The Source Theater Co., in its continuing effort to produce more plays than anyone else, has opened a new performing space on 14th Street with not one, but three plays rotating in repertory.

The space is simply not ready for public productions. Neither a creditable production of Harold Pinter's "Old Times," nor an underrehearsed version of Shelagh Delaney's "A Taste of Honey" is shown to best advantage in a theater where the backstage area is delineated by sheets of black plastic that ripple in the drafts, or where latecomers knock on the front door to get in. (The third play, "Bus Stop," by William Inge, comes up again in the rotation next week.)

To say these are bare-bones productions is to understate the case. There is nothing wrong with producing on a shoestring; the discouraging aspect of these shows is that the shoestring is not used very creatively. The playing area is unattractively bare, framed by the dingy back wall of the warehouse. Unused scenery is stacked within view. One positive note: The seats, rescued from a movie house, are excellent.

The dinginess of the environment is compatible with the dreary setting of "A Taste of Honey" in a down-and-out flat in Manchester, the latest residence of Helen, a jolly but completely undependable floozy, and her miserable teen-age daughter Jo. Jo, a sad, unloved girl with meager education, becomes pregnant by a black sailor. Her mother moves out into another marriage, and Jo's homosexual friend Geoff moves in.

This production, directed by Alan Hawkridge and Amir Korangy, is afflicted with several problems that can largely be attributed to lack of rehearsal. The small tasks of business, sweeping a floor or picking up cups, seem so awkward they dominate the stage. The same lack of development is apparent in the relationships between the characters, which are crucial to this plaintive, cynical view of working-class life in England. The performances by Jennifer Crier Johnston as Helen, Laurel Lefkow as Jo and Stephen Kelly as Geoff show promise, but are hampered by the bad habits and fussiness produced by unreadiness.

In "Old Times" Harold Pinter seems at times to be annoyingly opaque, at other moments fascinating and disturbing. A husband and wife await the arrival of the wife's old roommate; her arrival signals the start of a minuet of ambiguities. Were she and the wife more than roommates? Does the husband want to have an affair with the roommate? Is any of them telling the truth, and does it matter?

The linguistic precision of Pinter is particularly enjoyable in this play, in which the characters often speak in literary paragraphs. Trying to figure out what it all means is not the best way to approach this play, I think; it is rather a piece of music with recurring themes.

The performances are quite effective. Carole Myers as Kate demonstrates the power of a person who withdraws and rebuffs in subtle ways the attentions of those who pursue her. Rosemary Walsh is arch and charming as Anna, without missing the undertone of uneasy mystery, and Jack Hrkach is convincingly unhinged by the strange currents flowing around him.

The Warehouse Rep. continues through June 30.