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Does the power amp matter ?
- Thread starter crispygoat
- Start date
The only difference I can think of is weight, how noisy (fans) and at what level and in what way the clipping circuit kicks in and starts limiting the output.
The last point is probably the most important, for me anyway, I used to have a QSC PLX which was 300watts & 4 a side I seem to remember (sold it to go to uni) and that could go loud and keep getting loud when I turned it up and eventually would start clipping and at that point would simply not get any louder. My cheap replacement Peavy PV900 which is still 300watts a side is heavier, noisier and doesn't go as loud. DDT kicks in and a lot earlier and the perceived maximum usable volume is no where near the QSC.
No idea why, QSC is probably a completely different class amp.
The last point is probably the most important, for me anyway, I used to have a QSC PLX which was 300watts & 4 a side I seem to remember (sold it to go to uni) and that could go loud and keep getting loud when I turned it up and eventually would start clipping and at that point would simply not get any louder. My cheap replacement Peavy PV900 which is still 300watts a side is heavier, noisier and doesn't go as loud. DDT kicks in and a lot earlier and the perceived maximum usable volume is no where near the QSC.
No idea why, QSC is probably a completely different class amp.
That's just classy; I don't like what you said, so I'm on crack...
My issue with your post is not of tubes vs/ transistors. It' s one of bias and fairness. You categorically stated that all the people who do not prefer switching power supply amps are ignoring scientific fact in favor of 'gut feelings." That is not true.
You DID take sides unsolicited. There is no other way to take that post.
Why? Again, evidently I am wrong just because I disagree with you. Why is it meritless? I have rasied several questions that the supposed "science" crowd completely ignore precisely BECAUSE they do not have the scientific fact to back their position.
That's not accurate in my view.
That's a startling admission.
...but not all, which is what you said.
Yes you did:
That statement says that 6146 SVT's are cleaner than 6550 SVT's, which is false.
My view is NOT opinion. Look at the datasheets for Link Removed vs the Link Removed The 6550 puts out more power.
It may sound cleaner to you, but it isn't.
I personally have both an all-tube 200w SLAVE, or 'power' amp.
AND - a SS 1600w transistor power amp.
Very different animals. But that's totally subjective and opinion based.
For the sake of the thread - I won't post that here.
When I bought my Solid State power amp - I demoed out about 4 or 5 different brands of SS poweramps, all in different price brackets. And I have to be honest - I could not really tell any major perceivable difference.
Sure the data sheets supplied by the company's suggested which was better, but besides a very slight hiss at loud volumes on one or two amps (which could have been power supply I've been told) - they all sounded very similar, if not totally the same.
So that's when weight, size, power handling, heat, fans, price and length of warranty will make your decision for you.
Go try 'em out,
smo
AND - a SS 1600w transistor power amp.
Very different animals. But that's totally subjective and opinion based.
For the sake of the thread - I won't post that here.
When I bought my Solid State power amp - I demoed out about 4 or 5 different brands of SS poweramps, all in different price brackets. And I have to be honest - I could not really tell any major perceivable difference.
Sure the data sheets supplied by the company's suggested which was better, but besides a very slight hiss at loud volumes on one or two amps (which could have been power supply I've been told) - they all sounded very similar, if not totally the same.
So that's when weight, size, power handling, heat, fans, price and length of warranty will make your decision for you.
Go try 'em out,
smo
I must say I differ with the consensus here...
Yes, a power amp should not color the sound. Most of them do not, until they begin to reach their limits. When pushed hard, most amps will color the sound in some way.. usually not in a good way. Also, if you clip the input stage, obviously you will have some problems.
You may notice on the specs for most amps, they give distortion ratings in stereo for the entire frequency range, then they give 4 ohm mono distortion ratings for 1k only. Why? because the amp can't get those high numbers across the spectrum. The low frequencies in particular start crapping out.
