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Power Amps Questions

Discussion in 'Amps and Cabs [BG]' started by Oddman545, Jun 19, 2002.


  1. Hey,
    Ok. I know nothing about power amps, and I'm looking for either a head or a rack type thing to power a 4-10 and a 1-15 by Avatar. Now, at the local music store they have a used head that's 150 watts for $100. The reason it's so cheap is because it's been in the store for a year and no one wants it because it's old. But it's works fine. But, I'm don't think that'll be enough power, so I'm looking into power amps. Now, I know nothing about them. First off, are there specific types? Like, are there guitar power amps, bass power amps? Or is it just any should work with anything. Then, if I get a power amp, can I just stick it in a rack case and directly plug my bass into it, or do I have to have a pre-amp to make it work? The reason I'm asking is becuase if I can do that I'll save for a good pre-amp. I'll have $250 for a power amp and pre-amp, and I'm gonna buy used. This is my first rig, and I need something with enough power. I think about 200-300 watts should be plenty...so, do you think I could get a used poweramp about 250 watts or so, for $250 or less??? (less would be better). The cheaper the better so I can get a rack and a preamp...but sorry if I'm just talking away...but...I'd really appreciate it if you help me out :)

    Mike
     
  2. JMX

    JMX Vorsprung durch Technik

    Sep 4, 2000
    Cologne, Germany
    Look into used P.A. poweramps.
    They're powerful enough, roadworthy and with good protections. They sound as good or better than Bass poweramps, which are basically the same thing.
    Don't bother to look at guitar amps.
     
  3. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    Oddman545,

    You asked a few questions, so I'll try to answer them as best I can one by one...

    Q) Can I plug my bass directly into a power amp or do I need a preamp?

    A) Yes, you really do need a preamp. Any conventional instrument amplifier (i.e. guitar amp or bass amp) really consists of (at minimum) two components... a preamp (used to shape the tone and "somewhat" raise the signal), and a power amp (to generate enough voltage to send a much higher signal to drive the speakers). While you can technically plug a bass directly into a power amp, the output of the bass (even those with on-board preamps) probably isn't enough to drive the amp to full power. Chances are it would also sound thin. Most power amps are looking for a 0db to +4db input level, which is more than a bass can output on it's own.


    Q) Are there guitar power amps, bass power amps?

    A)To my knowledge there aren't necessarily "guitar" or "bass" Power amps (although both guitar and bass manufacturers make power amps). The purpose of a power amp is to amplify the signal enough to drive the speakers. It's the preamp's job to color the tone. NOTE: This isn't to say that the power amp won't color the signal, it will... but it isn't THAT significant, and you have no control over it. Check out the "RMX" or "PLX" series from QSC Audio (www.qscaudio.com).


    Q) Do you think I could get a used poweramp about 250 watts or so, for $250 or less?

    A) Probably (check out ebay.com), but probably NOT BOTH a preamp AND power amp for that price.

    Now, if you don't mind... I've got a question for you:

    Why are you looking to put together a rack system instead of just buying a bass head? Most bassists do the "rack thing" because: a) they like the flexibility of being able to swap out different components (i.e. preamps, compressors, etc.) or b) They want/need more wattage than most bass amps put out (i.e. greater than 1000 watts). Don't expect a rack system to be cheaper than buying a conventional bass head, if anything it will cost more (in some cases much more) by the time you figure in the rack, preamp, power amp, cabinets, and anything else you can think of to stick in there). In my opinion, if cost is an issue, and if you REALLY only need 200 or 300 watts, just get either a decent combo amp or look into a conventional bass head.

    Hope I've been helpful.

    - Frank.
     
  4. The reason I want a rack is so I CAN upgrade more later. I would like as much power as I can now, and I'll upgrade more when I need it. I'm not sure. There is a head I could get but it's only 150 watts, and I need more than that.
     
  5. Lackey

    Lackey

    May 10, 2002
    Los Angeles
    Well,, first of all I would NOT recommend splitting 300 watts into 2 EXTREMELY power hungry cabs,, you will have no volume and will probably blow up the whole rig. The Avatar 410 by itself handles 1200 watts, I would be wary about putting anything less then 600 into it. I just ordered one and I plan on putting 1000 watts into it.

    If you try turning up the volume loud on a 200-300 watt amp going into a 1200 watt cab,, clipping will probably occur,, and i've been to lazy to find the specifics,, but clipping can fry your speakers.
     
  6. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    The specs say "400 Watts x 2 into 8 Ohms (2 x 125 Watts RMS)", which means it's not really a 400 watt amp (more like 250 watts... it won't move "tons" of air, but you can get by with it in a small to med. size room). Probably doesn't have a "Bridge" mode (which would combine the two stereo amps together to send the combined signal to one output), but if you're using 2 cabinets you wouldn't need it. Looks like it's more suited to "DJ" type PA equipment, but it should do.

    Are you currently playing with a band?
    What type of music do you play?

    Peace,

    - Frank.
     
  7. Well....I'm gonna have the 410 alone for a long time. I thought the avatars only were like 300 someting watts RMS and 1200 peak. What's that mean? But all I would need is about 200-300 watts (for now) and I wouldn't have to put the volume up all the way.
     
