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GK 800RB 3-space rack --> Overheat?

Discussion in 'Amps and Cabs [BG]' started by NYC Ken, Jul 10, 2003.


  1. I'm sick of lugging around my 6-space SKB (sweaty guy in subway/taxicab). I run my bass "clean" (i.e. - no effects in the rack), so I picked up a 3-space GroovePak soft bag today. Yeehaw - sling it over my shoulder I can.

    But now I'm a little worried, b/c my amp, a GK800RB, is a 3-space head, with only convection dispersion of heat (no fan).

    Of course, I have a gig tomorrow night, and I thought I would use my new rack/amp setup on. Anyone (particularly you 800RB folks) have thoughts on whether perhaps I'm making a big mistake?

    I only run the 300W amp, and not too high (pre & master both at 12:00 or so).

    Thanks!

    [BTW - I did search the archives on this one - back in February one person complained about an overheating 800RB, but it also looked as if he/she was trying to push the amp hard. Someone on that thread also blathered on about biasing, which I thought was weird for a SS amp ...]
     
  2. Cantstandsya

    Cantstandsya

    Jul 27, 2001
    Fontana, CA
    Hey, that was me who "Blathered" about biasing.Solid State poweramps can become overbiased which would cause them to overheat :bassist:
     
  3. tripwamsley

    tripwamsley

    Jan 31, 2002
    Sulphur La,
    Well gee. If you don't back the rack up against a wall or something, it probably won't overheat. If you are still scared you can get some sort of cheap clip-on fan at Wally World to blow onto the cooling fins. The fan should just be able to zip up inside the rack. 800rbs don't have any kind of overheating protection by the way. Mine has always run with no problems. Hope this helps. And to Cantstandsya, I love ya bro, but I don't think he meant any harm about the "blathering" remark. Well enough of my blathering. Love to all.
     
  4. Good! Isn't that what we're all doing here? ;)

    Really? (Not "Really?" in the obnoxious way, but "Really?" in the surprised way.) I thought it was pretty rare for a SS amp to "become" overbiased once it's sealed up and delivered to the hands of a lowly consumer like me - while tube amps can require a good deal of fiddling, depending on everything from voltage differentials, to tube variations, the position of the tidal formations in various ponds, etc. (And yes, yes, I've used/owned and loved tube amps).

    But anyway, the point was only that I wasn't seeing much in the previous thread as to rack space requirements around GK heads, but more theorizing as to a problem with the amp or with the amp and cab setup.

    Thanks for the feedback, trip - I needed to hear that. What bothered me about the case is that the 800RB is (as you apparently know) only about 9.5" deep, while the rack case is a good 19" deep ... and without any space atop or below, I suddenly worried about all that warmth, trapped in a long sleeve of cordura and padding ... making for a hot little pig in a parka.
     
  5. tripwamsley

    tripwamsley

    Jan 31, 2002
    Sulphur La,
    It's a weird world and I'm sure that some trannie amps can have a bias freakout now and then. Good with things NYCKen! Let me know how things turn out.:)
     
  6. Cantstandsya

    Cantstandsya

    Jul 27, 2001
    Fontana, CA
    :D No harm no foul:D
     
  7. tripwamsley

    tripwamsley

    Jan 31, 2002
    Sulphur La,
    Dude. It's OK. Gimme a jingle sometime and we shall blather!:D
     
  8. I used the same Groove Pak on my RB800 - got kinda hot, so I got a computer fan from Radio Shack, and attached it to the heat sink fins. Ran ice cold after that.

    I did not have good luck with that GroovePak bag - it was much too deep for the amp head, and didn't hold up to frequent use. You can get a Pro Tec soft rack that's just the right size - I got mine at Music 123.

    Incidently - You really need a Furman RackRider with that head - they're known for suddenly burning out. All the pros I've known have 'em. You just get a four space rack, and put the Rackrider on top.

    Good Luck,

    Rob
     
  9. 800RB's are a workhorse and a great amp, however they do have a history of catching on fire. Mine did and it was in a SKB 4 space rack. I know a few other TB'rs who have had the same experience as well. Nothing like seeing yellow and orange flame thru the open 1/4 inch socket on the amp. So they can get hot and flame on. I got mine fixed and it still sounds great although it still has a funny acrid smell about it.
    Peace
     
  10. Cantstandsya

    Cantstandsya

    Jul 27, 2001
    Fontana, CA
    I shall do that:D In the meantime ,please pray for my wife.She is having surgery Monday morning:(
     
  11. tripwamsley

    tripwamsley

    Jan 31, 2002
    Sulphur La,
    they do have a history of catching on fire.

    There is no protection circuit at all in those things. They don't all catch though.
    Randy, the prayers are on the way up!;)
     
  12. Thanks for the feedback all ...

    In part based on the cautionary tone of the above, I took back the 3-space and got the 4-space Groovepak. Used it for the gig Friday night; pushing an Eden 210XLT, and fighting with a Marshall Half-stack, so I was good and loud. By the end of the set, the amp was warm, but not hot.

    [rob - I would have gotten that ProTec if I'd seen your post in time ... I may still do it.]

    Thanks for your help, everyone!
     
  13. What would you think if we added a fan to it?
     
  14. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    If you aren't pushing the amp too hard then you should be ok. You can easily tell. CAREFULLY feel the amp to see if it is getting hot during your gig. If it gets to the point where it is too hot too touch, then you need a fan or a larger rack bag.

    Convection cooling is not horribly efficient. You generally need lots of free flowing air to make it work right. Try the test above, but my guess is that you will need to help the amp out with additional air flow.
     
  15. By "we" assume you mean Gallien-Kreuger; and by "it" I assume you mean the design of the 800RB. [Or are you offering to retrofit my 10+ year old amp with a fan?]

    As to redesign ... I've played through any number of heads that have noisy fans (particularly the variable speed ones) - fine on stage, but for recording, perhaps it might be more of a problem.
     
  16. How many people use the 800RB in the Studio?

    I never notice the fan on the 1001RB-II.
     
  17. I dunno how many. I use mine in the studio occasionally. Although not necessarily by itself - when I use the amp, I'll usually run one channel direct, and one channel of a miked cab.

    That's great. But I'm a little confused about this exchange - as you apparently know, my 800RB doesn't have a fan on it ...
     
  18. Cantstandsya

    Cantstandsya

    Jul 27, 2001
    Fontana, CA
    I used the 1001RB in the studio and never noticed the fan at all.I think adding a fan to the 800RB is a great idea.I also like the idea Trip brought up awhile ago about making the 800RB 300 watts a side instead of the current 300/100 watt configuration.
     
  19. Just my thoughts. I had the same problem. The 800rb by today's standards is a very heavy amp for the power that is offers. I would't put it in a smaller rack because of the heat. I would also make sure the back is open and has ventilation. I left a screw space in the front of my rack for cross ventilation. I have mine in a (heavy like a Chevy, GenzBenz rack with a pwr switch and my Night Bass Processor. My speaker is a SWR Goliath Senior. I have own it for more years that I remember, senior moment. The 800 does have handles and rubber feet so you could carry it without the the SKB. The issue is current protection from environments with poor electrical. I actually bought a fan from Fry's but never used it.
    What I don't see on tb is more discussions about efficiency vs pwr vs weight. The 800rb is a great workhorse but so was the "Heavy Like a..Chevy. I just gave up the the battle and purchased a Aggie TH 500 with two cabs. Fact of the matter, for the last 5 years I mostly carry my MB150 with the extra MB cab and line out to the board when needed. The RB rig I used when at a club where I could leave the the rig. Fyi, the sound of the Aggie through the Goliath is stunning! The fan when practicing at home grows on me. Never the less, the days of carrying a bass, gig bag and heavy head, not to mention a huge cab is beginning to go the way of the Fleetwood Caddy's.

    Since when traveling the big concern is protecting the knobs and switches and not the hazards of the gig enviro. I would get a soft Gator type case and take it out at the gig., using the feet and handles that it came with. Then as soon as finances permit, (congratulation on the baby) get into a smaller high pwr class D rig. If your gig is not paying you enough to hire a roady, do you really need to carry that kind of weight - just saying!

    Lugging that weight adds up over time in terms of body wear and tear, and the cost in Medical bills may out weigh the benefit of the sweet sound you perceive now.
     
  20. brad houser

    brad houser

    Jan 4, 2008
    a GK 800 head does not classify as "heavy".