Another noise puzzle

this should be easier

Well, you guys seem to know a lot about what makes noises, good and bad ones both, tell me what’s going on in this case.

I have a fender reissue blues deville 4x10 amp. bought it last summer. Here is a link:

http://www.fender.com/products/search.php?partno=2232100000

When I play it now at any significant volume, with any guitar, it makes a very high pitched rattle - an electroinc rattle, not a mechanical one.

Bad tube?

Microphonic tubes maybe? The tubes themselves can start acting like little microphones. Also, sometimes the physical vibrations of the speaker can cause the tubes to rattle and that translates into rattles through the speakers. Usually this happens when the tubes are starting to get old. The tubes pins in the sockets may need reseating or may have a little corrosion on them.

Try tapping the amp when not playing and see if you can hear it through the speakers.

Bought it used? Don’t know the age of the tubes? Could be a tube. The classic test is to run some signal through it and tap each tube (especially the output ones) lightly with a pencil. The bad one will make the most noise. Haven’t always had success with that test, but…whatever…it’s something.

The reissue Fender’s sound o.k., but the build quality leaves alot to be desired. Those PCB mounted input jacks for example are worthless. And some of the reverb units have IC based drivers that aren’t socketed. I really hate non-socket mounted chips.

Hey, bet that amp has the tubes mounted upside down on the PCB. That’s another slightly sketchy design practice. The heat goes up to the socket and it’s connection to the board that way. There’d be spring loaded tube holders for the upside down bottles. When the amp is cold, remove the holders and the tubes, then put 'em all back and make sure the tubes are seated all the way. I don’t know if this reissue is fixed bias if it comes to changing out the power section. If you do wind up changing power tubes, change 'em all and get a matched set of new. More even loading that way…

Yes, upside down PCB mounted tubes, PCB mounted jacks, the whole ball of mass produced wax. The amp is new, less than 1 year old, but I don’t play rough with it, so although I knew the design was anything but the “boutique” they advertise, I didn’t think I would run into this sort of issue. :(

Good, I will go a tap tubes, if I have time to do that sort of thing this afternoon, since I will have another toy that will demand my attention first, arriving via UPS today.

:D :D

Follow Clava’s tips for sure but I have another question… Does the noise appear when the reverb is turned all the way down or switched off? I’m not familiar with that amp whether it even has reverb, adjustable controls, bypass etc…

Just a thought… reverb tanks (if present) can cause funny noises due to funky connections, bad driver tube etc…

D

It’s there when the verb is all the way down. It also responds somewhat selectively to pitch - it really comes alive when I play a “C”.

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It’s there when the verb is all the way down. It also responds somewhat selectively to pitch - it really comes alive when I play a “C”.


Yeah, that’ll be your C tube that’s gone wonky.

It’s best to replace the whole set of 12, but you can make do with just replacing the C tube.

Make sure they give you the correct tube, the B tube and the Db tube look very similar, and you know what morons they employ in Tubes-R-Us.
:D

I have heard that C tubes are getting hard to find :D

Does it matter if you use another guitar or a different instrument (keyboard)?

Dave T2

Well, I replaced the wonky C tube with a NOS telefunken one and now it doesn’t make a harsh rattle, sort of a softer rattle, now, it sort of sounds like Bing Crosby after a few too many martinis. Dunno what that is about. Say, Lemmy, can you get those tubes with absolute tuning rather than tempered? Or how about Carlos Alpha? :D

Dave2 - same sound with any guitar. Haven’t tried a keyboard. :)

Incidentally, these folks are really nice and send out cool catalogs:

http://www.tubesandmore.com/

Don’t be ridiculous Tom, considering the contents of your basement refrigerator you’ll be lucky to tell the difference between Carlos Alpha and the first twelve seconds of a cat in a Cuisinart.

(BTW, don’t use Carlos Beta, the only time I tried it my FM 10 crashed, and my Flugelhorn exploded. :( )

Anyway; you’ve apparently cured the probem…or so you think.

But, it’s another one of those cases of treating the symptoms and not the disease.

I see a lot of amps in the shop with the same fault, wonky C tube.

It’s caused by too much folk/country music played in C.

You rotate your tires yeah?

So, rotate your music too.

Half an hour of delta blues in open E is good. Or, accompany a sax player, and then you use all those weird ass Bb’s and Eb’s and stuff.

Mix and match Tom, give your tubes a break! :cool:

Well, Lemmy, I play in both keys - C and G.

Sorry to hear that about your flugelhorn. That must have been a difficult time. :(

I’d be careful there Tom. I heard of a fella down in Sardis, Alabama, who played in both C and G. They ran him out of town because of his moral terpitude.

T

I thought all 12 tubes were pretty much the same, and those little clamp thingy’s that hold the tube in the socket were tube capo’s. Guess ya learn somethin’ new every day.

Ah, the snow’s melting here in Illinois, and the power came back on last night. Good to be back in civilization. Life is good!

Have a great day everyone!
Don

I heard there was a big fight on the stage down at one of the local bars last week. Seems a banjo player and a sax player both sitting in at the same time, and they got into it over whether they were going to play every song in Bb or in G. The guitar player just stayed in E and kept his mouth shut.

Don

I hate to drag you guys into the 21st century, but don’t you realize you can replace all those tubes and all them other doohickeys with one single Interocitor?

I dunno, the digital modeling one gets with those berry interocitors just doesn’t sound like a signal passed through a real plasma conduit to me.

You guys are getting close to my latest invention. (When I get it working…) It is a 100 watt guitar amp with 4 channels that will fit in your shirt pocket and runs off of old toe nail clippings for an energy source…

D

"We’re not ugly! We just stink!" – Sponge Bob and Patrick

Hah! I’m way ahead of you guys. I don’t need no stinkin hardware. I just THINK the music – and nobody has ever told me that it was any less perfect that I hear it to be. The quality of the stomp-box effects is truly unbelievable.

T

Huh - I think in lo fi. :(