Fender Blues Junior Straight Six + Supreme Tube Board Combo
$ 199.00
The Fromel Straight Six mod kit and the Fromel Supreme Tube Board for Blues Jr, together. This combo includes both complete kits. The Straight Six instructions cover wiring the tube board for the Straight Six.
Straight Six mod kit
Introducing the Fromel Blues Junior Straight Six mod! Finally, vintage black panel tones from your Blues Junior!
The Straight Six mods literally transform the circuit of your Blues Junior to that of a 60s West Coast amplifier company in their glory days. All those classic, big, beautiful and expansive tones you love can now be yours!
The stock Blues Junior is a cool amp, sorta tweed-ish tones, and is a medium-volume grab-and-go workhorse, but I’ve always thought it could be so much more. The circuit has always bugged me: it’s really just a series of compromises to get it to do what it does, with each version that comes out fixing a problem that was there at the beginning. With the mods we get all of that out of the way for a simpler and classic signal path without the compromises the amp has stock. Less in the way and fewer compromises = cleaner, bigger and less noisy!
The Straight Six takes its name from the “Magic Six” settings on a black panel: Treble on 6, Mids on 3 and Bass on 2 (2 × 3 = 6!). After the mods your Blues Junior has very close to these same settings with the tone controls on noon, straight up, so Straight Six! But that’s not where they need to stay, because you’ll have more control overall over your EQ settings too.
The mods
- Replace the input jack with a high-quality chassis-mounted input jack. The stock PCB-mounted input jack is low quality and I couldn’t tell you how many broken ones I’ve seen!
- Cool the bias so your power tubes will last longer and be more reliable.
- Change the Fat switch to a full-frequency boost, still footswitchable!
- Change the tone stack to that of a vintage black panel amp, with more range on the knobs and the “Magic Six” settings straight up at noon.
- Change where the tone stack is in the signal path. This is the beating heart of these mods and what they share with every black panel amp.
- Change the circuit and raise the voltages of the phase inverter to that of a black panel amp: more clean headroom!
- Replace the power supply filter caps with different-value caps of much higher quality for tone, feel and reliability.
- Change the voicing on the reverb to sound like vintage black panel reverb, except usable through the whole range of the knob, from a little ambience to surf’s up! All while lowering the noise the reverb circuit adds to your amp. Big, beautiful and lush!
If you have the Supreme mod already, you’ll unfortunately need to buy the full Straight Six mod kit, as the two kits are completely different and only share a couple of small components. Though if you already installed those shared components, at least you won’t need to do it again!
If you have installed the Blues Junior Tube Board (or are planning to install one with the Straight Six), you’ll need to rewire it to work with the Straight Six, and the instructions cover that.
Your amp will sound amazing with just the Straight Six mod, but if you’re one of those folks who just can’t stop until your Blues Junior is absolutely all it can be, I have some modification recommendations in order of importance:
- Straight Six mod (of course!)
- Blues Junior Tube PCB
- The Soursound BJR-OT2 output transformer, specifically designed by Soursound for the Straight Six mods
- Eminence Alessandro GA-SC64 12” speaker
- Mojotone Bluebird 15W 1x12 pine cabinet
- Soursound SST-125C3A choke
I’ve been thinking about these mods for a couple of years now, and I’m very happy with how they turned out and so excited to share them with you. This is what I think the Blues Junior always should have been from the beginning!
Supreme Tube Board for Blues Jr
We have upgraded the Fromel Tube PCB Mod for Blues Jr: See description below for details. With over 100 boards sold I made some slight revisions.
You cherish your Blues Jr, and now it's time to take it to new heights. The Fromel Tube PCB is the solution to maximize your amp's performance, regardless of its version, from Made in USA to the cathode biased IV.
Experience a profound improvement in tone, feel, and noise reduction with the new Tube PCB Mod. We've fine-tuned every detail to deliver excellent performance.
Mods from Stock:
A cathode follower driven tone stack creates a smooth, compressive vintage feel. The stock Blues Jr leaves one of the gain stages in V2 unused, we use this for the cathode follower. The tone stack loads the signal down a lot, the cathode follower helps recover that signal while adding some musical compression.
Cathode biased for a touch responsive playing experience. Prior to the current version of the IV all Blues Jr’s were fixed bias and run hot if not modified. Changing from fixed to cathode bias solves all the bias issues for the amp and it sounds fantastic.
DC elevated heaters virtually eliminates heater hum, pushing the boundaries of silence. When we installed the first prototype, we were astonished by how quiet the amp was; I honestly don’t know why every amp maker does not do this to the heaters, it’s very simple and works incredibly well.
We've included a special mod to tame reverb noise because the amp was so quiet after the mods the reverb was irritatingly noisy even at 3, it’s a real easy mod, just clip one cap and we added it to the newest version of out our Supreme mod instructions and recommend it for all Blues Jr’s modded or not.
High-quality double-sided through-plated board sets for durability. The stock board is single sided and the PCB mounted plastic tube sockets are only secured by one pad and a bit brittle lead free solder. After a couple of tube changes the stress can crack these joints and this is one of the well known failure points on these amps.
These boards are double sided and plated through so the solder joint is very secure. All the traces on the PCB are the equivalent of 16 gauge wire. There is a ground plane to further reduce noise. Pre-soldered resistors, capacitors, and diodes make installation a bit quicker. I put all the instructions right on the PCB and there are detailed instructions with photos online.
The ribbon cables are replaced with individual pre-stripped leads. The kit also includes high quality ceramic sockets.
Changes:
- All board mounted components are SMD. Why? I can get a much higher rated component for the same cost as through hole for the same cost, resulting in a higher quality product without raising the price.
- Added in rush protection for the cathode follower so any 12A*7 or similar pinout will not get hurt.
- Modified the hole sizes on the PCB for easier install of the leads.
Our recommended tube set for this board is 12AX7, for V1, 12DW7 for V2, and 12AT7 for V3. 12AX7's in all three spots works fine as well.
The tube board is a great improvement to any model Blues Jr with or without the Supreme mods for the main board.
Install instructions
Blues Jr Straight Six mods guide · Blues Jr. Tube Board instructions · Blues Jr USA Tube Board instructions
Safety & warranty
Warning: These modifications WILL void your amplifier's warranty. Amps carry deadly voltages even when unplugged — follow the instructions carefully. If you're at all unsure of your ability to perform them, stop and have a professional do it, or send your amp to us.
No warranty: This kit and its instructions come with no warranty of any kind. Modifications are done at your own risk and you agree to hold the seller harmless against any and all claims. Tube amplifiers contain parts that operate at very high temperatures and deadly voltages; if you are not sure of your abilities, do not perform these mods.
All orders are processed within three business days. International shipments may be delayed up to six weeks depending on customs.
Share this item: