Power amp questions

BassistofGUN · #1 09-18-2011, 03:41 AM

So, a friend is selling me an SWR Amplite and Headlite for 500$ total, minus the cost of the Speakon to 1/4" cables, since my cabs are all 1/4" inputs.

Everyone I've talked to suggests that I run each one of them into a separate cabinet [I have a custom made mesa 2x10" and a 1x15" to match each rated for 300 watts] Each SWR runs at 250 watts @ 8ohms.

Just a quick wondering though, how do I run these each into a separate cab, if the power amp doesn't have a preamp in it? or how would I set this up?

Thank you for all your help with my somewhat novice questions.

open.eadg · #2 09-18-2011, 04:27 AM

Connect the preamp out of the Headlite to the input of the Amplite. This way both amps produce the same tone.

BassistofGUN · #3 09-18-2011, 04:38 AM

So essentially, take the 1/4" direct on the headlite, to the input on the amplite, then the 2 speaker outs to the cabs? but this would run my entire rig at 800 watts, and speakers are setup for 600 watts. Is there a way of doing each amp to each cab? or am I misunderstanding in how this works from my end...? Sorry, I'm new to the world of power amps.

open.eadg · #4 09-18-2011, 04:49 AM

With the pre out connection you simply send the head's pre sound to the poweramp. This won't bridge the amps' power. You still have to connect each amp to one speaker cab, so you get a two amp setup where each amp "sees" one 8 ohm cab.

In other words, setup like this: bass -> amplite -> speaker out -> cab / amplite pre out -> poweramp in -> speaker out -> cab

It's no rocket science, a power amp is the same as a normal amp head, but without a pre.

steve_rolfeca · #5 09-18-2011, 05:15 AM

Just to make sure we're all clear on this, you must never use extra speaker cables to connect both amps to both speakers at the same time. That would probably kill your amps.

BTW, I'm curious to find out what this setup sounds like. Please post your findings after you give it a go...

The reason for my interest is this: If you daisy chain both 8 ohm cabs to the speaker output of the Headlite, it'll pump 400 watts into the combined 4 ohm load. When you daisy chain the preamp out of the Headlite to the Amplite's input, each amp will provide 250 watts to its respective cab, for a total of 500 watts.

In theory, a hundred watt boost is pretty insignificant at this level, and the two setups "ought" to sound roughly the same. In fact, the techie in me thinks you might as well leave the Amplite at home. Talking theory once again, where the Headlite/Amplite combo would come into it's own, is driving a pair of FOUR ohm cabs. At that point, you'd have 800 watts total system power, from an amp setup that fits in a book bag.

However, that's just theory. With the Headlite/Amplite combo, the power stages wouldn't be working as hard driving an 8 ohm load. In real life, they might sound less stressed, the fans might not run as often, or there may be other sonic benefits.

Only one way to find out...

BassmanPaul · #6 09-18-2011, 11:24 AM

Quote:

Originally Posted by BassistofGUN

So, a friend is selling me an SWR Amplite and Headlite for 500$ total, minus the cost of the Speakon to 1/4" cables, since my cabs are all 1/4" inputs.

Everyone I've talked to suggests that I run each one of them into a separate cabinet [I have a custom made mesa 2x10" and a 1x15" to match each rated for 300 watts] Each SWR runs at 250 watts @ 8ohms.

May I suggest that you retrofit Speakons into your cabinets. It's a simple task to perform this. Some lightweight amps actually have two output sections that are run bridged. I don't know if the SWR units are such animals but they could be. Running in bridge the barrel of the 1/4" phone plug will be live with respect to ground. Thus an accidental short to ground could take out your amplifier.

bongomania · #7 09-18-2011, 11:30 AM

Also, read the manual. Seriously. The Amplite was designed specifically to provide extra wattage for the Headlite--so there should be some pretty simple instructions in the manual.

BassistofGUN · #8 09-18-2011, 02:45 PM

I'll see what I can do for the manual. I've only ever owned a Beheringer 1800BRX head, and that was easy to daisy chain. I'm just trying to get used to better gear seeing as my last stack was bought in a pinch to keep up with a guitarist that had much better gear.

I'll work with it and see what I can do.
Thanks for all your help and continued input on this case.

Edit:
Here's the back of the amps. So I see the preout, but I'm unsure about the input on the Amplite. Is this 1/4", or am I looking at it wrong. Again, thank you for all the help with my gap in knowledge.

bongomania · #9 09-18-2011, 03:52 PM

The input is a "combo" jack that can accept either 1/4" or XLR.

BassistofGUN · #10 09-18-2011, 04:00 PM

Okay, that's kinda what I thought.

So I would take [if I'm correct, to run this as a 500watt system, one amp to one cab]

Bass>headlite>speakon>cab and Preout headlite>input amplite>amplite speakon>cab.

From what I've seen your posts as, this is the correct way to wire this.

bongomania · #11 09-18-2011, 04:29 PM

That does sound right, although I'm curious about the jack labeled "direct" on the Headlite, since it's not part of the DI section.

BassistofGUN · #12 09-18-2011, 04:43 PM

I was as well. I'm not sure what its for. I'll look up the manual when I get back home, and see what's up with it. Anyway I run this I'm sure it'll be a solid setup for the money. I've put about 1,600$ [after purchasing these heads] into this setup, and it should have cost much more.