Bi-amping: SS for bass, and tubes for the mid and high end?

Discussion in 'Amps and Cabs [BG]' started by jsa0100, Apr 16, 2018.

  1. jsa0100


    Apr 6, 2005
    What about bi-amping a system with a powerful SS for the deep low end, to get the headroom and power from at big SS amp. And use a tube power amp for the mids and heighs to get a tube (power amp) sound, any experience?

    I know that Bi-amping is a bit 90's but i thing that some of this criticism is the lack find the right speaker combination.
  2. Wasnex


    Dec 25, 2011

    I ran a biamped "all-tube" rig in the 80s and was quite pleased. No reason to expect that running solid state on the bottom for lots of headroom would not also sound great, but your going to lose some of the "tube magic" using this approach. As a compromise you could run the crossover really low (say <100hz), but of course this would depend upon the volume you need and the power of your tube amp.

    To do it right you need either a tube amp that will take a line level input or some sort of device to shift the line level signal from the crossover/processor to instrument level. Otherwise your likely to get a lot of hiss. That's the only real problem I had with my biamped rig. I ran an Orban 672A between the preamp and power amp of an SVT with the HPF going to the input of a blackface Fender Twin. The Orban only had one level control, which had to be set at a compromise...setting the Orban too low for the SVT was required to prevent it from overdriving the front end of the Twin. I am sure an inline pad would have been very helpful, but I didn't know any better at the time.

    Also, IHMO, biamping has some inherent problems that need to be addressed if you want to get outstanding results. For example, 1. inexpensive crossovers don't typically sound great, 2. speakers that work well together must be used, and 3. EQ and time delay must be employed to ensure the speakers properly integrate and work effectively together. If you just cobble together some random equipment and don't bother with proper delay and EQ of the system, expect less than stellar results.

    I have an old GK 2000RB that I sometimes run in biamp mode and it's apparent that the system could benefit from some extra processing (delay) around the crossover to help the speakers integrate a bit better. The only tools I have are polarity, crossover frequency, and the physical placement of the speaker cabinets. It's been awhile, but I believe flipping the polarity of one of the cabinets and pushing the mid/hi box back a bit helps some. I suspect the GK's built in crossover is 12db which would have a 180db phase shift. I biamped the GK into a couple of different speaker combinations and my Greenboy Dually and EV SX300 seemed to get along relatively well, but I think many off the shelf full range speakers sound better.
  3. jsa0100


    Apr 6, 2005
    Thanks for a good and thorough answer.

    I have two tube amps that takes a line level inn, that is a Peavey Classic 60/60 and Mesa f-100. 100w head, they both have power amp inputs. I also have a Dynacord quality crossover 24db.

    At the low end i could use a 2x12" avatar with neos I also have two 15" B&C neo, at the high or mid. I have Eminence Kappa Pro - 10 mid bass. I was hoping to still get an all tube bass sound, but perhaps it's a good idea to look for a bigger tube power amp for the low end.
    Last edited: Apr 17, 2018
  4. The problem with biamping is taking it to the big league needs a very cooperative and well equipped sound crew to bring it to FOH. Just ask Billy Sheehan.
    JimmyM likes this.
  5. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Yep, worked absolutely great for me in my living room. Not snark, I just only had a 35 watt tube amp available for mids and highs at that time. Planning on revisiting this once I get a 100 watter built. That could very well end up handling the woofer side for me in some cases, I think. I'm using a DSP speaker controller for crossover, EQ, delay alignment, etc.
  6. Wasnex


    Dec 25, 2011
  7. Wasnex


    Dec 25, 2011
    IMHO, why not run the experiment with the equipment you have? Whether you need to get a big tube amp depends upon if you plan to run the rig into compression or distortion. Generally you biamp to avoid both (IMHO). Tube amps tend to be a bit less well damped. If you are running the system below the point where it compresses, the difference in damping is probably the biggest difference you will note in the low end. If you are planning to run the tube amp into compression but not distortion, you could easily add a bit of compression between your LPF and the big solid state amp.

    24db crossovers incur a 360 phase shift across the filters. As long as your drivers share polarity convention and no polarity inversion are occurring elsewhere in your signal chain you should not need to flip polarity. As a general rule it's probably best to cross the system over at a point that is well above the tuning of the mid bass cabinets, as all sorts of group delay issues occur when the port comes into play.
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