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Power Amp Replacing Head

Discussion in 'Amps and Cabs [BG]' started by PseudoSpaceman, Oct 29, 2013.


  1. PseudoSpaceman

    PseudoSpaceman

    Jul 5, 2009
    Hey All,

    Just wondering if anyone has ditched their head for a power amp. I recently bought a Darkglass B7K and I like the tone enough to completely bypass the EQ settings on my head. The head is a GK 400RB and has been having some weird issues lately and think it’s time to look for an alternative. Recently I’ve been going DI at most shows and all I’m really using it for is volume.

    Just a few questions:

    1) Would a power amp be compatible with my cab? A GK 212.

    2) What brands would you recommend?

    I would prefer something that would only take 2 spaces in a rack and is relatively inexpensive.

    Thanks in advance,


    Derek
     
  2. RickenBoogie

    RickenBoogie

    Jul 22, 2007
    Dallas, TX
    The ONLY thing you need to be concerned about, is whether or not the B7K has enough output to fully drive a power amp. Check the specs of the preamp, as well as the input sensitivity of the poweramp.
     
  3. PseudoSpaceman

    PseudoSpaceman

    Jul 5, 2009
    It has a pretty hot output from the DI, it just lacks a volume control. What should I be looking for?
     
  4. That may be an issue...

    Personally I really dig Crest and Peavey power amps in bass rigs. I run a ProLite 3.0 in my "big rig" right now.

    Is your cab a 4 or 8 Ohm cab? You should be looking at an amp that will put out about 400-500 watts at what ever impedance your cab is.
     
  5. PseudoSpaceman

    PseudoSpaceman

    Jul 5, 2009
    Isn't the power amp essentially a volume control though? Cab is can run 600w at 8 ohms.
     
  6. No, the power amp has an attenuator that will pad the input signal down, but it doesnt not prevent the amp from being driven provided the input is hot enough.

    Per the power rating, that is a thermal rating, and doesnt actually tell you what the power handling of your cab is. Depending on EQ that is going to fall somewhere between 400-500 watts or so. As long as you are mindfull of your signal chain, you can run any cab with any amp.
     
  7. Contact the pedal manufacturer, and get the output specs.

    Typically, a pedal is designed to work into a high impedance input, which a power amp is not.
    My PLX series uses a 6k ohm unbalanced input, which is what your pedal would feed.
    The Peavey IPR series uses a 7.5k ohm unbalanced input.

    You will need to check the pedal output voltage also.
    The Peavey requires [del]1.0v[/del] 0.775v to reach full power, the PLX requires up to 1.7v.
    If the pedal is designed only for typical bass amp inputs, it probably won't have a high output.
     
  8. Unless Peavey changed the specs the IPR series can be driven to full output with an input of 0.775V.
     
  9. dincz

    dincz

    Sep 25, 2010
    Czech Republic
    No problem. It's exactly the same effect as a master volume control on a head.
     
  10. It becomes a problem if you have a 3000 watt power amp bridged into a 212.
     
  11. Yes indeed.
    It is on the line right above the Input Impedance, and I missed it.

    It's always nice to be fact-checked, and corrected promptly.
     
  12. PseudoSpaceman

    PseudoSpaceman

    Jul 5, 2009
    Talked to the manufacturer, he says it should be no problem.

    Any other recommendations on brands just in case I can't find a Peavey?
     
  13. Franky Rumble

    Franky Rumble

    Oct 27, 2013
    Quebec
    I know Behringer has kind of a bad rep, but right now I use an EP4000 to drive my Tech21 RBI through a "wall of bass pain", well, I mean two 4x10s, two 1x15s, and a 4x12 (yes we have quite a large band practice space), and it packs a ton of clean mountain shaterring power! The amp itself sells for around 300$, wich is a good bang for the buck, the only downside is that it's quite heavy.
     
  14. I did the research, etc, skipped the IPR2 in favor of the Crest ProLite 2.0 (www.audiosavings.com).
    You can get one for $325 as a "demo" with full 5 year Crest warranty.
    Mine had a slightly bent rack ear... no big deal.

    The Crest does not have pimp LEDs of the IPR2, is a bit heavier at 12.8 pounds with steel chassis, has true 4th order crossovers at 100 Hz, better quality internals.
    I bi-amp mine, using the Parallel input, Ch-A < 100 Hz, Ch-B > 100 Hz.

    Link to Thread
     
  15. PseudoSpaceman

    PseudoSpaceman

    Jul 5, 2009
    Thanks a lot! I'll look into them.
     

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