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

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

About the only difference is the reverb circuit.  On the BJ the master
is just a way to add more overdrive and for harp that's nothing to write
home about regarding that amp....... and the middle, treble and bass
is nothing more than a tone control with finer tunings.   Tell ya what, I'll
head over to Field Guide and tell you which resistors and caps to change.

On 8/23/08, Rick Davis <bluesharpamps@xxxxxxxxx> wrote:
>
>  Steve, thanks for all the great info on the BJ.  The amp I'm working with
> is a Pro Junior.  Does this all apply to the Pro Jr, too?  I know they have
> the same basic amp circuitry....
>
> -Rick
>
>
>
> On Fri, Aug 22, 2008 at 10:46 PM, 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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>> > Harp-L@xxxxxxxxxx
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>> >
>>
>>
>>
>> --
>> steve
>> www.thunderharpmics.com
>> fattest tone on earth!
>> _______________________________________________
>> Harp-L is sponsored by SPAH, http://www.spah.org
>> Harp-L@xxxxxxxxxx
>> http://harp-l.org/mailman/listinfo/harp-l
>>
>
>
>



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