Fender Blues Jr BillM Mods (Custom) – Updated 8/25/19 Sound Clips Added

Due to popular demand, Hallman Labs finally have a few sound clips of my amplifier. This is the Blues Jr, combined with some of my custom pedals and of course, my Schecter Tempest Custom guitar. My friend, Kale Brown, helped me out and played my guitar, while I did the recording (mostly on a Tascam DR-05). The results are pretty good for what we put into it!

Pedals used at some point in the recording:

Boss RC-3 Loop Station, BYOC 2 Knob ESV Bender, Custom Crybaby Classic w/ Whipple Wah, MXR Uni-Vibe, TC Electronics Hall of Fame Reverb.

All wire for guitar/amp/effects pedals were Mogami 2524 with Neutrik plugs.

Note: We had a baby asleep in the house we were recording inside of, so we could only go so loud. I’ll try to add a better clip highlighting tube breakup/distortion at a later time. Other than that, Kale does an excellent job at showcasing this amplifier.

The only bit I captured with my Nady CM-100 + Rolls Mini-Mic Preamp -> XLR to USB

You can pick up on more detail in this recording than the rest, especially the high end.

Lighter playing (DR-05):

Louder playing with some breakup (DR-05):

Variety with a little talking (Crybaby Classic Wah Pedal, MXR Uni-Vibe) (DR-05):

I was a little worried about my modded Fender Blues Jr. I added some Siemens (EPCOS) filter capacitors and ELNA SILMIC-II into the signal path locations. I also put some vintage orange drops in to go with the newer ones.

After I finished installing everything I had no sound.. The tubes were heating up and I had voltage across the main PSU cap. I re-flowed any questionable solder joints and stuck with it. After 2 days I had her singing again!

Tubes shown:
2x 1961 Siemens EL84 6BQ5 rX3 (Tested 130%)
2x 1963 Sylvania 5751
1x 1961 Sylvania 12AY7

(For the curious, the two potentiometers separate from the rest, are the sparkle and presence mods from BillM)

This is from my thread on TDPRI, which can be found HERE, if you’d like to see the topic in its original entirety.

Most of this is copied and pasted from there because it was already so detailed and accurate to what is being used. My memory isn’t as good as the Internet!

Mainly this was my first venture into modding audio circuits, besides building BYOC (electric guitar effect pedals) kits and selling them.

Working with an amplifier and doing mods is so much fun, hearing the differences you can make is very rewarding. I encourage all readers who own a Fender Blues Jr. to try the “basic kit” BillM sells for all versions of the modern Blues Jr models, and the Fender Excelsior.

2021 Correction: BillM passed away a few years ago sadly. A year or more after, I asked his son for permission to carry on his tradition (hoping to replicate his circuits, which I could do already (but I won’t out of respect)). He did not yet give me permission. I have my fingers crossed, but don’t hold your breath. I understand whatever he decides and I wish him and their family all the best in the future. I know that Bill will be looking down over them and keeping them safe.

Article on “BillM”‘s Fender Modding site announcing he is back and working on a backlog of orders:

This is great news for all current and future Fender Blues Jr owner’s! I believe the two or three modern versions of the Blues Junior (made in last 20 years) is the best trade off between tubed audio circuits and their solid state equivalents. BillM and his son create some of the best Fender Blues Jr (“BillM”) mod kits for your money.

Most mods for tube based electrical equipment will run at quite the premium, if for nothing else, due to LETHAL currents & voltages being present. Without taking the proper precautions, doing a capacitor upgrade could end with your obituary, seriously. That isn’t a joke and this is why BillM does an excellent job instructing the customer how to build and/or install their kits. The main thing is to make sure you bleed any voltage off that is currently across the primary power filtering capacitor/s (applies to all amplifiers), before doing anything on the amplifier. Those filtering capacitors can generate lethal spikes of current, so do not even think about skipping that step.

You can find Bill’s Guide on bleeding the power capacitor/s here.

I purchased the Blues Junior knowing it was pretty much the perfect practice/home amp in the sub $500 range for that classic American tone. After spending some time with it and stumbling through the internet to BillM’s website (http://billmaudio.com/wp/) I decided to start modding the amp. I have a long history of modding PC’s, so I knew this would be a piece of cake with how simple the Blues Jr. is, circuit wise.

I started with some basic BillM mods, this is the list of mods I purchased/installed:

After installing all of those mods I was very satisfied with the tone. The only thing still lacking was the bass response from the stock speaker

At that moment in time the “budget” wasn’t the main concern and you are talking about a $200 speaker upgrade (that could be moved or sold at very little loss).

Here is a breakdown of everything you see in the completed pictures:

Blues Jr. – $429
NOS Tubes – $105
BillM Mods – $91
Speaker – $199
—————–
Total – $824

I went with the Celestion G12H Greenback because I have heard them compared to some other 12″ speakers. Nothing else that Guitar Center had come close to that G12H tone. Looking back, now I wish I had gotten a used Blues Jr (since I was going to void the warranty anyway), but you live and you learn.

Build Log Comments:

You can see info on a mod I did to the Tempest Custom here.