the29band 4 Posted August 19, 2017 I got my DT25 tubes replaced (both preamp and power) with the following tubes below, earlier this week. I confirmed that Line 6 recommends these tubes. The tech had also biased the amp post replacement. http://www.musiciansfriend.com/accessories/electro-harmonix-el84-matched-power-tubes/210092000118185?source=3TEM5KTBK http://www.musiciansfriend.com/accessories/electro-harmonix-12ax7eh-preamp-tube?source=3TEM5KTBK However, the amp is making crackling noises in Class A/B mode but NOT in Class A. Thoughts? Quote Share this post Link to post Share on other sites
psarkissian 362 Posted August 21, 2017 If it's not the tubes, then it can be one of two things. And that will have to be serviced by an Line 6 authorized service center. Quote Share this post Link to post Share on other sites
oscarguitar 6 Posted August 21, 2017 Does it crackle without anything plugged in? I had similar issue and found out it was a dodgy instrument cable. Quote Share this post Link to post Share on other sites
psarkissian 362 Posted August 21, 2017 Wondered that myself, but it only occurs with hummers. If it was the cable I would expect it pop and crackle on both hummer and single coil. Unless there's something odd with the cable ground, that it would only occur with the humbuckers. Quote Share this post Link to post Share on other sites
