Durst M601 - Bulb wattage?

[Thomas Ryer]

I recently bought a Durst M601 in mint condition. It came with a 150W bulb (+ identical new spare). Any idea if this might have been the original configuration / recommended wattage? The enlarger head gets very ( ! ) hot after a short while and even at f.16 I cant seem to push exposure times to more than max 10-11 sec which give me very little time to work on my print.. I haven't been in a darkroom in 20 yrs so quite rusty : ) Have I missed something or is the bulb wattage way to much? Also appreciate any info on use "modern bulbs" like LED etc. in the M601. Thanks!

 

[AgX]

Welcome!

Maximum 150W

Thus nonone would stop you from using a opalescant bulb of lesser power.

 

[bdial]

Even though 150 is the max, a 75 might work better, both for heat and your exposure times.
LED bulbs can produce a lot of heat due to the driver electronics and the heat sink that keeps the LED from burning up, they probably wouldn't be very happy in a tightly enclosed lamp housing.

 

[darkroommike]

I never used anything but a 75 watt lamp in my M601, it's a pretty efficient machine and has only 6x6 for maximum film size.

 

[AgX]

LED bulbs can produce a lot of heat due to the driver electronics and the heat sink that keeps the LED from burning up, they probably wouldn't be very happy in a tightly enclosed lamp housing.

LED at same light output have much lesser heat loss than incandescant lamps.
I thus guess your idea is their heat diffuser are so tiny, compared to the bulb surface, that they would need some airstream instead.