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Ampeg Stack Concerns

Discussion in 'Amps and Cabs [BG]' started by debris, Oct 3, 2009.

  1. debris


    Oct 4, 2008
    Raleigh, NC
    I just ordered a brand new SVT-15E from basscentral.com, and played it for the first time with my 410-HE out of my 450H head.

    For Reference:
    The 15 is an 8ohm cab rated at 200W RMS and 400W program.
    The 410 is also 8ohm, rated at 500W RMS and 1000W program.
    The head gets 250W at 8ohms and 450W at 4ohms, which it is now doing with both cabs hooked up to it (there is a very noticable volume increase even at 1 or 2 on the master volume).

    As sweet as this sounds and looks, there are a few tiny things that have my concerned with the matchup of these two cabinets.

    I started out plugging the head into the 410 and then plugging the 15 into the 410. This was causing some slight crackling in the 15 at higher gains, so I switched the order, which seemed to elliminate the problem. Running the amp out into the 15 first and then from the 15 to the 410 however made the 410 sound kind of quiet compared to the 15. When I put my head up to the cabs and played the 15 definitely sounded louder.

    Plugging each cab seperately into the amp worked fine, however there was some slight crackling in the 410 at first (it seemed to go away after a little while) after I had played the two of them together. That cab has played beautifully for 2 years with zero problems, and I would kill myself if anything happened to it.

    Switching speaker cables also seemed to have an effect on the crackling. It did it less with my older cable than with the one I just bought.


    What exactly is this crackling sound and why is it happening? Am I hurting my cabs with differing amount of power or hooking them up in the wrong order? Does it matter which output/input jack you use to chain the cabs together? I've never read anything online or in the Ampeg owner's manuals about that being important.

    I admit I am suspicious of the 15's 200W rating since my amp is dishing out 450...is this a problem for the 15 to have that much power going into it even though it's paired with a 410 rated at 500W?

    I would appreciate some help! :meh:
  2. NKUSigEp


    Jun 6, 2006
    Bright, IN
    First off, your increase in volume had very little to do with using the full 450 watts and everything to do with having another speaker moving more air. And who knows how many of those watts you were actually using anyways? Just depends on how you set your EQ, where your volumes are, and so on.

    Second, how you connect your cabs should have absolutely no affect on your sound, period. As long as your above the amp's minimum load rating, everything should be 100%. I once had issues with crackling noise too and it was actually coming from the amp. I forget what exactly was going on with it, but I'd say if it is an actual sound then it's your amp. If it's more like a drop or intermittent signal, it's something with your connection and you should check your cables and inputs/outputs.

    PS - doesn't your amp have two separate outputs? Why not just run a cable out of each output into each single cab?
  3. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Random ideas:

    It could be some sort of corrosion or wear & tear on the speaker jacks & cables. I've done a lot of gear repair, and my rule of thumb is that most problems are "mechanical" in nature, i.e., connectors, cables, switches, pots, etc.

    With the amp turned off, "exercise" all of the pots back and forth several times each. Even try a new signal cable from your bass to the amp. The problem could be coming from anywhere. The amplitude of the crackling could simply have to do with the 410 being up off the ground at ear level.

    Do you put the head on top of the speakers? If so, try it with the head on a chair to isolate some possible vibration issue.

    These are all guesses, but just some things to try.
  4. DaveF


    Dec 22, 2007
    New Westminster, BC
    You're hooking them up in series:

    Amp --> Cab1 --> Cab2

    This is giving you a total resistance of 16 ohms, and much less output.

    You should be hooking them up in parallel:

    Amp -->Cab1 AND Amp -->Cab2

    This will give you 4 ohms, and the full 450watts.

    Running the head into 16 ohms may have damaged the power section of the amp.

    Hope that helps!
  5. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    No, the jacks on the cabs are parallel, so he's still hooking them up in parallel.
  6. debris


    Oct 4, 2008
    Raleigh, NC
    That is an important distinction--I realize that that is the major factor in volume increase. I probably should have phrased my initial statement a little better in that case.

    I was not aware that the wattage was variable within the context of a single amplifier at a constant impedence. I guess I really don't know how to interpret wattage in that regard--it would make sense if it corresponds to volume that it is not simply a constant value.

    The min load is 4ohms, which it should be at. The signal does not sound like it's dropping out, which would allude to a hardware problem. There's just a crackling kind of static in the background of certain frequencies that mimics the sustain and intensity of the note.
    It happens mostly on low notes like the B at the 7th fret on the E string--notes that have more attack and sound the loudest.

    Yes it does. I tried it like that first and it didn't seem to work right. I don't know why.


    I do. I'm pretty confident that this noise it not vibration though--the head and cabs are very secure the way they are stacked, but I won't rule it out.
    I'll mess with their configuration and try some of those other ideas you suggested. Good tips btw! I'll remember those.


    That seems to make sense, since there was less sound coming from my 410.

    I hope that's not the case. The minimum rating is 4ohms, as I said before. The amplifier is also described in the owner's manual as handling a 16ohm load, so it seems like that should be alright.

    However, wouldn't more impedence just put a smaller signal to the speakers? Logically speaking, it seems like a lower output would have less of a chance of damaging the components. I don't really know how a power amp works though, so that may not be accurate.


    Whether the jacks were wired in serial or parallel crossed my mind when I was hooking them up. I honestly had no idea, so proceeding to hook everything up in spite of that may have not been a good idea in retrospect. :rolleyes:

    After looking at my manuals again, which I definitely should have done before attempting to set everything up, it says that the 410HE is wired in parallel, like you said, so a cable can be run from it into another cab. I would expect that the 15E works the same way, since both are SVT classic series cabs. The manual for the 15E is much less detailed than the one for the 410HE unfortunately, and doesn't have anything other than the general specifications.

