jt sound inc tube design electrical circuits next step recording engineer amps john gig gigging preamp sustain gain master knobs studio

TomasZewicz delivers classic rock and blues for stage or studio

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Blues - Schroeder Radio Lane
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Chicken Pickin' - Nash Tele
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Rock Riff - Schroeder Radio Lane Bridge Pup
The most recent session of Summer NAMM may have been without many of the big manufacturers, but that didn’t stop some lesser-known companies from taking advantage of the slightly muted vibe of the event to showcase their offerings. The more intimate setting also offered the PG team a chance to scout out some of the gear we normally might have missed. When I picked up some driving riffs cutting through the constant din of the show, I let my feet follow my ears to the TomasZewicZ amplifier booth. After chatting with John Tomaszewicz, the owner and chief amp designer of JT Sound, Inc., and checking out his offerings, I was pleased to have the opportunity to review the single-channel TomasZewicZ 1x12" 15-watt combo, the TZZ-15112.

Though he formed JT Sound Inc. a mere four years ago, John Tomaszewicz has been pursuing his passion for innovative tube amp designs since the early 1970s. An electrical engineer by training, John spent the early part of his career working for a large electronic manufacturer designing and testing a host of electrical circuits. After teaching himself tube amp design, John took the lessons learned from his day job (along with access to expensive electrical testing equipment) to begin designing tube amp circuits that “take the next step forward” rather than mimic a particular vintage vibe.

As a gigging guitarist and recording engineer, John wanted his amps to meet the goal of having exceptional clarity, responsiveness and enhanced frequency response. The result is an amp designed to excel in both the studio and onstage. An emphasis on reliability and serviceability are also incorporated into the design through the use of components that exceed their respective ratings.

The Benefits of Innovation
While the circuit design of the TZZ-15112 is unique, its aesthetics borrow from some timeless designs. Out of the box, the amp has a striking resemblance to the venerable Marshall 1974X 1x12 Combo, with its expertly applied black tolex covering, contrasting white piping and “Bluesbreaker” colored grille cloth. The top-mounted chassis utilizes a combination of black studio knobs (Cut, Gain, Sustain, Master Volume) and white “chicken-head”-style knobs for its passive tone stack (Bass, Middle, Treble, Presence) and Pre Amp Gain controls. The use of black and white knobs is a thoughtful design decision, as it proves useful in adjusting levels in low light conditions. The black control panel is finished off with a single input, indicator light, standby switch and power switch. The rear of the amp features an open-back cabinet design and with an effects loop, 4 and 8 ohm outputs, power input and a pair of fuses. All in all, a very attractive amp—my only quibble is that it lacks corner guards to protect it when you take it out to be heard.

Under the hood, its overall design reflects the hand of an experienced amplifier builder. The cabinet is made from 13-ply Baltic birch and features 1/4" finger joints. Situated in the cabinet is one 12" Veteran 30 speaker from Warehouse Guitar Speakers, LLC. This US-based direct seller of speakers produces well-executed versions of classic speaker models. According to WGS, the Veteran 30 takes all the goodness of the Celestion Vintage 30 speaker with a tonal improvement smoothing the “spike” in the uppermids. Housed in a spot-welded chassis made from heavy gauge aluminum, the circuit is constructed using a printed circuit board to maintain consistency, as well as point-to-point wiring for the chassis-mounted tube sockets. The amp’s modular design makes servicing easier for techs.

With an emphasis on reliability, TomasZewicz does not use any relays or switches in the circuit (other than On/Off and Standby) and every component used in the circuit has ratings that exceed the voltage and temperature environment over the required frequency band. Although TomasZewicz believes superior performance is achieved in the circuit design versus components used, the amp features a beefy custom Pacific power transformer (with two extra taps for the sustain circuit), an ultra-linear Hammond output transformer, PEC pots and Sprague Orange Cap Drop capacitors. The amp also features an array of JJ tubes that include a pair of EL84s in the power section and a 12DW7/ECC832 in the preamp, followed by one 12AX7/ECC83 and then three 12AT7/ECC81s for the makeup gain stage and the tube-buffered effects loop. The phase inverter tubes are run in parallel, adding a level of smoothness and fatness to its overall tone (think Matchless). Its cathode bias design does not require re-biasing, so tube tweakers can rejoice accordingly.

The TZZ-11512 has some interesting features that are worth noting. The integrated Sustain feature on this amp is a studio-quality design: a dynamic control device that offers just the right amount of compression with a hint of drive. It works in tandem with the Drive control to push the power section on the amp to the desired level of breakup. These controls could easily be sold separately as a discrete effect. The Cut knob acts as a low-pass filter on the power amp, and Presence offers more crispness to the overall tone. The Pre-Amp Gain knob adds an articulate, smooth drive tone that sits somewhere between a Vox- and Plexitype overdrive. The tube-powered buffered effects loop sounds great with no treble loss.

Plugging In
I took John’s advice and put all the studio knobs to zero and began dialing in certain tones. Pushing the Sustain and Drive up in tandem with the Pre-Amp Gain set around 3, I was instantly greeted with a tone that was filled with EL84 chime laced with tasty harmonics. Think REM- or Early Tom Pettytype tones. The passive tone stack also acts as a Volume control, and bringing up their respective levels brought out the responsiveness and articulation of the fundamental tone. With so much sustain at my fingertips, I found myself playing single-note lines at an ever slowing pace to enjoy the harmonic complexity of each note. Pushing the Pre- Amp Gain along with the Drive and Sustain knobs revealed a more-than-adequate power section with no discernable “sag,” as power chords barked with authority and solid string separation. I found the amp easily capable of handling both single-coil and humbucking pickups, with my favorite being a Nash “Keef” Tele loaded with a Lollar Special pickup in the bridge that consistently offered up a pleasing blend of drive and chime.

The Final Mojo
I was able to jam with the amp with another guitarist and a drummer and found the amp sat well in the mix. The amp’s responsiveness was evident as small changes in pick attack and guitar volume control brought substantial changes in overall tone. At times I found myself wanting more clean headroom with slightly less hum, but I’m sure TomasZewicz’s higher-powered EL34 heads and combos could offer the additional sonic real estate. It is great to see an original amp circuit in a “saturated” amp market; I suggest folks consider TomasZewicz’s offerings.
Buy if...
you’re seeking classic rock/blues tones that “cut through the mix” with articulation, harmonic complexity and tremendous sustain.
Skip if...
you require two channels, reverb or copious amounts clean headroom.

MSRP $1825 - JT Sound Inc. - jtsoundinc.com