Apparently your only problem is lack of a transformer. Very few clocks, with the exception of some Rainbird clocks (as I remember), use center tapped transformers for dual voltages. With this in mind, realize 24VAC is 24VAC. ANY 24VAC transformer will work as long as the output amperage rating is within limits of the clocks capabilities, and the clock doesn't use a dual voltage txfmr. In other words, a 20 or 30 VA txfmr will work fine if the clock can only fire one solenoid at a time.
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