Recently picked up a used L3 unfilmed WP 18UA PVS14.  It works great and I am very happy with it, but the manual gain control only really does anything in the first 2/3 of rotation, last 1/3 does nothing (yes its in a very dark room so ABC is not kicking in).  Plus at the low end of the adjustment the tube is pretty much off.  My NGI XLSH and ITT NE both use pretty much the whole range of the knob's adjustment and all the way dim they have more gain.

Since the bottom end of the gain is so low and it hits the highest gain 30% before the end of the knob travel there is less usable adjustment range so its pretty touchy compared to the others.  Just curious if thats normal with some tubes.

The ones I use at work are touchy as well.

Some don’t do anything in the first bit of travel and then they turn up.  

Others are similar to what you describe.

Figured it was somewhat normal, most likely some tolerance stacking in the components and it can go either way.  I only have a sample of three units so when one does something different it stands out.

What do you think of the low light performance of the L3 vrs your xls?

Well.

I know some people will disagree but not super impressed with the unfilmed L3.  

Specs are close, the 18um L3 is 2400 pc, .7 ebi, 32.5 snr 64 lpi 63k lum.  The XLSH is 2200 pc, .87 ebi, 33.5 snr, 81 lpi 69k lum.  Both look to have carson glass.

I though the unfilmed + the little lower ebi of the L3 would be enough to beat my 13 year old NEPVS14 with a green pinnacle tube (2000 pc, 26 snr, .13 ebi) in the dark closet of NV despair but neither the L3 or XLS can see what the old ITT does.  Once a little light comes in both the XLS and L3 pull away and after too much time in the dark the L3 might be 10% better if that than the XLSH.  Of course in starlight in the woods the XLS and L3 beat the ITT pretty handily, the higher snr of the XLS and L3 lets you see details that are lost in the noise of the ITT.

So super low light, the ITT is the clear winner but its not really a practical use, .13 ebi will do that I guess.

In starlight the L3 doesnt look that much better than the XLS, maybe since the lpi of the XLS is high, maybe because the XLSH is brand new who knows.  Both the XLSH and L3 have a fair amoung of fixed pattern noise, the L3 is maybe a tiny bit worse.

In brighter urban light the L3 just blows away both of them, the halo is about the same but the L3 seems to handle the bright lights much better and the whole scene through the tube stays a lot more even.  Both the ITT and XLSH get that weird distortion with almost any light source is around, the tube gets really bright an you have to go diving for the gain control.  The L3 does not get that weird streaky lines around light sources (not sure what its called), not sure if its because filmless or better autogating but its very noticeable when shooting steel plates with poop steel clad wolf ammo.

I havent had a lot of time with the L3, it may show some better performance in some different areas in the future.  Plus its a sample of one :)  Its close enough to the XLS that I am going to bridge the two of them, the XLSH is a little more blue but not a lot.

Everything you described is pretty much what I have heard repeated ad nauseum which is that for similar specs unfilmed might give you a 10-15 % improvement in darker settings vs a thin filmed unit.  Similar for a lack of streaking on bright lights.

I have only ever looked through my unfilmed unit with specs similar to yours so I can't give personal experience on that other than my unit does not have the gain issues you are describing.

I was expecting a little more, figured .17 less EBI and 10% more light for the filmless might have been a bit of an improvement but comparing specs between two different manufactures probably isnt the best way to go.

The gain thing isnt really a big deal, it works fine, just different from the two others I have here and wondering if was something common or not.