Re: [Harp-L] Harp Amp Project: Fender Pro Junior

["steve warner" <10reedsbent@xxxxxxxxx>]

One more thing: you can do all the tube changes you want, but keep in mind
how much the tubes are in comparison to 2 capacitors at about 2 bucks and a
few resistors and 25 cents each.   IF you know how to work on amps yourself
without killing yourself.

I did all those tube changes years ago with a BJ I had and nothing came
close to actually getting into the amp.

One more thing to take away from the trebly tone is to use a good HiZ
Dynamic element which will have alot more thickness without all the highs as
the amp already has that in abundance.


On 8/22/08, steve warner <10reedsbent@xxxxxxxxx> wrote:
>
> I've modded a few of these a several years back and off the
> cuff......First, the fat button in a BJ is a complete joke and does
> virtually nothing to take away  the trebly tone for harp.   The word "fat"
> sounds nice but it isn't.    2nd)  Get a 10A100 Weber or a 10A125-0 Weber
> speaker....it'll add crunch, break up and fatter tone.  I don't remember
> which fits, so you can email them and they'll respond  3rd) change the
> coupling caps to .1uF   4)  up the power supply dropping resistor so you
> have somewhere in the neighborhood of 140 volts on the preamp plates.  This
> you can play with to see what sounds best.  I've tested as low as 90, but I
> think it's  too low and takes away from the amp's bite.  The amp already has
> about 300 volts on the plates and that's just too much gain.   5th)   This
> can be tricky, so if you don't know what you're doing then have someone do
> it......Get a Weber WZ34 Copper Cap Rectifier Module.   I've played with the
> W5Y3, but 50 volts B+ being dropped is quite a bit with this amp and I feel
> causes a bit of muddiness and overall loudness to be dramatically reduced
> with the amps general design parameters.   A friend likes the 50 dropped
> volts in his, but I don't.  To each his own.
> Without the speaker change all the above parts comes to about 30
> bucks...maybe less depending how much the Copper Cap Rect is these days.
>
>
>
> On 8/20/08, Rick Davis <bluesharpamps@xxxxxxxxx> wrote:
>>
>> I'm looking for suggestions.  The other day I spotted a MIM (Made In
>> Mexico)
>> Fender Pro Junior at a very fair price on Craigslist, so I snapped it up.
>> I
>> owned a Blues Junior amp a few years ago but did not like it much. I may
>> have given up on it too early. So now I'll take a shot at its simpler
>> little
>> brother, the Pro Junior.
>>
>> Where the Blues Junior is a Master Volume amp with a FAT button and all
>> manner of bells and whistles, the Pro Junior is bereft of features. It has
>> two chicken head knobs: volume and tone. That's it. One channel; no
>> reverb.
>> The speaker in the Pjr is a 10-incher, two inches smaller than in the Bjr,
>>
>> What the two amps share in common is basic circuitry: 15 watts, two EL84
>> power tubes, a solid state rectifier, 12AX7 phase inverter, and a 12AX7
>> preamp tube. They also share the EL84's tendency to sound trebly and to
>> chime when driven hard. That is not a good sound for blues harp.
>>
>> Be that as it may, the Pro Junior is a pretty popular harp amp. I've heard
>> passably good tone honking out of these little amps at blues jams. Some of
>> my harp buddies swear that this or that speaker swap is the magic bullet
>> that transforms the Pjr into a monster little harp amp.
>>
>> This particular Pro Junior looks to be completely original, and it is in
>> excellent shape, the tolex and grill unmarked. The tubes are all
>> Fender/Groove Tubes/Sovtek and are almost certainly the tubes that came
>> with
>> the amp from the factory. The speaker is the original Fender Special
>> Design.
>> I played the amp and it sounds like… well, it sounds like a stock Pro Jr.
>>
>> I'd like to hear your recommendations for inexpensively turning the Pro Jr
>> into a better harp amp.
>>
>> Photos and details at the Blues Harp Amps blog:
>>
>> http://bluesharpamps.blogspot.com/2008/08/harp-amp-project-fender-pro-junior.html
>>
>> Thanks!
>>
>> -Rick Davis
>> The Blues Harp Amps Blog
>> http://bluesharpamps.blogspot.com/
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>
>
>
> --
> steve
> www.thunderharpmics.com
> fattest tone on earth!




-- 
steve
www.thunderharpmics.com
fattest tone on earth!