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Head Questions - Inner preamp? Supplementary power?

Discussion in 'Amps and Cabs [BG]' started by Alex, Jan 16, 2006.


  1. I didn't really know what to search for this, and in the FAQ IvanMike sid he needed preamp threads, so here you go!

    There is a "preamp out" output/input on the back of my B2R head. Can I solely use the preamp of my B2R and run it through a power amp? Also, if that is possible, would it be possible to rig up a power amp with my head so it supplements the power of my head. eg. if I bought a 150w power amp and ran it with my 350w B2R would I be able to push 500 watts?

    Thanks guys

    ~Alex
     
  2. Someone has to know!:ninja:
     
  3. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    yes, that should work just fine

    generally preamp outs run independent of the primary "normal" signal from the preamp going to the internal poweramp of a head

    i do that all the time.
     
  4. so you *can* just use the preamp, but you *can't* supplement the head's power?
     
  5. WalterBush

    WalterBush

    Feb 27, 2005
    Yuma, Az
    What do you mean by supplement the power amp's power? You can't plug the other power amp into the same speaker, if that's what your asking (actually, I'm sure you could find a way to do it, but it'll result in a smoking speaker and possible damage to your power amps.)

    Until I sold it a month ago I had an old B2 combo. I used the B2's preamp out to go to an SWR's power amp in, and ran my 8x10 off the SWR's power while the combo ran it's own 1x15 and an additional 2x15, if that's the sort of thing you're asking. I rarely got to use that huge of a rig live, but it was fun to plug in and shake stuff off the walls :bassist:
     
  6. What I mean is, can I plug a power amp into my B2R (power amp in?) and then run the B2R into my cab, getting the power of both the power amp and the B2R's power amp. Feelin' me?
     
  7. Passinwind

    Passinwind I Know Nothing Supporting Member

    You need a second cab if you want to use both power amps at the same time. As always, there's just no free lunch.;) To make this all make sense, you'd want a much bigger power amp than the one in your B2, not something smaller. Anything less than a doubling of power is essentially a waste of time, IMHO. 4-10X will be a lot more meaningful in many cases though. Unless you decide to biamp, which is another can 'o worms.

    BTW, the power amp in is not where you'd plug in another power amp. If you plug an amp's output into the Power amp input, smoke will happen right quick. That input expects to see a preamp level signal.
     
  8. A can of worms that will let me supplement the power of my B2R?

    Also, I've heard that heads are more powerful "bridged". How could I do that? It sounds like it requires 2 cabs, though...

    Also heard of "mono". Would this do anything? from the sound of it I might already be running "mono"
     
  9. Passinwind

    Passinwind I Know Nothing Supporting Member

    You'd still need a second cab and amp, plus a crossover if your head doesn't have one built in.

    Also, I've heard that heads are more powerful "bridged". How could I do that? It sounds like it requires 2 cabs, though...

    Bridging doesn't require a second cab, necessarily. The term generally refers to an amp with the options of being stereo or bridged. Take a look at the Talkbass AMPFAQ (see section 5): http://www.talkbass.com/ampfaq/ . Some bass heads are like this, but it's more common for standalone power amps. So in your case, you'd still need a second cab, plus a bridgeable power amp, or you could use the one cab with an external amp and just don't use the power amp in your head.

    Also heard of "mono". Would this do anything? from the sound of it I might already be running "mono"

    That's the mode you are currently running in, and there's still no free lunch.:cool: