GK MB 800 Help Needed

[PauBass]

I need a bit of advice from you guys that own or have played any of the Gallien Krueger MB amps, specially the MB800.

I have just received a GK MB800 and there's a few things I have noticed and I'm not so sure about:

- [color=#141414][font=verdana, geneva, lucida,]As soon as I turn the amp on there is a faint but noticeable background noise, kinda like a grainy white noise, not a hum. It is there always no matter what the gain, eq or master knobs are set to. Even with the mute on and no bass plugged in, it's still there. [/font][/color][color=#282828][font=helvetica, arial, sans-serif][color=#141414]I have tried different cables, different basses, plugging in a different room...but it's always there.[/color][/font][/color]

- The fan comes on pretty much after switching the amp on and it's quite/very noisy, noisier than any other amp I've had in the past (Ampeg PF-800, TH500, DB750, SVT4....) Even on standby the fan keeps running even after having played only for 2 minutes at low volume. It's quite loud even standing on the other side of the room , about 5 metres away

- [color=#141414][font=verdana, geneva, lucida,]Also when I switch channels it makes a popping sound if I am playing a note while changing the channel, but not if I'm not playing at the time.[/font][/color]

- The second Channel, seems to be quite a lot quieter than Channel A. Is this how it is?
As an example, right now Gain A at 12 with Master at 12 sounds the same as Gain B all the way up and Level-B at 12...is this normal?

Thanks!

Edited June 26, 2015 by PauBass

[Musashimonkey]

I'll have play later on my mb800 to look into the other areas, but for now:

Grainy hum - yep, I've had two with that and am thinking it may be due to RF interference or not very clean power. I've tried a cheap power conditioner, but that didn't resolve it. On mine it's only a quiet him and not an issue with normal playing volumes.

Fan running loud - nope, my fan is speed controlled and takes a while before it even kicks in, and then runs at different speeds so generally stud nice and quiet unless you're pushing it.

[Conan]

Can't say I've noticed these issues - and the fan is quiet enough at rehearsal and gig volumes. The bloody control knobs are too close together though! I keep knocking the adjacent ones when I try to adjust anything!

[PauBass]

[quote name='Musashimonkey' timestamp='1435322898' post='2807688']
I'll have play later on my mb800 to look into the other areas, but for now:

Grainy hum - yep, I've had two with that and am thinking it may be due to RF interference or not very clean power. I've tried a cheap power conditioner, but that didn't resolve it. On mine it's only a quiet him and not an issue with normal playing volumes.

Fan running loud - nope, my fan is speed controlled and takes a while before it even kicks in, and then runs at different speeds so generally stud nice and quiet unless you're pushing it.
[/quote]

Thanks and I'd really appreciate if you could check your amp for the other issues mentioned.

[quote name='Conan' timestamp='1435323194' post='2807697']
Can't say I've noticed these issues - and the fan is quiet enough at rehearsal and gig volumes. The bloody control knobs are too close together though! I keep knocking the adjacent ones when I try to adjust anything!
[/quote]

The fan on mine seems to kick in at full speed, and it's quite loud, after just a couple of minutes of playing at home low volume.

[Musashimonkey]

Had a little play to test out your points:

Channel B quieter - yep, it is quieter, this is so that you can add more gain on channel B to get an overdriven tone, channel B Level, and Master then allow you balance to volume to match channel A. To give you one clean and one distorted channel. Nothing to worry about.

Pop when changing - yep, I hear a little bit of what you're describing, not all that noticeable though, not a big or defined Pop, but I could hear a blip in the tone, definitely something that could be as you describe.

I find it a great little amp. Hope this helps.

[PauBass]

[quote name='Musashimonkey' timestamp='1435355207' post='2808150']
Had a little play to test out your points:

Channel B quieter - yep, it is quieter, this is so that you can add more gain on channel B to get an overdriven tone, channel B Level, and Master then allow you balance to volume to match channel A. To give you one clean and one distorted channel. Nothing to worry about.

Pop when changing - yep, I hear a little bit of what you're describing, not all that noticeable though, not a big or defined Pop, but I could hear a blip in the tone, definitely something that could be as you describe.

I find it a great little amp. Hope this helps.
[/quote]

Thanks a lot Musashimonkey!
Need to run the amp properly on Monday at full band practice volume but I'm convinced it's noisier than it should be, the channel switch pops and the white noise are quite loud....I'll report back.

[Musashimonkey]

No worries, hope it goes ok. At band volume I have zero issues with mine and can't find fault with it at all. I do get slight white noise which is noticeable at practice volumes, so I tend to use a PJB Bighead headphone amp at home, as it's crystal clear. As a gigging amp I love my mb800.