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Amp Jargon, some defining

Discussion in 'Amps and Cabs [BG]' started by The Urbs, Mar 7, 2004.


  1. The Urbs

    The Urbs

    Feb 23, 2004
    MA
    Hey,

    I need some help on some amp terms since Im looking around for amps and heads I always get stuck on what is all means like:

    What is ohms? is 4 better, 8? What the uses?

    What to look for in an amp head, the most watts?

    Stuff like that, gets me all messed up. And any of you audiophiles out there please add all you know into this thread!

    - Chris
     
  2. Yes, 4 ohms is better than 8 ohms and 2 ohms is better than 4. The more wattage the better: 200 to 300 watts for an all tube amp and atleast 1000 watts for solid state (500 is the bare minimum for a solid state amp anything less is gutless IMO) .
     
  3. need some help on some amp terms since Im looking around for amps and heads I always get stuck on what is all means like:

    What is ohms? is 4 better, 8? What the uses?
    Ohms is a unit of resistance to current flow. Most amp heads work best at 4 ohms although some will work at 2 ohms. If you plan on only using one cabinet it might be best to get 1 x 4ohm cabinet however, if you plan on using 2 cabinets it is best to get 2 x 8ohm cabinets because when you plug 2 x 8ohm cabinets into your amp head the total resistance is ½’d and becomes 4 ohms.

    What to look for in an amp head, the most watts?[/

    You can’t judge an amp head on watts alone but it is an important factor. As a rule the more watts an amp head will produce, the more head room it will have. Head room is the amount of power it will produce before distortion (sound like crap).

    It really comes down to matching components. It doesn’t make much sense to have a 1,000 watt amp head with a speaker cabinet that’s rated at 200 watts. Nor does it make much sense to have the apposite. Some smaller speakers need a lot of power to produce a decent volume while others can survive just fine with a lot less. This comes down to a term known as speaker efficiency. It is rated in db at 1 watt at 1 meter. The higher this number the louder the speaker will play with a given amount of power. A speaker rated at 97db will need twice the power as a speaker rated at 100db to produce the same sound level.

    Stuff like that, gets me all messed up. And any of you audiophiles out there please add all you know into this thread!

    - Chris
    __________________
     
  4. The Urbs

    The Urbs

    Feb 23, 2004
    MA
    Thanks for the replies, very helpful.

    What about power amps? When are they nessacary?

    Miked Amps, DI?

    Still more :help: :crying:
     
  5. Iv'e got a question too. Are tube watts louder than SS watts. If so, how much more (ie. 350 tube = ? SS approx.)?
     
  6. 300 to 350 tube watts can sound as loud as 1000 solid state watts IMO.
     
  7. The Urbs

    The Urbs

    Feb 23, 2004
    MA
    Tube amps?
     
  8. That is a very controversial question that has been debated over and over again. In my opinion (and I've got a ton of them) the answer is yes and no. 300 watts is 300 watts tube or SS but say both amps are operating at -3db that’s 150 watts. If you push the SS amp to +3db it will probably produce a terrible farting sound, however if you push the tube amp to +3db it will probably sound even better. Tube amps when driven past their rated power go into a sort of natural compression and the distortion components of the sound are much more musical than those of a SS amp. So what you end up with is a 300 watt tube amp can play as loud as a 600 to 1000 watt SS amp. However, it can still only produce 300 watts of undistorted, uncompressed power. The difference is that the tube amp can produce power above its rated power that is still musical and usable. The SS can't.
     
  9. kirbywrx

    kirbywrx formerly James Hetfield

    Jul 27, 2000
    Melbourne, Australia.
    Miking an amp means to put a microphone in front of the speakers, and what is heard/recorded is the sound that comes out of the speakers (cab)

    Now im not sure if my definition of DI-ing is the best, but ill give it a go.

    D.I. stands for Direct Injection. A DI has 2 inputs and 1 output. One coming from the bass, one coming from the amp, and one going to the mixing desk. A DI is used so that an almost exact replica of your tone is produced and put through the mixing desk, weather it is going to be recorded, or played through a P.A.

