Acoustic 370 first time user questions

[Panek]

Hey guys, I just bought an Acoustic 370 head that needs some work (which will be done in the next few days), and I have some questions regarding it...

The amp has 325W @ 1.6 ohms. They also give a spec of 205W at 3.2ohms, so I figured the amp is pretty much made for 4ohm/2ohm operation. That (and all the stories about legendary tone, etc.) is exactly why I bought the head in the first place. At the moment I'm in the process of building one 2ohm cabinet (2x Eminence Legend CA154 4ohm 15" speakers) for the head. I received it today and all I can see on the back are two speaker outputs, and they aren't separately marked as 2ohm/4ohm (as some other amps have it). Now, my question is - in order to get 1.6ohm out of the amp, do I need to connect two 4 ohm cabs? Or is it just going to run fine and give out the power I want, if I hook up the one 2ohm that I have?

It says here: http://acc.homeunix.net/images/manuals/370/370i.jpg that the 370 will produce 230 watts into one speaker bottom. Now, does this apply only to the 301 cabs, or all speakers in general? So, if I connect only one speaker output, is the amp gonna work at 3.2ohms, and will it go to 1.6 only with two speakers connected?

"Monitor Outputs" - are they pretty much line outputs, and are they "balanced"? Do they work in the same manner as the speaker outputs? Can I convert them into a more modern XLR output for easy connection into PA systems, soundboards, studio recording, etc?

Thanks for the help.

I apologize for noob-like questions, but it's actually the first amp of this type (I mean heavy-duty, world-class, etc.) that I've ever had, I've also never used a head + cab, only small combos, or I just hooked up my bass to my PC (AmpliTube). Now the situation in my band required to get something better with alot more power...

[BogeyBass]

The 2 speaker outlets go to the same place and are in parallel.

So if you attach a single 2 ohm load then yes it will have a 2 ohm load. you dont need 2 separate 4ohm cabinets to get the desired 2ohm load.
But if you did attach 2 4ohm cabs you would achieve a 2ohm load.
since again the outputs are in parallel and are pretty much connected to the same place internally

the head does fine at 8, 4, 3, 2 and 1.6 ohms.

if you already ordered the speakers then great have fun, otherwise i recommend just making a standard 4ohm 2x15
with the CB158's or the Delta Pro 15 which are in the same price range and the Delta pro will have much better highend
than the 158 or the 154.

[someparts]

The reason the 1.6 ohm number is thrown around with the old ACC stuff is due to the 301 cabs using a Vega 18" 3.2 ohm driver....two of those cabs running in parallel gets you that 1.6 number.

Don't sweat the difference, the 370 at 2 ohms will have plenty of power for any 2x15 setup. You can run a jack to each speaker and two cables but it's the same difference to just run the speakers in parallel to a single jack and run a single speaker cable to the amp.

The monitor out is a 1/4" unbalanced and the output on them can be too low for some stuff. You can have a balanced out added I'm sure but I wouldn't due to cost....just keep a direct box handy if you are playing somewhere where that rig isn't enough. Haha...

[Panek]

[b]

Originally Posted by BogeyBass

The 2 speaker outlets go to the same place and are in parallel.

So if you attach a single 2 ohm load then yes it will have a 2 ohm load. you dont need 2 separate 4ohm cabinets to get the desired 2ohm load.
But if you did attach 2 4ohm cabs you would achieve a 2ohm load.
since again the outputs are in parallel and are pretty much connected to the same place internally

the head does fine at 8, 4, 3, 2 and 1.6 ohms.

Thanks for the info... that's actually great to hear... after I fix the head and until I get my own cabinet, there's an old Peavey 4ohm cab that my guitarist will let me use...

if you already ordered the speakers then great have fun, otherwise i recommend just making a standard 4ohm 2x15
with the CB158's or the Delta Pro 15 which are in the same price range and the Delta pro will have much better highend
than the 158 or the 154.

I've already ordered them... besides, I'm not really going to go that much into the high end, but thanks for the heads up

Originally Posted by someparts

The reason the 1.6 ohm number is thrown around with the old ACC stuff is due to the 301 cabs using a Vega 18" 3.2 ohm driver....two of those cabs running in parallel gets you that 1.6 number.

