mfjord123 Posted December 12, 2009 Share Posted December 12, 2009 Hello all, Im a newbie here but I have a question, I did the JP1 mod on my valve junior and made it switchable. On this website is also an very easy gain mod: http://www.ultimate-guitar.com/forum/showthread.php?t=481701 . I wander if that mod works and if it can work with the jp1. (sorry for my bad english) Greetz:) Link to comment Share on other sites More sharing options...
TWANG Posted December 12, 2009 Share Posted December 12, 2009 No problem! You can put a pot in there for variable gain, too. Do add the 1M Resistor at R1 if you don't have that.. You can take the 68K R down to 10K, too. I read through a bit of that page.. and I've always skipped the master volume bit.. didn't do much. TWANG Link to comment Share on other sites More sharing options...
mfjord123 Posted December 12, 2009 Author Share Posted December 12, 2009 is it such a big deal putting that 1m resistor in it? im new to electronics but if it has to i think it isn't that hard. thanx for ur reply! Link to comment Share on other sites More sharing options...
TWANG Posted December 12, 2009 Share Posted December 12, 2009 It's right at the end of the board.. labelled R1 and R2.. they are a little tight together.. but I've never messed up there. The main thing is not too much heat.. so you don't lift the solder pad from the board.. and if you use a resistor that's 1 watt, like you should, I find it best to file the end to a sharp point.. so it doesn't hit the edge of the solder pad and push it off the other side of the board coming through. also keep it short.. just enough to pass through.. bend the resistor leads to the right distance between.. no sweat! First though make sure you don't already have 1M in there.. there's an online resistor color code reader if you don't have a meter. It's a big change in sound! Link to comment Share on other sites More sharing options...
mfjord123 Posted December 13, 2009 Author Share Posted December 13, 2009 Okay thanks! but if i don't do it, will something happen to my amp when i do that gain switch mod? cya Link to comment Share on other sites More sharing options...
mfjord123 Posted December 13, 2009 Author Share Posted December 13, 2009 o, yea my head is a v3 so it already has an 1m resistor at r2. that mod didn't work. when i switched it on there was a huge noise so i removed the switch. lucky for me i didn't drill a hole yet. would it be plausible to make a switch on r1 that will make it a bypass? will it also have a high gain effect? Link to comment Share on other sites More sharing options...
TWANG Posted December 13, 2009 Share Posted December 13, 2009 There's no 1M at R2. It's 68K stock in all versions at R2, and in some at R1. You can do a dual input mod, which means drilling a hole and adding another input jack, one lo, 68K, and one high, 1M, and the 1M does increase the amount of signal hitting the preamp so it would boost gain. If you got a noise on the other mod, you did something wrong. Maybe you need to look at your information again and check your work. TWANG Link to comment Share on other sites More sharing options...
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