    I dont think that explination is 100% correct, but for me its hard to put what a D.I. does into words. hope it helps though! Here is a picture that hopefully helps you (or someone else trying to explain it) out with the power amp/pre amp thingy ;)
     
  10. The Urbs

    The Urbs

    Feb 23, 2004
    MA
    Man that is a great diagram!

    Thanks for all the help! :hyper:
     
  11. I thought it stood for "Direct Input" but I also could be wrong. Of course the Volkswagen TDI stands for "Turbo Direct Injection" but I could be wrong again.
     
  12. Ty McNeely

    Ty McNeely

    Mar 27, 2000
    TX
    No.

    Tubes are simply able to handle being overdriven (and usually sound best when slightly overdriven).

    Tube watts and SS watts are exactly the same, no matter what anyone tells you. The reason they SEEM louder is because they can be driven to their full capacity, while most SS amps will clip before peak.
     
  13. kirbywrx

    kirbywrx formerly James Hetfield

    Jul 27, 2000
    Melbourne, Australia.
    So could i. chances are your right :p
     
  14. Ty McNeely

    Ty McNeely

    Mar 27, 2000
    TX
    Neither is better than the other. The number of watts that an amp can produce is dependent on the load that an amp can handle (measured in ohms).

    For example (numbers off the top of my head):

    an amp being used at 8 ohms might produce 250 watts, while the same amp used at 4 ohms might produce 400 watts. There is no "better" in this case.

    To get an idea of how it works, if you take two 8-ohm cabinets and plug them into one amp, you will then have a 4 ohm load. If you take two 4 ohm cabinets and plug them into one amp, you will have a 2 ohm load. If you take one 4-ohm cab and one 8-ohm cab and plug them into the same amp, you get a load of (I believe) 2.67. Now--some amps are DESIGNED to handle a load of 2.67, but others are not. If your amp is not specifically designed for it, it is not recommended to do this because it can literally fry your amp.


    What to look for in an amp head is totally dependent upon YOU. For example, if you play in small rooms of 50 people, you don't need 1500 watts to perform. On the same note, if you play auditoriums regularly, I wouldn't recommend using 60. The most important thing is that you like the SOUND that comes from the amp. After all--the sound is what you HAVE the amp for in the first place.

    If you hang around here long enough, you'll learn a lot. Enough to get you by, at least;)
     
  15. About the Direct Input thing, you can put your bass into a DI box, or you can come out of the amp if the amp has a line out (many amps have a blanced XLR output specifically designated as a DI out) but you would not typically plug your bass AND the amp's DI out into the same DI box. That would cause some major problems.

    You could plug the bass into a DI box, then plug the XLR output into the mixer while plugging the DI's 1/4 inch output into the amp. In effect the DI box becomes a signal splitter.
     
  16. People say that since my wife is Italian that I'm Italian by Injection. Is that the same thing? ;)
     
  17. I tested this theory with an Ampeg SVT 2 and a GK 800RB. Both are rated at 300 watts. Tonal difference was significant, but neither amp was louder than the other and both could be pushed into the 'rails' and still sound musical. I don't know how other solid state amps would do in that test, but as far as GK amps go, that theory doesn't fly.
     
  18. The Urbs

    The Urbs

    Feb 23, 2004
    MA
    Thanks for all the help! I have now gained adequate knowledge and feel empowered! :cool:
     
  19. I tested the theory with an ampeg svt-III pro (450 watts @ 4 ohms) versus an ampeg svt II pro (300 watts @ 4 ohms) both through the same svt classic 810 cabinet and found the all tube svt II pro to be louder. That being said I also found my vintage svt's to be louder than the svt II pro maybe because of the higher voltage (the vintage svt runs at 650 to 700 volts if I am not mistaken). Although I am not sure what the current voltage is that SLM svt's run at (maybe its all of that protection circuitry getting in the way), just my 2 cents...