Thanks for the info, I was actually wondering why Acoustic amps are the only ones where I've seen ratings such as 3.2ohm or 1.6ohm. I'd love to have a 301 cab or two, maybe in the future, who knows...

Don't sweat the difference, the 370 at 2 ohms will have plenty of power for any 2x15 setup. You can run a jack to each speaker and two cables but it's the same difference to just run the speakers in parallel to a single jack and run a single speaker cable to the amp.

That's what I'm going with. I will have them in parallel with a single jack.

The monitor out is a 1/4" unbalanced and the output on them can be too low for some stuff. You can have a balanced out added I'm sure but I wouldn't due to cost....just keep a direct box handy if you are playing somewhere where that rig isn't enough. Haha...

"Due to cost"? What do you mean? What would need to be done in order to have a balanced, XLR output? Is it that expensive?

In terms of volume, I know that the rig will probably be more than enough... at least that's what all Acoustic users say But in terms of convenience, that's another thing. It looks like my band will record at least twice this year, and we use our own equipment for recording, so I'd love to have a balanced output for easy connection into the soundboard. Aside from that, I mostly play punk gigs, and I know from experience that around here soundmen just connect the amps to the PA with XLR outputs. I've never seen anyone bother to mic a bass rig. I don't really know why. And to be honest, I don't even know a good mic to use with a bass cab...

[JimmyM]

Good mics to use with bass cabs:

EV RE-20
Heil PR40
Sennheiser MD421
Beyer M88

On a budget?

AKG P2
Shure SM-57 or 58 blended with a DI running lows below 100hz

As for the balanced out mod, it's not a hard mod to do for a tech. Shouldn't be prohibitively expensive. I'd never do it, though. The 301 sounds killer but I don't think there's anything about its sound that you couldn't duplicate to a large degree with an outboard DI. Plus it's a 370, and I have a thing about adding mods to classic amps. I'd much rather mic it. Only thing about micing, though, is even if you have your own mic, some soundmen will give you crap about it because they suck and can't figure out how to deal with a little bit of bleed.

[Panek]

Originally Posted by JimmyM

As for the balanced out mod, it's not a hard mod to do for a tech. Shouldn't be prohibitively expensive. I'd never do it, though. The 301 sounds killer but I don't think there's anything about its sound that you couldn't duplicate to a large degree with an outboard DI. Plus it's a 370, and I have a thing about adding mods to classic amps. I'd much rather mic it.

Thanks for the suggestions. I totally get what you're saying about modding vintage amps... if it weren't out of necessity, I'd never do it. I got the 370 because I was looking for killer, vintage sound, and a real workhorse that could handle anything... so I need to make sure it's up to par with at least some of the modern standards. Then again... I looked online for some DI-boxes and found lots, including a Behringer DI-20 that looks nice. There's also a couple of others... and they look pretty affordable. Might go with that actually...

Only thing about micing, though, is even if you have your own mic, some soundmen will give you crap about it because they suck and can't figure out how to deal with a little bit of bleed.

That's one thing I'm trying to avoid... like I said, around here it looks like nobody bothers micing bass amps. I've seen mic'ed guitar cabs, but nothing for the bass. Also, on the punk circuit, soundmen don't have a lot of experience with vintage amplification... musicians neither.

[someparts]

Originally Posted by Panek

In terms of volume, I know that the rig will probably be more than enough... at least that's what all Acoustic users say But in terms of convenience, that's another thing. It looks like my band will record at least twice this year, and we use our own equipment for recording, so I'd love to have a balanced output for easy connection into the soundboard. Aside from that, I mostly play punk gigs, and I know from experience that around here soundmen just connect the amps to the PA with XLR outputs. I've never seen anyone bother to mic a bass rig. I don't really know why. And to be honest, I don't even know a good mic to use with a bass cab...

For a punk gig I would both run a direct box out and have them mic a cab - best of both tones for stage and studio. Then again I'm rarely happy with a direct sound only so I'm a bit biased...