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Amp/Cab questions???

Discussion in 'Amps and Cabs [BG]' started by RedV, Jun 28, 2004.


  1. RedV

    RedV

    Mar 19, 2002
    Eustis, FL
    Ok, I've been searching talkbass literally all day. I've learned quite a bit, but there's still a few things I'm confused about.

    I'm looking into getting a head and hopefully a cab. I want to go this route so I can upgrade and add other cabs later on.

    The heads I'm looking at are the Behringer 3000xt and the Ashdown 300. They both fall into my price range and are both 300 watts. I've read the debates and opinions on both.

    Both of these heads are 300watts at 4 ohms. Now, from what I've learned, 4 ohms is the smallest load I could put on either of these heads. So basically I should be able to either run one cabinet with a 4 ohm rating or two cabinets with an 8 ohm rating each. Correct?

    Now, I also read I should try and have the cabinet have a higher wattage than the amp for safety's sake. Any truth here? Also, I think I read that if I am running the 300watt@4ohm head into a say 200watt@8ohm head, I won't be pushing the whole 300watts the head is capable of; probably more like 150. Is this correct?

    Finally, what the heck should I do?:) I'm almost positive I'll be getting one of these heads next month and I need a cab to go along with it. I was planning on either purchasing a 2x10 or 4x10 and then getting another 4x10 or maybe a 1x15 later on. But I don't want to spend any money until I have all this sorted out.

    Help!!!:) Thanks guys.

    Alex
     
  2. Emprov

    Emprov

    Mar 19, 2003
    You sir, are correct!

    You'll probably be pushing something like 170-185, more along those lines but you should be fine.

    Keep in mind that your tastes in tone and gear will change quite a few times over the next few years. I've searched long and hard for the perfect tone and I've come to realize that there isn't one -- it changes from situation to situation and year to year. I think that you're on the right track though and the decision on what to buy should come directly from what your needs are. Personally, I can envision very few situations where a 210/115 won't do the job but there's nothing wrong with a few 410's either. I started going the compact cab route last year and I haven't regreted it for a second.
     
  3. Chapbass

    Chapbass

    Dec 11, 2003
    Chicago, IL
    I think you might have it a little backwards. You normally (especially for bass instruments) want to have a more powerful head unit than the cab is rated at (usually around 1.5x, in that very general area at least).

    Using this rule makes sure you have all the clean power you need for the cab, plus a little bit of headroom for the instrument to "breathe" a bit. If you underpower your cab (especially by a good amount), you can blow your speakers from running out of clean room, if your not careful of course. Its definitely doable, you just have to watch what your doing.

    Yep, if your running 2 8ohm cabs in parallel, then youd be running at 4ohms.

    From my relatively limited experience with purchasing bass amps (yay for me and my lack of money), I've found that im quite happy with a 2x10, 1x15 combo. It depends alot on who else your playing with. I enjoy the 2x10 because then i can get the whole rig into smaller cars (my trans am, my guitarists corsica...). I play relatively quieter music (not that quiet, but not punkrock/heavy metal), so a huge full stack isnt necessary for me.
     
  4. RedV

    RedV

    Mar 19, 2002
    Eustis, FL
    Thanks Chapbass and Emprov.

    I'm glad I've got some of this right.:) I'll probably be using this rig for my band(rock) and also with a full jazz band. You still think a 210 and a 115 could handle both of those?? That's great news if it will!

    Stupid question, but if there's 2 speaker outs on the head and no pan switch this will obviously run the 2 cabs in parallel correct?

    And about the head wattage to cab wattage...I read quite a bit on this and I still don't get it. I hear opinions for having the head more powerful and opinions for having the cab more powerful. :confused: So for instance, if I have a 300watt@4ohm head and a 200watt@8ohm cab I would be running less from the head than the cab could handle and this would be bad?? Also, if I run the 300watt head, would it be more efficient to run two 200watt cabs, or two 300watt cabs? This stuff is making my brain hurt.

