Pluging A Power Amp Into A Bass Cab

sporks · #1 01-04-2012, 02:40 AM

I'm looking into buying a Mesa Boogie m180 Baron power amp. I'd be running it into a Sunn 2x15 or a Mesa Boogie 6x10. Before today, I didn't really know anything about power amps. I've asked a few poeple about this and its raised some concerns. I don't own a preamp. I'm really worried about blowing speakers and poping tubes. Are these concerns justified? Are power amps alright?
Also: I like playing REALLY loud. Like, favorite bands include Lightning Bolt and Sunn.
Thanks for the help
- sporkss

Eric Moesle · #2 01-04-2012, 10:29 AM

Bass -> preamp -> power amp -> speaker cabinet

Without a preamp, you will have no tone control, and your bass itself does not put out the voltage necessary to drive the power amp properly.

SRFSterling5 · #3 01-04-2012, 11:03 AM

You're gonna need a pre-amp. I have the BBE BMax pre-amp (non tube)
version and it really works for me. I finally have the sound I want and the
price of the BMax is around $300. Couple that with a good power amp and
good speakers and you're on your way.

BTW, you might look into the QSC power amps. I just got the QX7 model
and it rocks with 725W per side into 8 ohms. If you wanna play loud, this
thing will do it, and very clean too.

Dekker · #4 01-04-2012, 11:07 AM

Quote:

Originally Posted by Eric Moesle

Bass -> preamp -> power amp -> speaker cabinet

This is pretty much it. Most bass amps are a combination of pre-amp with power amp.

That said, you can get by if your choice of power amp has moderate input voltage requirements, and/or if you play through some effects processors that can put out a moderate voltage (0.750 or so).

Some power amps (think Crown XLS Drivecore) need around 1.5V on the input to derive the maximum output. I didn't scour the 'net, but didn't find specs for the Mesa you mentioned.

About blowing speakers/stuff, 2x150w shouldn't even make the speaker cabinets you mentioned sweat... (or did I look up the wrong amp?)

Dekker

rad bassman · #5 01-04-2012, 11:07 AM

i'm using a BBE BMAX preamp (the bit with the knobs on it, your tone controls etc), this is used for my DI to the front of house mixer and output to a PA power amp (in mono mode) to drive my fearful cabs, power amps these days can be quite a cheap way of getting alot of power behind you, im using up to 2 x 590 watts, its enough for me XD

BassmanPaul · #6 01-04-2012, 12:28 PM

This is a full tube STEREO power amp. Unless it can be bridged or paralleled you'll need two speaker cabinets to use it safely. It's also going to be extremely heavy.

Downunderwonder · #7 01-04-2012, 05:23 PM

I could be wrong but I thought m180 was the same as the d180 minus preamp section. 180w of overdrivable tubes, 4 or 8 ohms.

Jeff Scott · #8 01-04-2012, 06:01 PM

I'd put the Baron in my stereo system, instead!

wcriley · #9 01-04-2012, 07:06 PM

Quote:

Originally Posted by BassmanPaul

This is a full tube STEREO power amp. Unless it can be bridged or paralleled you'll need two speaker cabinets to use it safely. It's also going to be extremely heavy.

Hmm...it seems to be two completely independent amps, each with its own on/off switch, transformers, power cable, etc. Interesting.

Mesa Baron Audiophile Power Amplifier

bongomania · #10 01-04-2012, 07:14 PM

Quote:

Originally Posted by sporks

Are power amps alright?

Just in case it wasn't clear from a previous response, every "amp head" contains a power amp. The ONLY way you can drive any bass cab is with a power amp.

But as a couple people also noted, you'll need a preamp to drive the power amp.

walterw · #11 01-04-2012, 08:18 PM

anyway, yeah, using a straight power amp is a totally normal way to build a bass rig.

Quote:

Originally Posted by sporks

Also: I like playing REALLY loud. Like, favorite bands include Lightning Bolt and Sunn.

then this is not the amp for you.

180 watts of tube power equals a fuzzy grungy sound at moderate rock volume for bass; the guitar player's marshalls will crush you.

if it's tube boogies you're after, wrangle yourself a 400+ and you might have something.

Downunderwonder · #12 01-04-2012, 09:49 PM

Mesa M180 180 ALL TUBE Goodness! like this one? I saw another with BARON on it as well, it does have 12AX7 preamp tubes in it so you might get away with running pedals into it. Different animal from the more modern Baron hifi amp. That thing is more like a descendent of the M190 hifi version.

morgan138 · #13 01-08-2012, 08:11 AM

Quote:

Originally Posted by walterw

180 watts of tube power equals a fuzzy grungy sound at moderate rock volume for bass; the guitar player's marshalls will crush you.

if it's tube boogies you're after, wrangle yourself a 400+ and you might have something.

I don't know, both Sunn and Lightning Bolt are known for playing very, very overdriven to the point where the bass doesn't really sound much like what you'd expect a bass to sound like. This might actually be a great choice!

If it does turn out that the head will only run in stereo and can't be bridged, it won't be too hard to rewire a 2x15 so that you can plug into each 15 separately. You can buy Marshall-style switchable jackplates that make the wiring pretty simple and will allow you to go back to mono mode easily.

As far as the preamp thing goes, I'll second whoever said that with the right pedal you can sometimes do without one (although you'll have a lot less control over EQ and stuff since this would normally be part of the preamp). I had a friend who used to run a big muff right into the power section of a V-4b. He was actually into bands in the same general ballpark we're talking about here (loved Harvey Milk as I recall), so it might not be a terrible idea in this case...