Follow It Home Posted April 3, 2008 Share Posted April 3, 2008 How would you guys suggest getting more gain out of my Vjr. Like more distortion when turned up. Thanks! Link to comment Share on other sites More sharing options...
tunghaichuan Posted April 3, 2008 Share Posted April 3, 2008 How would you guys suggest getting more gain out of my Vjr. Like more distortion when turned up. Thanks! I've gotten good results with a clean booster. I have a Boss Blues Driver pedal that works well for this. I turn the gain all the way down and turn the level all the way up. This sends a nice hot, but clean, signal into the amp which slams the input. tung Link to comment Share on other sites More sharing options...
m-theory Posted April 3, 2008 Share Posted April 3, 2008 Read the mod 101 thread. Lots of ways to increase or reduce gain in the amp. Link to comment Share on other sites More sharing options...
Sollophonic Posted April 3, 2008 Share Posted April 3, 2008 I have done most mods to mine, changed resistors on inputs and between valves. I have changed valves for jjs and swapped out the tranny for a Hammond. All have given me loads more gain....... ....but at deafening volumes. For quieter level gain, you have really got to use some kind of pedal. Its so loud now though, I can gig with it. Sollophonic Link to comment Share on other sites More sharing options...
Follow It Home Posted April 3, 2008 Author Share Posted April 3, 2008 tung, how does that gain boost switch on the voodoo Vjr you made work? Link to comment Share on other sites More sharing options...
strangedogs Posted April 3, 2008 Share Posted April 3, 2008 I have a gain switch on my VJ head (also a bright and a standby switch) - it helps with lower volumes but it has more gain than I need usually when cranked up - I use a pedal for high gain sounds anyways. Had my head sold on Ebay but the guy won't pay or respond so I guess it's going back up on auction as I love my V3 combo so much! Link to comment Share on other sites More sharing options...
Follow It Home Posted April 4, 2008 Author Share Posted April 4, 2008 I was looking around, and I want to do a gain switch (low gain, high gain). and I figured out that i just have to wire a single throw switch to bypass...uhh I think it was R2 I know I jus tdont have the window open. Is that really it? why is it so simple? I guess I just dont know alot but I didnt realize that one resistor worked all the gain on an amp hahah. Link to comment Share on other sites More sharing options...
Follow It Home Posted April 4, 2008 Author Share Posted April 4, 2008 haha never mind it was r6 not r2. also what exactly does the bright switch do? I was thinkging about putting them both on. But a question. they both solder to r6 on the diagram I have, but the bright switch has a cap on it. is there enough room to solder them both there? if it comes to it I would rather just have the gain switch. Can I just solder to the short leads coming out of the resistor on the top of the board? thanks Link to comment Share on other sites More sharing options...
Zoki Posted April 4, 2008 Share Posted April 4, 2008 hey follow, if you're really looking for a real bright switch do the one that goes over the volume pot. after having tried the R6 version i just put a 100k there - mostly I've seen guys using 56k, but that was all I had and love it. there's a lot of good discussion around if you look enough, but the gist of it is that when you do ti over R6 it's really more of an upper mid boost...it easy and having it on a switch gives me a great option for use with my rear hummers or when i really want that extra chime..... Link to comment Share on other sites More sharing options...
tunghaichuan Posted April 4, 2008 Share Posted April 4, 2008 tung' date=' how does that gain boost switch on the voodoo Vjr you made work?[/quote'] Sorry, missed this one yesterday. The switch lifts the grounded end of R7 in the R6/R7 voltage divider. Works great. tung Link to comment Share on other sites More sharing options...
Follow It Home Posted April 5, 2008 Author Share Posted April 5, 2008 Zoki, do you know anymore about that bright switch, cause I dont know anything about it :-P. You said you did like the R6 one right? Do you think that there would be enough room for both the gain and bright switch? Tung, I hate to say it, but I dont really know what any of that means :-P. Link to comment Share on other sites More sharing options...
tunghaichuan Posted April 5, 2008 Share Posted April 5, 2008 Tung' date=' I hate to say it, but I dont really know what any of that means :-P.[/quote'] All it means is that the end of R7 that is normally grounded is on a switch. The switch when closed connects R7 to ground switching it in. When the switch is thrown, it disconnects R7 from ground, thereby removing it from the R6/R7 voltage divider. The voltage divider is there to pad down the gain of the circuit. Without R7 in the circuit, the gain goes way up. tung Link to comment Share on other sites More sharing options...
