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Location: 6 String Ranch | I just picked up a Fender Pro-Junior today, nice little 15 watt tube amp. The cabinet is solid ash done in tele white. Pretty little thing. Here's my question, when I play it I hear a slight rattle on some notes, almost like the tubes are rattling. I've noticed this on my Vibro-King too but never thought too much about it. It's not loud but it's there and this little amp will be played in small rooms so it will be more noticable to the dog who listens to me all the time now.
1. Anybody know what causes this?
2. What do I do to get rid of it?
3. Will it be worse if I wear a mauve shirt? |
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Posts: 2503
Location: Fayetteville, NC | Bill,
let me take a shot at this one...
1. Anybody know what causes this?
No not really, I'm not qualified to answer that question.
2. What do I do to get rid of it?
Throw the amp out??!
3. Will it be worse if I wear a mauve shirt?
Ask Al, He knows.... ;)
So how'd I do... Guess I flunked the Pop Quiz..
:eek: |
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Posts: 5750
Location: Scotland | Bill, I had a tweed Pro Junior which did exactly the same thing. Turned out that one of the output tubes was microphonic, and was amplifying the vibration of its own components. It's best to replace both tubes at the same time, even if one seems ok. It could also be one or more of the preamp tubes. N-O-S USA or Brit tubes are a better bet than just about everything else, but Sovtek & Svetlana are pretty consistent and about the best of the current Eastern Bloc production. Avoid the Chinese stuff, especially 12AX7 or 12AT7 preamp tubes. The pro Juniors are great little amps, I used mine for lap steel, killer Lindley tone.
I find most amps sound better if I wear green socks. Never tried the mauve shirt fix. |
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Posts: 79
Location: Toronto, Canada | I do not profess ANY expertise, but it may be that you have a bad tube. You may want to check your your tubes to see it one or more are going bad.
That's what happened on my Musicman 60 watter. Bad tube, same symptoms. Replacing the tube was the answer (in my case).
wemedge
addendum:
oops, Paul beat me to it, and much more eloquently... :) |
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Location: 6 String Ranch | Thanks for the advice, I'll check out tubes sometime in the next few months. That is what it sounded like, the internal bits of tube vibrating on themselves. I always found that wearing cowboy boots all the time I never needed to worry if my socks matched or what color they wear. Of course you look rather gay when wearing shorts....... |
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Location: Scotland | I never worry about the colour of my socks matching. If they're roughly the same thickness that makes a pair in my book. |
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Location: Upper Left USA | If you can manage to spill enough barbecue sauce on just about any mauve colored shirt - it'll either turn to brown or get tossed by your domestic support. Same goes for the colors salmon, chartreuse, wild orchid or fusia.
Besides, it'll smell better too. |
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Location: NJ | cwk
swap the position of the tubes in the circuit that will sometimes make it go away. It depends on where the tube is in the gain circuit.
otherwise I concur with PT with NOS usa or brit tubes, they are more consistent and are often less microphonic.
I run used telefunken preamp tubes in most of my keeper amps and they are great and most of them over 40 years old. I often steal them out of old hi fi gear much to the dismay of audiophiles. |
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Location: Midland, MI | Originally posted by Paul Templeman:
N-O-S USA or Brit tubes are a better bet than just about everything else,
You know, I wonder about that. I recently came across an article by some amp guy (I think it was in vintage guitar and his name was Butler or something, but, as usual, I digress...) that said that paying extra for NOS tubes was a waste. His take was that by now, all of the NOS stuff has been sooooo picked over/through that what's left and being sold as NOS is not terribly desirable (from a musical/technical POV, although from a DSW perspective, it may be...). I think the summation was that quality new tubes were a better, more reliable bet.
Anyone feel differently? Other than being able to say, 'The tubes in *my* amp are 1967-vintage Sylvania's with the unobtanium pentodes, man', that is, why not just buy something of a more recent manufacture? |
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Location: NJ | I have a rather large stash of NOS tubes and used ones. I know of many dealers and individuals that have them also.
