4cm and blowing fuses

[the_bees_knees22]

Hi!

My dad decided to give me his marshall jcm 2000 dsl since he wasn't using it so I decided to use it for my main amp, and just use the helix for fx.  (for now anyway.  I might end up going back to going back to my dt25 and just going straight into the fx loop with the helix.)  

Anyway, I seem to keep blowing fuses about every couple of weeks on this marshall.  It's kind of annoying.  I have the volume on the helix set to about 4 o'clock (compared to a clock face)  That sounds pretty even to going straight in sans helix.  

Is there a safe way to make sure you're never going in to hot from the helix so I'm not as prone to blowing a fuse, and still keep the volume fairly even to going straight in?  Or is this just apart of having a marshall, and I should just stock up on fuses? ha

[GlennDeLaune]

I believe that's an issue with the Output tubes in that amp. Similar thing happened to a friend of mine with that same amp and that was the problem. It probably just needs to be re-tubed and Biased.

[rvroberts]

It is definitely an amp issue - nothing to do with the Helix - don't matter how hard you hit the front end!  It's output not input. First thing to check is the speaker lead - make sure it never shorts out.  Use a speaker lead, not a guitar lead.  Be sure you speakers are healthy.  They likely won't sound too good if they aren't. Check the wiring in the speaker box is good. 

If that is not your problem, you need an amp tech - all the rest requires a decent knowledge of Valve amps.

[the_bees_knees22]

oh ok cool, good to know.

Yeah the speakers are all 100% brand new.  I just bought an orange ppc 2x12 (which is awesome btw.)  It probably is just the tubes.  I don't think they've been replaced in a couple of years.  (I have no idea when my dad last replaced them on this head)

[HonestOpinion]

I agree, highly unlikely this is being caused by the Helix. Years ago I had an amp that was consistently blowing fuses and as the above posters have indicated it can be speaker cables, tubes, speaker wiring, or any number of problems with the the amp. If I remember correctly In my case it turned out to be a used speaker cab I had purchased that had been wired/soldered improperly and was shorting out inside the cab. As rvroberts indicated testing with a different speaker cable as well as a different cab (although you indicate the cab is brand new so less likely a suspect) might be an easy way to start narrowing down the cause of the problem, if that doesn't help move on to tube swapping and hopefully avoid an amp repair.

 

Note: As you mentioned you are using this with a 4CM setup so make sure you are not running speaker outs from the Marshall directly to the Helix. That is something you want to avoid studiously. You may be experienced with 4CM setups but that is definitely a mistake some users newer to 4CM have made. I would go through my 4CM setup as well to make sure all the cables are in good condition and plugged into the proper inputs/outputs and the correct Helix and amp FX loops. You may want to try running with a simplified direct setup for a while (no 4CM) to see if this stops the fuse blowing.

[the_bees_knees22]

Cool yeah, I'll give all those suggestions a go!

Thanks a bunch!