TC-2r & TC-4r Tube Preamp/Crossovers

The TC-2r & TC-4r Tube Hybrid Preamp & Active 2-way Sub Crossovers

The TC-2r and TC-4r preamp/crossovers facilitate increased audio system power and performance by combining class-A vacuum tube signal amplification, an adjustable gain preamplifier, and active, top-quality crossover circuitry. Crossover frequencies may be independently set or bypassed, two sets of inputs are selectable via a front-panel switch, and each channel has independent volume control.

Of unique all class-A tube discrete hybrid design, the TC-2r and TC-4r provide maximum sound quality and two basic functions:

• TUBE PREAMP: dash-mounted, switchable dual input, easily adjustable, independent volume controls with variable 12dB (4x) class-A tube gain.
• SUB CROSSOVER: optional, independently selectable, 2-way, subwoofer crossover signal-separation capability for use in bi-amplifier audio systems.

The TC-2r has one pair of outputs, and the TC-4r has two pair of outputs. Both have two pair of stereo inputs selectable via front-panel toggle switch. Vacuum tubes perform signal gain. The power supply is isolated to help prevent system noise.

Designed and built for maximum reliability and sound quality without regard for cost, we feel the TC-2r and TC-4r tube preamp/crossovers help set the standard for high-end sound quality and musicality in the automobile.

  Sound & Build Quality

Niceities like durable stainless steel fasteners and hardware, machined tube sockets, gold/copper Teflon input connectors, expensive potentiometers, custom magnetics, quality capacitors and components, and Teflon wire were chosen for sound quality, reliability and (obviously) never to "save a buck."

Top quality parts. Smart, patented designs. Proven performance. Numerous glowing reviews. At this level of excellence every detail matters, and we believe we have them just right.

  TC-2r & TC-4r Facts

Active tube preamp; compatible with and enhances the sound of any amplifier

100% hand-made in USA, highest parts and build quality possible

Class A Vacuum tube signal gain; Discrete bipolar output drivers

In continuous production since 1992; Proven reliability, stability, durability

Isolated, supersonically regulated power supply

Remote turn-on current draw is approximately 20mA, very small

Idle current is approximately 1A (12 watts)

Dual stereo inputs with front-panel switch

Independently adjustable output volume knobs with 4x (+12dB) gain

Powerful 600 Ohm effective output impedance; 10kOhm input impedance

Standard DIN size for dash mounting; brackets also provided

Sturdy, steel and aircraft-aluminum chassis with durable hardware

Hand-wired, chassis-mount, Teflon/Copper RCA jacks

Turn-on & turn-off muting

  TC-2r & TC-4r FAQ

What's the difference between the TC-2r and the TC-4r?
Both are identical, except that the TC-2r has 1 sub + 2 outputs and the TC-4r has 1 sub + 4 outputs.

When used as a crossover with outputs set in "high pass" mode, each output of either the TC-2r or TC-4r can have an independent crossover frequency. Each output can also be independently set into "all pass" mode so that the full signal passes through with tube gain but without frequency modification by the crossover circuitry.

How often do the tubes need to be changed?
"Need" is subjective. Some owners elect to change tubes yearly. However, the tubes are operated conservatively and enjoy correspondingly long useable lifetimes: running the original tubes for ten years or more is not uncommon.

Subjective design goal?
Liveliness and musicality.

Objective design goal?
Reliability.

How long does it take to warm up and play?
About 30 seconds normally, and up to 60 seconds in sub-freezing temperatures.

Price?
TC-2r MSRP US $695. TC-4r MSRP USD $795.

The TC-2r and TC-4r are subwoofer crossovers made for bi-amplified car audio systems. Their class A tube discrete hybrid circuitry tastefully combines the musical warmth of tubes with punch and accuracy.

