The VL2500 uses a Phillips MSR 700SA lamp which has become refined to the extent that it's very dependable and stable in a working fully or not working at all type of way and not much in between.
4mm arc gap,
CRI 80, 5,600̊K, 55,000
Lumen, 750hr. There are other brands that make a similar but less expensive lamp similar to this but in a VL
fixture, they either might or might not work depending upon the individual lamp lot number. They also might not be as stable lamp to lamp in fully living out their lamp life. I don't for this specific
fixture recommend other lamps. Other fixtures... sure, these at times will have problems striking an arc with a other than Phillips lamp - and than again not at times.
The
Mac 700 also uses a very stable lamp it's HTI 700w/D4/75 or HTI 700w/D4/60 which is based upon the very stable
Mac 2K lamp design. It's a
bit brighter but potentially upon percentage wise won't have quite the lamp life in full output light as the above Phillips lamp. Than again it will cost a
bit less per lamp thus balance out in the end.
Arc Gap 4mm,
CRI (not listed but should be 90), 6,000̊K or 7,500̊K, 59,000 Lumens, 750hours. Phillips also makes a version of this lamp in 6,500̊K but a
CRI of 80 and all other data the same.
Lamp to lamp.. of course it depends upon the
fixture optics but the
CRI and luminous output of a
Mac 700 lamp is better. Again, still dependant upon what that
fixture is doing optically and the
Mac 700
fixture is using a double ended lamp. That means two holes in the
reflector as opposed to only one on the VL2500 - you will probably get some efficiency losses there alone.
The
Mac 700 is normally using a much higher color
rendering index lamp also which will make it "seem" brighter - about on the
level with a xenon
followspot. This or you three lamp choices.
In the end, both fixtures have their uses and I don't use moving lights. Lamp to lamp, I see a lot more
Mac 700 lamps come back as "bad" but than of course work were well over 100x more
Mac 700 fixtures are in
stock than VL-2500's. Both types of
fixture are constantly out on shows however but most of all the
Mac 700
wash fixture.