    Thanks again for the advice so far guys:)

    Alex
     
  5. Yossarian

    Yossarian

    Jun 24, 2004
    Virginia
    First off, you definitely need your impedances to match. If your amp is running 4 ohms, you need a 4 ohm cabinet or two 8 ohm cabinets.

    But yeah, people have been educating me on this whole amp/cabinet power thing, I've been researching a rig too, and basically what I'm told is you want more power in the amp than in the cabinet, because when you push your amp nearer to its limit, it causes clipping (distortion in your speakers) and that's bad news, it can kill your amp and/or your cabinet. If your amp is more powerful than your cabinet, you're more likely to get the full power you need for your cabinet without clipping. It's still gonna cause some problems if you push it all the way, though. So basically, either way you dont want to push it hard enough that it clips, but you might as well have more power because that way you'll give the cab all the juice it wants before the clipping starts.
     
  6. RedV

    RedV

    Mar 19, 2002
    Eustis, FL
    Ok, I think I got it. I want my amp to be more powerful than my cab so I don't have to turn the amp up to the point of clipping to get a good volume. Right?

    Ok, so if I'm using the 300watt head with two 200watt 8 ohm cabs, what will the total wattage/volume pumping out be for that situation? It would be 150watts to each cab right?


    Thanks again guys, I really appreciate this. You know, you can read and read, but sometimes you just need someone to point things out to you. I love talkbass:)

    Alex
     
  7. Yossarian

    Yossarian

    Jun 24, 2004
    Virginia
    Yeah it looks that way. Maybe you should aim for more power? We'll see what others say. What is your price range?
     
  8. Emprov

    Emprov

    Mar 19, 2003
    When it comes to matching power to cabs, I've heard some very strong arguments from just about every side. Personally, I use a 400w head with 2 500w cabs and I'm not hurting in any way, I love the sound. I've used 300w for 300w and I wasn't as pleased with the result. And, when it comes to matching ohms, you don't wanna go any lower than 4 and I've been running only 8ohms out of 800RB's, 400RB's and now my GBE 500H and never had an issue. Haven't heard anything that's convinced me that it's not ok.
     
  9. Acepiloto

    Acepiloto

    Aug 25, 2000
    Actually, you don't need to match anything. On solid state power amps, there is a minimum nominal impedence rating (ie. 4ohms, 2ohms, etc.) Therefore, you can run one or two 8 ohm cabs on a head rated at a min of 4 ohms. Two of course will be louder due to a bit more wattage, but mostly because of more air moving due to more speakers.

    Yes, basically the rule of thumb is, you can always turn down, but you can't always turn up. Do a search on clipping, and you'll have reading material for days.

    Exactly.


    Thanks, I've learned most of my knowledge by spending time reading, and reading, and more reading.
     
  10. Ty McNeely

    Ty McNeely

    Mar 27, 2000
    TX
    Any decent amp nowadays will have a switch to switch back and forth between impedences, so the Behringer SHOULD be switchable between 8 ohms and 4 ohms. Usually, people with a head with an impedence limit of 4 ohms usually only buy 8 ohm cabs, but if you happen to find the best cab (to your ears) and it's only 4 ohms, don't be scared of getting it.


    Next, the wattage limits of heads and cabs really make very little difference, except that you want to make sure that the output of your HEAD is at least CLOSE to the RMS (amount of power your cabinet can handle on a regular basis, not the PEAK power) power of your cab. If your head is too drastically underpowered, you could end up in trouble getting enough volume out of it, especially with the rock setup. I've heard of people running rigs with an output of 1000 watts into a cabinet that can handle only 300 watts with absolutely no problem, but the volume knob must be used sparingly.


    Lastly, SHOP AROUND before you purchase anything. You never really said what you limit was for purchases, but *GOOD* deals can be had in the used market if you just keep your eyes open. Nothing wrong with buying new if you can afford it, but don't be afraid to purchase something used, as long as you use your brain :)
     
  11. Chapbass

    Chapbass

    Dec 11, 2003
    Chicago, IL

    lol, Sorry emprov if it sounded like i was saying you were doing it wrong, I didn't mean that at all.


