1968 marshall plexi Trouble

[Mrkushandfriends]

HEY GUYS IM A NEWBIE I GOT A 68 PLEXI 100 WATT ITS A USED REISSUED BUT WHEN I HAVE IT CRANKED THE DISTORTION SOUNDS FUNKY IT SOUNDS AS IF MY GUITAR IS OUT OF TUNE--ISH BUT WHEN I TURN ON MY FUZZ FACE IT GETS LOUDER BUT ALOT LOUDER I THINK ITS THE TUBES CAUSE ONE WENT OUT RECENTLY AND ON 1 TO 10 IT WAS A 1... LET ME KNOW WHAT YOU GUYS THINK thanks!!!11

 

[janarn]

Filter caps!

 

[shredless]

speaking of CAPS....

hit your ****ing caps lock key

 

[Mrkushandfriends]

what are filter caps?

 

[Olde Growler]

Filter Capacitors are capacitors that block out extra electrical noises like 60 cycle hum. These Caps have electrolytes in them that dryout over the years and when they do, the product unwanted overtones sometime called "Wolftones". Changing these caps should only be attempted by a qualified guitar amp tech. The Caps store voltages that can kill. Ask your local music store that deals with Marshalls who does their service work for them.

 

[66SuperTremolo]

As has been mentioned take it to a good Tech for a service. Unless you have extensive experience with Tube Amps it is worth the cost to let a pro deal with it. Not being a Vintage Marshall you can safely take it to a decent tech who will replace what is needed and make sure it is healthy.

 

[Mrkushandfriends]

.

 

[Mrkushandfriends]

so can the filter caps make the amp sound not as power full when cranked ? so this would have nothing to do with the tubes then correct?

 

[Mrkushandfriends]

another thing i can jump the number 1 input (left bottom) to the number 2 input (top right) and plug into the top left and blend them but when i add the fuzz it sounds like horse crap so i run the fuzz threw the top right bassier channel when i try to jump the the bottom right channel #2 to the top left #1 and plug into the #2 top right and try to blend the volume 1 knob cant go higher then 2 with out squelling like a pig!!

 

[sct13]

The incoming power (wall power) Alternating current, is changed to DC Direct Current by the Rectifier circuit. The Rectifier circuit does not take out all of the Alternating Current, There is still "ripples" in it. The Filter Caps smooth out these ripples so the rest of the amp circuit is fed clean DC Voltage. It is a high voltage, more than 460VDC (depending) and its dangerous so don't attempt messing with these, even if the amp is unplugged.
If the filter caps are bad the amp will sound bad and present a bunch of problems because the current runnig through it is the wrong kind. It is possible to damage other components....

It is best to have a tech look at it. it is a common fault. Good luck.

You can check the tubes by removing and replacing them with new ones or known good ones at least. But your description sounds like filter caps. But of course it could be anything. Find a good tech.

 

[bulldozer1984]

he said its a re-issue so its not actually a '68.

So how old is the amp ?

 

[strat59]

Yes, you can't call it a '68 being a SLP Re-issue.

I wouldn't waste anymore time asking questions. Caps go bad and as they store and release the power as needed if they're bad they will make the amp sound bad.

Take it to a tech, nuff said.

 

[bulldozer1984]

Yes, you can't call it a '68 being a SLP Re-issue.

I wouldn't waste anymore time asking questions. Caps go bad and as they store and release the power as needed if they're bad they will make the amp sound bad.

Take it to a tech, nuff said.

But if the amp is only a few yrs old I doubt its the caps.

 

[strat59]

Possibly, but as he hasn't any experience with dealing with components containing high voltages or knowing how to trouble shoot. The simplest and best course of action is to get the amp checked over. If for no other reason to give it a service and check voltages, bias etc.

 

[bulldozer1984]

Oh yeh I agree with taking it to a tech.

 

[Gordon Thunderfuck]

I agree, a qualified tech should look into it. I had a junky MA100 that had solder traces lifted off the board at the power tube sockets..then later on had some really quirky issues..

I know(now) that I had a really shitty amp with random gremlins but it made me decide to try a DIY kit. Been happy ever since.