db = QSqlDatabase::addDatabase("QMYSQL", "Sphinx");
    db.setHostName("192.168.0.14");
    db.setPort(9306);
    db.open();

QByteArray ba("select id from lettersIndex where match('коллеги')");
    // Пробовал и без кодека, а так же со всевозможными кодировками
    QTextCodec* codec = QTextCodec::codecForName("Windows-1251");
    QString query = codec->toUnicode(ba);
    q.exec(query);

source lettersSource
{
                type = firebird
                sql_host = 192.168.0.14
                sql_port = 3050
                sql_user = user
                sql_pass = password
                sql_db = 192.168.0.14/3050:rc
                sql_query = SELECT l.ID, l.USERNAME, l.CAPTION, l.BODY,
                    DATEDIFF(second, timestamp '1/1/1970 00:00:00', l.logdate) as posttime
                    from LETTERS l
                sql_attr_timestamp = posttime
}
index lettersIndex
{
                source = lettersSource
                path = /usr/local/sphinx/data/lettersIndexes
                docinfo = extern
                min_word_len = 3
                min_prefix_len = 6
                html_strip = 1
}
searchd
{
                listen = 192.168.0.14:3312
                listen = 192.168.0.14:9306:mysql41

                log = /usr/local/sphinx/data/searchd.log
                query_log = /usr/local/sphinx/data/query.log
                max_children = 20
                pid_file = /usr/local/sphinx/data/searchd.pid
}

[Wed Feb 3 15:04:47.913 2016] 0.000 sec 0.000 sec [ext2/0/ext 0 (0,20)] [lettersIndex]
???????
[Fri Feb 5 10:25:22.623 2016] 0.000 sec 0.000 sec [ext2/0/ext 0 (0,20)] [lettersIndex]
?????»?»?µ????
[Wed Feb 3 15:05:22.284 2016] 0.000 sec 0.000 sec [ext2/0/ext 4 (0,20)] [lettersIndex]
коллеги