Tube Amplifier Services
Tube testing is 100% conclusive on shorts, leaks, emissions, transconductance and life expectancy. In-circuit tube testing, equally important, is also done.
These charges do not include Parts and Materials.
Complete Amp Tune Up - $50
RepairsTroubleshooting, eliminating noise problems, speaker replacement, cabinet restoration, reverb reconditioning, bias voltage adjustment, parts replacement, etc., will be based on a written estimate.
Blues Junior Modificationslink to Bill's Blues Junior Modifications
Old BJrs Sound DifferentThe first thing you should know, though, is that Fender has used two different circuit boards in the Blues Junior. The original green circuit board was in production from 1995 to early 2001. The later cream-colored board has been in production since mid-2001. Although the circuits are virtually identical (except for reverb), the cream board is much brighter, with livelier treble, than the green board. Where applicable, I've separated the mods appropriate to each.
Basic mods, green board: $90
1. Modified tone stack with Orange Drop capacitors
2. Rewired reverb, larger coupling capacitor (cream board spec), shielded input jack
3. Simple adjustable bias (adjusts both tubes simultaneously)
4. Retwisted and rerouted AC leads for hum/hiss reduction
5. Power supply stiffening: Remove existing 47uF cap; replace with two new 47uF caps for deeper bass, smoother breakup
Basic mods, cream board: $70
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: Add a second 47uF cap for deeper bass, smoother breakup
Presence Control $20
Potentiometer will be mounted on control deck in front of Fat switch. Adjusts from mellow, restrained tone to bright and aggressive. Connects to circuit board with Mogami low-noise coaxial cable, includes pull-up switch for use with Clean Boost.
Adjustable bias: (included).
Output tube bias can be adjusted through a large range, but not individually. Requires use of matched output tubes. Customer tubes will be biased to 24-25ma unless otherwise specified. Includes biasing instructions for future tube replacements.
Individually adjustable bias: add $50.
Output tubes are individually adjustable for overall bias and can be balanced. Customer tubes will be biased to 24-25ma unless otherwise specified. Includes biasing instructions for future tube replacements. Unnecessary unless you're a bias adjustment maniac.
Clean Boost module: Add $45
This 1x1” circuit module installs inside the amp and gives you a volume boost that’s about the same as that of the Fat switch, without the fatness. Its volume adds to that of the Fat switch, and can be wired to go on with the Fat switch or by itself on a pull-up on the presence control (if you choose the presence option). See link for more information.
Clean Boost footswitch control: Add $30
Converts Fat switch jack to stereo so 2-button footswitch (not included) can control both Fat switch and Clean Boost separately. Footswitch overrides panel settings when plugged in.
TwinStack: Add $5
This inexpensive mod changes your mids control from normal Blues Junior/Hot Rod operation to a Twin Reverb-style stack. It lets you drop out all of the mids for more incisive treble tone or more scoop. Reduces midbass heaviness and muddiness. The normal Blues Junior mids kick in at 5 and up, so all stock tones are available, too. Highly recommended!
New: Preamp Boost: Add $25
For clean headroom and sharp attack! Reworked power supply and plate voltages give more headroom, cleaner, more articulate tone, clearer trebles. Modeled after the voicing found on larger Fender amps.
Audio-taper master volume control: $20
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.
Metal replacement input jack: $20
Switchcraft jack with isolating washers to prevent ground loop hum. Connects to circuit board with Mogami low-noise coaxial cable.
Auxiliary speaker jack: $25
Plug in an additional 8-ohm cabinet for bigger tone. High-quality Switchcraft jack.
Line-out jack: $25
Reduces speaker output to line level. Switchcraft jack, same circuit as found on Marshall Studio model.
Power supply stiffening: (included)
An additional 47uF capacitor in the first filter stage halves the amount of ripple going to the output tubes for less hum and more reserve power for smoother bass and for incisive picking.
Ruby reverb tank: $45
The stock tank is metallic, harsh, and has short reverb time. The Ruby tank is dark, smooth, and has long, lush delay. So much, in fact, that it requires replacing the reverb control with an audio-taper pot (included) or you get too much. It's identical to the audio-taper master volume control, above. The Ruby tank is much better constructed than the Accutronics tank. If you like reverb, you'll love this setup.
Replacement output transformer: $90
I use a 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 4/8 ohm switch. The notes leap off your strings!
Other mods or repairs: Parts plus labor.
E-mail to discuss your needs.