    I think Ty nailed it right on the head. As long as your at least CLOSE in RMS watts between the head and the cab(s), and your in the safe zone as far as ohms is concerned, then youll be just fine.

    50 watt head trying to push a 4x10 and a 1x18 full stack...look out....

    but the same applies for a 2000 watt power amp pushing a 1x10 cab...

    But i mean as long as your in the same ballpark with the amps and cabs, you should be alright to at least get the vast majority of the rated watts out of both pieces of equipment.

    And yeah, definitely shop around. : )
     
  12. RedV

    RedV

    Mar 19, 2002
    Eustis, FL
    Thanks again everyone...I've learned so much from this site.

    I don't really have a spending limit. I'm making pretty good money right now. However, I would rather not spend a grand on the setup right now if I can avoid it. It just seems that there's so many other choices out there right now for a lot less dough.

    Now, does everyone think a 300watt head into say a 200watt cab would be enough for say a 300 person venue?? With adding another 200watt cab later on. Or should I be thinking bigger?

    On the other hand, I shouldn't be afraid of buying a 300watt@8ohm cab to go with the 300watt head(pushing roughly 175-180watts right??)? And then if I add say a 200watt cab later on(splitting 150 to each), that would be ok? I mean neither cab would be pushing it's full wattage and that's what I want....or at least close. Correct?

    I think I'm starting to get this. I'm gonna go read some more threads and see if I can pick up some more.

    And also, I have no problem buying used, so if anyone knows anyone, let me know:)

    Thanks again guys.

    Alex
     
  13. Ty McNeely

    Ty McNeely

    Mar 27, 2000
    TX
    With that being said, I'd stay away from the Behringer setup. There really are some EXCELLENT high-quality rigs that can be had for less than a grand.

    Shoot....I've used a Fender 60 watt 1x12 combo in an auditorium with 450 people in it. 300 watts would MORE than suffice for your needs :)


    Theoretically, you can run a 300 watt cabinet at 300 watts all day long and not do a thing to it. If you'll look at most cabinets, they'll have two power ratings: Peak power and RMS or contious power. RMS power is the amount of power tha cab can handle CONSTANTLY. Meaning you can run the 300 watt cab at 300 watts and do no damage. The PEAK power rating is the amount of power the cabinet can handle in short bursts. So, assuming you did get a 300 watt head and a 200 watt cab, you would most likely be just fine unless you tried to run the head at full power, which is never advised anyways, unless it is a tube amp, and even then it's still not good to do so.

    Well, I don't know if you were aware or not, but there is a classifieds section of TalkBass. There is ALWAYS some really good rigs for sale down there, so take a look!
     
  14. josh_m

    josh_m

    May 5, 2004
    Davie, Fl
    All of this is good advice, this is the way I see it.

    You should have more power than you need, and keep you cab close to that in handling. The point where you can't safely turn up the volume is when you may want to consider a new rig.

    As far as impedance is concerned, I have a hartke 3500, which is 4ohm stable, meaning I can use any combination of speakers as long as the load doesn't go below 4ohms. There are a lot of resources on the internet which can help you figure out impedance and power, as well as explain how series/parallel works and how to wire them to get the impedance you need (i.e. a cab with 4x4ohm speakers and a 4ohm total load.) I don't worry so much about how many watts my head is putting out really, as long as it sounds good, doesn't clip, and is loud enough why should I care? I just know not to bring it below 4 ohms.

    To answer your question, yes, that will be plenty loud I think, unless the cab is really ineffiecient.

    That brings me to efficiency. Things get complicated here because there has to be a compromise. I have a very large cab with very efficient speakers, the sound is great and I can get more volume than I using very little wattage. The problem is it doesn't fit in my car, so my compromise was size. You can also get a really small cab that sounds amazing, but you will need a lot of power to hear it at its full potential. Then you get the small cabs that can be LOUD, but they generally don't sound good.