Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TerryD on August 12, 2013, 09:03:34 pm

Title: Fender Blues Junior ~Distortion~
Post by: TerryD on August 12, 2013, 09:03:34 pm

I'm getting low volume distortion, sometimes ghosting and sometimes just willy nilly.  Any idea what it is?  Where can I get a schematic for this?  They don't have old fashioned picture schematics like Fender used to have, do they?  Could the filter caps be shot on this already??  I tried switching preamp tubes and I didn't luck out.

Title: Re: Fender Blues Junior ~Distortion~
Post by: phsyconoodler on August 12, 2013, 09:21:45 pm

You have two power tubes too you know.Sounds like one is shot.Get a new pair in there and see what happens.If that doesn't do it you have other issues.

Title: Re: Fender Blues Junior ~Distortion~
Post by: stratele52 on August 13, 2013, 04:50:02 am

SCHEMATIC ; There is a Blues Junior III too .

This one is for Blues Junior;  Check also resistor at V3 Phase inverter tube R12 , R14 and other

http://support.fender.com/schematics/guitar_amplifiers/Blues_Junior_schematic.pdf (http://support.fender.com/schematics/guitar_amplifiers/Blues_Junior_schematic.pdf)

Title: Re: Fender Blues Junior ~Distortion~
Post by: TerryD on August 13, 2013, 07:36:58 am

I'll check the power tubes...thanks  and thanks for the schematics.  Terry

Title: Re: Fender Blues Junior ~Distortion~
Post by: stratele52 on August 13, 2013, 07:38:40 am

Quote from: TerryD on August 13, 2013, 07:36:58 am

I'll check the power tubes...thanks  and thanks for the schematics.  Terry

New tubes ALWAYS need bias check and ajust if needed.

Title: Re: Fender Blues Junior ~Distortion~
Post by: Jack1962 on August 13, 2013, 09:54:58 am

There are 4 versions of the blues junior.

Title: Re: Fender Blues Junior ~Distortion~
Post by: TerryD on August 13, 2013, 10:17:53 am

How do you tell what version one has? Thanks.

Title: Re: Fender Blues Junior ~Distortion~
Post by: stratele52 on August 13, 2013, 10:33:12 am

Quote from: TerryD on August 13, 2013, 10:17:53 am

How do you tell what version one has? Thanks.

You have to look a the circuit in the amp , what is the value of parts , resistor OR  if you have any date on your amp with date of version .

But for your problem no need for now to know wich version you have.