Author Topic: Advice on power amps (Read 301 times)

a_martin · « **on:** April 27, 2012, 07:25:57 PM »

Hello fellow Bic heads,
I've neither owned nor kept up to date with the world of Bass Riggs since the early nineties. Recently I started doing some research and collecting components. Thus far I have an Alembic F-2B, Bag end infra mxb, Bag end deep red 18 subwoofer and a deep Red 4x10 cab.
I am missing power amps and am looking for advice, opinions, and experiences relating to power amps. I'll need one to power the 18 and another to power the Quad 10. I'm not going to get into ohms and watts. I can sort those things out on my own with a spec sheet. I am interested in hearing about things like tone quality, features (not advertising verbiage), reliability, and manufacturer reputation. I?m looking for accurate amplification with minimal noise and distortion.
Thanks for your replies,

Arunas

cozmik_cowboy · « **Reply #1 on:** April 27, 2012, 09:03:28 PM »

I?m looking for accurate amplification with minimal noise and distortion.

If you're willing to take bullet-proof reliabilty along with that, you want Yamaha. Most neutral amps I've ever heard, & the only ones that've never quit on me mid-gig.
(edited for mis-spell)

Peter

(Message edited by cozmik_cowboy on April 27, 2012)

elwoodblue · « **Reply #2 on:** April 27, 2012, 09:49:09 PM »

My Stewart World 2.1 has been 100% reliable for me...even on hot outdoor gigs when the mackie 2600's went for a thermal hiatus.
The sound is all there ( little coloration ).

slawie · « **Reply #3 on:** April 27, 2012, 10:23:09 PM »

The only thing I can give you a heads up about is to make sure the input impedence of the power amp matches the output impedence of the F2B. These two figures should ideally match so that you get full output power to your speakers

slawie

cozmik_cowboy · « **Reply #4 on:** April 28, 2012, 06:56:50 AM »

I guess I should add that, while I have used many power amps, I have no experience with Stewart, but ? - z is not the first person I've heard say really good things about them (though everyone seems to use the World series, which has been discontinued).

Peter

hammer · « **Reply #5 on:** April 28, 2012, 08:05:30 AM »

I'll second Peter with respect to Yamaha neutrality and non-colored sound. With the Phil Jones 9B & 6T cabs I use it makes even my early 70s EB-3 sound clear.

sonicus · « **Reply #6 on:** April 28, 2012, 10:18:43 AM »

Over the last 4 decades I have come across many different power amps . Over the last few years that I have been on this forum the opinions on power amps have been request a few times that I can recollect . I have offered my best opinion a few times as well on this subject . Here is a link to those threads;

bigredbass · « **Reply #7 on:** April 28, 2012, 04:31:11 PM »

OK, so Wolf, whaddya like ?

J o e y

sonicus · « **Reply #8 on:** April 28, 2012, 05:22:31 PM »

Hi , Joey
Currently I like Crest Power amps such as a CA9 , Fa901 , Vs900.

I like my old Yamaha P-2200's as well but they take up lots of space.

I would recommend getting a used Crest Ca9 for some one putting a rack system together. I would also recommend having your signal processing/preamp rack separate from a power amp rack .They can be stacked together but in separate racks not only for weight and transporting ease but also for EMI noise isolation purposes.

Wolf

edwin · « **Reply #9 on:** April 28, 2012, 07:26:48 PM »

I've used a number of different power amps. If weight is no concern, then a Crest CA9 is at the top of my list as it can be found for $500 or less and has the best bottom of just about any amp I've tried (unless money is also no object, then a 9001 is pretty awesome!).

Sadly for me, weight is an issue. I went to a Crown XTi4000, which is a great amp. Much, much lighter and almost as good sound, although the bottom end isn't quite as slamming. Still big though.

Last week, I was perusing Craig's list and found a QSC CX1202V, which is an install version of their top of the line Powerlight 2. After throwing in some Speakon outputs and 1/4 inputs, I took it to a gig last night and it's amazing. As much deepness as the Crest, although it seems a little quicker and it weighs much less than half. I only used one channel into 8 ohms and there was much headroom to spare. I don't know if it's an amp I'd seek out as the street price seems to be around $2k, but for $175, it was a steal. I've still got a few mods to make to make it a bit more user friendly, but I think the Crown is going to go on sale pretty soon.

JuancarlinBass · « **Reply #10 on:** April 29, 2012, 01:20:32 AM »

I would also recommend having your signal processing/preamp rack separate from a power amp rack .They can be stacked together but in separate racks not only for weight and transporting ease but also for EMI noise isolation purposes.

Not only that but, if, like me, you ever get in situation where you can ask for backline amplification (which may or not be in good shape, but that's another point), you can only bring your preamp/processing rack and shape your sound there, then go to P.A. and whatever they may have on stage. It may not be the best sound on stage, but you will have at least assured a nice tone shape on the P.A. system. I currently have it set that way, a 4spc rack with a tuner, a Yamaha PB1 preamp, a DBX173x compressor, and a Digitech RDS1900 DDL set up for chorus. When using power amp/biamp system I normally use a QSC GX5 power amp, and that is almost always enough to drive a Harke 4x10 and a Mesa RoadReady 2x10. That... or either the Hartke HA2000 driving a custom 2x10 cab or even the 4x10 alone.

a_martin · « **Reply #11 on:** April 29, 2012, 05:59:33 AM »

Thank you Ladies and Gentlemen,

I have been following the thread with interest and picked up several good points.

1) build separate racks for power amps and preamp/processor.

2) check input and output impedance between all components - I have a question on this one.

3) Power amp Manufacturers in the running (more research needed): Yamaha, Crest, QSC, and Crown.

Regarding matching impedance: The way I imagine the component line up is:
signal->F->2B->Infra MXB-> power amps. I have the specs from the F-2B Data sheet stating the output impedance are: stereo outputs at 40K and mono at 90k. The Bag end MXB specs for output impedance at less then 50 Ohms but no input impedance information, or at least I don't recognize it if it is there. While I consider myself a relatively educated individual I??ll admit I have short comings in electronics. I??ve started the self directed study of electronics several times but for what ever reason it has not stuck as well as other subjects.