ailing SVT or bad cab

Discussion in 'Amps and Cabs [BG]' started by Wounded Paw, Jul 12, 2002.

  1. I've been using an early 70's SVT head for a few years now and it's always been more than enough volume wise, played paired with a new ampeg 410. I've recently purchased a new SWR 212 that I've been using in conjunction with the 410 to load the amp properly (2 8ohm cabs). Instead of getting more volume I'm getting less, I even tried running the SWR212 as the only cab but the volume was the same. Where I used to have to keep it down to practice with the band I'm now pushing the amp to get enough to hear properly. We are a very loud crust/grind type of band but I'm beginning to worry about the head. It's just been in for repairs, biasing, new preamp tube, and while it's better it still doesn't have the juice it used to. Is this the amp giving up or is something funny with this SWR 212 cab, it's a new product they call the 'Twelve Pack'. The sound is nice, very ballsy but I just can't get the volume.
    Wounded Paw
  2. Rickenbackerman


    Apr 17, 2001
    Laurel MD
    How are you hooking up the cabs? You should be daisy-chaining them off of one output on the head for a 4 ohm load, not plugging each cab into the head. By pluggin into both outputs, the amp wants to see a 2 ohm load.
  3. tried it both ways but the thing is I still don't get the same volume using the SWR 212 by itself as I used to get using the 410 by itself. And by the way I'm pretty sure those old SVTs see both speaker outputs as parrallel so daisy chaining or not it will see a 4 ohm load using 2 8 ohm cabs.
  4. lneal


    Apr 12, 2002
    Lee County, Alabama
    I know a lot of people mix cabinets on the same power amp channel, but I never thought it was a good idea. These are completely different cabs with, I'm sure, different impedance curves which may be your trouble. I think you should have bought another Ampeg 4x10 box. Or an 8x10 SVT box.
  5. Rickenbackerman


    Apr 17, 2001
    Laurel MD
    Yes, the amp will 'see' 4 ohms either way, but there is a difference between what the amp 'sees' and what it 'wants to see'! This is because they're not parallel outputs, they're switching jacks. When you use the main output, the cab runs off the 4 ohm transformer tap, and when you use both outputs, you're coming off the 2 ohm tap.

    At any rate, you should be using only the main speaker output, and then daisy chain the second cab off of the first. As for volume, you're comparing 2 twelves to 4 tens, along with other variables. The 4x10 has more cone area, and it also may be more efficient... but either way, using both cabs should be louder than using just one!
  6. Okay, I understand that and will try daisy chaining. My main concern was with the drastic difference in volume levels compared to using the 410 by itself before. Like you said, two cabs should be louder than one. Also a 212 by itself should be comparable to a 410, not so far off that I have trouble being heard. The SWR is rated for 400 Watts while the ampeg 410 is only 300 watts so mebbe the SWR is not very efficient. Dunno
  7. Well you were definitely right about the daisy chaining. I always knew that was an option but I was under the impression that the early svt's didn't switch impedance when both speaker outputs are used. Anywayz, it's all good now, I've turned the volume down several notches and I can hear everything just fine. That swr 212 rilly has a lot of balls to it.