Members Guitarist4life Posted May 8, 2010 Members Share Posted May 8, 2010 I bought a pair of SED 6L6gc power tubes for my hot rod deluxe about 5 years ago, but I never used them because the lowest I could go with the bias pot was about 82mA..These were marked "28" at the tubestore.com place. Now that I need to replace the old 6l6 I have, I would like to see if I can bias the SED first. I heard that replacing a resistor on the bias circuit would change the range of the bias pot and allow lower mA readings. I'm no expert in electronics, but I find my way easily around with the soldering iron and replacing caps and resistors here and there...the problem is that I have no idea what resistor I should replace in this case, much less what value.. lolI would really appreciate if someone who knows about this helps me. Here's the schematichttp://www.schematicheaven.com/fenderamps/hotrod_deluxe.pdf Using the coordinates on the side and bottom of the document, the bias circuit is at (A, 5), The bias pot is marked R82. Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted May 8, 2010 Author Members Share Posted May 8, 2010 bump Link to comment Share on other sites More sharing options...
Members Pepi Posted May 9, 2010 Members Share Posted May 9, 2010 Experiment with R77. Bring it up in value to bring down the -50v to the bias circuit. Try 150k ? Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted May 25, 2010 Author Members Share Posted May 25, 2010 Experiment with R77. Bring it up in value to bring down the -50v to the bias circuit. Try 150k ?Thanks! Does it matter what wattage? The stock R77 100k resistor looks like 1/4 watt (judging by the size ) I only have a 1/2 watt 200k and I wanted to try that and see if it works.. but I'm afraid of burning something because of the wattage. Link to comment Share on other sites More sharing options...
Members HKSblade1 Posted May 25, 2010 Members Share Posted May 25, 2010 You are fine jumping to 1/2w. Just don't go 1/6 or 1/8w Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted May 25, 2010 Author Members Share Posted May 25, 2010 You are fine jumping to 1/2w. Just don't go 1/6 or 1/8w Ok, thanks! Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted May 27, 2010 Author Members Share Posted May 27, 2010 Experiment with R77. Bring it up in value to bring down the -50v to the bias circuit. Try 150k ?It didn't work : /Im sure it was the 100k (r77) I was messing with. I tried a 200k resistor and it didn't change much... With the stock 100k, the lowest it would go was 82mA, with the 200k the lowest was 75mA.. Then I tried a 470k and the lowest was still about 75mA. Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted May 27, 2010 Author Members Share Posted May 27, 2010 bump Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted June 2, 2010 Author Members Share Posted June 2, 2010 : / Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted June 2, 2010 Author Members Share Posted June 2, 2010 Come on guys, I really need some help. I would really appreciate it. Link to comment Share on other sites More sharing options...
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