SWR Grand Prix problem

[markkoelsch]

Hello, I just received a used SWR Grand Prix from a seller on EBay. He said it worked, but it has issues. The thing is this...I could try to return it, but if I could fix it without too much difficulty I would as I have wanted one of this for some time.

Anyways, my standing rig consists of a Trace Elliot GP12, a Crown Powerbase 2, and a 4x10. I know all of that works fine. I literally disconnected the GP12, and put the SWR in its place. I set the preamp master to 0, set an appropriate gain level (about 6-7), and turned up the master. So, much to my dismay there is a little, highly distorted sound coming out, and occasionally my speakers would go to pull excursion as if hit by a dc signal. While playing, the input meter on the preamp function normally. So, i shut everything down, verified it was connected correctly, and tried again with the same results. I replaced the cables to the same result. I opened the top to make sure that the tube was firmly in place, which it was. I made a quick look to see if there were any obvioulsy loose wires, and there are not.

So, do any of you have any ideas on how to proceed? Things to check that I might have overlooked? Amp repair people in the Milwaukee, Wisconsin area? Should I jsut return it to the seller?

Thanks in advance,

Mark Koelsch

 

[BassBod]

Maybe try another tube first? Also, see if you've got anything on the headphone output - its hissy on these but worth checking. My GP got thrashed in transit (bent case and DOA tube), but it worked fine in the end.

 

[markkoelsch]

I tried another 12ax7 from a Tubeworks combo I have. Exactly the same thing came out, so I know it is not the tube. My headphones are at the office, but I will bring them home tomorrow to try. I am thinking it might just be best to try and get my money back as I really do not have a ton of cash to try and get it fixed.

Maybe try another tube first? Also, see if you've got anything on the headphone output - its hissy on these but worth checking. My GP got thrashed in transit (bent case and DOA tube), but it worked fine in the end.

 

[GreyBeard]

Get your money back.

 

[bgavin]

I don't know how common the Grand Prix is on the used market, but I do know they are no longer made. If you have Jones for one, get it repaired. Same holds true for the Ampeg SVP-Pro.