Fromel OT-18 by SourSound - Output Transformer

$ 199.00

Introducing the Fromel OT-18 by Soursound Output Transformer: Unleash the Vintage Tones of Tweed and Black Panel Amps on Your Blues Jr or Pro Jr!

Discover a whole new world of tone with the Fromel OT-18 by Soursound Output Transformer. Created in collaboration with Bryan Sours, the owner of Soursound, a renowned expert in transformer design.  This custom-designed transformer will revolutionize your sound and transport you back to the golden era of vintage amplifiers.

Our journey to creating the Fromel OT-18 began when I first connected with Bryan Sours. His expertise and passion for transformer design are unparalleled. After a captivating two-hour conversation, we delved into the details of my modded circuit for the Blues Jr, including the new Tube PCB. We discussed the tonal vision I had in mind, and a few weeks later, the first prototype exceeded all expectations.

This remarkable output transformer offers two distinct primary taps at 8 ohms, each delivering a unique sonic experience:

  1. 8k: Experience the magic and majesty of the legendary Tweed era. This setting provides a smoother top end and a more compressed yet open-feeling touch sensitivity. It's the perfect choice for fixed biased amps, which includes the majority of Blues Jr models currently available.
  2. 6.5k: Prepare yourself for unparalleled clarity and punch. Immerse yourself in the iconic vintage black panel sounds that you never thought possible from a Blues Jr. This option is recommended for cathode biased amps, such as the latest version of the IV and, of course, when combined with the Fromel Tube PCB. Brace yourself for days of tonal bliss!


The core iron used in this transformer is substantially larger than that of the stock transformer. Despite the increased core size, the mounting centers remain identical to facilitate easy installation without any modifications or drilling of the chassis.

We were simply astounded by the tone and clarity of this output transformer. The sounds that emanated from the Blues Jr were nothing short of mind-blowing. It’s like taking a dark pair of sunglasses off the amp. 

Crafted meticulously in small batches in Portland, Oregon, each Fromel OT-18 by Soursound is a handcrafted masterpiece. Bryan Sours's expertise and dedication to craftsmanship shine through every unit. Please note that due to the artisanal nature of production, there is a lead time of approximately 4-6 weeks, so don't hesitate – secure your place in line today!

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