Gallien Krueger 700RB amp

emo panda · #1 12-08-2011, 09:39 AM

Hello everybody

I bought used bass amp GK 700RB for really good price (250€), but when i realized that there must be fan in the amp. I open the amp and the fan is in it, but it just isn't working, although the fan is connected to the two pins where should be.

It seems like the fan is broken, what do you think?

it has two pins, something like this:
http://t0.gstatic.com/images?q=tbn:A...5-nOoQOG8XUXmr

And which fan i should buy to replace it?

thanks!

mouthmw · #2 12-08-2011, 09:56 AM

The fan doesn't come on until amp heats up a bit. How long have you played through the amp and how do you know the fan doesn't work?

emo panda · #3 12-08-2011, 11:19 AM

That's on newer amps 700RB-II. I have the first series, and the fan must come on when the amp start. I already had one amp which was the same, but fan comes on when i start amp.

I play one-two hours a day for 3 days and the fan didn't came on so far..

bluesrx · #4 12-08-2011, 11:27 AM

The first series 700RB and the 700RB-II's fan work the same. They are activated by a heat sensor. If you have been playing it for the time you've indicated, it should have come on.

Do this.... turn the amp on for about 15 seconds then turn it off. Watch the fan blades closely. There should be a little tick (turn) of the blades when you shut it off.

emo panda · #5 12-08-2011, 01:33 PM

I have tried that now, for 15 seconds, but the fan didn't move at all

emo panda · #6 12-09-2011, 08:19 AM

I have played now for two hours, very loud and the fan haven't move at all..what could be wrong?

lbwdog · #7 12-09-2011, 08:59 AM

I'd call G-K Customer Service. They've always been very helpful for me, although I haven't needed them for several years.

My fan (700RB II) would come on only after a particularly grueling set. Never at home when practicing.

emo panda · #8 12-09-2011, 11:53 AM

well,...they were fast!

Brian from gallien replied to my email:
The fan is temperature controlled and does not come on when you first turn on the amp. It only cones on when the amp reaches a certain temperature.

It's cool if this is true...but why in my other amp (which is the same) the fan comes on at the moment i turned on the amp?

bluesrx · #9 12-10-2011, 05:13 AM

someone probably modified it...

craig.p · #10 12-10-2011, 07:10 AM

Emo, Brian's response, its accuracy notwithstanding, neither addresses nor answers your question. Is it true that this amp is in an enclosed case with no convection cooling designed in? If so, then that fan should be coming on when you're using the amp even moderately. (My assumption is an output stage that isn't ridiculously over-spec'd and run ridiculously cool, which I believe is a safe one to make.) The fact that you have an identical amp whose fan's behavior lines up with the closed-case design only bolsters my argument. Also you got the amp for cheap euro, which in this context suggests the amp has shut down due to overheating in the past. This sounds like an easy problem to fix, even if you simply remove the fan and place a quiet ball-bearing fan on top of the fan vents aiming down. I think those cases pull air in from the top and send it out the front vents, but check with your other amp first.

Chuto · #11 12-10-2011, 07:16 AM

Quote:

Originally Posted by emo panda

well,...they were fast!

Brian from gallien replied to my email:
The fan is temperature controlled and does not come on when you first turn on the amp. It only cones on when the amp reaches a certain temperature.

It's cool if this is true...but why in my other amp (which is the same) the fan comes on at the moment i turned on the amp?

I have 400rb IV and the fan turns on only when the amp reaches a certain temperature but, on the other hand, I used to have ashdown mag300 and its fan turns on immediately so i think it depends on amp.And I also think theres nothing wrong with your amp

craig.p · #12 12-10-2011, 07:46 AM

Another possibility I can think of is that the tolerances for fan-on temp and fan-off temp are spec'd extremely wide to allow for production variations, and that you (Emo) might have gotten one at the hot end of the spec. However, I am still not comfortable with an amp of this (non-contractor) class running in an unvented box putting out even moderate power with the case fan not spinning, especially in light of the first unit you have (or had) that behaves more to expectations. The sample-to-sample inconsistency may be by design, or it may point to a problem with the second unit.

Analogpower67 · #13 02-25-2012, 05:46 PM

Hi,
I own a 700RB combo (bough new ~2007) that had a few issue as soon as it came out of the box ! : 50W tweeter amp would come one only a few hours a week ! (lazy ?)
Customer service doesn't have any answer...
so I was wondering what else could be wrong as a problem, most of time, never comes alone !
I realize that the fan was also not working when the amp was on, But : the manual explains what other folks already said : would come on only when power section starts to heat. So to be sure that the auto fan is ok in a few minute : connect your computer audio Out to your amp In and Google 'Youtube Bass test or Hertz test' and then slowly push the amp 'hard', Fan should progressively start after a few minutes, if not, change it !
p.s : start test at 0 (volume)...