Dismiss Notice
Join The Good Vibe Zone today, and hangout with the nicest bass community in the world :)

Amp stack question

Discussion in 'Bass Amps & Cabinets' started by boston asphalt2, Mar 21, 2007.

  1. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    Ok, this is what I have for my bass rig at the moment:

    Gallien Krueger 1001 RB-II: 700W + 50W biamp (700 to woofer, 50 to tweeter) Now, does it put out this much power per channel? Like, if I have both of my cabs set up, does each one get the 700W + 50W?


    Next question:

    If each of my cabs is rated for a lower wattage than what the amp puts out, what is the end effect on the cabs? Is this what causes clipping?

    Ive been using my practice amp ffor vever and tonight finally went back to my rig, and I forgot that when I really punch the strings at a decent volume, I get heacvy distortion sound, even if its not that loud. ive ruled out everything except wattage (no torn cones, loose cones, nada).

    SO, if my amp does 700W, and my cabs only take 350W and 400W, does that mean I am overdriving them? Is this what is also causing the clipping at what I consider lower than normal volumes?




    Im looking at possibly either getting a less pwoerful amp, or higher rated cabs, but I want to get some clear answers to my questions above. THANKS
     
  2. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    oh, and the impedances on my amp and cabinets both say (4 ohm or 8ohm) so I guess those match up.
     
  3. Berin

    Berin

    Joined:
    Jul 2, 2006
    Messages:
    67
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Launceston, Tasmania
    What cabs are you running? Are they both 8 ohm?

    Your GK head will put out 700w into 4 ohms (2x 8 ohm cabs) or 460w into 8 ohms. So if running 2x 8 ohm cabs, each will see 350w. The 50w power section is used to drive the tweeter in compatible GK cabs, although you can re-wire other cabs to take advantage of this feature.

    Clipping is caused by under powering and is very bad. It causes your amp to put out DC and will very quickly destroy speaker voice coils. Over powering a cab is much safer and will do nothing to damage the speakers if used correctly. I feed a 600w cab 800w, no problems. It's called head room 8)

    As for the distortion you are hearing, have you tried reducing the gain on the amp? If you feed too hot a signal into the preamp you'll get distortion. Go back to your user manual or download it from the GK site and have a look at the suggested sequence to set up the gain.

    Actually, here is the bit from the manual:

    5. Level and Master Volume settings:
    Set the Master Volume to 12 o’clock. Turn the Input
    volume up as you play. Try not to turn it past 1
    o’clock unless you want an overdrive effect. If the
    yellow clip light turns on, press the -14db button in.
    If it is still on, try turning the volume down on your
    bass.
    At this point:
    You should be hearing your bass quite well. You can
    use the Volume and Woofer-Master to achieve a
    comfortable sound level. Remember: If you need
    more volume, turn up the Woofer-Master control first.


    As a rule, the GK amps are normally very clean sounding. Don't forget to do the simple things like check the battery in your bass and the condition of your cables too. Also, take out any effects pedals you may run to rule them out too.

    Hope that helps.

    Berin.
     
  4. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    here is the front of the amp:

    [​IMG]

    The "woofer" knob under bi-amp control would be the master volume, and the "volume" knob under input is the input volume, correct? So, Im getting input clipping, so I need to cut back on the input volume, but then if its not loud enough, I just turne up the woofer volume.

    I think I got it. Gracias.
     
  5. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    Im running Eden 115XLT and a 210XLT, and the only impedance it says on the site is 4 ohm or 8 ohm, which I guess means its available in either impedance, but the cab itself doesnt say......what is the issue if Im running 2x 4 ohm? isnt that effectively 2 ohm? is that bad?
     
  6. avionix543

    avionix543

    Joined:
    Nov 2, 2006
    Messages:
    1,204
    Likes Received:
    33
    Trophy Points:
    48
    Location:
    St. Augustine, FL
    I wrote a nice long reply to this question earlier then my computer crashed. Lucky for us, Berin had exactly the same ideas :) . A pair of 4 ohm cabs will only be a problem if the 1001RB isn't designed for 2 ohm operation. I'm researching a way other than metering to see what resistance your cabs are... Have you visited the Eden Forum? It's not as easy to navigate as this one but there's some good info over there... I'll see what I can find on your cabs. ~M~

    ps- been to ups recently :wink: ?
     
  7. Berin

    Berin

    Joined:
    Jul 2, 2006
    Messages:
    67
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Launceston, Tasmania
    I believe you have it right in regards to the volume (gain) and woofer (master). Hope that solves your problem. Has the clip light been flashing? Also, the boost control apparently ads a certain amount of distortion too.

    I would think it unlikely that you have 2x 4ohm cabs. 8 ohm is usually the norm. Two 4ohm cabs will give a 2ohm load and with your head that would be bad. The GK's aren't 2ohm stable and will cause the head to shut down or possibly do some damage.
     
  8. avionix543

    avionix543

    Joined:
    Nov 2, 2006
    Messages:
    1,204
    Likes Received:
    33
    Trophy Points:
    48
    Location:
    St. Augustine, FL
    Alrighty then Graham - I found it... Look on the back of your cabs where the tweeter attenuation pot is. There is a sticker on that plate. In the upper right corner there should be some numbers printed identifying the model number, serial number, and resistance of the cab. One of mine -'02 model - has a "Z" with 8 next to it (Z being an electronics abbreviation for resistance) and the other one - '07 model - has the Ohm symbol with a 4 next to it. Look for the 8 or the 4, and you'll know what you're dealing with. ~M~
     
  9. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    did you get my PM from the other night? I take it you did. I am sending the bass off this week, and i will send you a tracking number and such when its off! :D
     
  10. avionix543

    avionix543

    Joined:
    Nov 2, 2006
    Messages:
    1,204
    Likes Received:
    33
    Trophy Points:
    48
    Location:
    St. Augustine, FL
    Excellent! ~M~
     
  11. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    ok, so I played with my amp and I still get some dirty sound when I pick hard. Not the type of dirty sound when the string slaps the pickup or neck, but the kind like Im driving it through a very slight fuzz box.

