Bill is out of the shop and Andrew is currently our one-man-band. While he works on months-old amplifier mod services, expect a delay in kit shipments.
We appreciate your understanding and patience!

Wrong Trimpot in Basic Mods Kit

Our distributor sent us an unknown number of the wrong bias adjust trimpots for the basic mods kit, both cream and green. They’re supposed to be 50K, but the incorrect ones are 5K. The correct ones are marked, Y 503; the incorrect ones are marked, Y 502. We believe the majority of them went out August 5, 2015.

Please inspect your basic mods kit and let us know if you have the incorrect trimpot we will replace it immediately. The trimpot on the right, Y 503, is the correct one.

y502 vs y503-1

Fender returns to green circuit board on Blues Junior!

The new material is shiny green but otherwise identical to cream board Series III.

The new material is shiny green but otherwise identical to cream board Series III.

There goes the distinction between the older circuit design (green board, 1995-2000) and the new layout (cream colored, 2001 to present). The photo below is a new Series III Blues Junior, but with a green, transparent circuit board. The components and layout are identical to all the cream-colored boards. You can see the Series III faceplate at the top.

This will doubtless cause some confusion among “old green” and “new green” owners, but as long as it was built after 2000, the existing cream board mods work properly.

Excelsior and Excelsior Pro Live on at Billm Audio

Fender has discontinued its Excelsior and Excelsior Pro, but we’re continuing the Excelsior and Ex.Pro tone control. It easily replaces that funky little switch with greater range and smoother tone, plus a pull-up switch that bypasses all tone components and gives you the amp’s unique raw tone. We’ll also endeavor to bring the tremolo depth control to production. All the engineering is done; we just have to make the instructions as bulletproof as possible. I’ve designed both mods to be strictly on the top of the circuit board; no resistors or capacitors need to be removed.

Remember, either the TO20 or TO20B output transformer fits perfectly and improves sound quality, especially bass perfomance.

Here’s a testimonial from one of our new customers:

Got my order yesterday and installed it today. Good God, this amp came alive! I had previously retubed with JJs and couldn’t really hear much improvement, although some. I like the tone all the way down, middle and all the way up. It’s like I bought a new amp! Thanks for your product.



Billm Audio is Back in Business!

May 5, 2015 Update: Billm Audio is open for business again! Thanks to my son Andrew’s heroic efforts, we have cleaned up the backlog, and all but a few kits have been sent. I’m about to start a new series of cancer treatments, but I’m told these will not be debilitating, unlike the previous ones.

We haven’t reopened the comments pages yet, but will shortly. I still have several amps that are here for modification or repair, but I’m working on them as quickly as possible.

Andrew and I thank our loyal fans, and we look forward to working with all our present and future customers.

– Bill

Introducing: The TO20B Output Transformer

David Allen and I have been working on a premium-quality output transformer for well over a year. We have developed a new bifilar-wound unit (the center tap is not only the center of the number of turns but also exactly one half of the total resistance) with improved bass response. We’re calling it the TO20B because its specs are the same as the TO20, but it is a different design internally. It is a more “hi-fi” approach than our old school/vintage style TO20. Like the TO20, it uses the more-efficient, grain-oriented M-6 lamination steel, has pretinned leads, and, of course, is made in the U.S.A. The TO20, with its more vintage-oriented layered winding, stays in the lineup.

The TO20B features an electro tin plated finish. Rated 6,600 ohms primary to 8 ohms secondary, it is ideal for a 2xEL84 or a 2x6V6 amplifier using an 8 ohm speaker load. It’s the same physical size and weight as the current TO20 unit. With 2-13/16″ mounting centers it is a perfect upgrade for many popular amps and drops right into the Blues Junior, Princeton Reverb, Pro Junior, the Excelsior, some old Gibsons and others. Read more…

New Power Transformer for 30W of Blues Junior Goodness

Billm Audio’s ongoing collaboration with David Allen of Allen Amplification pays off again–a real upgrade power transformer! The new TP24 power transformer fits exactly and addresses a number of Blues Junior modification issues:

  1. More heater power for octal conversions. While it’s not necessary for 6V6 output tubes, it’s essential for getting full power from the 5881 or 6L6GC.
  2. More plate voltage. An additional 30-40 volts of B+ provides more headroom without exceeding the 400 volt rating of the coupling capacitors.
  3. More reserve power. There’s lots of current on tap for a powerful, effortless sound.
  4. Designed for the Blues Junior’s bridge rectifier power supply and includes the bias/solid state winding.
  5. Cooler running under load, no overload or sag issues, as you would get with the stock PT and 5881s or 6L6s.

Click for larger image.

As you can see, the TP24 has nearly twice as much core as the stock power transformer and has an internal bell end for maximum hum protection. The TP24 benefits any Blues Junior, but it delivers the most with 5881s or 6L6s when paired with the TO26 output transformer.

New video: Here’s a link to a demonstration of the TP24 with EL84s. The higher voltage brings out the glassy nature of the EL84s, which the Blues Junior otherwise masks. The presence and sparkle controls help you dial back if you find it a bit too aggressive: Billm Blues Junior with TP24 and EL84s

New! The bias board gives you proper bias regulation for all octal tubes with the higher voltages produced by the TP24.

Continue reading ….

New! The Sparkle Control

With the Series III, introduced in September, 2010, Fender implemented a “sparkle mod,” which means that they removed a voicing capacitor, C9 on the cream board, which limited the amp’s high-frequency brightness. The Series III is definitely brighter than previous BJrs, but it can also be harsh and strident, even irritating. The Sparkle Control makes the amount of sparkle reduction adjustable from zero (stock Series III) to the same as the series II, to even darker, like the old green board (1995-2000) Blues Juniors. When you pull up on the knob, it defeats the control and gives you the stock BJr III amount of sparkle. Read more here: Sparkle Control.