The TC-50 is a deceptively simple two-way loudspeaker based on a 6-1/2 inch acoustically suspended woofer and a 1 inch dome type tweeter. Its crossover network is truly state-of-the-art, in parts quality, circuit layout and, of course, design. The compact speaker is the result of exhaustive research and the latest technology in computer assisted optimization. Designer John Bau had indeed pushed the limits with tools available for the period, creating a time-aligned design with remarkable imaging qualities. Close tolerances were maintained during production and units were serialized to ensure a optimal left/right matching.
The TC-50 was produduced in Walnut and Oak wood laminates, glossy black vinyl laminate and there was a single run of 10 in glossy piano black finish. John Bau stated "Opus One [Pennsylvania] (who sold more TC50's than anyone by far) wanted to offer a black finished cabinet. Their owner, Tasso Spanos, wanted a "real" piano black. We (i.e. Spica and the cabinet maker) weren't sure it could be done in a cost-effective manner, so we all agreed to do a run of ten. After finishing them, the cabinet maker said no way, he would have to charge a hefty premium for them. So after that we went for a vinyl black laminate, which I thought looked pretty good."
TC50 Reviews:
Absolute Sound
- Spica TC-50 March 1984
- Spica TC-50 May 1994, vol 19, issue 95
Audio Magazine Spica TC-50 March 1984 
The Audio Critic Spica TC-50 No. 16 Spring / Fall 1991
International Audio Review Spica TC-50 (date not known)
Stereophile
- February 1984, Spica TC-50 VII-2,
- August 1986, Spica TC-50 IX-5,
- January, 1988, Spica TC-50 XI-1,
- February 1988, Spica TC-50 XI-2,
- October 1989, Spica TC-50/TC-50i XII-10
- October 1991, Spica TC-50 XIV-10
- October 1993 Spica TC-50 XVI-9
- October 1989, Spica TC-50/TC-50i XII-10
Awards:
Stereophile the Hot 100 Products, No. 75: Spica TC-50 loudspeaker
Bau's ugly ducking of a time-aligned two-way miniature showed that great sound could be produced from a speaker without the designer having to throw unlimited sums of money at the problems.
Specifications:
Released: 1983, est. 20,000 total sold (post) approx 7,500 TC-50's / 12,500 TC-50i
Description: Two-way, stand-mounted loudspeaker.
Drive-units: 1" soft-dome tweeter, 6.5" pulp-cone woofer.
Low-frequency alignment: sealed-box Q=0.78.
Crossover frequency: 2kHz.
Crossover: high-pass slope, approximately first-order, 6dB/octave; low-pass slope, fourth-order, 24dB/octave, Bessel; both drivers connected with the same polarity.
Frequency response: 60Hz-17kHz (-3dB).
Sensitivity: 84dB/W/m.
Nominal impedance: 4 ohms (3.6 ohms min. at 4kHz).
Amplifier requirements: 25-100W.
Maximum power handling: 50W continuous, 100W peak.
Dimensions: 15.5" (394mm) H x 13" (330mm) W x 11.6" (295mm) D
Weight: 20 lbs (9.07 kg) each.
Price: $420/pair (1984) / $450/pair (1986-1988); $550/pair in oak or walnut
Schematics:
Replacement Drivers:
In January 1988 Spica began shipping the revised TC-50 or TC50i (pictured). Easily identified by the shape of the felt surrounding the tweeter, early TC-50 units have a rectangle hole while revised units have a square hole.
TC-50 (early)
- Woofer: HIF 17JS 2 CA12, 4 Ohm Audax (FR) / Polydax (US) (specs for 8 ohm)*
- Tweeter: HD 100 D25, 4 Ohm Audax (FR) / Polydax (US) (specs for 8 ohm)*
TC-50i (improved, pictured, post 1988)
- Woofer: HIF 17JVX 2CA 2, 4 Ohm Audax (FR) / Polydax (US) (specs for 8 ohm)
- Tweeter: DTW 100 TF, 4 Ohm Audax (FR) / Polydax (US) (specs needed)
* The specs for HD 100 D25 and HIF 17JS 2 CA12 provide the correct response curves etc. however, the 4 ohm version of this driver was used in the TC-50.
