Power amp for Avalon U5

I can't comment on a range of power amps, but about an hour ago I received a Stewart World 1.2 power amp in the mail and I will use it with my U5. It's a 1-space amp. I'll let you know what happens.

 

I've been using my QSC PLX3002 with my Avalon U5 for the last 18 months and they are most righteous together. Last night I rehearsed with my band using my new cab, The Big One, and together with my RIM Custom 5 the tone was without a doubt the best live bass sound I have ever heard. Absolutely incredible!

Alex

 

I saw the plx2 3102 for 750 at a local gc a couple days ago, I was mightily tempted, since it is half of the weight of my rmx 1450.

 

It's probably not the direction you had in mind but FWIW, I'm using my GB Shuttle as a "power amp" for my Avalon U5. lol, 600 watts and together they weight in at 10-12lbs...you won't find a lighter combination haha


-J

 

QSC is one of the top choices for a lot of clean power in a light weight package. Also one of the Genz reps here actually recommended the Shuttle for that purpose too! Even though it's a complete head, it can be used as a power amp and as Q said there's not much more power you can get in such a small and lightweight package (of what's easily available on the US market, in current production, prices and participation may vary, see store for details ).

The one thing is- if you want light weight, a U5 plus a power amp in a 4-space rack is not light weight no matter how you slice it. I understand that you already have the U5 and that it's great for many people's tastes, but if light weight is a consideration I would look to a preamp that is not only lighter than the U5, but doesn't require the added weight of the rack space needed to house it.

 

very few. i think ampeg may have made a 2 space mono power amp at one time. stewart is the only single space that comes to mind and that's stereo but you can bridge it.

i would go with using the u5 open and getting a gig bag for it. then i would get a light weight poweramp like a qsc plx or stewart and throw it in a 2 space rack case. That's pretty much what i do now except i pair my stewart 2.1 with a small discontinued swr head that is about 13" x 11" or so. Very compact and light

 

I was going to say the same thing! My shuttle 6 sounds pretty good just plugging my VT bass pedal into the FX return. A good 600watt power amp at less than 4 lbs and under $600. The head is pretty good by itself as well.

Just a thought.

 

Keep in mind that the U5 is a little down on output for driving a power amp.

Look for an amp that has an input sensitivity of +4dB which is about 1.2V. or you'll have trouble getting full output from your power amp.

I use a U5 with a PLX 2402 that has an input sensitivity @4ohms of 1.3V and @8ohms of 1.5v

The amp has so much power to spare that it's never been an issue for me and I love the rig but, if I was playing LOUD with an inefficient cabinet, it might very well be.

Just another thing to think about.

 

A commonly over looked issue. Some folks rave but they are playing Sunday Brunches. Hit it with some big noise and this voltage discrepancy rears itself big time.

 

The input sensitivity of the World 1.2 is 1V at 8 ohm. Is that good or bad for the U5? (I have no idea how this stuff works--while we're at it, which output should be used to go from the U5 to the power amp, the mic XLR or the line XLR?)

Although I haven't plugged the U5 into the power amp yet I did give it a spin with my Focusrite Platinum Bass Factory preamp/channel strip, and it sounded excellent. The improvement in tone over the power section of the AI Clarus SIII I've been using was very noticeable; and considering that I've been using the Clarus as the power amp for my U5, and I've loved the sound, I think I'm in for good things when I plug the Avalon into the Stewart.

 

Although I haven't plugged the U5 into the power amp yet I did give it a spin with my Focusrite Platinum Bass Factory preamp/channel strip, and it sounded excellent. The improvement in tone over the power section of the AI Clarus SIII I've been using was very noticeable; and considering that I've been using the Clarus as the power amp for my U5, and I've loved the sound, I think I'm in for good things when I plug the Avalon into the Stewart.[/QUOTE]

Sorry, OT
How would you describe the tone difference between the Stewart and the AI? I wouldn't think either would effect tone very much. I ask because I just won a Clarus on ebay but I had also been contemplating the Stewart World 600 for my Bassbuddy.

 

The U5 has tons of output - max input level of 24dBu, up to 30dB of gain and a maximum output level of 30dBu. It can drive any power amp to full power with ease.

Alex

 

Alex,
Will your U5 drive your 3002 to clip without the input of the U5 clipping like crazy?

Mine won't. I may need to have it looked at.

 

I need to do some more rigorous listening than I was able to do in the five minutes between explaining to my wife that I wanted to see if this new piece of gear worked and when she had to split, leaving me with the 16-month-old to take care of. I'll do it this afternoon when the baby goes to daycare, maybe post some soundclips.

My initial impression was that the Stewart sounded a little cleaner, more transparent, and a bit smoother than the Clarus power amp. And I could have sworn that the cabinet sounded like it was under better control--like the speaker could go louder before breaking up or something. But you know what happens when you get new gear--the ecstasy soon fades and you realize you really didn't change that much.

The Clarus as a power amp is really really great; that's what I've been using with the U5 for the past several months, and that's the rig that has given me my new-found appreciation for truly great tone. And also, when you see a Stewart power amp in person, even the single-space ones, and you're used to just schlepping a tiny Clarus, your first thought may be "I've made a huge mistake." I know I was feeling that way yesterday--it's a big old hunk of metal and it needs a rack case, and you really need to allot two spaces to it (even though there are plenty of reports on here of people cramming it into one space with stuff right above and below it with no problems). So anyway, don't feel any buyer's remorse about getting a Clarus instead of a World 600!

 

Easily. And I've never ever managed to clip the input of my U5. When I was wondering about getting a U5 I remember reading some posts about the input not having that much headroom - were they your posts?! Because the U5 can handle speaker level input it should be able to handle pretty huge input voltages without clipping.

Last rehearsal I once lit the clip limiter LED on my PLX3002 and that was with the gain controls on the amp at 12 o'clock.

I'm guessing something is up with yours!

Alex

 

You know I never really paid that much attention to it because getting 80% output wasn't an issue when I rarely need more that 25% of what a 2402 is capable of.

I'm assuming that the signal LED flashing indicates input signal clipping which I can make happen around 2 o'clock if my PJ5's preamp is flat (which it usually is) or maybe around 10 o'clock if I'm using a little low end boost.

Oddly, I goofed with it a little at my last gig and forced the signal light to just about solid on with the amp gain way down and couldn't detect any audible clipping which, with an Acme cab you would certainly hear if it was present.

I guess I better call Avalon and get some info when the left coast wakes up in an hour.
I may just be stupid. The thing sounds awfully good for being messed up.

Thanks for the heads up. Sorry for the hijack.

 

The signal LED does not indicate clipping, it just indicates that a certain amount of signal is being output (somewhere around 0dBu IIRC). RTM!

Alex

 

I only have access to what's posted at AVALON for the U5 which is thin at best and makes no mention of the signal light beyond it having one.

I tried to RTFM and apparently generated an ID10T error.

Given that the signal light isn't a clip light and is basically providing a completely useless piece of information then the U5 will in fact drive a PLX to full output with no trouble what-so-ever.

I am now if not smarter, better informed. Thanks. Saved me a long distance phone call right there.