Changing the input jack on a Marshall Valvestate combo amp

SOURCE: Line 6 Spider 2x12 100w combo - Input jack issue

Its a 1/4" mono Panel-Mount Audio Jack
and can be bought at
Radio Shack, Best Buy, Any Music Store
Click Here

Average price about $3.00

SOURCE: marshall valvestate 8080 1. when i turn the buttons they make a cracking sound 2.when i play on it the sound becomes very quiet

When turning the knobs you might get a crackling noise if the amp is old, The knobs get worn. Either you can replace them or repair them with a tiny squirt of WD40. Check youtube videos for help.

As for the fading sound, That would be your valves ... They need to be replaced ... I suggest taking it to a repair dhop for that because they need to be matched.

SOURCE: The input jack on my Marshall MG100FX has fallen

I just had this problem and wasn't able to find the solution on line, so, here 'tis.

Take off the six screws on top of the amp cabinet. Unplug the speaker plug from the amp jack.The metal amplifer box can now be pushed out of the back of the cabinet and the input jack remounted. I had to force the box a bit as it was glued in just enough to tack it into place. (I was afraid to force the electronics box out so I took the entire cabinet apart piece by piece until I could see there was nothing left holding it in.) I found that prying it this way and that with a butter knife helped crack the glue.

SOURCE: i've a marshall valvestate vs 102 r and i want to

Why would you waste the time to try and modify it? What do you hope to gain? The designs are usually optimized with the parts they build them with. Even the speakers are selected to match the cabinet characteristics.

If you are dissatisfied with the unit, sell it and buy another that you like. It is unlikely you will get any better performance than the basic unit as supplied. You will waste a lot of money for nothing. If you want good bass for instance, use nothing less than a 15 inch and preferably 18 inch speaker or a quad of 12 inch ones.

Remember the performance is not only the speaker but the cabinet air volume and sound ports. For midrange and highs, use a horn with driver. Finding good PROFESSIONAL music rated speakers will be hard. Do NOT fall for the idea of using car stereo speakers for instrument music, that is futile as they are not designed for that function. Those are very inefficient speakers to start with.