  8. So would that amp work and stuff???
     
  9. Oh...you replied before I put the two new posts on. I am in a band, and we play rock type stuff. The only time I'd need about 200-300 watts would be parties and things. Everywhere else we'd play there are PA's which we could use so I could mic it.
     
  10. geshel

    geshel

    Oct 2, 2001
    Seattle
    :rolleyes: Just because the Avatars handle 1200w doesn't meant they're inefficient. From what I've heard they're pretty efficient (ie not "EXTREMELY" power-hungry). There are a number of people here who have them and I don't remember them saying they needed gobs of power. 1000w into a 4x10 is Acme territory :)

    I think 150w into a 4x10 and likewise into a 1x15 would be pretty loud.
     
  11. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    :confused: :eek: What (I think) Lackey is trying to say is that you DON'T want to push the amp too hard (i.e. turning the volume above 5 or 6) or it will clip, which will eventually damage the speakers. Because the Eminence speakers that are used in the Avatars are designed to handle "Lots" of watts, it may not sound as loud (with that power amp) as a cabinet that has, say a 300 or 400 watt RMS rating, but it still should be enough to drive the cabinet.

    Oh, another question... Do you ALREADY have the Avatars?
     
  12. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    Thanks Geshel, you stated it much better than I did.... "Efficiency" was the word I was looking for :D

    Now, does someone have any energy left to explain "RMS" vs. "Program" vs. "Peak" to Oddman545? I'm "typed" out :oops:

    - Frank.
     
  13. No. I don't already have the avatars, and they are not in the mail yet or anything like that.
     
  14. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    At least it's bridgable.

    BTW, since no one else posted...

    RMS stands for "Root Mean Square" and it refers to the math involved to get to its value. An RMS value is really a measure of the "heating effect" of a sine wave (I'm no expert on this, but I'm sure I'm getting more involved here than you really want to know :p).

    Anyway, the "RMS" rating is the wattage the speaker can handle for long periods of time. "PEAK" is the amount of "spike" wattage a speaker can handle (short surges of power, about a tenth of a second or so). Some manufacturers have started to list the "PROGRAM" watts because it looks better on paper (usually twice the RMS rating) and many people tend to confuse it with RMS. If a manufacturer says "100 watts program", it's a pretty meaningless statistic since there are no exact established rules for how to measure "program material". Like I said... an RMS measurement is for a continuous full range signal over a extended period of time. "Program" is pretty much just playing music.

    ...And that... is the "rest of the story".

    Peace,

    - Frank.
     
  15. Well. What I'm really looking for is this. I have about 200-300 dollars to buy the most powerful poweramp I can find. This one seems to be it. Would YOU go with that? If so why? If not, why? Also, I REALLY wanna thank you guys for explaining this to me. Most is over my head, but I'm really starting to get this. But, do you think this is a good poweramp, because at that price I could get a good rack case and a preamp and EQ....good stuff. I'm REALLY hoping this works the way i'm thinking because of the price.

    Michael
     
  16. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    Get the QSC RMX850 (http://qscaudio.com). 200 watts RMS per channel into 8 ohms, 300 watts into 4 ohms. The RMX line is QSC's budget line (made in China), but if you do some searches here on talkbass and on the newsgroups, you'll find that they're the best quality amp in your price range. Quite a few bassists are using the RMX amps in their racks.

    Most places are selling it for $299, including Zzounds, who provides free UPS ground (You'll need it too... This thing is heavy, about 40lbs).
    http://www.zzounds.com/love.music?p=p.QSCRMX850&z=1409065687146

    EDIT: You may be able to find it even cheaper on ebay.com (.http://search.ebay.com/search/searc...=MetaEndSort&ebaytag1code=0&query=QSC+RMX+850):)

    And the added bonus is... Bob Lee, from QSC frequents TalkBass and is always available to answer questions.

    Peace,

    - Frank
     
  17. Really though. Is the 1000watt amp a good deal though? I like how powerful it is, and I can afford it. I really want it, but I wanna be absolutely sure it'll work. So, is it a good deal?
     
  18. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    Ok Michael... I'm going to do your homework for you :(, and do some quick checking on the newsgroups. Ok, ready? Here's what I found so far within a few minutes (click on the links below)...

    Here are some of the discussions that have taken place regarding Pyramid amps...

    http://groups.google.com/groups?hl=...F8&oe=UTF8&q=Pyramid&meta=group%3Drec.audio.*

    http://groups.google.com/groups?hl=...+amp&ie=UTF8&oe=UTF8&hl=en&btnG=Google+Search

    http://groups.google.com/groups?hl=...F8&oe=UTF8&q=Pyramid&meta=group%3Drec.audio.*

    Ok. NOW... Let's look at the buzz going on about the QSC RMX...

    http://groups.google.com/groups?hl=...&ie=UTF8&oe=UTF8&q=QSC+RMX&btnG=Google+Search

    http://groups.google.com/groups?hl=...C+RMX&hl=en&lr=&ie=UTF8&oe=UTF8&start=10&sa=N

    http://groups.google.com/groups?hl=...UTF8&oe=UTF8&q=QSC+RMX+850&btnG=Google+Search

    Sorry to rain on your parade, but there is truth in "you get what you pay for" ;)

    - Frank.