Preamp/Poweramp setups

[Guttermouth]

i had a qsc rmx850 for a while and thought it was great.

[Kindness]

Any professional power amp will be able to deliver excellent low end response. In a lot of cases an integrated bass head will have a low end enhancing EQ curve built in even with the EQ flat that pre/power amp setups typically don't have. This can certainly lead to the impression that the dedicated head has more balls and is probably the basis for that idea. All power amps are not created equal but most pro-level units will be sonically indistinguishable from each other when gain matched and operated within their linear ranges. How power amps behave at and beyond their clean limits is what separates the men from the boys, so to speak. For low end, an amp that clips relatively gracefully and doesn't have a limiter circuit will typically sound better than an amp that limits and/or makes nasty crackling sounds under clipping. And in most practical situations, amplifiers reach their limits way more often than people realize, often on transient peaks too fast for the clip lights to react. That being said, don't be fooled into thinking one power amp is superior to another without making sure the playing field is leveled. You need to gain match. If you don't, the amp with more gain will invariably be perceived as sonically superior. And comparing an integrated amp to a preamp/poweramp setup is right out because there are too many other variables to make any judgement on the quality of the power sections.

 

[L. Ron Hoover]

Bull{censored}. {censored}ty power amps suck for bass: not all power amps are created equal, you know. Cheap power amps tend to "sag" and lack punch, and it's very noticeable at low frequencies. Keep in mind this what was said by the OP, you're misquoting: This statement CAN be true; it's certainly not true of all power amps but it is certainly true. I (and my bandmates and even girlfriend) heard the difference in punch moving from a cheap-ass VLP-300 to the RMX, and then another level of clarity of punch going from the RMX to the LMII (which IIRC uses class H technology very similar to the PLX series)

RMX: Class-H with conventional power supply.
PLX: Class-H with switched-mode power supply.
Markbass: Class-D with SMPS

I'm not sure you could attribute the sonic differences between the LMII and the RMX (which one?) to the power amp alone as there are other variables at work, unless you drove the RMX with the preamp of the LMII, and even then you're not guaranteed to have the same gain structure.

[wades_keys]

 

RMX: Class-H with conventional power supply. PLX: Class-H with switched-mode power supply. Markbass: Class-D with SMPS I'm not sure you could attribute the sonic differences between the LMII and the RMX (which one?) to the power amp alone as there are other variables at work, unless you drove the RMX with the preamp of the LMII, and even then you're not guaranteed to have the same gain structure.

 

I don't use the preamp section of the markbass; I use a sansamp into the FX return.

 

I appreciate your technical know-how, I really do.

 

But this didn't start out as a technical discussion: it started out as a PRACTICAL discussion.

 

I can hear the difference in "punch" with the same preamp into the power section of the LMII, my girlfriend can hear it, and my bandmates can hear it.

 

It's not EQ either or a frequency curve: it's a clarity and definition of sound - a response - call it punch, whatever.

 

I know what EQ can do to sound - {censored}, I've been playing amplified instruments for damn near 30 years, ya know?

 

And for gain structure: if you'll notice in my rack I have a submixer with VU meters.

 

I get my gain as close to unity as possible by using those VU meters; sure, there's going to be a little wiggle room, but not much.

 

As often happens on this forum, I get jumped on for some perceived technical inaccuracy, while other posters can make naive blanket statements that go un-challenged, such as this:

 

 

Jerkness is on about the "not being able to handle low freqs", b/c that just is retarded from the outset.

 

 

Yeah, I guess those in pro sound that can HEAR THE DIFFERENCE between amps in a sub/bass application are all just RETARDED.

[Kindness]

snip

 

 

Simmer down.

 

You haven't been jumped on, but you have provided inaccuracies that have been addressed. If you don't want to be corrected, don't make inaccurate statements.

[ThudMaker]

....If Mesa made a bass pre, I'd be going pre/power right now, TBH.

Yep. I'd climb right on that bandwagon, too.

[RSBro]

Yep. I'd climb right on that bandwagon, too.

Ben Strange @ TB has the ONLY Bass Triaxis in existence. I bet it's pretty slick. I think he runs it through a Power 400+ or whatever it's called. He's had some insane Boogie gear over the years and still currently.

[wades_keys]

Simmer down. You haven't been jumped on, but you have provided inaccuracies that have been addressed. If you don't want to be corrected, don't make inaccurate statements.

 

BS

 

The only inaccurate statement in this thread worth addressing is this one:

 

 

Jerkness is on about the "not being able to handle low freqs", b/c that just is retarded from the outset.

