The standard 8BitWave module includes footprints for constructing a working tzxduino, an Arduino-based audio for computers such as the ZX Spectrum. The main module can take care of all needed circuitry to make it a tzxDuino compatible device (Maxduino firmware is recommended), but a faceplate can be added to make it all a bit nicer as well as making it look like a cassette tape. A backplate doesn't really add much other than protecting the components themselves, by doing so also giving the user the feeling of not handling bare electronics. See 8BIT-Wave for all related shared projects.

There are quite a few tzxduino-variants available to you already, but I tried to allow for quite a few options for audio amplification: you can build the traditional LM386-based amplifier directly on the board, or you can cheat and just use a PAM8403 module with volume controls. Direct sound without any amplification at all, is always an option - should you choose to go that route.

https://www.pcbway.com/project/shareproject/8BitWave_Faceplate.html