73 50 watt Marshall making flange type sound

[75lespaul]

Telltale sign of a particular part going bad? My buddy's amp, which may soon be mine, makes a strange sound. Say you pound a chord then just let it ring out, as it tails off it almost sounds like it's flanging or phase shifting. Very lightly, but there just the same. I just put three brand new GT 12AX7-M preamp tubes in it (wow...just changed the whole amp for the better) but it still makes that sound as it did before the swap.

 

[kevlar3000]

Re: 73 50 watt Marshall making flange type sound

Filter Caps?? Can get a lot of goofy sounds when they go. I would get it looked at real soon.

 

[Rich_S]

Re: 73 50 watt Marshall making flange type sound

+1 on filter caps.

 

[75lespaul]

Re: 73 50 watt Marshall making flange type sound

Are they one of the components under the chassis, or the big blue things by the tubes and transformers?

 

[Rich_S]

Re: 73 50 watt Marshall making flange type sound

Big blue things.

There are a few other electrolytic caps that might want changing at the same time - bypass caps on preamp tube bias circuits.

Are you thinking of doing this yourself? If so, PM if you need help.

 

[Vasshu the humanoid typhoon]

Re: 73 50 watt Marshall making flange type sound

Yeah do not get zapped man!

 

[75lespaul]

Re: 73 50 watt Marshall making flange type sound

Big blue things.

There are a few other electrolytic caps that might want changing at the same time - bypass caps on preamp tube bias circuits.

Are you thinking of doing this yourself? If so, PM if you need help.

Me??? HAHAHAHAHAHA :laughing:

I'm scared of STATIC electricity, let alone the real thing, lol. I was considering giving biasing a shot though. I'm getting into trying different tubes and stuff and I don't want to pay a tech every time I switch tubes to bias. As far a biasing, if you don't, (A) can you slap in some tubes and play it for a few minutes just to hear what they sound like or (B) will that hurt the amp and/or tubes plus you're not hearing the correct sound anyway.

 

[kevlar3000]

Re: 73 50 watt Marshall making flange type sound

Get those caps addressed real soon, or you will blow that thing up, there will be nothing left to bias.. It is telling you it has a prob and if those are 35 year old caps they are about 25 yrs too old.
:fingersx:

 

[J Moose]

Re: 73 50 watt Marshall making flange type sound

Yeah dude...

Get that amp to a tech ASAP & have it recapped.

If the filter caps go down, tubes...output tranny, maybe power tranny if you're SUPER unlucky.

You'll have one gnarly headbox & chassis though!


BE VERY CAREFUL!!!

The filter caps carry enough juice to end your exsistence on this planet.

It's not terribly hard to change them & you can probably DIY if you can handle a soldering iron well enough to make a cable or replace a pickup. But if you have ANY doubt about your ability to do the task, take the amp to a tech.

Peace.

 

[75lespaul]

Re: 73 50 watt Marshall making flange type sound

I'll just bring it on over to Dave's Sound and let him do his thing. I blew up so many electrolydics in Electronics class in the 70s I became very paranoid of electronics. Plus I got zapped REALLY good by a 65 Fender Deluxe. I had just finished playing it after I bought it and took the chassis out and WOO HOO! I don't know what I touched, but luckily it must have been almost drained cuz I felt the charge go up my arms into my chest. Scary moment. I was tired for like half an hour after that and never pulled a chassis unless the amp was off for hours after that. That was around 87.