Parsing ASCII-Only string

Yess, I am still struggling with RegEx.

What I have done so far is to validate a string whether it consists of printable ASCII chars only.

///<summary>/// The name of the host which has originated the Syslog message
///</summary>string host;
///<summary>/// Gets or sets the name of the host which has originated the Syslog message
///</summary>publicstring Host
{
    get { return host; }
    set
    {
        Regex regex = new Regex(@"(\40-\176)");//Printable ASCII characters only
        Match match = regex.Match(value);
        if (match.Groups.Count == 1)
        {
            host = match.Groups[1].Value;
        }
    }
}

Is there a shorter way of approaching this?
Also, the RegEx currently produces no match if there is an invalid ASCII char in the string, what would I need to do to just remove the faulty part?