Valve Junior Possessed by Satan

[wedgeSG]

Help...VJ might need an exorcism! The candidate: Ver.2 with Marshall mods, $$$tubes, and a Hammond 125-ESE. Knob just past halfway, running through an E-H English Muff'n into a Marshall 1960A cab. Not at all cranked, l'il louder than normal house levels but not make cops come loud. Been playing about 1 and half hours. Then IT happened, a scream like a Hell Tortured Evangelist ripped from my Bletchly Box. Imagine being dimed-out with uncontrollable feeedback going on, while a meth-crazed chipmunk gnaws thru your cable at the exact instant it's stuck by lightning. Following this Satanic shriek...silence, like no power dead silence...followed by return of sound at a much lower volume. Tone is hollow, dead, low frequency only, no mids or highs at all. Panic, I shut everything down, wait for heart rate to subside and check all connections...nothing looks suspect. Mix a drink, and continue to calm down. 15 minutes later power-up and see if the demon has released my Brit Buddy from his evil grasp. Not yet, with all knobs at the unchanged settings; power, volume, and tone have returned but only to about 50% of previous output and this is intersperced with the most Science Fiction static this side of a black and white Elvira picked B-movie. Crap! I swapped heads and guessed the VJ would need to be annointed with Holy Water while a priest yells "the power of Jimi compels you!" to survive this one. Head swapped, all is good. The demon has possessed the head, not the cabinet. Following afternoon, I'm greeted by a large crow on my front porch railing that takes flight as I approach the house. A really cold breeze blows through for a second, I thought it odd, but dismissed it. I picked up the VJ and hooked back up as it had been the night before, Mufff'n included. It's as if nothing had happened. No weirdness, no hints that something was about to go psycho all over again. Something had went full-tilt gonzo only a few hours ago...what the livin' hell is going on? OK, maybe no news is good news, but should I be preparing for the worst? Should I be on the hunt for a tech of the cloth? Was this the shriek of the damned? Stuff like this rarely "just happens". Can anybody shed any light on this paranormal occurance or offer any insight as to when or if a return visit might be likely? What steps might I take to drive it out before it's gotten an even firmer grasp upon it's tubular soul....

 

Wedgie

[Jan Vigne]

My first thought would be a bad tube. However, I've never seen a tube heal itself. You can try new tubes if you have spares as it might be a piece of oxidation on the pins/connectors that needs to burn off or be removed mechanically by the act of pulling and replacing the tube. Otherwise, just remove the tubes and reseat them a few times to ensure a tight fit on the pins. Be careful to align the tube pins properly and not to bend any pins as you're just about certain to damage the tube trying to straighten it out. The tip of a ball point pen without the ink cartridge installed is a good tool for that job. Slip it over the pin and down to the base of the tube so you are bending from the right spot.

 

Here's what else might temporarily heal itself after the unit cools down, cold solder joints and caps. Either will take at least the minimum of a visual inspection of the board. I doubt you'll see a bad cap if it didn't go out completely but you might see something else going on in the vicinity of a bad cap - a burned spot on the board or the end of the cap or near a resistor. If you're not up to removing the chassis from the cabinet and doing a look around, then I would call whoever did the mod for you.

[mjlewis22]

Entertaining post.

 

If the VJ was a Line6 product this would be totally understandable, because Line6 amps do get their 1s and 0s mixed up sometimes and do weird stuff. Kind of like a computer, you just turn them off and back on and theyre fine. Tube amps dont have any 1s and 0s so I dont know...its possible you touched or got near a Line6 that day and gave the VJ some bad ju-ju.

 

Sounds like based on what you described that the crow and the cold breeze took away whatever it was.

 

You may have already done this but make sure to eliminate every component...guitar, pedal, *cables*, etc before zeroing in on the head. However, if you can isolate the head as the culprit/victim, I'd say +1 to the bad solder joint theory.

 

Sorry this post was stupid and not very helpful...sometimes I just feel like talking.

[Jan Vigne]

Entertaining post.

 

If the VJ was a Line6 product this would be totally understandable, because Line6 amps do get their 1s and 0s mixed up sometimes and do weird stuff. Kind of like a computer, you just turn them off and back on and theyre fine. Tube amps dont have any 1s and 0s so I dont know...its possible you touched or got near a Line6 that day and gave the VJ some bad ju-ju.

 

Sounds like based on what you described that the crow and the cold breeze took away whatever it was.

 

You may have already done this but make sure to eliminate every component...guitar, pedal, *cables*, etc before zeroing in on the head. However, if you can isolate the head as the culprit/victim, I'd say +1 to the bad solder joint theory.

 

Sorry this post was stupid and not very helpful...sometimes I just feel like talking.

 

 

 

You might also be wary of the cable you were using at the point of Demonic Discombobulation. New or old there are reasons for a cable to be bad internally but not show the problem externally. Cold solder joints inside molded plugs are a usual first suspect in cable failures and subsequent amplifier destruction. If you can unscrew the jackets on your plugs, give them a thorough visual inspection. If you were quite honestly enjoying your new amp as much as you infer, you might have leapt when you should have crouched and thrown the cable's innards for a loop.

[jefrs]

You have a gremlin infestation.

 

This sounds like a candidate for loose connection or dry solder joint.

 

You have moved the amp, this is similar to thumping them or the approved NASA technique of "assist with lunar boot".

 

I would start by removing, pin inspection and replace the valves, re-seating them often works the trick.

 

Look under the hood for any push-on plugs and sockets, re-seat them.

 

Inspect the board for anything looking burnt in the fires of hell, toasty resistors and such.

 

Dry solder joints are more difficult to spot. The lead-free solder they have to manufacture with these days has very poor wetting properties. Prodding solder joints with an insulated pick is a job for the uninitiated to leave to a tech that is a fully paid up and insured member of a dangerous sports club. Me, I'm likely to re-solder anything remotely suspicious with genuine flux-cored tin-lead solder.

 

At this point it could be any number of things, even a small cap shorting out, you need to take a look for damage. I had a similar one when a small 220pf shorted, nothing visibly obvious but noisy and low volume, eventually a resistor blew, easy fix.