Follow It Home Posted April 5, 2008 Author Share Posted April 5, 2008 Maybe if I was looking at something I would understand better. So all I have to do is wire a single throw with one end wired to R7 and the other to R6? Sorry if this is really annoying. Link to comment Share on other sites More sharing options...
tunghaichuan Posted April 5, 2008 Share Posted April 5, 2008 Maybe if I was looking at something I would understand better. So all I have to do is wire a single throw with one end wired to R7 and the other to R6? Sorry if this is really annoying. If you look at the schematic one end of R6 is connected to the .022uF coupling cap coming from the first half of the 12AX7. The other end of R6 is connected to R7. This junction of R6/R7 is connected to the input of the 1meg volume pot. The other end of R7 is connected to ground. With R7 connected to ground it forms a voltage divider with R6. With the stock values of 1m/1m for R6/R7, the signal coming out of the junction of R6/R7 is cut in half. If you take a switch and wire it so that it connects between the other end of R7 (the end not connected to R6) and ground, you have what is called a ground lift switch. The switch breaks the connection with the other end of R7 and ground, which effectively takes R7 out of the circuit. With R7 out of the circuit, you no longer have a voltage divider. Take a look at the stock schematic on my site and see if you can follow along with what I just wrote. http://www.diycustomamps.com/images/schematics/vj_stock_schem.pdf tung Link to comment Share on other sites More sharing options...
Follow It Home Posted April 5, 2008 Author Share Posted April 5, 2008 Thanks tung, looking at the schematic helped alot, I understand it now, but dont think I could do it haha. Would you have to unbolt the PCB and lift it up and solder to the underside? I hate to ask, because its rather selfish, but do you have any schematics that are like specific to this mod? really dont like try and make one if you dont, its just easier I suppose haha. Link to comment Share on other sites More sharing options...
Zoki Posted April 5, 2008 Share Posted April 5, 2008 Zoki' date=' do you know anymore about that bright switch, cause I dont know anything about it :-P. You said you did like the R6 one right? Do you think that there would be enough room for both the gain and bright switch? Tung, I hate to say it, but I dont really know what any of that means :-P.[/quote'] Ouch! Sorry - buunch of errors on that last post - pretty new too at this too..... First, what I meant to say was that I liked the bright cap over the volume cap much better than the one on R6.... If you want to give this a try, let's say you're standing over the chassis looking towards the back of the amp - you can put the cap over the two right connections of the volume pot and have a listen. As mentioned I used the 101k (100pf) that I got at radio shack, but I've seen that alot of folks use a 56pf (other error - should have been 560k not 56k). It gives my amp a much brighter response at lower volumes and then when I turn it up I switch it off except for when I'm using the back pup on my hummers.... Link to comment Share on other sites More sharing options...
tunghaichuan Posted April 6, 2008 Share Posted April 6, 2008 Thanks tung' date=' looking at the schematic helped alot, I understand it now, but dont think I could do it haha. Would you have to unbolt the PCB and lift it up and solder to the underside? I hate to ask, because its rather selfish, but do you have any schematics that are like specific to this mod? really dont like try and make one if you dont, its just easier I suppose haha.[/quote'] Yes, to do this on a stock board, you'd have to remove the PCB to get to the underside. You would then unsolder the leg of R7 closest to the edge of the board. You need a suitable SPST switch to switch R7 in and out of the circuit. Using some hookup wire, connect one side of the switch to the unsoldered leg of R7. I would insulate the joint. Then connect another length of hookup wire from the PCB where R7 was soldered to the other side of the switch. Since R7 is now only connected to the board by one connection, I'd probably put a small dab of RTV silicone on it to keep it secure. I don't have a layout diagram for this. When I did the mod I was using one of Ken's turretboards from turretboards.com. It is easier to do this mod on a turret board than it is on a PCB. tung Link to comment Share on other sites More sharing options...
Follow It Home Posted April 6, 2008 Author Share Posted April 6, 2008 OOOk now it makes total sense :-). But wouldnt cutting R7 out of the circuit stop the circuit? Or is there another path, so basically what this does is switch off = R7 in circuit, Switch on = R7 out of the circuit right. Thanks alot tung :-) Link to comment Share on other sites More sharing options...
M29 Posted April 7, 2008 Share Posted April 7, 2008 Remember to be careful of the voltage in this amp that can kill you. M29 Link to comment Share on other sites More sharing options...
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