90s Gallien krueger 400rb

[Masonc]

Hey, I recently bought a '90s Gallien-Krueger head off eBay.
I'm having an issue with it. When I plug it into my cab, it just starts humming and when I plug my bass in, it makes no noise. I've tried it with 2 different basses and guitar cables. Was wondering if anyone has had similar issues or has an idea on how to fix it?
Thanks

 

[father of fires]

Old amps have all sorts of problems. First step is to clean the effects loop jacks or insert a patch cable to make sure that's not the issue. Do you get signal at the effects send or the direct out?

 

[Masonc]

I've tried putting a patch cable in the effect loops and it didn't seem to change any thing. I'll give it a good cleaning when I get home.

 

[KevInDaBassment]

If the cab and all cables are "Known-Working", you're gonna need to find a qualified amp repair tech to have a look. Even if cleaning out some jacks and jostling it around gets something coming out the speakers, that can change at any time. Time to ask yourself how badly you want this amp to work.

You can find used 700RB-II heads for likely around what you'd be in for this amp plus service charges. If you can return it, I'd just do that and put the money towards getting a head in better condition.

 

[ardgedee]

If it arrived DOA, return it or demand a refund. There are plenty of working units available, it's not worth taking extra measures to restore something that might be unrepairable.

 

[Masonc]

Thanks everyone. I think ill end up returining it and getting a refund. Found a newer 400 rb -IV on Facebook near me for a good price so hopefully that works out

 

[Gervais Cote]

I had a GK 400 RB-II for several years and got rid of it because of humming, hiss and scratchy pots.

I now use a Traynor SB 500H that gives me all the GK did and it's dead silent. As a bonus, it's feather light. So happy with that move !

 

[Geddaric]

I had 2 different GK 400s (1 was a backline) and both acquired input jack issues. This is no help, but at the time I understood that this was not uncommon.

 

[Gervais Cote]

I had 2 different GK 400s (1 was a backline) and both acquired input jack issues. This is no help, but at the time I understood that this was not uncommon.

I had the same issue on mine but it was very easy to replace and did it myself.

 

[Masonc]

I think my input jacks need to be replaced. My guitar cable pretty much just slides in and out of it

 

[shirojiro]

Mine would make a really loud buzzing noise when you put any sideways pressure on the input jack.

I fixed this by resoldering the input jack connections to the board.

This is a second generation 400rb though.

 

[Masonc]

Update: I went to a pawn shop over the weekend and saw an old 700rb for a good price and I ended up getting it. Such a sick amp