Sayyiduna Jabir (may Allah be pleased with him) said: Sayyiduna Bilal (may Allah be pleased with him) used to call the adhan for Zuhr as soon as the sun passed the meridian, and sometimes he would delay the iqamah, but he would not delay the adhan.
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1934