adding a Power Amp

[johans]

hi guys,

i am using an SVT3-Pro head which for now is more than enough power for me, if in the long run i will need more power, instead of changing say to SVT4-Pro, i am thinking of getting probably a QSC power amp and run it through the SVT3-Pro ... what do you think?

is it possible to do that? i've never use any power amp before, can anyone told me how do you hook the power amp and SVT3-Pro? so i will still connect my speakers, my input jack as usual to the SVT3-Pro right? any of you have this kind of setup, an existing head + some power amp for more balls?

thank you guys

 

[Ben Clarke]

My angle is that to increase output, the best way to do so is at the speaker end.

In example, say you have a 300W amp. Pretty beefy, but you need more volume. You could pony up and buy a 600W amp. That's a lot more money, usually, and only buys you 3dB more output. Not much for your dollars. You could add a speaker, and gain maybe 5dB, with 3dB coming from the extra speaker, and the additional 2dB from increased power of most SS amp designs when operated at lower impedance soeaker loads. Again, not much for you money there, either.

In my mind, increasing the efficiency of the speakers you use can net you 10-15dB more output, and can be done rather inexpensively. The manufacturers don't want you to think this way, because your 1200W top of the line, high profit (nothing inherently wrong with that, BTW) monster amps suddenly become completely unnecessary for most of us.

 

[tkarter]

My angle is that to increase output, the best way to do so is at the speaker end.

In example, say you have a 300W amp. Pretty beefy, but you need more volume. You could pony up and buy a 600W amp. That's a lot more money, usually, and only buys you 3dB more output. Not much for your dollars. You could add a speaker, and gain maybe 5dB, with 3dB coming from the extra speaker, and the additional 2dB from increased power of most SS amp designs when operated at lower impedance soeaker loads. Again, not much for you money there, either.

In my mind, increasing the efficiency of the speakers you use can net you 10-15dB more output, and can be done rather inexpensively. The manufacturers don't want you to think this way, because your 1200W top of the line, high profit (nothing inherently wrong with that, BTW) monster amps suddenly become completely unnecessary for most of us.

What is the best way to increase your speaker efficiency?

tk

 

[Ben Clarke]

Ah, I thought my wording might be unclear there. Existing speaker cabs may be modified to increase efficiency by porting or otherwise increasing effective box size (to best take advantage of design parameters of the driver itself), but the highest efficiency can be obtained by using a driver of high sensitivity and horn-loading it. This is really the only way to get really high efficiency and maintain LF extension. In a direct-radiating design, there's always a balance to be struck between efficiency and LF extension, one at the expense of the other. Which is why we need big amps to drive the inefficient speaker designs common to the market today.

 

[Kennyhoe]

Are you already running the SVT-3 at 4 ohms? Poweramps aren't very expensive, you could get a QSC RMX 850 for around 3 bills. Then you would have roughly twice the power he has now with the option of adding extra speaker surface if you wanted to.

 

[Ben Clarke]

That's only $100 per dB.

 

[tkarter]

Thanks for the explanation.

tk

 

[Ben Clarke]

No problem.

BTW, my home stereo speakers are a 3-way, fully horn-loaded design, and put out 104dB with 1W input. They are unbelievably clear and undistorted with my 30W McIntosh tube amps. That's why I have this bias towards horn-loaded designs... It's not just max output, it's the lack of distortion at all levels that I really think is important. On the other hand, my B-15 can get a bit wooly at high volumes, so...

 

[technik]

I dont understand

 

[johans]

guys

thanks for all your help
but all your replies are far more complicated than what i asked for

now i am running svt3pro yes on 2 speakers, im just wondering in order to add up more power to my rig, yes i am looking at QSC RM850 or 1450, ... my question is ... How do you connect the power amp to the svt3? that's all

 

[Ben Clarke]

The expensive, easy way to go is just take a line from the pre out of the SVT ( I'm assuming it has one) to the input of the power amp, then out to your speaks.

