Omega D2 LED Diffusion Head

[cardiomac]

Beautiful work. I've never been able to get the crinkle-coat finish like that!

Thanks. I'm using Krylon brand paint and lay on two thick coats before putting the parts in an oven at 170 degrees F. The paint wrinkles in about 10 minutes but takes about 3 hours in the oven to cure fully. The marred finish near the heatsink was caused by silicone heatsink compound. I've figured out a way to avoid this in the future. In this prototype the heatsink is not painted but in future models it will be. The slight loss of heat transfer that results from the paint will be made up for by enlarging the heatsink. I tried it with a painted heatsink and it looks stunning!

I'd buy one if it could be shown to have an even illumination comparable or better than traditional light sources and if it were for beseler. The vacuum/blower attached to my beseler dichroic head really spoils the tranquility of darkroom work.

The evenness of illumination appears to be nearly perfect, both by meter and by exposing paper with no negative in the enlarger. This took some doing because it is non-intuitive. One would think that simply spacing the LED's evenly would be sufficient but it is not, at least not in the enclosure I'm using. No fan is needed. Purposely leaving the LED's on continuously for an hour causes only a modest warming of the heatsink. Unfortunately, I still don't have access to a Beseler to make something for that enlarger, but it is on the agenda because Beseler's are so popular.

As to the timing issue, the easiest thing would be to put a relay between the power supply and the head. Use something with a 120v coil, and you can power it with your existing timer. Something like 220919310097 would replace your timer and provide a relay. I'd put a switch in parallel with this item or your relay to allow override for focusing/composing.

It is easy to do but to limit legal liability I want everything electrical to be UL approved, especially on the high-voltage side.

Thanks again for your comments.

[jp]

If you could stick to a time schedule for it's return, I'd send you my beseler 4x5 dichroic head for a couple weeks if you wanted to do that sort of project. Sending a whole enlarger would be difficult.

A larger load or smaller power supply might reduce the 2s delay you speak of.

Sell it "power supply optional", and people will figure out a way to time it. Or have someone overseas sell a relay interface. Without a relay, instead of a power input jack on the head, you could have a remote cabled box for the power input from the power supply and a pushbutton & toggleswitch to operate the head. Probably an extra $20 that way

[cardiomac]

If you could stick to a time schedule for it's return, I'd send you my beseler 4x5 dichroic head for a couple weeks if you wanted to do that sort of project. Sending a whole enlarger would be difficult.

A larger load or smaller power supply might reduce the 2s delay you speak of.

Sell it "power supply optional", and people will figure out a way to time it. Or have someone overseas sell a relay interface. Without a relay, instead of a power input jack on the head, you could have a remote cabled box for the power input from the power supply and a pushbutton & toggleswitch to operate the head. Probably an extra $20 that way

Thanks for the offer. I may take you up on it in a few weeks after I've gotten all the kinks worked out of this project.

[cardiomac]

Problem solved! I replaced the switching power supply with a transformer power supply and the lamps now come on virtually instantaneously! With this problem solved I'm going to go ahead build a few units for sale. The only parts I lack are the machined aluminum pieces. It will take about two weeks to receive them from the shop. Finished units should be available in three or four weeks. After that I'll start on something for the Beseler 45.

[Roger Cole]

I have one of his first LED lamphouses and it works great. I need to find a box and send it back because he's offering to upgrade it with the latest changes for free. I did some testing compared to my incandescent lamphouse and can see no difference between them in evenness or contrast. The LED is just about exactly between a 75W 211 and a 150W 212 bulb in printing speed. I made some exposures with no negative for comparison but I'm on my iPhone now and don't have access to them.

I wish there were some way to use above lens filters though. I just replaced my faded ones for neatly $60 and would have to get a new set AND keep them clean AND get the filter rod holder thingy for all my lensboards, or swap one around.

[Fotch]

I would be interested in your Beseler 45 model.