Blues Junior Input jack beauty ring

[Fender Guy]

I found it:

It appears I was looking at the blim mods (thought I was looking at another forum/poster).

http://billmaudio.com/wp/?page_id=34

When I mod green board Blues Juniors, I always replace the input jack with a Switchcraft all-metal input jack (see kits). I bypass the feedback-prone circuit board traces entirely and wire it directly to the preamp input resistor with shielded coaxial wire. I highly recommend the Switchcraft input jack with all green board mods.

[Firestorm]

BILLM (http://billmaudio.com) sells a switchcraft jack prewired with Mogami coax. I assume it includes instructions.

Be forewarned; this is a pain because you have to remove the circuit board. If you're going that far, you may as well make the bias adjustable too. Fender runs the EL84s too hot (Well, like almost everybody else does too). Good for tube sales.

[Fender Guy]

Looks like what I will probably get when time:

http://billmaudio.com/wp/?page_id=65

Switchcraft all-metal Input Jack: $10
You can replace the plastic input jack with an all-metal Switchcraft jack (the industry standard). It comes prewired with Mogami low-noise coaxial cable and includes two Switchcraft isolation washers (one flat, one shoulder washer) to eliminate the possibility of ground loop hum. Requires removing the circuit board and desoldering the old jack with desoldering braid or a solder sucker pump. The green board version bypasses a noise-prone portion of the circuit board.

[Fender Guy]

Firestorm you beat me to it !

I am not too concerned with pc board removal. I worked around computers for years. I had to take Vibroverb reissue apart to get to a pot that had noise. It was a royal pain getting to it (it should not be that much to take apart), but it was. Not hard, just kind of a pain like you said.

[iknowjohnny]

Fender runs the EL84s too hot (Well, like almost everybody else does too). Good for tube sales.

Man, you got that right ! Those BJ's eat tubes like nothing else.

[sixstringer]

I’ve installed the Billm mods in a number of BJr’s. The PC board comes out easily after the blue and brown OT wires are slipped off their connectors on the PC board (then the board can move down and out). I used to add shielding to the plastic input jacks but now a Switchcraft jack goes in every time. It’s an easy mod that provides a permanent fix to the problematic plastic jack that plagues the Hot Rod series of Fender amps.

The bias mod transforms the BJr into a more versatile, better sounding and louder amp all by itself. Adding the tone stack mod, and presence control make it even better. And adding the boost switch board (10-12 db boost, I think) puts the BJr in the realm of a true gigging amp. A complaint about the stock BJr is that it sounds “small” or “boxy” and everyone wants to change the speaker to fix it. Changing the speaker can make for a better sounding BJr for sure, but adding the Billm mods first will make a much more significant difference.

[andyhardy]

I think this will work

http://angela.com/fenderstandardamplifi ... pjack.aspx

[sixstringer]

The problem with the original PC mounted plastic jack is that it gets torqued around with the plugging and unplugging of the guitar cord. tightening the nut to limit the jack movement only works for a while and then the jack's plastic threads strip and the solder joints on the PC board begin to fail. Replacing the stripped jack with a new OEM jack just starts the process over again. The metal jack is isolated from the PC board, preventing the PC board connections from being compromised. You have to remove the PC board to replace the plastic jack so you might as well upgrade to the metal jack and be done with it. The PC mounted input jack is just a poor design, similar to the PCB mounted tube sockets on the Hot Rod series of Fender amps that also have a limited lifespan.