I wanted to know what users of the Durst 138 and 184 enlargers use as condensor light sources as I understand that the manufacturer of the original bulbs no longer produces them. Durst Pro USA offers a halogen replacement that requires head modification and is expensive and they also offer a digital head with a computer controller that is expensive times three. Is there a cost effective alternative that will produce enough power while at the same time be consistent across the negative area? Comments? I thank you for your assistance in advance.