The Embedding model is only involved in the "R" part (retrieval). You need to use the same embedding model for indexing and retrieval, though, that is important

The Embedding model is only involved in the "R" part (retrieval). You need to use the same embedding model for indexing and retrieval, though, that is important. The Embedding model is independent of the actual LLM used in generation. You can use any embedding model with any LLM. In fact ada is only one option and there are lot of really good embedding models, also ones you can easily run local, or ones which are a lot of better than ada, readily available. ada is not the best choice in all cases.