This is an amplifier kit no longer offered through Trinity amps of Canada. I have built two so I can retain one for myself. The design provides an efficient, single ended (one power tube and an efficient preamp stage) amp that, using 2 additional switches in the bias circuit, allows you to substitute any octal tube from a 6V6 producing about 5 W, to an EL34 producing about 10+ W. I prefer a KT77 which is similar in power and gain to an EL34 but more touch sensitive like an EL84 powered amp.

Many of us are discovering that smaller amps that can be played in their sweet spots without being told to turn it down or set up in the next town over. This amp’s impressive range of volume and tone allows it to hold it’s own in a typical bar or smaller venue with a drummer that isn’t trying to play for an arena event, or a band mate who doesn’t quite know what his Marshall’s volume control is for. It also shines in cleaner modes for blues, jazz, and even some acoustic work.

The control panel and circuit are described in the accompanying slides and help define the “Swiss army knife” qualities of this impressive amp.

The Tweed Deluxe style cabinet is cherry and maple and comes with build documentation.

$1795.00

Two important push/pull options are found on the control panel, visible in the photo. The 1st is labeled “Gain“ and is a significant option. Pulled up, it removes the negative feedback loop. Negative Feedback is always on in Fender amps, controlled by the presence knob in Marshalls, and non existent in Vox styled circuits. It evens out a player’s pick attack, but at the expense of touch sensitivity. Country pickers and shredders use negative feedback so that none of their rapid fire notes get lost. Blues and Jazz players prefer the touch sensitivity to allow their nuanced picking to add volume control note by note and emotive effect to their playing. My personal playing style removes the negative feedback which allows the KT77 to be more emotive than a typical octal circuit allows.

The 2nd switch alters the circuit for the bass control to “fatten” the amp’s tone. The speaker is a 12” Celestion Gold voiced custom speaker made by VinTone in Redhook NY.

Modern improvements to the original circuit’s design (basically a small Fender) include a Master volume, and a variable power switch which provides standby and graduated power. All the controls are very interactive and allow satisfying volume and tone from bedroom levels to small venue gigging., and yes, they do go to 11.

Here is the interior of the Tramp’s chassis showing the quality of my lead dress (neatness and accuracy when I run the wires and solder them to their connection points).

Visible on the outside bottom of the chassis are the two switches to change the bias needed to change from a 6V6 power tube to its larger octal cousins.

You can also see the VinTone Custom speaker. The cabinet back is open so the speaker’s front projected output is warmer and round from the lack of closed back damping effect and the added backward projected sound. An impedance selector provides 4, 8, and 16 ohm output capability, so extension speaker can be utilized to “move more air” if you need to.

Mod never intended this amp to be built as a combo style amp, but I didn’t want to build it as a head and cab design. It took some planning to build as a simple “grab and go” amp.

The power and versatility of this little box is impressive. Absolutely capable for practice sessions for most blues and pop bands, and even local bar venue gigs if your drummer doesn’t play like he’s Thor wielding a pair of magic hammers.

The cherry and maple cabinet is sized to use the cover for Vox AC10-c1 amplifiers.

More details regarding the circuit and internals are with the following slides. Build documentation comes with the amp.

The MOD 102+ is a second generation design based on their 5 watt 102 model. It is a true single ended class A style amp meaning it uses only one power tube (an EL84 in this case) and no negative feedback loop. The result is similar in character to a Vox AC 4, with some important differences. The plus version of this amp adds a pull up switch to each control knob. A mid boost is added to the bass knob, bright is added to the treble knob, and turbo is added to the volume knob. All controls are interactive and effective with turbo providing a grit that’s great for classic rock and blues.

The top center panel is the cover for the internal circuitry. Access to the tubes is by removal of the speaker grill on the front of the amplifier.

I installed an Eminence Li’l Buddy 10”hemp cone speaker with a wattage rating high enough to always allow a clean sound, but would break up without getting fizzy if yu use the turbo setting or an overdrive pedal.

You can see that this is a straight forward circuit, as well as my consistency regarding clean wire routing and soldering.