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GK 700 RB (Mark I, I assume) - good deal?

Discussion in 'Amps and Cabs [BG]' started by John Swartz, Dec 3, 2018.

  1. John Swartz

    John Swartz

    Apr 9, 2008
    D0D41EA8-6D81-4D5A-AA4E-386EAE434294. Saw this in a local shop - don’t need it, and don’t have a GK cabinet so I might not be able to take advantage of the full bi-amping capability, but I’m still tempted. If I’m decent shape, is this a good deal?
  2. AdamR


    Sep 24, 2007
    Bethel CT
    Its a fair deal. MarkIIs go for around $300. The Bi-amp feature is nothing special in my opinion. Some love it. I dont use it.
  3. petrus61

    petrus61 Supporting Member

    Careful with those mk.1’s. There’s a reason there was an RBII.
  4. Wasnex


    Dec 25, 2011
    From what I have read, the MkII got a bump in power, a minor revoicing to warm up the preamp, and a cosmetic update. Output of the 700RB jumped from 380W to 480W at 4 ohms.

    The Mk I amps are getting pretty old by now. Mine is doing fine, but if there are problems to look out for please be specific.
    LBS-bass likes this.
  5. Jeff Scott

    Jeff Scott Rickenbacker guru.......... Supporting Member

    Apr 11, 2006
    I had two of those 700RB amps. Buy with confidence, unless there is a problem with the amp. If all is good these will serve you well.

    BTW - I never bothered with the bi-aming feature on the 700RB; I ran them into a pair of EV B-210 cabinets.
    Wasnex likes this.
  6. petrus61

    petrus61 Supporting Member

    Widely known heating issues related to IIRC the preamp. Specifically they would send a huge surge of power to the cabs upon shutting down and in many cases wouldn’t turn back on or repeatedly go into failure mode. Not an isolated incident and the problem was more widespread with the 1001’s, which also got an overhaul for the same reason. Of course it wasn’t every single unit, but enough of them were affected that GK for a time was offering board replacements. There are some units floating around with the factory “upgrade”. They feature the RBII pres with the mk.1 380w power sections, but there’s no way to tell without popping one open. There’s one sitting in my drummers rehearsal space right now and has run like a champ since the factory repair.

    Unless one knows for sure or is willing to pay for a possible repair, buyer beware.
  7. Wasnex


    Dec 25, 2011
    Good to know; thanks.

    Mine seems to work fine. The power soft mute occasionally allows a loud thump when the amp is turned off, which I believe is what you are describing. I am actually not sure if this was a mulfunction or an accident because I turned the amp off and on twice fairly quickly. Some time must pass before the circuit resets on mine.

    The circuit that controls this is on the power amp module, according to the schematic, and has nothing to do with the preamp as far as I can see. There is a timer chip that can go flaky that resets the protection circuitry and mute. Another TalkBass member replaced the timer chip to fix his MkI.

    Also, if the amp malfunctions, the Mk II preamp and power amp cards are retro compatible. You won't get the extra power though as that comes from the MkII's larger transformers.

    I do agree with Caveat Emptor. Also, since the MkI are so old and MkIIs can be had for very reasonable prices, I would buy a MkII. It common to find 1001RB MkII for <$400
  8. The age might work in your favor,
    since I would expect that the ones that had issues would have
    self destructed and/or been updated by now.

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