 

There's nothing at all RETARDED about hearing the difference in low frequency response and clarity between different power amps.

[Kindness]

BS The only inaccurate statement in this thread worth addressing is this one: There's nothing at all RETARDED about hearing the difference in low frequency response and clarity between different power amps.

 

 

That's already been addressed.

[RSBro]

@ W-K: you're on my ignore list so I don't see your posts but I saw it my email notification, and there's a BIG difference between perceived "punch and clarity" vs. "able to handle low bass and a B string", which the latter the OP addressed.

The former I agree with you, which is another reason I don't run pre/power anymore. It to my ears anyway doesn't sound as full or punchy as a hybrid/combo amp. How much of that is due to technical jargon, and matching gain stages @ unity or wtf ever, I couldn't even begin to fathom. But ALL true power amps I've played/owned handle low bass and a full B string without a sweat which is what the OP asked and I addressed from my own multiple experiences.

[tylytle]

I use a Crown XTi2000. Love it. loads of power and lowend punch.

[ThudMaker]

If you take a decent amp from QSC, Crest, Crown or any others from the quality amp manufacturers, the only way for there to be any audible difference is if you change to l_/\// cables on one amp and use cables bought from the Clearance Bin with other amps tested.

[wades_keys]

there's a BIG difference between perceived "punch and clarity" vs. "able to handle low bass and a B string", which the latter the OP addressed.

 

As usual, it comes down to semantics.

 

"able to handle low bass and a B string" possible meanings:

B string will sound like muddy, undefined {censored}

power amp will burst into flame

power amp will go into protect mode

 

pick 1 or all 3, and argue accordingly if you wish.

[L. Ron Hoover]

I don't use the preamp section of the markbass; I use a sansamp into the FX return. I appreciate your technical know-how, I really do. But this didn't start out as a technical discussion: it started out as a PRACTICAL discussion. I can hear the difference in "punch" with the same preamp into the power section of the LMII, my girlfriend can hear it, and my bandmates can hear it. It's not EQ either or a frequency curve: it's a clarity and definition of sound - a response - call it punch, whatever. I know what EQ can do to sound - {censored}, I've been playing amplified instruments for damn near 30 years, ya know? And for gain structure: if you'll notice in my rack I have a submixer with VU meters. I get my gain as close to unity as possible by using those VU meters; sure, there's going to be a little wiggle room, but not much.

Right, and that's all fine. I'm not saying that there isn't or can't be a difference between the power amps but that you need to make sure you're addressing all the variables before coming to a conclusion. It looks like you're controlling all the variables except for one really important one: Power amp gain. Do you know what the voltage gain of the Markbass power section is? Because it's quite likely not the same as the QSC's voltage gain and that can make a huge difference in how you perceive the sound. If the MB is a couple of dB hotter than the QSC, you might not perceive the increase in overall volume, but you will perceive the louder one to have more punch. This is well-documented in the literature on psychoacoustics.

You might be surprised at the differences that subtle broad-band EQ can make without being perceived as EQ as well... Of course, there may indeed be a difference between the two power amps with everything matched, which would most likely be attributable to behaviour at the limits as I mentioned before.

I'm not jumping on you, I'm just pointing out that sometimes anecdotal evidence is not necessarily telling you the whole story.

As often happens on this forum, I get jumped on for some perceived technical inaccuracy, while other posters can make naive blanket statements that go un-challenged, such as this: Yeah, I guess those in pro sound that can HEAR THE DIFFERENCE between amps in a sub/bass application are all just RETARDED.

Some of them are. Again, in a lot of cases, these folks are doing flawed tests to come up with their conclusions. I did it for years, until I realized that you need to match gains. A lot of the "differences" I heard between power amps went away when I did that. Matching gains also gives you a better idea of how the amps behave at clipping, which is really where the differences between power amps become apparent.

[moogieotter]

Are some people saying that "All pro-level power amps are the same" again?

[Kindness]

Are some people saying that "All pro-level power amps are the same" again?

 

No. In fact, the opposite has been stated very clearly by the most knowledgeable poster on the subject. If you are coming in here to start {censored}, you're looking for a ban.

[moogieotter]

No. In fact, the opposite has been stated very clearly by the most knowledgeable poster on the subject. If you are coming in here to start {censored}, you're looking for a ban.

 

 

I am not trying to start {censored} at all. I am genuinely confused about what the most knowledgeable people have said.

[Kindness]

I am not trying to start {censored} at all. I am genuinely confused about what the most knowledgeable people have said.

 

 

Then take some time to read it.

