Aristo cold light transformer question

[HartleyFalbaum]

I have obtained two Aristo D-2 units, one standard, one D-2 Hi. Both with broken tubes. I wanted to upgrade the tube to V54 anyway, so--I bought the package for very little. In checking the transformers--(I didn't want to buy a tube unless the transformer worked!)-I found the "Hi" unit produced about 1850 V, and the secondary had a resistance of about 3,000 Ohms. The standard unit produced about 1850 V also, but secondary resistance was 600,000 Ohms. Neither unit has shorted secondary wiring. Supposedly, the new tube will work in either unit. My question--is one unit bad, and if so, which one? I am going to adapt the good one to a Omega D4 (incandescent) Chromega, whose light output is pretty dismal.
Thanks

[Luis-F-S]

I would suggest contacting the folks who bought out Aristo. L

[HartleyFalbaum]

I already did--they don't know. That information "disappeared" with Aristo. I was hoping someone here knew.
Thanks

[EdSawyer]

600k sounds really high for any transformer secondary...

[Eric Woodbury]

These are ballasts and not transformers; a small difference when you drop them on your toe, but for coldlights, significant. The one with 600K ohms is probably AC-coupled, meaning there is a capacitor in there tricking your meter from proper measurement. It would also stop any DC-current flow. My guess is that they are both fine and even if not, neither would damage a coldlight. The voltage starts high to ignite the gas and once 'lit', its impedance of the gas drops (negative resistance), and the ballast limits the AC-current and reduces the voltage.

Don't exceed the input voltage on your voltage meter or you'll be fixing that next. With high voltages, use a multi-megaohm resistor (several 10 mega ohm) divider and multiply the answer appropriately.

Oh, keep one hand in your pocket. The voltage won't kill you, but if DC, the landing will; if AC, you'll need a new pacemaker and clean chones.

{Post 1000 !}

[williaty]

Have you actually been able to get in contact with the people making the new V54 tubes? I tried and couldn't get a response out of the company.

[HartleyFalbaum]

williaty--try this- http://www.light-sources.com/solutions/specialty-fluorescent/products/aristo/ I have spoken with Louise several times and ordered a tube yesterday.
Eric Woodbury--thanks for the reply---my education continues!

[HartleyFalbaum]

I forgot to add--Eric---I used a Fluke high voltage probe for the measurement--thanks for the warning.

[HartleyFalbaum]

Just a follow up to those who were kind enough to answer my original question. The new V54 tube came, and it works on both units! I got an old school Lektra-8 timer that works, so I am now fabricating the adapter for my Omega D4, and I'll be good to go!
Thanks All!

[HartleyFalbaum]

OK, so I finally completed my darkroom, adapted the Aristo to the Omega D4, and actually made some test prints. Used Ilford Multigrade Delux RC, Ilford filter set, Dektol developer. Printed a Kodak 1/2 stop step wedge, by contact, using a #0 filter. Got 6 stop range, about what I would expect for #2 paper. Tried a #3 filter and got about a 3 1/2 stop range. I actually printed a favorite negative that actually looks pretty OK. I have written to Louise Kessler for more info, but I am thinking I'll need a CC30Y filter in line as well. The light has plenty of power--my have to really stop down or add ND above lens. have any of you experienced extra contrast with the V54? Thanks

[Bob Salomon]

OK, so I finally completed my darkroom, adapted the Aristo to the Omega D4, and actually made some test prints. Used Ilford Multigrade Delux RC, Ilford filter set, Dektol developer. Printed a Kodak 1/2 stop step wedge, by contact, using a #0 filter. Got 6 stop range, about what I would expect for #2 paper. Tried a #3 filter and got about a 3 1/2 stop range. I actually printed a favorite negative that actually looks pretty OK. I have written to Louise Kessler for more info, but I am thinking I'll need a CC30Y filter in line as well. The light has plenty of power--my have to really stop down or add ND above lens. have any of you experienced extra contrast with the V54? Thanks

Optimal lens performance will be 2 to 3 stops from wide open. If you need to stop down further use ND above the lens.

[Drew Wiley]

Here's the deal with V54: It's a blue-green bulb. I happen to have a big high-power custom version for one of my 8x10 enlargers. But the V54 is most efficient if
you learn to split print with actual deep blue vs deep green filters. Of course, you can use it completely unfiltered too. Most of the time I try to print directly onto
VC paper, then merely tweak with a colored glass filter over the lens if needed. Graded papers obviously see only blue. But yellow passes some green while attenuating some blue, while magenta passes some blue while attenuating some of the green, depending on the strength of your filter of course.

[HartleyFalbaum]

Thanks, but that doesn't answer my question. The V54 is supposed to be right for VC papers. My experience so far (limited to be sure) is that it doesn't, really , quite do it. Is that a common experience, or did I get a bad tube? I appreciate your experienced advice a lot--thanks.

[HartleyFalbaum]

OK sorry to bother everyone. After drying the step wedge tests, and a look on a light table, I find the "0" filter produced a Exposure scale of 13 "half" stops, and the "2" filter a scale of 10 "half" stops. Wedge steps were 0.15 each. So-looks like it is not as far off as I initially thought. I can work with that. Thanks everyone.

[HMG]

My understanding (a positive way of saying no firsthand experience) is that the v54 bulb should give you a full contrast range without the cc30y rosco. This Ilford document (http://www.ilfordphoto.com/Webfiles/2006130201152306.pdf) recommends use of a cc40y filter with the older W45 bulb, but expect contrast to "bunch up" at the higher end.

However, in a recent test of the Zone VI (non VC) head, and a cc30y rosco filter, I got what I considered to be a fairly even distribution of contrast across the 1 to 5 range. I did not test the exposure range with each filter.

[Eric Woodbury]

A CC-yellow is a minus blue, which would curtail the higher contrast range. A V54 does not require and you should not use a CC. There is a little flat spot in the #4 or #3.5 spot of the range, but no big deal. With a very strong blue filter, one can go beyond what the contrast filters will give you, maybe a half grade. It's so blue that I can barely see it and dodging is difficult.

[HartleyFalbaum]

Thanks--Interesting bit of useful info. Made a real print from a "real" negative (not a step wedge) today. Used # 2 MG filter, no extra yellow. Actually looks pretty good, so will proceed with other printing. Thanks for the help.