 

[Ben Clarke]

Just looked at the specs of the SVT. You have a variable line level output. Use that output into the power amp and another set of speakers, then you're basically running two rigs, with seperate volume controls for each.

Still seems like along way to go to gain a few dB of output.

 

[johans]

by the way

anyone want to sell their rack cases?
i am looking for a 2 or 4 space, used is fine, as long the latches still good.

anvil, ata, grundorf, molded all are welcome ...
let me know

 

[technik]

The expensive, easy way to go is just take a line from the pre out of the SVT ( I'm assuming it has one) to the input of the power amp, then out to your speaks.

So let say he bought a power amp in e.g. 1000W, that means he will eventually get only the 1000W or 1000W + 450W (svt-3 pro) = 1450?

Because now we assume the svt3 as the pre-amp same as (svp-pro) right?

 

[xshawnxearthx]

you would plug it into the power section, just useing the svt 3 pro for the pre amp.


i am having the same problem. on my svt 3 pro, i have to shut off the eqbecause i am never happy with it on, and i just have the knobs on my music man in the halfway detent, because if i have it all the way up, my amp peaks out like woah.

so i have my gain like 1/4 and the volume cranking, along with the volume on my dbx662 up to like 3/4's it is still lacking a bit. if its mic'd no problem, if we are playing a hall, our an outdoor gig, it just suckkkkkks major ass.

im actually upgrading to the svt 4 pro, or the mesa 400+ i wan tto check out either or and go from there.

 

[Mobay45]

I turned off the EQ on my Hartke 3500 the first time I played my Stingray through it and haven't turned it on since. With so much control on the bass, I just don't seem to have a need for EQ at the amp. I can't imagine what a Bongo would be like with it's splt mid controls.

 

[xshawnxearthx]

I turned off the EQ on my Hartke 3500 the first time I played my Stingray through it and haven't turned it on since. With so much control on the bass, I just don't seem to have a need for EQ at the amp. I can't imagine what a Bongo would be like with it's splt mid controls.

i originally had a hartke, bought so much stuff to make it sound good, then i realized the amp just wasnt for me.

for some reason, the eq's on amps just suck with the stingray, unless i want a really warm jazz tone, or a very bass driven melodic r&b style, but for what i do, its always off.

ive found if i can crank the eq's on the stingray(without peaking everytime i hit the strings) it would be amazing. the sound is so bass and rich, even at the mid dentent, its prefect.

 

[Ben Clarke]

So let say he bought a power amp in e.g. 1000W, that means he will eventually get only the 1000W or 1000W + 450W (svt-3 pro) = 1450?

Because now we assume the svt3 as the pre-amp same as (svp-pro) right?

Using the pre out would bypass the power section of the SVT, while the variable line out wouldn't affect the Ampeg's operation at all. Adding a rig in that way (assuming 1000w amp with the same speaker setup as the Ampeg) would add about 6dB in volume.

 

[Ben Clarke]

if its mic'd no problem, if we are playing a hall, our an outdoor gig, it just suckkkkkks major ass.

That's why they make PAs. I carry my own mic and DI. I never want to hear that the engineer only has an SM57 leftover for the bass!

 

[xshawnxearthx]

yeah, if we are playign a club, or a big venue, i always bring a mic because if i dont, its either direct from my bass through the system, or the di on my amp to the system, which without the cab, it always sounds nasely.


so i sucked it up, and bought a really good mic, and now i insist that they do not use the di box and only use the mic. nowi have no problems with the sound through a huge house sound system.

the genre my band played(hardcore/punk) its usually a hall show, with a pa thats just for the vocals, which usually makes it sound good. 7 times out of ten, its a hall show where we dont mic anything. it always sounds good.


im just a sound guys worse nightmare. up untill i had the mic, i would be a pain in the ass about putting a mic on it because they were so headstrong on the di. they usually say they would but done have a mic, now that i bring th emic, they really have no choice.