Power Amp question

There are those on this board far, far more qualified than I am who can answer your first question.

However, regarding the advantages/disadvantages, I can provide some input, since I've just bought a whole new rig.

If you buy separate components (as I chose to) you have a lot more flexibility in terms of picking features that match your needs. With a head, if you buy the front end you want you're stuck with whatever power the manufacturer sees fit to give you.

For example, I wanted a lot of power for headroom purposes, so I knew I wanted at least 900 watts or so. If you look at amp heads with that much power, you wind up with a lot of stuff you may not want. In my case this was the SWR SM-900... a fine amp, but I don't need stereo or biamp capability, or a built-in limiter.

What I wound up buying was an SWR Grand Prix preamp and a Stewart World 1.2 power amp. The total cost was hundreds less than the SM-900 would have cost me (all this is used gear... my new rig cost $700 total), puts out 300 more watts into 4 ohms and has just the features I want. And the WHOLE DEAL weighs less than 17 lbs. Figure about 25 after I put it in a rack.

Also, if I want to get something different in the future, I can sell just the part of the system I want to replace. I lust after the Aguilar 680, but can't afford it. After saving my pennies, some day I will... but I won't have to shell out for another power amp, provided the Stewart holds up (which it should).

 

A good PA style solid state power amp shouldn't affect the tone much. About the only way a power amp shapes tone is if you buy a tube one and drive to its limit, but that's more of a guitar thing.

As for buying the two components seperately, it gives more overall flexibility for what you are looking for (tone and power), and the possibility of upgrades. Plus, higher wattage power amps are easier to find than powerful heads.

 

i too am looking into switching from a head to a rack systtem. exactly what featured do you SWR Grand Prix preamp and Stewart World 1.2 power amp have? What type of music do you play? what cabs do you power with it? what is it's totalk whattage?

 

A Poweramp / Preamp system may give you more flexibility. If you need more than say 1200 watts of power, it is the more economical to go with a separate poweramp. Bass Heads with that much power have high prices. There are some very cheap power amps on the market that deliver alot of power - a Nady SPA 2400 goes for under $400 new with 2400 watts bridges into 4 ohms. Note: I wouldn't buy a Nady Amp but they are cheap.
A Poweramp / Preamp system allows you to have a more module setup. This is true if you have multiple amps and cabinets. Maybe you have a 400 watt poweramp for smaller gigs and a 2000 watt poweramp for larger gigs. It is probably cheaper to have a single preamp with 2 poweramps than to have 2 bass heads with the same amount of power.
On the other hand if you have a bass head, you can always use it as a preamp to drive another poweramp for larger gigs.

 

I apologise for butting in into this thread, but after reading so many reviews and manuals I'm starting to think that the power amp is the way to go.

If you have a head, say HA3000, would taking a signal from the line-out and putting it into power amp line-in be a "normal", that is reasonable, way to do it? Or is it better to have a dedicated pre-amp for these purposes?

Also, would this mean that using bass cabinets for taking the sound out of the power-amp is normal too? Is this how it's all done in the pro-world? Sorry, I'm a little confused!! Any help would be appreciated. Thanks.

 

My head has a 'preamp out' jack on the back, I assume any line out jack would function the same way as being able to feed a power amp.

And yes, if you're running a PA power amp as part of a bass rig you should still use bass speaker cabs.

 

Thanks! That clears it up a bit, appreciate it.