FDP Home Page / FDP Forum / FAQ's

The FDP is made possible by the following companies and individual members like you.
Please use the links below to show them we value their sponsorship.

WD Music

Antique Electronics Supply

Jensen Loudspeakers

Musician's Friend

Amplified Parts

Guitar Center

Sweetwater

Amazon

Yellowjackets Tube Converters

Apex Tube Matching

MOD KITS DIY


* God bless America and our men and women in uniform *

* Illegitimi non carborundum! *

If you benefit and learn from the FDP and enjoy our site, please help support us and become a Contributing Member or make a Donation today! The FDP counts on YOU to help keep the site going with an annual contribution. It's quick and easy with PayPal. Please do it TODAY!

Chris Greene, Host & Founder

LOST YOUR PASSWORD?

......................................................................

   
FDP Jam
Calendar
Find musicians
in your area!
  Search the Forums  

FDP Forum / Fender Amps: 1985 - Current / Pro Junior Hum with Cable Inserted

Central Scrutinizer

Canada

Pete V
Mar 7th, 2017 10:53 PM   Edit   Profile   Print Topic   Search Topic

I have a tweed Pro Junior, not sure the year, which I've had for a couple of years but haven't used for awhile. From reading postings on this site and others I get the impression this in an inherently noisy amp but I haven't come across my specific issue in any of the postings. I have no problem with the amount of hum present at idle, it is when I plug a cable into the input jack that it becomes unacceptable. If I plug in a short 1/4' pedal connector it squeals like a piglet. If I plug a standard length guitar cable in it hums very loudly. If I take the opposite end of the plugged in cable and wave it around near the components in the chassis the hum increases. If I wave it near the power tube nearest the preamp tubes I get that high pitched squeal again and if I do the same near the other tube the frequency response of the hum becomes more bass prominent. The filter caps were replaced a few years ago so I haven't troubleshooted for a bad cap yet. I have tried various tubes and it doesn't appear to be a bad tube causing this. I don't think this is the common scenario that can be fixed by fixing the lead dress etc,, as I said the hum level at idle is completely acceptable, it's only when something is plugged into the input jack. Any ideas?
- Pete V

(This message was last edited by Central Scrutinizer at 12:55 AM, Mar 8th, 2017)

Richard L

Netherlands

Mar 8th, 2017 03:15 AM   Edit   Profile   Print Topic   Search Topic

With no cable in the input jack, the input is shorted by the jack socket, so no surprise that it's quiet. What happens when you plug the guitar cable into a guitar ? Noisy - quiet ?

Central Scrutinizer

Canada

Pete V
Mar 8th, 2017 05:37 AM   Edit   Profile   Print Topic   Search Topic

The noise is still there with guitar attached. I should add that turning the volume down to zero eliminates the hum.

Central Scrutinizer

Canada

Pete V
Mar 8th, 2017 09:06 AM   Edit   Profile   Print Topic   Search Topic

So it turns out I was wrong, plugging in an actual guitar makes a difference. I was fooled by the amount of hum I was getting from the single coils in my Tele and selecting the middle position did not eliminate the hum as I expected (which seems strange to me as the in between positions on my Strat do eliminate the hum). Bottom line is under normal circumstances it turns out there is no significant noise problem. Thanks!

Richard L

Netherlands

Mar 9th, 2017 02:57 AM   Edit   Profile   Print Topic   Search Topic

Good news !!

Te 52

Laws of Physics

strictly enforced
Mar 9th, 2017 10:51 AM   Edit   Profile   Print Topic   Search Topic

"...selecting the middle position did not eliminate the hum as I expected (which seems strange to me as the in between positions on my Strat do eliminate the hum)..."

You will only get hum-cancelling in the middle position if the two pickups are reverse-wound, reverse-polarity (RWRP). Most modern Teles are, but older ones or vintage-correct models may not be.

You can tell if the pickups are reverse polarity by holding a compass near each pickup. If they both read N or both read S, they are not reverse polarity and there is no easy way to make that pair hum-cancelling.

If one reads N and the other reads S, they are reverse polarity and should be hum-cancelling or can easily be wired to be hum-cancelling.

FDP Forum / Fender Amps: 1985 - Current / Pro Junior Hum with Cable Inserted




Reply to this Topic
Display my email address             Lost your password?
Your Message:
Link Address (URL):
Link Title:




Moderators: Chris Greene  Iron Man  reverendrob  

FDP, LLC Privacy Policy: Your real name, username, and email
are held in confidence and not disclosed to any third parties, sold, or
used for anything other than FDP Forum registration unless you specifically authorize disclosure.

Furtkamp.com 
Internet Application Development

Copyright © 1999-2017 Fender Discussion Page, LLC   All Rights Reserved