New to Power Amps and Need Help

BargainShopp3r · #1 02-02-2012, 04:54 AM

I find so much useful information on this forum, I think its time I actually post something. Sorry if its lengthy.

Right now I'm using an MXR M80 basically as a distortion pedal, but I'd like to use it as a PreAmp/DI, but I'm just getting into buying better gear, and was weighing the option of the Power Amp route. But I can't tell which Power Amp would be best for running my rig.

Current Rig: Squier VM Jaguar HB>Boss GE-7 EQ>MXR M80>Behringer BX4500H>Ashdown ABM 8x10 Cab.

I just got a new job, and the vocalist in my band works at Guitar Center, so I'm trying to buy up some gear. I'm not limited to what is available through GC though.

So where should I go from here? Looking for a tone reminiscent of Circa Survive.

Thanks for the help!

basscooker · #2 02-02-2012, 05:40 AM

With what i see here, removing the Behringer will help.

but really i'm not sure anything you have here has sufficient preamping (removing the head) also could i suggest using the GE-7 at the final stage in the chain before the amp. get a power amp that is mono or will bridge. shop for RMS ratings around 1/2 of your cabs power rating to 3/4 at most. also don't forget about your cab's impedance. is it 8 ohms or 4?

To Behringer: "You are the weakest link, goodbye.":P

bongomania · #3 02-02-2012, 05:45 AM

Start by finding a power amp with a very low input sensitivity rating, like 0.7 V to 1.0 V. This number is found in the spec sheet. A low sensitivity rating means your pedal can do a stronger/better job of driving the power amp.

Alternately, you can use a micro amp head as a power amp! Just plug your MXR into the effects loop return jack, and it will bypass the preamp built into the amp head.

The benefit of using a traditional racked power amp is you can easily get thousands of watts if you want. The benefit of using a micro head as a power amp is that they are so small--as long as you only need 350-500 watts.

BargainShopp3r · #4 02-02-2012, 05:52 AM

Yeah I know! It was only $75 on craigslist and I needed an amp asap.

So I couldn't run the M80 DI pedal as a pre amp? I intend on getting a BBE sonic maximizer, a real EQ (Rackmount or Bass pedal haven't decided), and some sort of compressor.

The cab is 1200W continuous, and 4ohms

@bongomania well this is where I get lost, because i can't find any mono power amps, and I don't understand "bridging." and how much power do I really need? We play mostly in bars and smaller venues.

basscooker · #5 02-02-2012, 06:10 AM

a 400 watt to 600 watt amp or channel will be a good match, i think. bridging is combining the two channels of a stereo amp, and is typically a feature you only need to push a button to use. the reason i asked about the cabinet's impedance is because you may get an amp which has power ratings listed for a two, four or eight ohm load. if your amp has a rating of 500 watts at 2 ohms, your four ohm cabinet will not coax all 500 watts from the amp. now if you get an amp that is 500 watts pr channel at four ohms, you have an extra channel open, because your cabinet only needs one side to be pushed, leaving an open channel to use for something else like your floor monitors. i would suggest saving a little dough and find an amp that pushes 400-600 watts into 4 ohms bridged, set and forget. btw the reason to stay below a cabs watts rating is b/c this rating is junk 90% of the time. you almost definately fart out a cab with 3/4 of actual power rated. this measurement is actually a thermal electrical spec that tells when you can do damage to the internal speaker coils, not a mechanical rating for the speaker cones. one spec to seek out if you can for your cab is the xmax specs for the drivers in it. this can help you decide as well about how much real world headroom you have way down low.

bassguppy · #6 02-02-2012, 11:38 AM

here's my advice...which may be worth a pittance.

I've spent serious cash throughout the years on gear that eventually left me wanting more. To save you some of the trial & error many of us on TB have encountered I say either get yourself a bass head either a micro which nowadays are 1000+ watts or a standard conventional head (Ashdown ABM, Ampeg SVT, SVT4 or 7PRO, or dozens of others). If you do go for a power amp, QSC, Crown, or Crest are the power amps of choice here (my personal fave was the QSC RMX1450. nice lower cost quality amp, cheap used, and bridged will give you 1400 watts @ 4ohms). Don't worry about it being over your cabinet wattage as you can just turn the attenuators down.

Only my opinion also but I would not "color" your tone with a sonic maximizer or rack EQ. Most heads have more than adequate enough EQ to please 95% of the bassists out there. If anything a pedal EQ could be used for any songs that may need it for a desired effect. Compressors? I like compression so rack or pedal is OK with me if that's what you're after.

You have a nice cab that I'm sure will handle any gig you encounter.

rpsands · #7 02-02-2012, 12:20 PM

The peavey IPR series is the only power amp suitable for that other than the old heavy Crest stuff with the selectable input voltage.

Downunderwonder · #8 02-02-2012, 12:56 PM

How does GC go with their staff giving huge discounts to their buddies? Big box store here fired a lady for buying dvds on her staff discount for her niece! Hardarse manager spotted titles and figured it out. The policy was "no buying goods on behalf using staff discount". GC probably has something similar.

bongomania · #9 02-02-2012, 03:06 PM

GC has a rule absolutely forbidding buying gear for anyone else but yourself. I wasn't fired for doing it, back when I worked for GC, but I got a warning that I would be fired if it happened a second time--and all I had bought was some cheap accessories like drum heads!

bongomania · #10 02-02-2012, 03:08 PM

Quote:

Originally Posted by rpsands

The peavey IPR series is the only power amp suitable for that other than the old heavy Crest stuff with the selectable input voltage.

No, there are others. E.g. my Carvin DCM had an input sensitivity of 1.0 V, and a few of the QSC ultralights have switchable sensitivity as well.

bongomania · #11 02-02-2012, 03:15 PM

Quote:

Originally Posted by BargainShopp3r

i can't find any mono power amps

Don't worry about that. For one, you can use just one side of a "stereo" power amp, no penalty for doing that. For another, many stereo power amps can be bridged to mono.

Quote:

Originally Posted by BargainShopp3r

I don't understand "bridging."

Basically it is a system that allows you to combine two power amps (like both sides of a stereo power amp) into one mono high-wattage output. The important thing is to be very careful about reading the directions for the specific amp, because not all of them can be bridged; many of them use different methods or connections for bridging; and they may be particular about only bridging into a certain ohm load.

Quote:

Originally Posted by BargainShopp3r

how much power do I really need? We play mostly in bars and smaller venues.

It depends, but IMO you probably don't need more than 500 W in many cases, especially in small venues.