I experience a high burn out rate when I use 250W bulbs in my Beseler 45MX. The PH212 150W have never burnt out on me, but these fade and pop on me at a rate that seems a bit fast. Is it the bulbs or my enlarger? If it's the latter, would a voltage adapter help reduce their failure rate? I love using them on my bigger enlargements, because I can hold good depth of field, and still have reasonable enlarging exposure times, but I would love to find a way to fix this issue. Thanks in advance for any advice. Cheers!
I use these bulbs as well , for the reasons you mentioned.
I buy a case at a time as they do burn out much faster.
The Omega Enlargers that I use are only rated for the 150w and the 250w is not recommended for these reasons.
You may try replacing the lamphouse wiring configuration, I just didn't think it was worth it. I go through approx 40 bulbs a year which costs me around $225 per year.
I find the extra speed well worth the cost of bulbs.
I use the hot PH213 250W bulbs on a Omega D5 condenser head. I have 'modified' the enlarger head slightly to move air and thus the heat out of it quicker via in inflowing and outflowing computer fans (2 total) mounted in place of the the two plastic fins (ears) on the side. This seems to extend the life of the bulbs considerably. Modified is a misnomer as this only needs a phlillip screwdriver and the fans to do it.
You can run the fans constantly or have them plugged into a your enlarger timer to come on after exposure (this helps reduce the extremely tiny amount of vibration you may or may not get with your set up).
I use the PH213 250W bulbs because I have mounted (via a tiny spacer to reduce newton rings) a 6" round opal milk glass difusion at the bottom of the lens assembly.)
This give cold light head type difussion enlargement quality while still be able to use the standard ilford MG variable contrast filters.
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