Unfortunately there are counterfiets out there. When you start to make money on somthing be sure that someone will surely figure out a way to fake it. So you have to be careful, buttom line if your ears can't tell the difference, go for the cheap stuff. Kinda like beer or wine, why waste imported bock beer on people that drink Bud all the time?? |
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Location: Florida | I think the pro-junion only has four tubes. Preamp, phase splitter, and two EL84 power tubes. The others are 12AX7's.
Swapping the two 12AX7's MAY show some benefit, but prolly not.
Also ya know... the pro-junion goes into overdrive pretty easy (about as easy as my Ford). Is what you're hearing a bit of pre-drive raspiness? |
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Location: 6 String Ranch | No this was at real low volume once the amp got fully heated up. And then only on certain notes, A but not E etc. |
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Location: The Great Pacific Northwest | What Al said, swap the tubes they might be going a little "microphonic." I had forgotten about that symptom when my Trace Elliott started doing it. Didn't really matter the volume wise, but hitting a low G it would sound a little like a tapping on a reverb spring.... sorta.. but only on the low G as I recall. You can also tap on the tubes with the eraser end of a pencil. That may also reveal the culprit, but not always as the sound is a function of the physical vibration rattling the tube elements in an odd way.
From a Hammond Organ site... but it fits... and some fun organ oddities.
A microphonic tube is one whose electrical characteristics are affected by mechanical vibrations. (This is a flaw.)
If you lightly tap on a microphonic, while your organ and/or amp is on, you'll probably be able to hear noises coming from your speaker.
Microphonic tubes can often be a cause of feedback, buzzing noise, distortion or other bad sounds. If you find one, you should replace it. If you can tap time on your organ case and hear the taps in the speaker, you need to start hunting the mic.
Hammonds can become microphonic in other ways too.. the expression pedal works a capacitor which can become a capacitive microphone if the blocking cap leaks tube plate voltage onto it. If the microphone seems to be inside the transformer can beside the preset bars, the transformer core can take a permanent magnetism and become a dynamic mic.. degauss the transformer. |
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Location: Houston, TX | You may want to ask that question at the Fender Discussion Page for amps. I use it for tips on my new Cyber-Twin. I found this link for Pro Jr Club.
http://www.fenderforum.com/forum.html?db=&topic_number=233659
There's probably some "this amp rocks!" threads, but I did see some useful discussion of tubes and mods if you read through it.
Hope it helps. |
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Location: NJ | ". . . I always found that wearing cowboy boots all the time I never needed to worry if my socks matched or what color they wear. Of course you look rather gay when wearing shorts . . . .'
You've obviously must've seen the "Naked Cowboy" performing on the streets of Manhattan with his guitar . . . . .
 |
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Location: SoCal | I donno about the nekkid cowboy, but the car is very cool. |
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Location: NJ | This clown's built a rather lucrative career being a "freak on the street" . . .
www.nakedcowboy.com |
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Location: Fayetteville, NC | Shhhh...Now everyone will know Cliff's Secret Identity. :rolleyes: |
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Location: Scotland | I saw the Naked Cowboy when we were in Manhattan last Summer. No sign of him in March though, I guess he's not tough enough to bare his tackle during a New York winter. Cliff, have you seen the guy who does the Latin-Amercan dance routines with an inflatable sex-doll? I think he works on Union Square subway. Now that was entertaining, and apparantly he makes a very good living. |
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Location: NJ | Temp;
The NC does in fact appear around the city in the Winter, but it's usually at brief, prime "photo-ops" going on in the City, so that the "hairdo" on the 6:00News can say ". . even the NakedCowboy braved today's blizzard . . " (ho-hum . .)
Yeah I've seen the guy dancing with the blow-up dolls . . . . QUITE entertaining!!! |
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Location: 6 String Ranch | Boots and male bare legs. I rest my case.
Nice car, not the original hubcaps though. |
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Location: NJ | . . . not the original hubcaps though . . .
:D |
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Location: NJ | cwk
rodders love those 59 caddy hubcaps.
often wish i had a pile of them than a pile of ovations |
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Posts: 10583
Location: NJ | cwk
rodders love those 59 caddy hubcaps.
often wish i had a pile of them than a pile of ovations |
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Posts: 14842
Location: NJ | I'm thinkin' of goin' with BabyMoons on the PTCruiser . . . . |
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