nunonaos 0 Posted February 29, 2016 Hello, I started this topic is this section because you don't have a section for my amp. I know my amp is a bogner but they told me that it was manufactured by line6 so I'm seeking help with you. When I connect my footswitch, sometimes the amp randomly changes channel. I have a friend that also has that amp and his started to randomly switching channels even with the footswitch connected. I believe this is a problem with the relay switching, maybe it gets overheated os something... Can you provide some kind of help? Thanks Share this post Link to post Share on other sites
psarkissian 283 Posted February 29, 2016 It can be three things,... -The power tubes (valves)haven't been replaced and re-biased in 18-20 months. If they are getting old and failing, then they may be pulling down other circuits. -Or if the tubes (valves) are not the specified tubes (valves) for the product, the bias and heater voltages might not be correct for other tubes. -Could be the foot-switch circuit in the back of the amp. Both would have to be looked at by a Line 6 authorized service with access to service info and Line 6 technicians for that and other products. Tube (valve) amps have high voltage lines which are shock hazards in them, and should be serviced by an authorized technician who knows that product. 1 Share this post Link to post Share on other sites
nunonaos 0 Posted March 2, 2016 It can be three things,... -The power tubes (valves)haven't been replaced and re-biased in 18-20 months. If they are getting old and failing, then they may be pulling down other circuits. -Or if the tubes (valves) are not the specified tubes (valves) for the product, the bias and heater voltages might not be correct for other tubes. -Could be the foot-switch circuit in the back of the amp. Both would have to be looked at by a Line 6 authorized service with access to service info and Line 6 technicians for that and other products. Tube (valve) amps have high voltage lines which are shock hazards in them, and should be serviced by an authorized technician who knows that product. So you're saying that it's probably the tubes that are causing problems in the channel switching? Yes the tubes have more than one year... Share this post Link to post Share on other sites
psarkissian 283 Posted March 2, 2016 If the tube is wearing, the cathode-to-heater current may leak too much and that may sag a supply line. The relay would not fully energize, it could dither. Share this post Link to post Share on other sites
nunonaos 0 Posted March 6, 2016 If the tube is wearing, the cathode-to-heater current may leak too much and that may sag a supply line. The relay would not fully energize, it could dither. Ok,i'll try a tube swap and post the resulta.Thanks a lot Share this post Link to post Share on other sites
psarkissian 283 Posted March 7, 2016 It needs to be re-tubed with the specified factory tubes, no substitutes. Go to a Line 6 authorized service tech for this. With Bogner designed tube amps, the way the gain stages are set-up, these amps are unforgiving when it comes to any modifications. Then they must be biased to specifications. Best to go to a Line 6 authorized servicing, as they will have access to our service data and information. These are valve amps with high voltages, shock hazard is not to be taken lightly. It should be serviced by someone who thoroughly knows this product's circuitry. Share this post Link to post Share on other sites
jered1011 0 Posted September 1, 2016 Hi was there ever any resolution to this problem I am having the same problem. New power tubes JJ 6L6GC have been installed and biased to 350mV per tube, as stated in the service manual. Still the problem persists. What should I do next? Thank you Share this post Link to post Share on other sites
psarkissian 283 Posted September 2, 2016 <p>Wrong tubes.</p> <p>Stick with the specified Ruby 6L6GCMSTR for the power tubes.</p> <p> </p> <p>JJ's are nice tubes, just not in these amps. The gas to vacuum</p> <p>proportions isn't spec for these amps. Same goes for Mesa and</p> <p>Groove Tubes.</p> <p> </p> <p>As a result, the 350mV bias would be incorrect. You just don't use</p> <p>the same bias on a different tube. It's a combination of the <em>characteristic </em></p> <p><em>curve</em> variation between manufacturers, what the gas to vacuum proportion</p> <p>is, the gain structure of the circuit, and the correct bias for those specs.</p> <p> </p> <p>These are <em>not</em> the tube amps of old where you can willy-nilly swap tubes, use</p> <p>then use the same bias and then expect it to work right. A lot more going on</p> <p>here than swapping and biasing tubes.</p> <p> </p> <p>Stick with the specified Ruby's. Have an authorized service center deal with it.</p> <p> </p> Share this post Link to post Share on other sites
psarkissian 283 Posted September 2, 2016 Wrong tubes. Stick with the specified Ruby 6L6GCMSTR for the power tubes. JJ's are nice tubes, just not in these amps. The gas to vacuum proportions isn't spec for these amps. Same goes for Mesa and Groove Tubes. As a result, the 350mV bias would be incorrect. You just don't use the same bias on a different tube. It's a combination of the characteristic curve variation between manufacturers, what the gas to vacuum proportion is, the gain structure of the circuit, and the correct bias for those specs. These are not the tube amps of old. You can't willy-nilly swap and bias tubes and then expect it to work correctly. There's more to it than that. Stick with the specified Ruby's. Have an authorized service center deal with it. Share this post Link to post Share on other sites
