How do you remove a space before a citation in LaTeX?

The cite package tries to be clever and insert spaces before references when they are necessary. For example if you type

Here is some text\cite{xxx}.

then it will insert a space after "text". This behaviour can be turned off completely by

\usepackage[noadjust]{cite}

Alternatively, if you want this behaviour in general but have problems in isolated cases, you can insert a small space

(\hspace{1sp}\cite{All14} says...)

1sp is the smallest non-zero space in TeX, roughly 1/100 of the wavelength of light according to the TeX book.

\documentclass{article}

\usepackage{cite}

\begin{document}

Blah Blah (\hspace{1sp}\cite{All14})

\bibliography{Ref}
\bibliographystyle{alpha}

\end{document}

This is an old post, but I believe that the unwanted space is only a minor effect of a wrong approach, so I have also another suggestions:

1. Do not use cite. This package is to format numeric citations, so I think that have little utility with an alpha style where references are the bibtex keys. Without the package, (\cite{All14}) will work as expected.

2. Do not use parenthesis. The reference already use brackets as delimiters, so a additional delimitation is completely superfluous.

3. OK, for some odd reason you need cite and references with double delimiters. In this case the delimiter format is controlled by \citeleft and \citeright. So, to obtain what you want you can use \renewcommand\citeleft{([} and \renewcommand\citeright{])}, so you only have to use \cite{All14} to have ([All14]).

Besides, a little (opinion-based) comment: If possible, avoid bibkeys as references. It is not inelegant, but the next.