That being said, just know that headroom is key. Crown recommends an amp's rms rating should be 1.5-2 times the speaker's rms rating, and the amp should not be operated above 7. I totally agree.
Yes, a power amp should not color the sound. Most of them do not, until they begin to reach their limits. When pushed hard, most amps will color the sound in some way.. usually not in a good way. Also, if you clip the input stage, obviously you will have some problems.
You may notice on the specs for most amps, they give distortion ratings in stereo for the entire frequency range, then they give 4 ohm mono distortion ratings for 1k only. Why? because the amp can't get those high numbers across the spectrum. The low frequencies in particular start crapping out.
That being said, just know that headroom is key. Crown recommends an amp's rms rating should be 1.5-2 times the speaker's rms rating, and the amp should not be operated above 7. I totally agree.
I must say I differ with the consensus here...
Yes, a power amp should not color the sound. Most of them do not, until they begin to reach their limits. When pushed hard, most amps will color the sound in some way.. usually not in a good way. Also, if you clip the input stage, obviously you will have some problems.
You may notice on the specs for most amps, they give distortion ratings in stereo for the entire frequency range, then they give 4 ohm mono distortion ratings for 1k only. Why? because the amp can't get those high numbers across the spectrum. The low frequencies in particular start crapping out.
+1.. that has been my experience. It seems that there are different levels of low end delivery from various SS amps that have very similar published spec's. Until VERY recently, the very lightweight power amps did seem to lack a little oomph in the low end compared to their lead sled brethren. However, it seems the low end delivery of big, heavy toroidal power supplies and uber lightweight switching amps (and everything in between) is becoming more similar by the day... which makes me and my back very happy
Hello ZGotts,
Do you happen to have a link or reference to a manual or other doc when Crown states this? I'd like to research it.
thx
My systems comprise of pre-amps containing tubes and SS Stereo poweramps. I run my pre-amps flat and do any tone shaping I need using my pickup blend and/or my onboard controls. I did at one time think of building a pre-amp without any contols except gain but never got round to it. I use both Carvin (DCM1000 & DCM1500) and Mackie (FR-M1400) power amps and I use which ever one I grab first. They all sound the same to my old ears. For me the biggest part of "My sound" comes from my speakers (Acme B2), my basses (Carvin six strings) and my hands.
Would I use an all tube amp? Yes, but at my age I no longer relish the thought of carrying one. Can you imagine what a 1KW tube amp would weigh or cost? Truth be told I don't much relish the thought of toting my SS poweramps either. I am thinking of going with class D so called 'digital' poweramps. I played through a 1 rack space Peavey in a rehearsal room and was pleasantly supprised by it.
A lot is said about how an amp behaves at it's limits. In this regard tubes are better than SS however I never drive my equipment that far. If one of my amps begins to struggle with the demands I make, I would simply buy a bigger amp. IMHO driving an amp to it's limits is abuse and will lead to premature failure. But then that's me, I'm sure others will disagree and more power to them.
So to answer your question IMO and in my experience one poweramp is much like another. Kept within it's ratings and not overdriven it really doesn't matter all that much if you use tube or SS. SS stereo amps are SO cheap at the moment I think you should consider using one.
Good luck with whatever you choose to do.
Paul
Bob Lee (QSC)
In case you missed it, I work for QSC Audio!
- Jul 3, 2001
- 12,668
- 2,036
- 67
- Disclosures
- Former Technical Communications Developer, QSC Audio
Bongo, I don't make statements in favor or against switch-mode or conventional power supplies. I don't inherently like or dislike either type. Either can be designed and implemented well or poorly. The proof ultimately lies in their performance supplying power (they don't perform any EQ functions) to the amplifier circuitry.
seamonkey- no link, just lots of time floating around on their forums. It's apparently a standard rule in pro audio. Do a search on here for over/under-powering speakers, lots comes up on the matter.
