Sonic differences between amp head vs preamp+power amp combos.

Discussion in 'Amps and Cabs [BG]' started by El Raro, Mar 19, 2014.

  1. Could someone explain to me roughly what the difference in sound is between your standard amp head and a preamp+power amp combo? I've been tossing up trying a preamp+power amp rig for its power but I just don't know how it fares sonically compared to a dedicated bass amp head. Is a pre+power rig suited to one certain type of music over the other? Or is there really no significant difference at all in sound quality/tone?
  2. CL400Peavey

    CL400Peavey Supporting Member

    Nov 7, 2011
    Grand Rapids Michigan
    The tone of any rig will be dependent on the application of the components. Be they in one head unit, or in separate boxes.
  3. johnpbass


    Feb 18, 2008
    Glen Mills, PA
    IME, in a pre/power amp setup, the tone is really pretty much derived from the preamp. Typical "better" power amps do not color the sound in any way. Many amp heads, on the other hand, have a bit of baked in tone coming from the power section as well and that combination of pre and power in the head gives you a little something extra.
  4. Jim C

    Jim C Spector#496:More curves than Sophia + better sound

    Nov 29, 2008
    +1 to the above.
    It's apples and oranges compared to brands.

    I can tell you this; an Ampeg SVP-CL pre into a 1500 Watt Ampeg power amp does not sound like a 1500 watt SVT.
    It sounds close and will make an inefficient cab louder but will sound different; not better or worse but just different.
  5. bluesdogblues


    Nov 13, 2007
    Sorry, OP..but for me the question is almost like: "What are the Feel Differences between 'Van' and 'Bus' " LOL
    I mean, ..what brand? what type? what Pre + Power Combination?..
  6. I probably should have phrased the question a bit better. It was late and I wanted to post the question up quickly before I went to bed and forgot about it in the morning lol.

    What I REALLY wanted to ask is what is the benefit of running a pre+power rig compared to a standard head? Brand-wise, let's say I'm looking at either a BBE B-MAX or even a Sansamp RBI into a Crown XLS2000 for a pre+power rig. I've also been eyeing a GK 1001RB-II if I stick with a standard amp head.

    Just want an idea of what both rigs would sound like. I realise that the preamp will have a lot to do with the voicing of teh tone but I'm wondering if the power amp will help deliver a cleaner sound at higher volumes. All amp heads I've tinkered with to date seem to clip at relatively low levels (around 1 o'clock) and distort...and not in the good overdriven way either. Just muddy fartiness.
  7. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Your suggested RBI rig is pretty much what I use...only with an RPM and 2500. The XLS2000 will drive just about any enclosure you can imagine. Dollar for dollar, the separate power amp is a better value in terms of sheer power but, if it does not produce the desired outcome, you're not gaining any territory. I do enjoy rolling a handful of different pre's through my rig just to shake things up.

  8. Fuzzbass

    Fuzzbass P5 with overdrive Supporting Member

    Advantages of a pre+power "rack rig":
    • Modularity -- if you have enough power but want a different tone, then you can replace the preamp rather than the entire head. Likewise, if you're happy with your tone but need more power, you can replace the power amp.
    • Protection -- rack rigs are typically contained in racks (duh) with lids for the front and back that protect the knobs.

    • Higher cost (usually)
    • Trickier to design and set up (but once you get used to it, no big deal)
    • Heavier and bulkier than most modern bass heads, HOWEVER my 40 pound rack rig gets reasonably close to the vintage SVT tone with less than half the weight

    Modularity is the big advantage for me, so that's why I've mostly used rack rigs over the past two decades. I have a number of different preamps and it's relatively easy to switch from one to the other if I feel like having a different tone at a particular gig. Also, my #1 rack rig is four spaces (4U), with a 2U power amp and two 1U preamps. I typically use just one of the preamps, and the other is there as backup... or variety. :)

    Those are different animals, tone-wise... just do research on the tone characteristics of each. Tone comparison does NOT include the power amp: modern power amps will not color your tone. But sure, you'll want to check the power specs of the Crown vs. the GK head to ensure that both will meet your needs. Good luck!