Series III Blues Junior: First Review

Back on September 1, 2010, when the Blues Junior Series III was introduced, I went to Guitar Center and bought the first one they’d been shipped. I promptly took it home and had in pieces on my bench. Fender claims a bunch of improvements, but only two of them affect tone: the “sparkle” mod and the new Lightning Bolt speaker. continue reading…

Anthony Stauffer reviews Billm Mods

Anthony Stauffer, proprietor of the Stevie Snacks and Old Tone Zone sites, had some mods done. Here’s his review:

Plug in headphones or play through good speakers for full effect.

His amp was the first to get the new coupling cap mod that’s now standard in all the basic kits.

Introducing: The TO20 Output Transformer!

Low-and-wide design: Maximum performance, minimum space.

This brilliant new output transformer, co-developed with Allen Amps’ David Allen, is a breakthrough for the Blues Junior, Pro Junior, Princeton Reverb Reissue, and Super Champ XD. Designed from the ground up to provide big-transformer performance in the least possible space, the TO20 is built by respected US manufacturer Heyboer, fits the stock mounting holes in all of these amps and has the same height as the stock transformer. The “widebody” core is made of premium M6 steel, which has superior magnetic properties, allowing maximum efficiency and power transfer from primary to secondary. The low-profile TO20 outweighs the stock OT by at least half a pound! Continue reading.

A Very Special Blues Junior

p5150233-1This is the 1000th Billm-modded Blues Junior.

New! I finally added some sound files so you can hear what it sounds like.

Or as close as I can figure, given the number of components I’ve ordered over the years, shipping records, etc.

I decided to pull out all the stops on this one. I started with a basic black Blues Junior, the perfect platform for a stealth amp that can blow away some much more expensive hardware.

With 5881s, it puts out 25 watts and sounds awesome!

Read more about it here.


June 17, 2011, Added Installing a Jewel Light
June 13, 2011, Added Installing Blues Junior Tilt-Back Legs
April 22, 2011, Added Removing Rusted Screws, Relic Blues Junior
April 3, 2011, Added Pro Junior and Pro Junior Adjustable Bias, with video
March26, 2011, Added 1967 Princeton Reverb Refurb
March 4, 2011, Added Tracking Down Hum in a Blues Junior
January 20, 2011, Updated Re-tension Your Tube Sockets, Resolder Output Sockets
September 6, 2010, Added video to Removing the Circuit Board
September 1, 2010, Added Series III Blues Junior: What’s Different?
April 6, 2010, Added “Fixing Simple Printed Circuit Board Mistakes
July 16, 2009, Updated “Aftermarket Knobs: Bad Idea” with a cure for shaft wobble.
May 19, 2009, Added “EL84 vs. 6V6 vs. 5881
May 11, 2009, Updated “The TwinStack Mod
May 1, 2009, Updated, added speaker reviews. “The Right Speaker for your Blues Junior
April 26, 2009, Added standby power switch to available Mods and Services
April 16, 2009, Updated, added speaker reviews. “The Right Speaker for your Blues Junior
April 2, 2009, Added “The Right Speaker for your Blues Junior
April 2, 2009, Added “Footswitches for Fat/Clean Boost Footswitch Option
March 31, 2009, Updated “Blues Junior Revision History” with speaker basics
March 27, 2009, Added ECC88 info (very bad idea), “What About Tubes?
March 15, 2009: Added “Bad Caps in New Blues Juniors
February 19, 2009: Interviewed at the 5th Fret blog
February 8, 2009: Added “Aftermarket Knobs: Bad Idea
February 7, 2009: Updated “Warning”
February 6, 2009: Added “Blues Junior Revision History
February 1, 2009: New information and photo, “What About Tubes?

New! Standby Switch for Blues Junior

By popular demand! People have been asking me for years for a standby switch on the Blues Junior, and here it is.

carling_closeupThere isn’t room inside the chassis for another switch next to the power switch, even if you relocate the pilot light. Yes, you could cram a cheesy little switch in there, but we’re talking high voltage here, and only a heavy-duty switch will do. Fortunately, Carling, the same company that makes the power switch that’s in your Blues Junior, makes a clever progressive switch. It has three positions: off, standby, on–very logical. In standby, the high voltage supply is cut off. The filament and bias supplies receive power.

The kit is super-easy to install.

Read more here or order it from the Mod Kits and Services page.

New Home of the Billm Mods


Welcome to the new home of the Billm mods for the Fender Blues Junior and other amps. This is the main site; information on my old site, is probably out of date.


Not all Billm mods are created equal! Some amps advertised on eBay as new, with Billm mods, are neither built by me nor use my kits or parts that I specify. I have had the occasion to examine a couple of these amps, and I believe that some of the components used and workmanship do not meet my standards, nor industry/safety standards. I’m not about to teach an imitator how to do a better job, so I won’t go into detail here, but as a potential purchaser, you should make an informed decision. Also, some clone kits use incorrect parts that do not fit well or may cause hum.

Now I see the main offender claiming on eBay that Blues Juniors are cathode biased and that adjustable bias is DEAD WRONG (his emphasis). Um, Blues Juniors are not cathode biased. Then he includes a quote from Randall Smith (Mesa Boogie) that mentions bias but is otherwise completely irrelevant. I see that I’ve embarrassed the guy into providing isolation washers, but he still isn’t using shielded wire on the input jack.