Gold/Silver mods?

[Cole]

Happy Thanksgiving All!!

So i'm thinking that the gold/silver mods here look pretty good. Has anyone done these?

http://www.diycustomamps.com/images/schematics/VJ_gold_silver_mods_schematic.pdf

If i did these however i would do R6/R7 both at 100k. What kind of tone do these mods

give? I've decided i'm just going to add a tweed tone, gain control on R7(is this the best

place to install one), A C3 switch, and either R6 on a switch or cGils parrallel R8/R9(maybe both)

I know the tweed tone on my Vj right now i used the values cGil said he liked but don't

remember what they were. could you please remind me. And also what value pots do i need

for the gain control and for the tweed control? Also what kind of switch do i need for the

C3, R6, and R8/R9 switches.

Thanks!!!

 

i wish sewatt would start workin so i could just use the faq.

[Eracer_Team]

yes, although most don't refer to gold/silver mod's anymore...

It's probably best to wait till www.sewatt.com is back up at the end of the week to discuss amp modifications; this forum can get a bit testy on mod discussions.

[Cole]

I will ask again when sewatt is back up. is there a reason people don't do these anymore?

[Eracer_Team]

oh they still do them, they just don't call it gold/silver anymore..

also this is a REV2 diagram... you may not need to change as many parts if you have a Rev3 VJ (many of the mod's originally talked about on this forum about rev1/rev2 amp's got updated into the production rev3 amps... Thanks Epip Admin's for listening)

 

ok... this is from the PDF you have in your link. The red items is what they changed... So starting on the left and working right across the pdf...

R1/R2 create your input signal; right off the top you are dumping 50% of you signal to ground. but putting R1 at 1meg and lowering R2 to 10k you increase the signal to the 1st pre-amp stage.. This will brighten the amp up right away.

Also moving the R1 to the other side of R2 will give just a little more brightness.

R6/R7 creates the 2nd divider... by lowering R6 will increase the signal but will also increase the brightness a bit. Don't jumper R6 like the PDF says, its way too much.

R7 dumps your signal to ground, by keeping it high you send most of the signal to the tube, by lowering it you control how much gets dumped to grnd. That's why most people put a pot on the R7 BUT.... if you don't put a resistor on the 3rd leg that goes to ground you can dump 100% of your signal to ground and you won't get any volume... (see my other post just a second ago) but you end up putting a fixed resistor on the 3rd leg of r7 to ground thus keeping the VR1 as the volume pot and not r7.

R8 they changed to 1.5k and R9 to 680 they change the sound in the pre-amp just a little warmer sounding.

the R14 to 300 from 220 changes the current across the el84, its generally agreed to keep the current on the el84 at 38~40 milliamps.

The C5 change to 1000uf tightens up the bass.

C4 & C3 pass too much bass along... even this document has them at 4.7uf is probably too much bass for most single coil players, most humbuck players would drop these to 1uf.

and lastly the R10 increase to 1k/3w is to compensate for the higher than 110vac in north America, which most houses run at 120~124vac.

swapping the Rev1/Rev2 OT for the hammond is good for tone but not so much for a Rev3 VJ

 

We don't talk mod's on this board much anymore since there has been a strong contingent of recent Valve Junior users that state you don't need to mod a VJ.

So we keep the mod talk to sewatt.

 

There are voltages in the amp that came make you wake up dead, so read all the saftey documentation before testing voltages with your body.

[Cole]

Thanks for the reply! I can't wait for sewatt to get back up and running! I plan to have C4 at 1 uF.

C3 will be stock im just gonna cut JP-1 and put it on a switch. Im gonna put R6 and R7 at 100k.

Thanks