DEMETER TGA-3 TUBE GUITAR AMPLIFIER REVIEW

Guitar Player
By David Hicks

Product Profiles: Demeter TGA-3 Amplifier

James Demeter builds an incredibly good-sounding amp, and his all-tube TGA-3 is a versatile, roadworthy unit that delivers a broad variety of textures via its three channels. Simple and functional in its layout, the amp is attractive yet utilitarian.

The 3-channel preamp was designed to emulate the sounds of a '59 Fender Bassman (clean channel), a vintage Marshall (edge channel), and a modern super-sustaining lead sound (lead channel). Color coded knobs, yellow for clean, green for edge, and red for lead, and color-matched LEDs on the footswitch make for easy changes and quick identification of preamp-channel status.

Dual 3-band passive equalizer sections allow independent tone settings for both the clean and dirty sounds. Even with the EQ set to extremes, this amp never gets biting or mushy. The effects loop uses tube technology, so no solid-state devices are ever introduced into the signal chain. Send and return level controls enable operation with virtually any effect. Stereo return circuitry allows the signal from an effect's second channel to return to the amp and then be output to a slave power amp. A control governs the stereo balance between the head and an outboard amp.

The power amp employs push-pull tube-circuit design. For added convenience, Demeter has included a bias switch for easily changing from 6550 outputs to 6CA7s (or EL34s), and a balance control adjusts the output section to obtain the best results. The TGA-3's well-built cadmium-plated steel chassis (including a top cover) protects the internal components and maximizes noise rejection. Most of the high-quality components are mounted on a single printed-circuit motherboard, but Demeter still prefers to use chassis-mounted tube sockets and control pots for highest reliability. Numerous off-the-board wires and signal leads could cause noise problems in a lesser-quality amp, but the TGA-3 is as quiet as any I've tested. As in most modern amps, light-dependent resistor devices (LDRs) deliver instantaneous and totally silent channel switching.

Inside the sturdy cabinet, the top-mounted amp provides an under-chassis tunnel effect to cool the transformers and allow proper tube ventilation. Perforated metal front and rear grille panels add protection and visual style. Normally covered in Ozite, this test amp was painted with a tough plastic paint called Zolatone. Demeter says that this finish may soon be available as an option.

While you can tweak and tweak the TGA-3, it's very easy to just turn it up and go. The clean channel is, sure enough, mellow and fat, just like the old Bassmans. The EQ controls have well-chosen frequency centers and allow just enough throw to vary the tonal nuance without ever compromising the basic sound. If you prefer a chunky, vintage-style rhythm texture, you'll appreciate this.

Likewise, the edge channel does a fine job of duplicating a particular vintage sound. With the boost control deactivated, the tone and, especially, the amount of distortion remind me of the old non-master-volume Marshalls. It's slightly bright with a little growl on the peaks at low volume. At higher volumes, it creates more distinct harmonics suitable for bashing great, thick chords. With the boost control engaged, the edge channel responds more like an enhanced Marshall with added gain, yielding a great lead sound with a ripping high-harmonic content.

The exceptional lead voice brings one word to mind: smooth. The amp responds well for endless controlled feedback, but because the harmonic content is fairly low-level, the texture is never growly or harsh. The gain structure allows great dynamic range, so the amp cleans up nicely as the guitar is turned down, but screams when pushed.

I tried this amp with a variety of guitars, equipped with various single-coils and humbuckers, and I couldn't find any combination that yielded less than stunning results. In every case, the TGA-3 makes the most of the basic guitar sound. While this amp isn't inexpensive, its hand-built quality is worth the extra cost. Besides, what price can you put on a great sound? If you get your hands on one of these amps, you'll never let go.

Vital Statistics

Type of amp: All-tube guitar head

Features: Three independent channels, separate 3-band EQ for clean and dirty sounds, stereo effects loop for operation with slave power amp, adjustable return and send levels for effects loop, selectable 6550 or 6CA7 output tube operation

Power rating: 75 watts RMS

Dimensions: 18-1/2" x 9-1/2" x 11"

Weight: 34 lbs.

Options: Choice of enclosed amp top (reviewed), rack-mount unit, or combo; there's also a tube guitar preamp without power amp, and a stereo slave power amp

Front panel, top row (L-R): Channel 2 Boost/edge switch, gain, and master; channel 3 gain and master, channel 2 and 3 treble, middle, and bass; effects loop send/submaster level control; lead channel dark/normal switch

Bottom row (L-R): Channel selector switch, input jack; channel 1 bright switch, channel 1 gain and master, treble, middle, and bass; effects loop send/sub master; stereo effects loop return level controls; presence control; on/off LED; standby switch; power switch

Rear panel (L-R): Line cord, fuseholder, output balance control, bias switch, speaker jacks (4, 8, 16 ohms), effects loop section (return, send, and stereo return an slave amp output), auxiliary input, channel switching jacks (two 1/4" and one 5-pin)