We show that, if time comes when quantum algorithms can be used for universal parallel computation, the "quantum-parallel" computer hardware will most probably be a classical physical system corresponding to a Hilbert space and the actual realization may be the combination of analog and digital circuits. We first point out the practical difficulties of universal quantum computing which may prohibit practical applications as universal computers. Then we show how to apply analog microelectronic circuits to realize the architecture, data processing and parallel computing abilities of quantum computing via Hilbert space computing with analog circuits. Such a Hilbert-space-analog (HSA) computer simulates the Hilbert space and its operators, and it is able to use and test quantum algorithms developed for the real quantum computers. Such a computer would be free of most of the practical difficulties of realizing and running a real quantum computer. This computer can be made universal. It is remarkable that by using the same numbers of transistors as in today's PCs, such a HSA computer can manipulate ~107 analog numbers corresponding to ~22 qubits, simultaneously, by quantum-parallel processing.