TC-50 Crossover
Two versions of the TC-50 exist, the TC-50 and the TC-50i. Spica started shipping the 'improved' TC-50i units in January of 1988 (around Serial number 7500). The change was brought on when the supplier for the woofer surrounds out went out of business and Audax (FR) / Polydax (US) had to find a new supplier. In order to match the efficiency gain of the new woofer, Spica had to incorporate a new tweeter, modify the crossover, alter the felt padding geometry (rectangle became a square), and they doubled the doping coating on the woofers. (SLUG post). You could also send your speakers back to Spica for a $200 upgrade, so some early serial numbered TC50s also have the factory upgrade.
The TC-50/TC-50i crossover is not complicated, but you need to understand about service codes. Spica would carefully test and grade each woofer. Then based on those parameters a service code was assigned and paired with a matching crossover . For this reason, it is unlikely that your components will match these exactly.
Spica TC-50 |
Spica TC-50i (improved) |
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| Type | Qty | TC-50 Schematic | Qty | TC-50i Schematic |
| Elect. Cap. 50V | 3 | 4.7 ufd (C1, C2, C8) | 3 | 4.7 ufd (C1, C2, C8) |
| Elect. Cap. 50V | 1 | 33 ufd (C4) | 1 | 40 ufd (C4) |
| Elect. Cap. 50V | 3 | 0.33 ufd (C5, C6) | 1 | 0.33 ufd |
| Elect. Cap. 50V | 1 | 3.1 ufd (C6) | 1 | 3.1ufd (C6) |
| Mylar 50V | 1 | 0.22 ufd (C3) | 3 | 0.22 ufd (C5, C7, C9) |
| Mylar 50V | 1 | 0.22 ufd (C9) | 1 | 0.1 ufd (C3) |
| Metal Film 1/2 watt | 3 | 1 Ohm (R1,R2,R3) | 1 | 2 Ohm (R1) |
| Metal Film 1/2 watt | 1 | 4.1* Ohm (R2) | ||
| Metal Film 1/2 watt | 1 | 2.7 Ohm (R3) | ||
| Inductor | 1 | 1.02 mH 0.23 Ohm (L1) | 1 | same (L1) |
| Inductor | 1 | 0.778 mH 0.23 Ohm (L2) | 1 | same (L2) |
| Inductor | 1 | 0.353 mH 0.11 Ohm (L3) | 1 | same (L3) |
Values are listed here will likely not match your values. Crossover components were determined by the service codes of the woofer. |
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