For My Fender Pro Jr........

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zozoe
Posts: 249
Joined: Tue Dec 10, 2019 5:39 am

For My Fender Pro Jr........

Post by zozoe »

Greetings again~ I have this here PJ that's been rehoused into a slightly larger cab with a 12".... It sounds good,,,, good and clean!!
My intention is to get some nice breakup at 9 or 10 instead of 12,,, and even at 12 it holds pretty tight. I'm no tech, I can read & follow a schematic & PCB, but I know diddly about component value fixes other than clipping a bright cap....

Right now, I'm running EL844's in it, while messing with a lower gain 1st preamp tube, like an AU7 or AY7 & anything in between.
It's cool, it's funn, & I could probably pull off a small to medium size gig..... BUT I'm curious to know if I revert back to the 84's, is there a small handful of component changes that might drive the 84's to OD, again, at 9 or 10, and sound ANY better than the allegedly sub-par 844's I'm running, OR am I mistaken, and the 844's may be the silver bullet, & my experimenting is on the right track?? Please be specific with possible value changes. 😏

I wanna make a 'Lil growler out of this thing!!
FWIW, I'm driving some Hammond style alnico 12" that sounds great, & most of my gtrs are Strats, typically with a beefy bridge pup~

Many thanks, folks~ॐ💃
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sluckey
Posts: 3528
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Location: Mobile, AL
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Re: For My Fender Pro Jr........

Post by sluckey »

Use a 12AX7 for V1 and V2. Put a 10µF cap across R4 and another 10µF cap across R11. Remove C2 and R6. Replace R5 with a jumper wire. Reevaluate.
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zozoe
Posts: 249
Joined: Tue Dec 10, 2019 5:39 am

Re: For My Fender Pro Jr........

Post by zozoe »

thanjs Sluckey,, in essence what will this get me,,, what I'm looking for? And stick with the EL84's?

Thanks~
sluckey
Posts: 3528
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Re: For My Fender Pro Jr........

Post by sluckey »

yes
Stevem
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Re: For My Fender Pro Jr........

Post by Stevem »

I would also audition lifting one end of R27 ( the feedback resistor) off of the output transformer.
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caps8419
Posts: 44
Joined: Fri Sep 19, 2014 5:49 pm

Re: For My Fender Pro Jr........

Post by caps8419 »

For a more gradual volume control try a 16mm J taper pot. Fender sells a 1M version with pcb mounting bracket. Chop the bracket off and you are good. This will effectively lengthen the volume pot travel at low volume settings but will then become more linear past 2 or 3 and just saturate. You may not like the change but it can work well in different circuits. I did this on a PRS MT15 with a hair trigger master volume. It's actually usable now.

Michael
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