with a Sansamp RBI and a BBE BMax and I'm always happy. They are a little more high maintenance than other amps and you need to make sure you leave at least 1 rack space between the amp and another component because they can get hot and use heat sinks to dissipate the heat. Got mine used for $400 of a fellow TBer and new they run in the $750-1000 range, one of the best pieces of gear I ever bought.

 

[johnk_10]

Sorry to burst your bubble, but class D amps go against the ohms law formula .................

you previously stated full power (3000 watts) at 7 amps. there is no way that your (or any amp) amp can produce 3K watts with 7A amps of current. but if you think so, that's fine................

 

[tallboybass]

Surprised no one has mentioned the QSC PLX1804. 1800 watts, 13 lbs, shallow depth.

 

[fourstringburn]

you previously stated full power (3000 watts) at 7 amps. there is no way that your (or any amp) amp can produce 3K watts with 7A amps of current. but if you think so, that's fine................

You need to argue it with a Engineer like Bob Lee who is available on this forum. Until then, no need arguing. I'm telling you what a amp meter reads and what the spec's are.

You are using ignorance to decide what is and what not.

 

[Mr_Sore_Fingerz]

Crowns are AWESOME power amps, I run a Behringer Europower 1500 (considered by many to be "junk") and have ran it faithfully for almost 2 years now with no problems whatsoever out of it. Plenty of volume, no tonal coloration (I use a Sansamp RPM, so I want only it making the tone), and I've never had any functionality issues with it either. I bought mine used as well!

Anyhow, if you can, I'd say go with the Crown or a Carvin power amp. I'd look at price and wattage first, just like Bongo was saying.

 

[johnk_10]

You need to argue it with a Engineer like Bob Lee who is available on this forum. Until then, no need arguing. I'm telling you what a amp meter reads and what the spec's are.

You are using ignorance to decide what is and what not.

no argument here, but you're referring to it's 1/8 full power duty cycle rating and NOT full RMS power output, just like you did in the other thread. i read the post where agedhorse (engineer at genz-benz) stated that no amp can put out 3K watts rms drawing 7 amps if that's what you're referring to.

Thanks John!

Of course, it's preposterous to think that this amp draws 7 amps while delivering 3000 watts continuous and even more misleading where fourstrigburn says he measured it... no way. It draws slightly more than 30 amps at rated output of 3000 watts RMS. Now, take the 1/8-power FTC duty cycle derating and it's closer to 7 amps (adding in the proper derating and power factor figures).

and fourstringburn, i do not appreciate your ignorance comment. i've been an amp tech for more than 30 years. what's your excuse?

 

[jbybj]

I read somewhere on this forum, or maybe over at Alembic, that the damping factor has to do with how spiffy the low freqs get transduced.

I had a Crown XLS 202, lightweight, enough power for my use. Loved it. Damping factor of less than 200. Then I got a QSC PLX1602 for a great price used. more power, a little bit lighter, and a damping factor of over 400, ( I think). It sounds great too.

Now I don't really know what damping factor is, but if you have a choice, I'd say go for more! More Damping!

 

[johnk_10]

the damping factor indicates the ability of an amplifier to resist a change in it's output signal. for a bass amp, i've always considered that the higher the damping factor (to a point), the better the amps' ability to control low frequencies without becoming 'mushy'.

 

[TheWoodShed]

I've run a QSC PLX 2402 for nearly 10 years without a single issue.

 

[fourstringburn]

you previously stated full power (3000 watts) at 7 amps. there is no way that your (or any amp) amp can produce 3K watts with 7A amps of current. but if you think so, that's fine................

no argument here. i read the post where he stated himself that no amp cannot put out 3K watts rms drawing 7 amps if that's what you're referring to.
and i do not appreciate your ignorance comment. i've been an amp tech for more than 30 years. what's your excuse?

You apparently no little about class d amps. Are you telling me my amperage meter is lying? Do you know more than Bob Lee and others? I'm an not and do not claim to be a tech.

The facts are there, my amp has only a 12 amp breaker, get yet Mr. tech? breakers are often about 2 times the max draw aren't they Mr. tech? The spec's give 2 ratings, one with 1/8 pink noise and 1 with 1/3 pink noise as a testing value. Bob Lee has stated to me on this forum that the 1/8 pink noise rating is more of a real world figure not the 1/3 severe rating. Do you not know the difference between 1/3 and 1/8 pink noise ratings? most amps give both these ratings also.

Do you dispute Bob Lee's synopsis? At 1/8 pink noise the amp draws about 7 amps. An amperage meter confirmed this using the amp at full volume as I stated earlier. Have you tried a class D amp in your tech room?


Contact Bob Lee and get a professional consultation on this. I freely admit I'm not a tech or engineer but I surely don't argue facts if I don't know what I'm talking about. That is the definition of ignorance.

 

[johnk_10]

You apparently no little about class d amps.

you obviously have no idea about how any amplifier works, (class d or otherwise). if you did, you would understand why your claim of 3000 continuous watts RMS at 7 amps is impossible. and BTW, yes, i do own a few class amps, but there is no sense in educating you of that if you are unwilling to learn.

