switchblade combo

[clay]

Hi,
I've owned a Hughes and Kettner Switchblabe combo 100w for a little less than a year. I've only played 5 or 6 gigs with it and I rarely use it for practice. During the third gig on the second night it blew the anode fuse (still looks powered up, No sound) During every gig since it has gotten worse. By this I mean the fuse blows sooner. Last weekend it lasted 2 sets on the first night.
I've been in contact with H&K and they are not much help. The nearest authorized service is over 1000 miles from me. I am hoping someone cen help.
Could it be a power tube? how can I test this? ect.
Also, I have heard one can remove power tubes to reduce the amp's output power. Will this work with any tube amp? Is it not a good idea?
ANY help with these questions will be GREATLY appreciated.
Thanks
Clay.

[killart]

Hey there, sounds like maybe a transformer problem?
Whatever you do, get the amp to some kind of tech ASAp as this problem will continue. I really can't see how it might be a tube problem. Are you using the tubes that it came with?
Also, removing power tubes is more a tone thing than anything as your amp will break up faster. That's all.

[samuraisoundman]

They certainly don't provide much useful info on their website, do they?
First off, power tubes CAN cause a fuse to blow. And removing a pair of EL34s from the circuit WILL reduce the output by 50%. This is why that makes the amp "break up earlier". Which pair of EL34s? On most Marshalls (i.e., Super Lead 100), it is the OUTER pair to remove. Don't know which ones on your H & K. I am surprised (more like shocked) that they didn't include a "Half Power" switch on this amp. This is nothing more than another Stand By switch, but it simply regulates one pair of power tubes, as opposed to all 4. Cheap decision.
Just curious, are you adding any speakers to the amp on these gigs? Have you replaced any of the internal speakers? Tube amps can be very sensitive to improper loads that the output transformer wasn't designed to work with. I've been repairing/modding tube gear for over 30 years and have seen some real crap happen. Usually at the worse possible time, like in the middle of a gig. You need to get the amp to a qualified tech and describe the issue so that he/she can duplicate it. Simply replacing the fuse is no fix, and can cause more damage by not addressing the causal component. Unless you are a tech with training on HIGH VOLTAGE electronics, keep your hands outta the amp!