I read a great response today in another thread that said it doesnt really matter (over or under), just as long as you have a rig that is a bit more than what you need for the gigs you do. Thats a good way to close that argument.
One other thing that hasnt come up: published vs. real-world performance. Case in point: my main head, a mesa m-pulse 600, vs my backup, preamp -> behringer EP1500. The behringer is rated over twice the power, yet the mesa is just as loud, if not louder. Anyone else have similar stories?
My opinion? You get what you pay for. Save up for something good, then don't worry about it.
I read a great response today in another thread that said it doesnt really matter (over or under), just as long as you have a rig that is a bit more than what you need for the gigs you do. Thats a good way to close that argument.
One other thing that hasnt come up: published vs. real-world performance. Case in point: my main head, a mesa m-pulse 600, vs my backup, preamp -> behringer EP1500. The behringer is rated over twice the power, yet the mesa is just as loud, if not louder. Anyone else have similar stories?
My opinion? You get what you pay for. Save up for something good, then don't worry about it.
Well, like tube amps, watts and volume is a topic for another thread. Or better yet, go read some of the closed threads on the heavily debated issue.
Bottom line - watts does not equal volume.
Most people by default think that 1200 watts is 'twice as loud' as 600 watts. Not so. That's not even a doubling in head room.
By the way, back on topic...
I can't tell an audible difference in tone from my Mackie FR1400 (1400 watts at 4 ohms bridged), QSC CX 302 (1400 watts at 4 ohms bridged) and my Behringer EP2500 (2400 watts at 4 ohms bridged). I can tell you that the Behringer weighs a TON in comparison to the Mackie and QSC (I think it's 67lbs!).
Yes Powersamps matter! I've AB'd QSC and Stewarts and the Stewart was SO much cleaner, therefore better for modeling in my book, than the QSC.
Stewart World series amps are great.
Oops... I just sawthat QSC has posted here. No offense sir.
Yes Powersamps matter! I've AB'd QSC and Stewarts and the Stewart was SO much cleaner, therefore better for modeling in my book, than the QSC.
Stewart World series amps are great.
Oops... I just sawthat QSC has posted here. No offense sir.
To be sure, did you AB the QSC and the Stewart with the exact same bass, preamp, and effects path and with the same speaker cabinet? In other words, did you try to duplicate the tests as much as possible? Did you match gain as well?
There are some threads on here about proper procedure and setup when AB'ing equipment. The unfortunate truth is that while you may think you have done everything to do a proper AB, you may have missed something simple such as proper gain matching that could sway or skew the results in a negative, and therefore incorect manner. I tend to think this may be the case with your test, especially considering you mention the issue of one power amp being 'cleaner' (a subjective term, no less) than another. When by design all solid state power amps should be clean when operated within their published ranges and specs.
If you did follow proper AB test procedures, my apologies in advance. You failed to mention that in your post.
alexclaber
Commercial User
Even if there is a difference when tested properly - which I doubt - the variation is still minuscule compared to the variation in speakers. In which case, what speakers are you using? They better be amazing!
Alex
I think the Poweramp does matter.
I've had a few and each upgrade saw a vast improvement.
Starting with QSC to Crown and a couple others. Now it's chord Electronics and I'm very happy with it.
More important though than the parts of a system( or somewhat as important) is that the components get along.
I've had a few and each upgrade saw a vast improvement.
Starting with QSC to Crown and a couple others. Now it's chord Electronics and I'm very happy with it.
More important though than the parts of a system( or somewhat as important) is that the components get along.
Everything - power amp, preamp, cabs, bass, fingers, etc. - matters. The degree to which it matters to some may be more or less than the degree to which it matters to others.
One thing on which most will agree - it doesn't matter to the audience as long as you're rockin' and groovin' baby
One thing on which most will agree - it doesn't matter to the audience as long as you're rockin' and groovin' baby
Sorry, sir, but your post is wrong.Sure, in a wrong kind of way.
Grandma always said two wrongs make me right.