 

[Jim Carr]

Surprised no one has mentioned the QSC PLX1804. 1800 watts, 13 lbs, shallow depth.

+1
I second the QSC PLX1804. If I were going to replace my LEAD SLED (Crest CA-6) with something power amp-like under 48 lbs (21.8 kg), it would probably be that QSC unit.

My 75 lbs 4-space rack is getting "unattractive" since I compared it to a Carbine M6 and now have a Shuttle 6.0 as my B rig. Light weight and good sound can co-exist, it seems. Perhaps heavy stuff is going on sale?

My advice is to buy used. A lot of LEAD SLEDS are hitting the market now that light amps have proven themselves. I got my CA-6 for under $550 US. A good pre and a Crest CA-6 driving a 610 Epifani rig is a magnificent (and possibly very loud) thing.

 

[fourstringburn]

you obviously have no idea about how any amplifier works, (class d or otherwise). if you did, you would understand why your claim of 3000 continuous watts RMS at 7 amps is impossible. and BTW, yes, i do own a few class amps, but there is no sense in educating you of that if you are unwilling to learn.

your claim of 3000 continuous watts RMS at 7 amps is impossible

so why does my amp have only a 12 amp breaker and not a 15 or 20 amp breaker? answer that Mr. engineer!



Apparently you aren't man enough too accept a challenge. I given you facts from an respected Audio engineer/tech and test results I have done to confirm it, but you ignore it.

If you ever have the intestinal fortitude, PM Bob Lee with my claim and yours. Till then, Good night!

 

[mulchor]

so why does my amp have only a 12 amp breaker and not a 15 or 20 amp breaker? answer that Mr. engineer!



Apparently you aren't man enough too accept a challenge. I given you facts from an respected Audio engineer/tech and test results I have done to confirm it, but you ignore it.

It's a little rule made up by Isaac Newton.

It suffices to say that if you can get 3kW from 7 amps 110V, we'll have solved the world's energy problems.

 

[Jazzdogg]

"Can be" huge differences, sure, but it's not common for the differences to be easy to hear, never mind huge. For example certainly an all-tube Mesa or Ampeg power amp is going to sound different than an Acoustic Image Focus SA. But the extremes are not the norm--and the norm is very small differences.

As one common example, the Crest CA9 has a very, very low input sensitivity rating, while the Stewart World series that people like to contrast it against has a very high input sensitivity rating. If you feed the same preamp, with the same settings, into both--the Stewart will sound weak and thin, and the Crest will sound mighty and ballsy. But the source of the difference is in the usage, not so much the power amp.

Now, that's not to say they sound identical--they have different components, they will sound a little different. But when used properly, their tone difference is not huge at all.

And sometimes "you get what you pay for", but not always--for example my Carvin DCM power amp was fairly cheap, but it has served me faultlessly (and sounded great) for years. Really though the reason I put price at #1 was not to encourage going cheap, but rather to say that when buying a power amp I will set my budget first, then find the power amp that will do the best job within my budget. If you've got a tall budget, then you can move straight to the next item in line.

You said it so well that it warrants repeated reading. Well said, sir. I am in complete agreement.

I've used QSC and Carvin power amps for both bass and PA, and have never been disappointed by either.

The subtle differences that separate the very best amplifiers from the competition may be worth the cost in a quiet listening environment like a recording studio (or my music room at home ), but for working professionals, the additional cost might not be justifiable on a business basis. I'm willing to trade dollars for reduced weight, but I'm reluctant to pay more for a subtle improvement in sound quality that may not be audible during a gig - especially if it carries a higher price tag and weighs more.

I tend to establish how much power I need, then I survey the market until I've found several amps of known quality at various price points. Then I decide how much I'm willing to spend, and whether trade-offs are warranted, e.g., weight versus cost.

 

[bongomania]

I also plug this in to a amp meter to verify and sure enough with the amp dimed, the meter showed less than 8 amps draw.

Dimed how? The amount of current it draws is very much dependent on the input voltage you feed it, not just the position of the gain knobs. So since "diming" the knobs is only one small part of the equation, how did you determine that you were outputting 3KW?

Here is the CD3000 spec's copy pasted from Crest audio if you still doubt...

CD3000
current draw (120VAC) 1/8 power, 4 ohms 7.0A

According to that specs page, the 7.0 A figure is only for when it's plugged into a 20 A circuit. Plugged into a normal 15 A circuit the rating is 4.5 A. But aside from that, do you not see what you copy-pasted, that these numbers are only valid at 1/8 power? 1/8 of 3KW is 375W.

Also my amp has only a 12 amp breaker.

Wrong, your amp has a 20 A breaker. It's on that spec sheet.

so why does my amp have only a 12 amp breaker and not a 15 or 20 amp breaker? answer that Mr. engineer!

You might want to re-read the specs before insulting other people.

 

[bassguppy]

maybe my ears are not the most critical but....

I've owned a QSC RMX1450, PLX3002, PLX1804. I currently have a Crown Xti 1000.

The QSC RMX1450 and Crown Xti1000 were my favorites.

Crown also has their NEW XLS Series amps (not the old heavier series). Lightweight at 11lbs and not too deep.