 

 

Any professional power amp will be able to deliver excellent low end response. In a lot of cases an integrated bass head will have a low end enhancing EQ curve built in even with the EQ flat that pre/power amp setups typically don't have. This can certainly lead to the impression that the dedicated head has more balls and is probably the basis for that idea. All power amps are not created equal but most pro-level units will be sonically indistinguishable from each other when gain matched and operated within their linear ranges. How power amps behave at and beyond their clean limits is what separates the men from the boys, so to speak. For low end, an amp that clips relatively gracefully and doesn't have a limiter circuit will typically sound better than an amp that limits and/or makes nasty crackling sounds under clipping. And in most practical situations, amplifiers reach their limits way more often than people realize, often on transient peaks too fast for the clip lights to react. That being said, don't be fooled into thinking one power amp is superior to another without making sure the playing field is leveled. You need to gain match. If you don't, the amp with more gain will invariably be perceived as sonically superior. And comparing an integrated amp to a preamp/poweramp setup is right out because there are too many other variables to make any judgement on the quality of the power sections.

 

[RSBro]

I addressed only the 4th post in this thread. And IME with various pre/power setups, most high-end amps have zero issues handling low bass freq's. YMMV. Does it give off a perceived sound difference? Possibly. But I don't know enough to get the most out of a pre/power setup, so I leave it to the pros to put it all in one big-ass 3U box for me!

[moogieotter]

Any professional power amp will be able to deliver excellent low end response. In a lot of cases an integrated bass head will have a low end enhancing EQ curve built in even with the EQ flat that pre/power amp setups typically don't have. This can certainly lead to the impression that the dedicated head has more balls and is probably the basis for that idea. All power amps are not created equal but most pro-level units will be sonically indistinguishable from each other when gain matched and operated within their linear ranges. How power amps behave at and beyond their clean limits is what separates the men from the boys, so to speak. For low end, an amp that clips relatively gracefully and doesn't have a limiter circuit will typically sound better than an amp that limits and/or makes nasty crackling sounds under clipping. And in most practical situations, amplifiers reach their limits way more often than people realize, often on transient peaks too fast for the clip lights to react. That being said, don't be fooled into thinking one power amp is superior to another without making sure the playing field is leveled. You need to gain match. If you don't, the amp with more gain will invariably be perceived as sonically superior. And comparing an integrated amp to a preamp/poweramp setup is right out because there are too many other variables to make any judgement on the quality of the power sections.

While this may be the posting of an expert who is technically correct. What practical information does this give to the OP or members of the forum?

1. Don't get one with a limiter and

2. Anything pro level is going to be the same.

3. Or maybe make sure you are ok with the sound at clip level.

*page break*

Reminds me of an old joke:

A man is flying in a hot air balloon and realizes he is lost. He reduces height and spots a man down below. He lowers the balloon further and shouts:

"Excuse me, can you tell me where I am?"

The man below says, "Yes you're in a hot air balloon, hovering 30 feet above this field."

"You must work in Engineering or Information Technology," says the balloonist.

"I do," replies the man. "How did you know."

"Well," says the balloonist, "everything you have told me is technically correct, but it's no use to anyone."

The man below says, "you must be in Management."

"I am," replies the balloonist, "but how did you know?"

"Well," says the man, "you don't know where you are, or where you're going, but you expect me to be able to help. You're in the same position you were before we met, but now it's my fault."

[Kindness]

 

1. Don't get one with a limiter and 2. Anything pro level is going to be the same. 3. Or maybe make sure you are ok with the sound at clip level.

 

 

I'm sorry that's what you get out of the post.

[moogieotter]

I'm sorry that's what you get out of the post.

What do you get out of that post? Or more specifically, if I was not a dense moron, what would I get?

[Kindness]

 

What do you get out of that post?

 

 

I can't state it any better than it's been written.

[moogieotter]

I can't state it any better than it's been written.

Sorry.

Not all of us are subject matter experts on all aspects of musicianship, and maybe that's why we used the internet to reach out and communicate with other more wiser musicians in hopes to expand our knowledge.

Is there like a HCBF with training wheels or something where the great unwashed and those without professional degrees and engineering backgrounds can grown and learn, without seeming like they are acting like a "retarded doosh" ?

[ThudMaker]

What do you get out of that post? Or more specifically, if I was not a dense moron, what would I get?

What I get out of that posting is that if I set up the gain structure of a QSC PLX, Crest CA, Stewart World, etc. to be the same, the sonic difference between the amps will be inaudible, provided the amps are operated within their clean limits.