Single Stroke Series Amplifier

$1,495 - $1,595

Condition: Custom Built



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Our new "SINGLE-STROKE", TUBE DRIVEN REVERB TWEED has roots going back to as early as 1947, but is probably more loosely based upon a modified 1955, Princeton® 5F2/5F2A "Tweed" amplifier. For those who want the "bottom line", this amp sounds amazing, has a small footprint, can easily be carried to gigs and has tube driven reverb. It has an amazing 18" of speaker cone area (8" and 10" speakers installed), yet it will fit in a small trunk or closet and can be used for recording, practicing, and gigging. For those who are interested in more technical details, please read on...


The 5F2A and subsequent iterations had a single bias configuration based upon a fixed value capacitor and resistor network on the cathode of the preamp. We have added a three-way toggle boost/voicing switch that acts on the first triode's preamp's bias resistor permitting the preamp to take on very different voicings within the same amplifier. With the ability to change the way the first preamp operates, the "Single Stroke" can be set to produce a standard blackface shimmer, a fat-like tweed /brown sound, or a plexi-like crunch, and all at the flick of a switch.

Then, a small portion of the signal is sent to another tube for processing as the reverb driver. After the signal passes through a spring reverb tank, it is sent back through the reverb recovery amp and mixed with the remaining driver signal before being amplified by the KT66 power amplifier. The KT66 operates in true, single ended, Class-A cathode biased operation. With the three way boost switch, the "Single Stroke" can instantly take on three separate and distinct characteristics and voicings.

The "Single Stroke" uses the first half of a dual-triode, 12AX7 for its preamp. A second 12AX7 serves as the reverb mixer and recovery amp, while the remaining portion of the first 12AX7 is used to drive the KT66 power amplifier. With a KT66 the "Single Stroke" puts out approximately 10 watts output into a the dual Jensen speakers. The "Single Stroke" comes standard with a Jensen P8R and P10Q, utilizing the dual 10" and 8" speaker combination to utilize the full 18" of total speaker cone area. This creates a harmonically rich output that is not possible to capture with a single 1 X 12" configuration. The "Single-Stroke" has a large output transformer to efficiently couple the output power to the two speakers.

A single Tone control provides the full spectrum of tone by allowing more signal to pass to the output stage. The inclusion of larger filter capacitors in the power supply sections contribute to not only a higher level of DC regulation and filtering, but also a cleaner and tighter bass, especially at greater volume levels. Carbon film resistors are used to maintain a low noise levels and vintage carbon comp resistors are used in critical tone locations. Rectification from AC to DC is accomplished with a 5Y3 glass rectifier. The use of the glass rectifier results in greater control over compression and sag. The current tube compliment creates a very finger sensitive amplifier where pick and playing style control compression and attack.

Because this amp compresses at reasonable volume levels, it lends itself to being an excellent recording amp, a gigging amp in small venues, or an amp that is perfect for warm-up and practice prior to playing in larger venues. Its small footprint allows it to travels well, whether to a gig or to a college dorm room.

Our cab is constructed of solid finger jointed pine. Our "Single Stroke" is covered in 1950's style "luggage Tweed" with an Oxblood grill. As with all FireBelly amplifiers, the "Single Stroke" is hand built one component at a time, using only the best tone components. Filtering is accomplished with oversized Sprague and F&T electrolytic capacitors. We also use foil in oil coupling caps for their dynamics, speed, focus and correct timbre and depth of field. Basically, they just sound great. This amp produces natural compression and breaks up at reasonable volume levels, but also produce a wide myriad of tones from its three-way boost/voicing switch and characteristic full lower end from the KT66.

This "Single Stroke" has usable clean headroom and a volume control that is very linear. The volume does not jump to full from 2-3 on the dial as with many amps, but slowly increases with the gradual rotation of the volume control until the amp starts to compress around 5-6 on the dial. It can be coaxed from traditional rock to blues to jazz to crunch quite easily due to the voicing/boost switch and various ways in which the preamp can be biased. This amp offers is a perfect combination of the very best of features of the Champ® 600, 5E1, 5F2, 5F2A as well as features that have never been integrated into these models.

All tubes are hand selected and include a 5Y3GT rectifier, 12AX7 dual triode pre-amp and driver, 12AX7 reverb driver and recovery amp, and a KT66 as your amp's power output tube with 12 watts of RMS power. The "Single Stroke" can also be configured with a 6L6GC output tube for lower output power of approximately 10 watts. There is a switchable impedance control with its multi-tap output transformer and can be set at 4 or 8 ohms output depending upon speaker configuration. The output transformer is connected to two gold plated, isolated RCA jacks that virtually eliminate any possibility of ground loops in the circuit. Of course, the dual Jensen internal speakers can either be used as part of the combo or a separate speaker cabinet can be connected running at either 4 ohms or 8 ohms.

The Single-Stroke can typically be built and shipped out within 6 weeks from date of order. It can also be delivered in almost any other color, although it is offered in is traditional tweed and oxblood combination. This amp is being produced in a limited quantity. If you have been searching for an amp that it tonally rich and would like an amp that can be coaxed into beautiful creamy tube type distortion from a combination of compression from the preamp, poweramp and speakers and would like an amp that operates at reasonable volume levels, look no further. This amp brings together the perfect combination for gigging, recording and just plain fun with almost unlimited tonal combinations available through the use of the dual speaker setup and the 3-way preamp bias control. This amp provides a way of controlling the tone and the volume in a manner that has previously been unavailable in production models of this vintage. Please contact us if you would like more information or click onto the order page so we can build one for you.


Single Channel, Single Input with 3-Way Voicing Switch

Single Ended, Class-A, 12 watts RMS Output with KT66

(10 watts with 6L6GC)

12-12AX7, 1-KT66/6L6GC, 1-5Y3GT, Dual Speakers

1 - 10" & 1 - 8" Combo, Tube Driven Reverb

Stock #120995115


Hand wired point-to-point style

Class "A" Single Ended (cathode biased), KT66 Power Amp or 6L6GC

Tube Driven, Spring Reverb

3-Way Voicing/boost toggle switch on preamp input

Period Correct, Dual Jensen Speakers with 18" of cone area

(Jensen P8R and P10Q)

Mallory M150 Tone Coupling Capacitors

Oversized Sprague Atom and F&T Filter caps for better DC regulation

Carbon Film Tone Resistors

Metal Oxide Power Resistors

Gold plated, independently isolated RCA Jacks

KT66 or 6L6GC Output tubes

Switchcraft Jacks, Carling Switches


One Year Warranty On All Parts And Workmanship

Certificate of Build Authenticity

Operation Manual

72-Hour Burn-In Prior To Shipping!

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Call: ( 310 ) 701-1950

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