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Title: Tube bias adjustment Post by: MAG-LEV on January 28, 2011, 11:17:39 PM Could you tell me if the tubes in the Rock It need bias adjustments - if I change tubes or order it without tubes?
Thank You, DB Title: Re: Tube bias adjustment Post by: plasticvonaband on June 13, 2011, 12:27:09 AM AFAIK the Rock-It is Cathode Biased. No adjusting except by adjusting the bias resistors
Title: Re: Tube bias adjustment Post by: Jennings on January 17, 2012, 12:43:57 PM Just like the Vox AC30 (and others)...just take the old EL84s out and pop new EL84s in. Best to use a set of four matched valves, but basically you won't need to worry about bias adjustments.
Title: Re: Tube bias adjustment Post by: Big Goon on January 28, 2013, 05:45:17 PM Be sure to buy a matched quad of power tubes. Ther is a way to use 2 matched sets putting one matched set as the center 2 and the other matched set as the outer 2 but that is a bit risky and you may have some noise or other problems. There are a few tricks to figuring out if noise problems are caused by mis-matched tubes. ther are verbose explinations on the web.
Title: Re: Tube bias adjustment Post by: wyatt on January 29, 2013, 03:49:30 AM Be sure to buy a matched quad of power tubes. Ther is a way to use 2 matched sets putting one matched set as the center 2 and the other matched set as the outer 2 but that is a bit risky and you may have some noise or other problems. There are a few tricks to figuring out if noise problems are caused by mis-matched tubes. ther are verbose explinations on the web. Not when they all share the same cathode resistor, which they do in the Rockit when set to full-power. If you re-design use a cathode cap/resistor for each pair, you can use two separate matched pairs. If you use seperate cathode cap/resistors for each tube...you can use singles, because they'll each bias individually. |