kustom defender v50 bias check/adjust

[jskeen]

Hey Guys,

I've about googled myself silly looking for details on this, and come up empty. Does anybody know if this silly autobias feature they advertise on these things actually changes anything? I read that its not a true autobias and does need to be set when changing tubes, but the procedure seems to be classified tighter than Hillary's girdle. Anybody have a schematic/procedure on it?

Thanks
James

[DrGonz78]

Google'd it... Simply type in "Hillary" and you'll see what you talk about. Oh wait... No stop!!

I did find the manual online and it has this to say. "The amp uses a mixed-bias system, which is a combination of fixed and self-bias techniques to give the user the best of both worlds." So it seems that the silly auto bias feature must do something very basic and then you can dial it in to preference. Seems absolutely useless to me, lol.

Kustom Defender V50 Owner's Manual (Page 12 of 16)

[Pistolpete]

I just opened up my Kustom Defender 50W and I can't find any trimpot or other possible way to adjust the bias. So it looks like it's completely auto-bias, contrary to what the manual says? I don't know much about tube amps and didn't intend on adjusting the bias (i don't even have a tester), just troubleshooting what seems like a preamp problem in mine and looking for other telltale signs of problems while prepping to possibly change out the power tubes in the future if necessary. I would like to at least understand how to adjust the bias in case I need to later on!

[Pistolpete]

Ok, scoured the net a bit more and found some threads in other forums that indicate that there is no need to bias tubes in the 50W Defender. Fixed my issue too by swapping out all three preamp tubes