    I unplugged my 2x10 and played jsut the 1x15. The sound was fine. I then played through JUST the 2x10 and the sound was there. I took off the grille over the speakers and checked the cones. No rips. I tightened the grille so it would not shake, and the sound still happens.

    What could possibly be in this cabinet making this noise? Possible that one of the speakers is very slightly loose or something? can anyone list possible things to check on the cab? thanks!
     
  12. avionix543

    avionix543

    Joined:
    Nov 2, 2006
    Messages:
    1,204
    Likes Received:
    33
    Trophy Points:
    48
    Location:
    St. Augustine, FL
    I've come across a few posts over on that Eden forum about this kind of problem. The most common cause seems to be a bit of hot glue that has come in contact with the back of the cone and rattles loose after a while. Easy to check - remove tweeter attenuation plate and look inside with a flashlite at the back of the speakers. If you don't find anything there that looks loose, unhook the speakers one at a time and find out which one is making the noise. I'm looking at getting two new XLT 10's for my Metro because the new XST cab sounds great but I think the XLT's (five years old) have just about had enough and are getting ready to die. All my neighbors are gone so I finally had a chance to run the rig at a decent volume and ran into distortion from the older speakers. I'll let you know what I find out about them if you want. ~M~
     
  13. TBS

    TBS

    Joined:
    Jan 19, 2006
    Messages:
    299
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Spain
    You have forgot a very important issue here

    EQ

    10" speakers will distort that way if the signal is heavy on low end, even at low volumes.

    I always check the 10" cabs EQing low bost on the bass and the amp, most of the brands I have checked (except for multi woofer crossovered cabs) will distort at some point even at low volumes.

    On the other hand I have played a low F# a fourth below Low B through a 2x10" cab without distortion and decent volume, but the lows where flat on the bass and on the amp.

    Clipping occurs whenever the signal wave amplitude reaches a point which the corresponding clipping elemnent can not go further. You can have a clipping preamp input from a hot instrument signal, a clipping preamp output/poweramp input because too much gain on the preamp or a clipping speaker because the signal wave has so big amplitude that the cone can not move so far away. This means you can have a clipping speaker from a clean signal, it is clean, but it is too big for that speaker to reproduce at that level.

    Boosting lows results into producing huge amplitude signal waves.
     
  14. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    sooooo, does that mean I can't get the full sound and feel from my thumb 5 through a cab stacked w/ 10s? i dont buy that notion considering my bass is set slightly flat on the amp and set even on my bass.
     
  15. TBS

    TBS

    Joined:
    Jan 19, 2006
    Messages:
    299
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Spain
    flat = no cut no boost

    I suppose when you say even you mean that.

    If your settings on lows/ lower mids are that way, then it must be other problem.

    I just pointed out the EQ thing because it is easy to check and it happens quite often with 10"s.

    Good luck solving your problem then.
     
  16. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    yeah thats what I mean
     
  17. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    thanks TBS and avionix, tomorrow is the day of reckoning. I opened up the back of the cab and didnt find anything that could cause a problem. I pulled the grille off the front of my 2x10 and went at the speaker screws with my screw driver. I was able to turn each screw an average of 3/4 a turn without too much difficulty! I tightened them up a lot more and tomorrow I will plug in and see if it makes any effect.

    I hope it isnt something like an EQ issue because the sound from my Thumb through that stack is PERFECT ex ept for the minor distortion.

    Also, I plan on unpugging one speaker at a time and trying it, but from the way its wired, it looks like I cant do that. I could be wrong, and I hope I am :wink:


    thanks again for the help guys, and if you have any suggestions let me know. Im looking at a 4x10 for 600 USD (Eden 410XLT). The guy also has an Eden amp and is willing to sell both for 1100...........Im almost tempted to get the amp thats made to compliment the cab the best. WIll probably work much more flawlessly.
     
  18. avionix543

    avionix543

    Joined:
    Nov 2, 2006
    Messages:
    1,204
    Likes Received:
    33
    Trophy Points:
    48
    Location:
    St. Augustine, FL
    WT800? That amp with the 410XLT is rumoured to be damn near perfect from what I hear :D .. Now you've got me fiddling with the EQ and gains on my rig too! ~M~
     
  19. Grgzilla

    Grgzilla

    Joined:
    Mar 5, 2006
    Messages:
    10,981
    Likes Received:
    34
    Trophy Points:
    48
    Location:
    sydney, australia
    Hi Graham,
    I once saw a guy use a plastic funnel like an ear trumpet to isolate each speaker individually.Might be easier than dissconnecting each speaker individually. :wink:
     
  20. boston asphalt2

    boston asphalt2 Official Forum Pain in the Ass

    Joined:
    Jul 10, 2006
    Messages:
    2,378
    Likes Received:
    194
    Trophy Points:
    63
    Location:
    Massachusetts, USA
    WT500 Highwayman
     
Loading...