The sound is surprisingly natural and lively. Voices are sensual, without breakup or exaggerated sibilants. Low frequencies are at once quick and full-bodied. Image depth and soundstage are conveyed with the correct size and spacing. None of the threadbare transistory noise normally associated with car audio is present. The TC-2r and TC-4t are designed to be excellent sounding audio components.

The crossover function can be indepdently set or bypassed per channel, allowing the TC-2r or TC-4r to be used as a vacuum-tube pre-amplifier signal level adjuster, with up to +12dB (4x) of tube signal gain and two switchable stereo inputs.

Both the TC-2r and TC-4r are designed by ear to sound good and built by hand to last a lifetime. Quality volume controls and Teflon/silver/copper wire is used throughout. The sturdy steel and aircraft-aluminum chassis sports high-quality gold/Teflon RCA jacks and stainless steel hardware that won't strip out. The faceplate is uncluttered and straightforward: Control knobs are single function, easy to grasp, and do not pull off in your hand. Miniature vacuum tubes are profiled through a window in the faceplate, giving an unmistakable look.

The TC-2r and TC-4r were designed to perfectly complement the excellent sound quality and reliability of the BaM-235ab mobile tube amp. Every component part has been chosen for optimum sonic performance.

All Milbert Amplifiers equipment is hand made, burned-in, and thoroughly tested and auditioned in the USA.

The TC-4r is the same as the TC-2r but with two more high frequency channels (five total independent volume controls) for use in four-channel systems.

Built for the car yet comfortable even in the finest home or studio audio systems, the TC-2r and TC-4r are tube preamp/crossovers with finesse, purposely designed to deliver true high-end, home-quality sound for the car.

• Size and weight: 2"H x 6-15/16"W x 5"D; 3lbs.
• Power consumption: 12 watts nominal (1A); 24 watts max.
• Sensitivity and impedance: 100mV to 2Vrms; 25k Ohms in; 600 Ohms out
• Signal gain: 4:1 gain high-pass & low-pass
• Crossover points, slope: 60, 72, 80, 100Hz, independent; 12dB/oct Butterworth
• Frequency response: +0, -3dB 20Hz-60kHz
• Hum & noise: -90dB from 20Hz-60kHz (unweighted)
• Warranty: one year parts & labor; return freight paid

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The Function of a Crossover

Since half of the energy in the ten audible octaves (20Hz-20kHz) resides below 120Hz, an active subwoofer crossover like the TC-2r or TC-4r can distribute the audio workload between two amplifiers and appropriate speakers. Incorporating the warm sound of tube signal amplification, the TC-2r and Tc-4r sound lively and warm, accurate and musical, exciting and real.

Consider a bi-amplified system comprising a good signal source, a TC-2r or TC-4r tube crossover, a BaM-235ab car tube amp driving good satellite speakers, and a transistorized amp driving a subwoofer in an enclosure.

At frequencies independently set by its internal switches, the TC-2r or TC-4r separates the incoming full-spectrum audio signal into two halves via its smooth 12dB/octave Butterworth filters. The powerful low frequencies then go to the transistorized amp and subwoofer speaker which are designed to best reproduce them. The BaM-235ab and its satellite speakers, relieved of the cumbersome bass, can excel at reproducing the delicate high frequencies.

Independent front panel volume controls on the TC-2r and TC-4r allow left-right balance adjustment as well as relative volume adjustment between the subwoofer and high frequencies. This offers a convenient way to turn up the subwoofer when driving at high speeds, overpowering the increased road and wind noise which would otherwise obscure the bass.

In addition to subwoofer volume control, the TC-4r allows independent four-channel high frequency volume control. This overcomes the drawbacks of conventional balance and fader controls which give a volume increase in one channel only at the expense of a relative volume decrease elsewhere.

  TC-2r & TC-4r Owner's Manuals

Comprehensive Owner's Manuals are available online. Please register and login for access.

  TC-2r & TC-4r Price & Purchasing

The TC-2r and TC-4r Tube Preamp + Crossovers are available directly from the factory and from authorized dealers worldwide: Call or email.