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Fender Blues Junior III with Billm Audio modifications . Now it sounds awesome, not boxy, muddy or dull. Also, now has quality components. Rawk!!

Item purchased as new old stock from a local music store and immediately shipped to Billm Audio for $350 in mods. Mods were personally performed by Andrew Machrone (Bill's son).

Amp mods:
Basic Mods (cream board):
1. Modified tone stack with Orange Drop capacitors
2. Simple adjustable bias (adjusts both tubes simultaneously)
3. Retwisted and rerouted AC leads for hum/hiss reduction
4.Power supply stiffening: Upgrade main filter capacitor to 100uF, low ESR type for deeper bass, smoother breakup
5. Larger, high-performance preamp coupling caps for better frequency response, more "Fender" tone
6. TwinStack mod converts tone stack to Twin Reverb-style operation, eliminates muddiness, increases tone control range.

Filter Capacitor Replacement (3x 22uF)

Audio-taper master volume control:
Hate the way the loudness jumps up between 1 and 2 on the master volume when you're trying to play quietly? The audio taper control expands the 1-2 range to 6 or so, then things get much louder beyond that. Ideal for home/apartment playing; doesn't affect maximum loudness.

Audio-taper reverb control:
The same audio-taper control also works well for the reverb. It extends the range in the same way, making it smoothly progressive at the low end, so if you're always stuck between too little and too much reverb, it's an easy fix. If you get a Ruby reverb tank, you should have this mod to control its greater sensitivity.

Upgrade TO22 output transformer:
This is high-quality David Allen-designed Heyboer transformer that has about three times the mass of the stock transformer, which gives clearer, stronger bass, smoother mids and highs, less hum, and better transient response. Includes aux speaker jack with automatic 4/8 ohm switching. The basic mods are essential to get the best performance from this or any other upgrade output transformer.

Cathode follower tone stack driver:
Half of one of the 12AX7s (V2) in the Blues Junior is unused. This mod puts it to work as a cathode follower to drive the tone stack. The Fender Bassman, some versions of the Twin and Pro-Amp, and many Marshalls use a cathode follower before the tone stack. It's a low-impedance, high-current source, which provides cleaner bass and a greater sense of transparency or clarity. It's a subtle change, suggested for the purist looking for ultimate clean tone and more touch sensitivity when cranked. JJ ECC832 (12DW7) tube to replace your existing V2. It makes an audible improvement over a 12AX7.

Standby/Power Switch:
This clever switch replaces your stock power switch with a three position off-standby-on switch. Looks stock, great for cool-down between sets or guitar changeovers. More information here:

Metal replacement input jack:
Switchcraft jack with isolating washers to prevent ground loop hum. Connects to circuit board with Mogami low-noise coaxial cable.

Colored Jewel Lens conversion:
Replaces the dinky plastic lens with a proper jeweled lens and a white LED. Color = Blue.

Links (for reference):
Billm Audio:

No issues. Fully functional, in good condition.

Cash only. Price reduced, firm. Local pickup only. Not interested in trading. If it's posted it is still available.

Will not respond to offers of sending a cashier's check.

fender, amp, amplifier, blues jr, blues junior
  • do NOT contact me with unsolicited services or offers

post id: 6714633130



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