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Power Amp Question...

Discussion in 'Amps and Cabs [BG]' started by fivesecondzero, Jan 31, 2005.

  1. I've seen alot of rigs here and have noticed alot of you going the preamp/power amp route instead of using a regular bass head. I've been looking into this a little and what are the advantages/disadvantages to going the pre/power route vs the regular way?

    Edit - IF I did go the power amp route, what would I need to make it happen right, and would getting something like a POD or other amp emulator help?
  2. Tedintheshed

    Tedintheshed Banned

    Oct 8, 2004
    Columbus, Ohio
    Well, I like the versitility involved- you can go a lot of different routes.

    Most of all, I like the headroom. My modest QSC out muscles pretty much any bass head out there. I can power 4 full stacks if need be. That's overkill I know, but the headroom it offers contributes to the sound considerably.

  3. bassisten


    Sep 15, 2004
    Bergen, Norway

    Well, I chose the preamp/slave route because of the easy setup (everything in 6U) + the big weight-issue (with all-tube amps). My rack now weighs 20kg...!

    I have now got 1600w QSC-amp made sweet by a Demeter HPB-1 preamp, it's an all-rounder if you kow what I mean...

    You can get all sounds out of this baby... -or should I say these? :bassist:
  4. PlayTheBass

    PlayTheBass aka Mac Daddy Supporting Member

    Dec 7, 2004
    Carmichael, CA
    For me, it's flexibility in the long haul... once you get a power amp with enough good, clean power to properly drive any cabs you might use, then you're free to try preamps until you get one that floats your boat.

    Conversely, if you like the tone of your pre-amp, you can "grow" your power amp as necessary to match your playing situations.

    I personally think the power amp contributes less to my tone than the preamp and cabinets, so I like to keep the power amp constant while I've periodically varied the other two.

    Sean Mc
  5. My switch to pre- power is gradual and ongoing. At one time I had an Ampeg B2R head. I like the tone but it didn't have enough power for my needs. A power amp is the most cost effective way to boost your power so I scanned the web until I found a deal and I jumped on it.

    I have since sold the B2R and have tried a variety of preamp configurations. That's something I would never be able to do with a head.
  6. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    the main thing is flexibility with the pre power setup. oh, and they tend to be LOUD. no emulators needed, all a preamp and poweramp are are the two seperate components of a head put in seperate boxes, (although the poweramp will generally be stereo and a lot more powerful than a head).

    downside, its bigger and heavier than most heads.

    you really have to decide if it's for you. i wouldnt have a pre-power setup if i didnt need the extra volume. plenty of times i've used a head and bypassed the preamp and used another pramp into the effects return or poweramp in.
    actually right now on over 1/2 of my gigs i've been leaving my demeter pre at home and using my swr electric blue head as a preamp and running it into my stewart 2.1
  7. ErnieD


    Nov 25, 2004
    I now have 2 heads I use regularly, a GK1001RB-I and (whenever it gets back from repairs) a Ashdown ABM Evo 500. I can live with these two heads for most gigs, both put out a bit over 500w with my 2-8 ohm cabs. But if I required more power, could I maybe buy a new/used QSC, Peavey, Crown, etc. PA amp and run it with either the above heads? Using what, the effects in/out? . I have always just used heads only, but after seeing so many threads on pre/pwr setups here on TB, I think it could serve my purpose too, eventually. So for now could just using my heads preamp and an extrenal power amp be something I could do for those times I need more juice? If so, any down side to using this system to get my feet wet as opposed to an actual pre/pwr rig? If all thoughts are good on this idea, I need to get back to y'all later to see how I go about hooking such a rig up, thanks for any/all replies. E.
  8. MJ5150

    MJ5150 Terrific Twister

    Apr 12, 2001
    Olympia, WA
    Yes, you can do it. I don't know the wiring specifics on each of your amps, but the owners manual will let you know how to hook it up.

    There are more than a few guys here that have a setup similiar to what you are proposing. A perfect way to enter the power/pre setup. You have one half of the equation already purchased, and you know the tone you will get from it. Typically, the next question after buying a power amp is "What preamp do I need for such-and-such tone?".

  9. Thanks for the replies. I like the idea of being able to change amp sounds with a preamp configuration change. Its going to be a little of an expensive jump, as my research so far shows pre-amps aren't cheap. But from what you guys say the power is going to be much cleaner instead overdriving the crap out of my HA3500.
  10. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    like 5150 said, its a great way to enter the pre/power world by using your head and a poweramp.

    ideally your head will have a 1/4" jack labeled "lineout" or "preamp out" that's what you would plug into a poweramp (using a "y" cord if needed) if not you can see if your "effects send" 1/4" out is post-eq (most are). in that case you can use that as a preamp out. some amps (like eden) have a very low level pre-eq effects send so you can't use it. fortunately eden says you can use the headphone out as a "line out" but you do have to be careful as the master volume affects that output. soem other amps that don't have a line out or post-eq effects send and do have a headphone output MIGHT be able to be used that way, but i'd check with the manufacturer 1st.

    as long as both of your existing amps have effects send and effects return jacks it's easy for you to find out if they are pre or post eq. just plug into amp #1, run a cord from the effects out into the effects return of amp #2, and plug a speaker into amp #2. then see if the eq of amp #1 has any affect on the tone of the sound coming out of the speaker on amp #2. then reverse the experiment.
  11. I checked and the back of the HA3500 has an effects out but no line out. It does have a XLR direct out that you can set to pre or post EQ, but I don't know if that will work or not. I'll just have to see if the effects loop is pre or post EQ or not.

    If I used this setup, with a crossover and then used both sides of the power amp, one side highs/mids, one side lows to two cabs..would that be an efficient way to biamp?

    Just trying to figure out all my options.
  12. Not to highjack the thread but does anyone know of any one rackspace power amps? If so then I could stick one in my fender bassman 210 combo because I just replaced the speakers with Deltalite 410 neos and the combo will handle 600 watts now. I like the pre on that amp too so if I could get more power it would nice.