I need help choosing an amp!

davidabrooks · #1 08-17-2011, 12:43 AM

Hi everyone! I need some advice! I have two 8ohm SWR Goliath 4x10 cabinets, and I'm not sure which amp (or amps) to buy! The cabinets are each rated at 700 watts (which is probably conservative) and I want to get as much volume as possible out of the cabinets without endangering them! I'm a rock bass player, but I wouldn't mind if the amp and cabinets could also be used with a stereo keyboard (one channel to each cab). I don't mind using a separate pre-amp if needed, and I'm open to possibly using an amp for each cabinet, but it would also be nice if the rack didn't weigh a ton! Help please!! Thank you very much.

Road Bull · #2 08-17-2011, 12:49 AM

You may want to check out the Genz Benz Shuttle 9.2.

Genz Benz Shuttle Max 9.2 - YouTube

I just got one to match my Eden 410XLT 8ohm. Sounds pretty sweet.

500w @ 8ohms
900w @ 4ohms

Good Luck

davidabrooks · #3 08-17-2011, 10:04 AM

Thanks for the reply, Road Bull! I checked out this amp. I like it but I have a couple concerns:

1. It's only 500w into 8ohms. So that means using it on one of my cabs won't be fulling taking advantage of the 700w+ capability of the cabinet. Add in my other cab, creating a 16ohm load, and it will be even quieter. I really want to get as much as I can out of my speaker cabs. Or were you thinking I would get one for each cabinet? If I do that I don't think I want dual pre-amping and tone controls?

2. I don't think I would ever use the tube channel as I like a super clean tone, so I might be paying for something there that I wouldnt use?

What do you think?

bassplayerbob · #4 08-17-2011, 10:10 AM

Quote:

Originally Posted by davidabrooks

Thanks for the reply, Road Bull! I checked out this amp. I like it but I have a couple concerns:

1. It's only 500w into 8ohms. So that means using it on one of my cabs won't be fulling taking advantage of the 700w+ capability of the cabinet. Add in my other cab, creating a 16ohm load,

Combining those cabs would give you a 4 ohm load and with those cabs and head your intestines will vibrate!

davidabrooks · #5 08-17-2011, 10:15 AM

I will confirm with my resident physicist but wouldn't adding a second cab increase the resistance on the amp? The load would only go down to 4ohm if I decreased the load. Please explain the math if I'm wrong, and thank you too for replying!

bassplayerbob · #6 08-17-2011, 10:37 AM

Quote:

Originally Posted by davidabrooks

I will confirm with my resident physicist but wouldn't adding a second cab increase the resistance on the amp? The load would only go down to 4ohm if I decreased the load. Please explain the math if I'm wrong, and thank you too for replying!

Many folks more qualified than me will chime in very soon on the tech side but running 2 8 ohm cabs on a normal bass amp or poweramp will always make 4 ohms. That's why most amp company's rate their head at 4 ohms because most, not all, cabs are rated at 8 and people will run 2 cabs and get 4. That's why if you have 2 4 ohm cabs you can't use a head with a 4 ohm min load.

jeff7bass · #7 08-17-2011, 10:41 AM

Carvin.com - Guitars, Amplifiers & Pro Audio

Look at their two best amps, the BX1500 and the B2000. Both are VERY powerful and flexible. Great prices too.
The BX1500 has two powerful amps, each with it's own volume knob so you can EQ the cabs separately in bi-amp mode. Great features!

Evil Undead · #8 08-17-2011, 10:43 AM

Running two 8 ohm cabs in to an amp will make a 4 ohm load. So you're best getting an amp with a minimum impedance of 4 ohms, which most are.

Bass_Pounder · #9 08-17-2011, 10:52 AM

Quote:

Originally Posted by davidabrooks

Thanks for the reply, Road Bull! I checked out this amp. I like it but I have a couple concerns:

1. It's only 500w into 8ohms. So that means using it on one of my cabs won't be fulling taking advantage of the 700w+ capability of the cabinet. Add in my other cab, creating a 16ohm load, and it will be even quieter. I really want to get as much as I can out of my speaker cabs. Or were you thinking I would get one for each cabinet? If I do that I don't think I want dual pre-amping and tone controls?

The ratings you are quoting are the THERMAL ratings only (wattage at which will melt the voice coil).

The real world MECHANICAL limitations of most speakers is roughly half that (350 watts).

Additionally, getting the difference of 200 watts (from 500 to 700 watts) is less than 2bd which is a minimal gain at best.

Also, as the others above have already stated - connecting two cabs to a head is almost ALWAYS a parallel connection which results in a lower ohm load (4 ohms in your case).

davidabrooks · #10 08-17-2011, 10:56 AM

Good info here, thanks everyone! I've always been a bit confused about the ohm thing. Now, I will back to which amp to choose!

RickenBoogie · #11 08-17-2011, 11:27 AM

I suggest that's it's a personal preference thing choosing an amp. If it were me, I'd go Mesa M6 or M9 Carbine, and call it a day. That would be monstrously loud, and tight, and punchy. You may prefer a different tonal goal. Only you know. One thing for sure, with 2 8 ohm 4x10's, rated at 700 watts each is indeed a 4 ohm load to the amp, and the actual *useable* wattage they'll take is probably around 700 watts, combined. Fact is, a 300 watt amp will make them loud, but headroom is your friend. I'd look at amps in the 500-1000 watt range.

davidabrooks · #12 08-17-2011, 11:47 AM

I will look into those amps, thanks. But I'm still wondering if there's an amp that can do double duty as a stereo keyboard amp? (two inputs) I'm sure these two SWR cabs would sound great with my keyboard, and wouldn't it be great if I only had to buy one amp that I could use for both instruments!

bassplayerbob · #13 08-17-2011, 12:11 PM

Quote:

Originally Posted by davidabrooks

I will look into those amps, thanks. But I'm still wondering if there's an amp that can do double duty as a stereo keyboard amp? (two inputs) I'm sure these two SWR cabs would sound great with my keyboard, and wouldn't it be great if I only had to buy one amp that I could use for both instruments!

Bass and keys to a mini mixer to a stereo poweramp?

davidabrooks · #14 08-17-2011, 01:44 PM

Yes, now after looking around a bit I've found a versatile power amp that runs 700w stereo, and I see I can use a stereo or mono source (and run in parallel)..

XP7000, XP5000, XP3500, XP2500, XP1000 | Power Amplifiers | Products | Yamaha Pro Audio

I'm thinking that this amp would work for bass or stereo keys, but I would need to buy a decent bass preamp... Suggestions or comments??

bassplayerbob · #15 08-17-2011, 01:54 PM

Quote:

Originally Posted by davidabrooks

Yes, now after looking around a bit I've found a versatile power amp that runs 700w stereo, and I see I can use a stereo or mono source (and run in parallel)..

XP7000, XP5000, XP3500, XP2500, XP1000 | Power Amplifiers | Products | Yamaha Pro Audio

I'm thinking that this amp would work for bass or stereo keys, but I would need to buy a decent bass preamp... Suggestions or comments??

Sans amp seems to tickle a lot of panties around here. I have never owned one but a friend uses one and loves it.

Pickebass · #16 08-17-2011, 01:59 PM

Get a power amp and pre of your choice. Most good power amps, without spending a large sum of money will put out between 500-600 watts (can't think of one 700 watt per channel at 8 ohm to be honest). I would recommend a Crest CA-6 (heavy but loud and clear), QSC PLX 1802, and a Stewart Audio 2.1 (not sure of they make them any more).

With about 500 watts of continuous power, you should be too loud for your own hears!

davidabrooks · #17 08-17-2011, 02:13 PM

The amp I linked above is 700w each 8ohm channel! It seems perfect, now to choose a pre amp...

RickenBoogie · #18 08-17-2011, 02:16 PM

Just remember, 700 watts per channel into 2 cabs rated at 700 watts each is fine, BUT can still be potentially fried unless you use common sense. An amp rated at 700 watts can produce spikes of 1400 watts, and a spkr rated for 700 watts will only really handle about 350.

rpsands · #19 08-17-2011, 02:18 PM

Gk Mb500 if it's just you.

If you want to use a separate pre for a piano rig, get a Drivecore 1500 power amp.

Mojo-Man · #20 08-17-2011, 02:22 PM

Choosing a Amp, is a very person thing.
Don't rely on other peoples tastes.
Go to a good music store and try out as many amps as you can find.
You should know what tone, wattage, shaping you look for in a amp.
It's a pain sometimes, but in the long run you will get what you want. ( and save money)