Amp Volume Swell Problems

[CBA]

Hi-O.




I have a tweed Fender Blues Deluxe 40W amp. It's not the reissue, but the MIA kind.

Anyway, it's been a good chap for a long time, but recently it's been doing these weird volume swell kind of things, and they're unpredictable. Sometimes it's like loud for a minute, quieter for a minute, and back and forth. Sometimes it's fine for five minutes, then kinda drops out, then comes back at full force immediately.

I took it to the amp repair guy two towns over (he'd fixed my amp in the past), and he couldn't really find anything wrong with it. He put in two new inputs, re-soldered a bunch of stuff, and generally cleaned it up. He couldn't duplicate the problem either.

So but anyway it worked fine for one show (our guitarist used it while I played bass), and then its first time back to work it started doing the swelling bullshit again.

So I just played it for like an hour trying to figure out what the goddamn problem is. It starts off alright... like it went for twenty minutes or so without a swell, then it kinda dropped down a little as I was doing some looping with my El Cap. Then I tried different distortions like a The Elements and an IC Big Muff. It almost seems like the clean tone is totally fine until you start cramming distortion at it... like you turn on the The Elements and it drops, then you turn on the Big Muff and it's fine, but then it drops, then you turn them off, then the volume swells back up after a few seconds. This doesn't happen all the time, but I can duplicate it every once in a while.

But yeah, you have the distortion on and sometimes it will drop volume gradually and the sound gets really compressed and over-saturated, like more than your distortion pedal is. Same with a RAT, Big Muff, Elements.

The best I can tell, and I have no clue, is that it might be the speaker... like it can't take distortion anymore, or like only sometimes, so it kinda peters out, then recharges or something. It's really weird. Do speakers do that? It's a 12", whatever came with the amp.

HUH?


Any tips?


C

[sonidero]

There is this...



Also VauxhallandNick was having an amp problem and I think it was the Tube plate or something... Check the Tubes first...

[Officer Bukowski]

I was having the same problem and a couple days later my cable stopped working. It hasn't happened since I used a different cable

[skullservant]

@Officer- SAME WITH ME HOLY SHIT

[CBA]

Well I did just get a new cable, but the other one is still old.

It still happened when our guitarist used it the first time, but not the second time.

SONIDERO:

Do you have one of those that I can read?


C

[sonidero]

You have to select it and view image then ctrl + till it gets bigger... It's still blurry... Try this one...

*edit wrong one hold on...

It's not a chart but this page is helpful...

http://www.geofex.com/ampdbug/ampdebug.htm

[Officer Bukowski]

Well I did just get a new cable, but the other one is still old.

It still happened when our guitarist used it the first time, but not the second time.

SONIDERO:

Do you have one of those that I can read?


C

It was an intermittent problem for me too and it was with a fresh cable. I'd suggest just trying to recreate it with a cable that you KNOW is legit to be sure.

But it could just be something else I dunno

[sylnau]

Different cables is a good idea.
You might also connect it to a cab to see if it the speaker.

[autopilot]

volume potentiometer

[rfurtkamp]

Is it related to the signal level you're slamming the inputs with?

It may not be distortion but rather something gone awry with one of the preamp tubes or something in the preamp that doesn't like a hot signal.

Does it do it on the clean channel on the amp, or when you have the OD channel on, or both (If I recall the BD has switchable channels, I haven't used one in years but I have a HRD).

Try input #2 by itself and see what it does.

[CBA]

Welp, here's what I've found.

I used a totally luscious and hi-quality Mogami guitar cable that I am SURE has no problems directly into the amp. I tried Input 1, Input 2, with and without the overdrive channel on, mild drive, high drive, no drive, etc...


The swelling still occurs. It's a weird thing... it's almost like it goes along with some of my dynamics... like I'll be playing quiet, so it will kinda dip down to the lower volume, then I'll start to play a little harder and it will swell back up to the main volume.

The other thing I can't tell is if the "main volume" I mentioned is actually the right volume, or if it's LOUDER than it's supposed to be. That almost seems like it's the case.

At any rate, when it's quieter, the clean sound is notably (though not incredibly) scratchier... or like less defined. Then the volume swells up and it's just LOUD... like super full and ready to go. But again, it was intermittent for the half an hour or so that I was testing things.


So it's definitely the amp. Now... tubes, speaker, circuitry?


Thanks everyone for your suggestions!


C

[kosta]

Junkyard Guitar in RO has a good amp tech (though I'm sure there's gotta be somebody in A2...) I have that same amp but haven't had that problem. I have had to have mine tuned up a few times though. Dude in Royal Oak / Ferndale that Junkyard used got mine tip top again.

[CBA]

Junkyard Guitar in RO has a good amp tech (though I'm sure there's gotta be somebody in A2...) I have that same amp but haven't had that problem. I have had to have mine tuned up a few times though. Dude in Royal Oak / Ferndale that Junkyard used got mine tip top again.

Yeah, I've taken it to this guy near Orchard Lake twice... the first time he fixed it up alright, the second time was a month ago for this problem... but he couldn't duplicate the swelling, so it was hard to figure out what was wrong with it. Same shit happens with my car troubles... it fucks up for me then the people that can fix it can't duplicate the problem.

I've been to Junkyard a few times, but that was like RIGHT at the beginning of my dissent (or enlightenment) into guitar knowledge, so I didn't know a Nike from a Likey or a Trikey.

There's a guy in Jackson, Al's Diner, that fixed my amp up a long time ago. Maybe I'll give him a ring.

Thanks!

C

[Officer Bukowski]

Welp, here's what I've found.

I used a totally luscious and hi-quality Mogami guitar cable that I am SURE has no problems directly into the amp. I tried Input 1, Input 2, with and without the overdrive channel on, mild drive, high drive, no drive, etc...


The swelling still occurs. It's a weird thing... it's almost like it goes along with some of my dynamics... like I'll be playing quiet, so it will kinda dip down to the lower volume, then I'll start to play a little harder and it will swell back up to the main volume.

The other thing I can't tell is if the "main volume" I mentioned is actually the right volume, or if it's LOUDER than it's supposed to be. That almost seems like it's the case.

At any rate, when it's quieter, the clean sound is notably (though not incredibly) scratchier... or like less defined. Then the volume swells up and it's just LOUD... like super full and ready to go. But again, it was intermittent for the half an hour or so that I was testing things.


So it's definitely the amp. Now... tubes, speaker, circuitry?


Thanks everyone for your suggestions!


C

Ahh. Keep in mind that I don't know shit about amps, but I think it's probably one (or more) of the tubes.

How old are the tubes in there and what brand are they?

[hclapp219]

Two things I would try would be replacing the tubes and trying it in a different building (or at least outlet). There could be some weird power stuff going on in your house.