The TEA1 triode equalization amplifier is a phono stage available in four different versions to meet a wide range of needs – all designed to satisfy the expectations of the most demanding music lovers. All versions share a common circuit approach featuring a zero loop feedback circuit with passive RIAA equalization. All feature two phono inputs, one with switch selectable resistive and capacitive loading allowing the user to fine-tune performance to the chosen phono cartridge. With the exception of capacitors in the audio circuits and related power supplies, parts quality is identical in all four versions. All resistors are top quality precision metal foil types. I/O connectors are custom made gold-plated machined oxygen-free copper.
The TEA1b is the base model TEA1. In the TEA1b, the two phono inputs each provide 54.5 db of gain. Resistive and capacitive loading can be adjusted by toggle switches on the PHONO 2 / Variable Load input.  The base model uses CJD Teflon capacitors for all but the highest value capacitors (2.0 micro Farad and higher) in the audio circuit which are polypropylene bypassed by Teflon.
A capacitor upgrade is incorporated in the otherwise identical TEA1bc, replacing a number of high value polypropylene capacitors with multiple 2.0 micro Farad CJD Teflon capacitors.
The TEA1bt upgrades the base model by adding premium wide-bandwidth audio transformers to the PHONO 1 input to provide the higher gain and very low noise required by low output moving coil cartridges. The active circuit is modified to reduce its gain to 45 db, offering the user one HIGH GAIN transformer coupled input (PHONO 1) with 63 db of gain and one LOW GAIN direct input (PHONO 2) with 45 db of gain.
The fully configured TEA1 includes both the transformer option and the capacitor upgrade.

Designed to precisely track the prescribed RIAA equalization curve, the TEA-1 assures absolute tonal accuracy. The low-gain audio circuit of the TEA-1 is comprised of two cascaded single-ended triode amplifiers. The circuit is a zero-feedback design, to eliminate the temporal inaccuracies that negative feedback introduces. RIAA equalization is established by a passive network between the two gain stages. Careful implementation of this fundamentally simple circuit results in extremely wide bandwidth, and low distortion, without resorting to negative feedback. Precision wound input transformers provide the additional 18 dB of gain for the high-gain inputs.

The ideal dc power supply circuit is simply a zero impedance path to ground. Any deviation from this ideal is fully reflected in the audio circuits. Thus the power supplies are as important to audio performance as the audio circuits and must be accorded equal attention in design. In the TEA-1, each stage has its own discrete regulated DC power supply. These power supplies have been carefully designed for minimum impedance, even at the highest audio frequencies, to prevent the power supplies from degrading music reproduction.
The full potential of any circuit design can only be realized if executed with the highest quality parts. The audio circuits of the TEA-1 use only conrad-johnson's proprietary Teflon capacitors. In the power supplies, all capacitors are polypropylene and Teflon composites - there are no electrolytic capacitors anywhere in the audio circuits or their dc power supplies. The audio circuits and related power supplies both use high-precision laser trimmed metal-foil resistors, designed for ultra-low inductance. All parts in the TEA-1's RIAA compensation network are 1% tolerance, to assure precise tracking of the RIAA curve. Input and output connectors are gold-plated, machined oxygen free copper. Even the hookup wiring has been carefully selected for optimal audio performance.

Specifications

Gain (TEA1 and TEA1bt):             Low Gain Input - 45 dB   High Gain Input – 63 dB
Gain (TEA1b and TEA1bc):       Both Inputs – 54.5 dB
Overload (TEA1 and TEA1bt):       Low Gain – 110 mV      High Gain – 12 mV
Overload (TEA1b and TEA1bc):       Both Inputs – 50 mV
Hum and Noise: Direct Inputs – 82 dB below 10 mV input
High Gain (TEA1 and TEA1bt) only – 80 dB below 1 mV input
Phase: phase correct
Ouput Impedance: below 200 ohms

Mechanical
Dimensions:  15.5"D x 19"W x 3.315"H
Net Weight:  23 lb net

All conrad-johnson products are carefully hand assembled and each is thoroughly tested to assure conformity to our exacting performance standards. Our confidence in these components is reflected in our three year limited warranty covering labor and parts. Service is a top priority at conrad-johnson. In the event that a product does require service, it will be handled promptly and efficiently.

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conrad-johnson design, inc. 2733 Merrilee Drive Fairfax, VA 22031

phone: 703-698-8581, fax: 703-560-5360