    In my case then, whatever I do will run in parallel because my cabs are wired in parallel?

    Interestingly, both the manual for the 450H and the 410HE say to use the Speakon jack when your amplifier is operating at or near full capacity. Are 1/4" jacks really that lesser of a quality? The manual calls them "convenient," and recommends the Speakon jack for power amps over 150watts, permanent enclosures or for the first cab in a line of daisy chained units.

    This would explain the variation in sounds I was getting from different 1/4" cables.

    Two of these situations apply to my rig--it appears to be the thing to do then?
  7. NKUSigEp


    Jun 6, 2006
    Bright, IN
    Then I'm willing to bet it is your amp. It should work flawlessly having a cable coming out of each of your amp's outputs into separate 8-ohm cabinets. If it's not, then something is DEFINITELY wrong with your amp and you need to have it checked out.

    EDIT: check your cables and jacks first since those are a much cheaper fix.
  8. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    when playing, are you clipping the amp? and do you have the limiter on? cos i have a svt450, and if i peak out the amp, and DONT have the limiter on i get some crackling at times.... its from overdoing the powersection.
  9. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    First off, as Jimmy pointed out, this post here is completely wrong. All the speaker connections on both your amp, and the 2 cabs are wired parallel, so any way you hook it up, it's all good. I'm not sure what your crackling sound is, but I will mention, that as a rule, a 410 paired with a single 15 is not the best set up. As you've already determined, the 15 is rated for 200 watts, vs. the 410's 500. This means the 15 will be being pushed to, and possibly beyond it's limits, while the 410 is just cruising. It limits your rig. Try this, take the 15 back, and get another 410he. Who knows, might even cure the crackling, but beyond that, it will match up perfectly with the other 410he, and your rig will kill. Good luck.
  10. This is correct. The listed "450W @ 4Ohms" is a peak value. When the amp is not delivering to the maximum of its ability, you're not hearing 450W.
  11. I prefer seperate amp to cab cables to minimize signal loss. Daisy chaining sends 100% of the signal through the first cable which will create more signal loss vs send 50% through 2 seperate cables.

    Sounds like the crackle is in your amp or cords. Previous posters have addressed this.
  12. debris


    Oct 4, 2008
    Raleigh, NC
    I always keep the limiter on. The peak light does go on on occassion, and did so more than usual when using both cabs together.
    EDIT: Do you think the power amp has sustained any kind of serious damage from this, or is this just something I shouldn't be doing more of? I've only had the amp for a couple days, and have played through the both speakers about several times.
  13. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    I HIGHLY doubt you have hurt the amp... i run mine into 2 410s, and have wired it however i want.. and its great...
    the 410 to the 15 combination is probably making the 15 accept a bit more than the 200 watts its comfortable with and givin you some noise...
    the 15 to the 410 combination is making the 410 quiter, i would guess, cos you have a 200 watt cabinet in front of the 500 watt cabinet. And while those crossovers in the back of the cabs are supposed to be direct, its kinda like pedals givin ya tone suck, i wouldnt be surprised if the cab caused some loss due to being lower rated.

    (im sure some electrical genius will make the above statement sound like it came from a tard, but...)

    also, with both cabs running it will more likely clip more because you are much more likely to hit the 450 watts.

    is the crackling really loud, or kinda like the hiss and pop you can get from a horn when you have a single coil jazz hooked in?
  14. eyeballkid

    eyeballkid Supporting Member

    Jul 19, 2009
    Also, since you say that youve only had the amp a few days, does it say made by SLM in the USA on the back? or is it made by LOUD? cos THAT could be the issue in my experience. Alot of folks i have encountered have had unwanted noise from LOUD made ampegs.
  15. debris


    Oct 4, 2008
    Raleigh, NC
    I don't know what that sounds like unfortunately, but the crackling I'm getting is a dull kind of background surge, which kind of goes along with the volume of the note played.

    The 15 is new, so it was made in Vietnam, and yes it says Loud Technologies on the back. My 410 and 450 are both made by SLM in America (woot woot).

    I wasn't originally intent on buying a new 15 for that reason, but I did because there were no used ones on the forum or in the music stores in my area, and probably just because I wanted to have it, which now seems like not the best decision I have ever made. :meh:
  16. debris


    Oct 4, 2008
    Raleigh, NC

    I am planning to return my 15E to BassCentral this week, and have replaced it in my rig with another 410HE, which I got tonight at Sam Ash.

    This one is used, made in America, and sounds massive.
    No problems whatsoever. I also switched to running both cables out of my amp, with one into each cab. As I said before, something seemed arwy the first time I did that, but now it works great.

    All in all, I am out around $100 in shipping between North Carolina and Florida plus the difference between the two cabs (~$50), so about $150 total. Despite this, I now have what I want and what will work the best for my sound and in my rig, which is the most important thing when all is said and done.

    I also learned to be a little more careful when buying something like an SVT cabinet, especially online where shipping costs come into play. This was my first time making that scale purchase on my own, and I jumped the gun a little. Well, a little being about $150 worth of bullets. Had I done some more thorough thinking about the 15E, I think I could have saved some serious green in the long run. But hey, that's how you learn this stuff.

    Interestingly, I just remembered that I was reccommended to get a second 410HE to go with my first one in a previous thread, which I posted before I was that serious about getting a second cab.

    +1 to JimmyM. It's in my house now, and it sure is something to behold. Almost as tall as I am, and I'm 6'2"!

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