The Art of Hand-Wired Circuitry

The Art of Hand-Wired Circuitry

We consider every Fat Jimmy Amplifier we build to be a work of art in and of itself, a sonic and visual masterpiece inside & out, to be appreciated in all regards by discerning musicians for generations to come.

You can give the exact same amplifier schematic to 20 different amp builders, and you will end up with 20 amps that all sound quite different from each other.   It’s not just a matter of ‘what’ you do, but how you do it.

Every single part of an amplifier circuit contributes to its sound.  From the obvious components like the signal passing capacitors and resistors, to the not-so-obvious: transformers, solder composition, physical layout, etc.  Everything makes a difference.  And everything we use has been carefully considered and selected in the construction of your Fat Jimmy Amplifier.

colonel-50-face-detailFat Jimmy Amplifiers are hand made to exacting standards, one at a time, with a tremendous amount of attention paid to detail.  We use a hand picked selection of vintage, NOS, and modern components in each and every Fat Jimmy Amplifier. Each component is specifically selected for it’s sound, performance, and function at its specific location in the circuit.  You might find NOS Blue Molded, Mullard Mustard, paper-in-oil, Black Cat, Sprague, or CDE (Cornell Dubilier) signal caps right next to premium new production Jupiter Condenser ‘vintage tone’ signal caps.  Again, every capacitor is specifically selected for its tone, performance & location-in-circuit.  It’s truly incredible how one single component, if it’s the right component in the right place, can have such a substantial impact on the tone and performance of an amplifier.  Some might say we’re splitting hairs.  But split 20 or 30 or 40 hairs… MAN that all adds up!

NOS Allen Bradley carbon comp resistors

Some of our NOS AB stash…

We use a high percentage of NOS Allen Bradley carbon composition resistors throughout our builds.  Carbon comp resistors are responsive and organically “alive” in an amplifier circuit!  Their resistance actually fluctuates & changes with heat, voltage, and current flow.  This is a major consideration in the feel and response of our amplifiers, and a major factor contributing to the feel and touch sensitivity of many of the vintage classics.  These resistors actually ‘breathe’ and respond to your playing, touch & dynamics!  All resistors in our builds are measured, and even matched where necessary.  Carbon or metal film resistors might be found where that specific sound or stability is called for (including some rare & tasty NOS classics)…

Vintage paper wound trannys in a '63 Brownface Fender Deluxe

Vintage paper wound trannys in a ’63 Brownface Fender Deluxe

We utilize the most finely crafted paper wound transformers available in all Fat Jimmy Amplifiers. Paper wound transformers and modern plastic bobbin transformers have different sounds. While plastic bobbin may be desired in some amplifiers & some circuits; we believe that only real paper wound transformers are capable of creating true and authentic ‘vintage tone’.

Paper wound transformers are found in all of the classics.

Ours are made in the USA on the very same machines Schumacher used to make Fender’s transformers in the 60s & 70s.  (And these days most of our trannys DO have metal bell-end covers).

We use vintage style solid core cloth covered wire for the signal path and most of the circuit. We use modern PVC or teflon insulated wire for high voltage applications where safety is a major consideration.

Fat Jimmy Custom Circuit Board

Fat Jimmy Custom Circuit Board

Proper lead dress, grounding, and layout are considered art forms and are of paramount concern and focus in all Fat Jimmy Amplifiers.

When an amp looks this good on the inside, you’d better believe it sounds that good on the outside…

Fat Jimmy Amplifiers are built one at a time, by hand, from the ground up.  Custom chassis made of high quality steel (or aluminum in some cases) are fabricated right here in Sonoma County, California.  Then they are carefully prepped, loaded with hardware, and wired by hand with a mix of NOS, vintage and modern components.  All connections are made one at a time, by hand; soldered point to point in the true vintage style.

At Fat Jimmy Amplifiers, amplifier construction is an art form.