Members bluesboy Posted September 18, 2008 Members Share Posted September 18, 2008 HI all. I just won a fender blues jr on ebay, and ive been reading up on it from various sources. Apparently these guys are biased really hot, without a whole lot of difference in sound, but it kills the power tubes alot faster. The easiest way to change is this is to change some resisitors.... I guess my specific question is which resistor to change where, and what is a good value resisitor to use? Sorry if this has been discussed before, but i couldn't really find what im looking for. and yes, ive heard of BillM, but his site doesn't tell you what to put where, (at least that I could find) because then why would you buy from him? So any input on the subject? Do I need any bat wings or mouse bones? (joke for someone here) Link to comment Share on other sites More sharing options...
Members bluesboy Posted September 18, 2008 Author Members Share Posted September 18, 2008 BTW I was thinking of popping in some JJ power tubes... im pretty sure they have a reputation for being pretty hearty and handling higher voltages. any thoughts? Link to comment Share on other sites More sharing options...
Members bluesboy Posted September 18, 2008 Author Members Share Posted September 18, 2008 no love for me Link to comment Share on other sites More sharing options...
Members tommythelurker Posted September 18, 2008 Members Share Posted September 18, 2008 http://home.comcast.net/~machrone/bluesjunior.htm You might also want to learn how to use google. Oh, and from what I've heard, JJ's have a reputation for being unreliable. Link to comment Share on other sites More sharing options...
Members bluesboy Posted September 18, 2008 Author Members Share Posted September 18, 2008 http://home.comcast.net/~machrone/bluesjunior.htm You might also want to learn how to use google. Oh, and from what I've heard, JJ's have a reputation for being unreliable. but do i need batwings? and why would i need google when i have you? Link to comment Share on other sites More sharing options...
Members tommythelurker Posted September 18, 2008 Members Share Posted September 18, 2008 No bat wings necessary and I won't always be around to tie your shoes for you Link to comment Share on other sites More sharing options...
Members guitarcapo Posted September 19, 2008 Members Share Posted September 19, 2008 I recommend replacing the one resistor instead of the variable pots. It's easier and you really don't need THAT much flexibility Link to comment Share on other sites More sharing options...
Members bluesboy Posted September 19, 2008 Author Members Share Posted September 19, 2008 No bat wings necessary and I won't always be around to tie your shoes for you haha, true enough, true enough. to guitarcapo, that was my intention was just replacing the resistor Link to comment Share on other sites More sharing options...
Members Johnny Z Posted September 19, 2008 Members Share Posted September 19, 2008 HI all. I just won a fender blues jr on ebay, and ive been reading up on it from various sources. Apparently these guys are biased really hot, without a whole lot of difference in sound, but it kills the power tubes alot faster.The easiest way to change is this is to change some resisitors.... I guess my specific question is which resistor to change where, and what is a good value resisitor to use?Sorry if this has been discussed before, but i couldn't really find what im looking for. and yes, ive heard of BillM, but his site doesn't tell you what to put where, (at least that I could find) because then why would you buy from him?So any input on the subject? Do I need any bat wings or mouse bones? (joke for someone here) Is it a greenboard or creamboard? It's really easy to do, I've done 2 greenboards, haven't done a creamboard, I guess enough haven't burned up for one to reach my door yet. I found replacing the R31 resistor which is a 22k with a 33k worked pretty good, I went higher looking for more clean and tried a 39K but liked 33K better and the tubes will run cooler. Bill recommends a 27K I tried one but I came to the conclusion a 33K was my best choice. Link to comment Share on other sites More sharing options...
Members tommythelurker Posted September 19, 2008 Members Share Posted September 19, 2008 Is it a greenboard or creamboard?It's really easy to do, I've done 2 greenboards, haven't done a creamboard, I guess enough haven't burned up for one to reach my door yet. I found replacing the R31 resistor which is a 22k with a 33k worked pretty good, I went higher looking for more clean and tried a 39K but liked 33K better and the tubes will run cooler. Bill recommends a 27K I tried one but I came to the conclusion a 33K was my best choice. The "best" value for the resistor is going to vary depending on the tubes (as well as personal taste), which is why some people like a pot, so they can adjust it for a particular tube without swapping out a bunch of resistors. Link to comment Share on other sites More sharing options...
Members Johnny Z Posted September 19, 2008 Members Share Posted September 19, 2008 The "best" value for the resistor is going to vary depending on the tubes (as well as personal taste), which is why some people like a pot, so they can adjust it for a particular tube without swapping out a bunch of resistors. True, if I had a variable handy I would have put one in. But it only takes me about 30 seconds to change the resistor. And with my substution box I can dial in any restance. Link to comment Share on other sites More sharing options...
Members guitarcapo Posted September 20, 2008 Members Share Posted September 20, 2008 Mine has the pots. Bill installed them himself...but I'm too lazy to get a bias tool for EL84s so I just swap out the tubes without biasing or matching. My amp sounds great and I've used the same pair of Mullards in there for 2 years now. Link to comment Share on other sites More sharing options...
Members Johnny Z Posted September 20, 2008 Members Share Posted September 20, 2008 Mine has the pots. Bill installed them himself...but I'm too lazy to get a bias tool for EL84s so I just swap out the tubes without biasing or matching. My amp sounds great and I've used the same pair of Mullards in there for 2 years now. Not to worry, there really is no exact bias setting but a working range. Some people tend to try using the bias as a tone control, which it isn't. Usualy they end up running it to hot and the tubes suffer. I still don't understand why Fender biased it so hot, I think they know better. The 2 BJ's I've rebiased sound just as good and maybe better than before. If they were trying to squeeze out every last watt, they should have built a better amp to start with. Link to comment Share on other sites More sharing options...
Members bluesboy Posted October 5, 2008 Author Members Share Posted October 5, 2008 radio shack is currently my source for resisitors... is there a better place? there are different wattage resisitors. what wattage would be best, or doesn't it matter? Link to comment Share on other sites More sharing options...
Members tommythelurker Posted October 5, 2008 Members Share Posted October 5, 2008 Radioshack sucks. But unless you have a good local electronics shop in your area it's probably your best bet and is ok for the occasional ordinary resister. If you're buying more than a few or something more "specialized" mail order is probably better but it's expensive for just a couple resistors. As far as the wattage, if you talking about a resistor to adjust the grid bias voltage, 1/2 watt is fine. Link to comment Share on other sites More sharing options...
Members bluesboy Posted October 5, 2008 Author Members Share Posted October 5, 2008 Radioshack sucks. But unless you have a good local electronics shop in your area it's probably your best bet and is ok for the occasional ordinary resister. If you're buying more than a few or something more "specialized" mail order is probably better but it's expensive for just a couple resistors.As far as the wattage, if you talking about a resistor to adjust the grid bias voltage, 1/2 watt is fine. cool, thanks much Link to comment Share on other sites More sharing options...
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