After ordering a bunch of cool white LEDs from PBL a month ago, I checked back last week and saw that they now carried warm whites in a few (but not all) styles so I decided to try them out.

Ablaze 1 LED Warm White Frosted and Flat (not available in concave yet)
http://www.pinballlife.com/index.php?p=product&id=1882
http://www.pinballlife.com/index.php?p=product&id=1883

4 SMD "F-ing brite"'s Warm White
http://www.pinballlife.com/index.php?p=product&id=2561

(Available in both bayonet #44/#47 as well as wedge #555's)

I tried the 1 Warm White LEDs in the backbox. They are much warmer than the harsh blueish cool white Ablaze's, but they have a strange pinkish/purplish tint to them. They may be acceptable in a backbox, but don't think they'd work well for PF GI. For the playfield, for sure, the best style I found was the CoinTaker 2 LED frosteds that have a much more incandescent tint and much much larger throw at the base. (See attached picture).

ablaze_ww_compare.jpg

I then tried the 4 Warm White SMDs in the 3 pop bumpers on my High Speed. I had previously tried the same SMDs as cool white and found them to be too hot "up" so I put in a piece of paper under the center of the of the cap that really helped it distribute it to the sides of the cap and down around the skirt. However the cool whites were really harsh (too blue for me), so I tried the warms, and am quite happy with them. With the paper installed the light diffusion very closely matches a #44 incandescent. (See attached picture)

In fact, for the pop bumpers, since mine are opaque red, I couldn't find any CoinTaker LEDs work anywhere near as well as the 89 cent PBL 4 SMD's, not even the 4 side + 1 top design from them.

pbl_4smd_compare.jpg

Which ones did you try? PBL just got in these warm ones in the last week IIRC. As you can see by the pic, actually none of them are as bright as the #47's in the backbox. I did tons of testing on the backbox and playfield with about 8 different styles from CT, and 3 of them were dimmer than a #47 and 4 were way brighter, only the 2 LED frosted warm whites came close to a #47 in the backbox or a #44 on the PF.

Yep, they have the best throw possible due to the heavy frosting, unlike the light frosting on the Ablaze 1 LEDs.

I think I could use the Ablaze warm whites (with a couple well placed cool whites as I have) for my High Speed backbox.. in fact the CT 2 LED WW frosted leaves a small light purple dot behind the red in the center of the letters due to the condensing of the light on the top of the dome. Oddly enough the Ablaze WW 1 LED frosteds that look pinkish with the glass off actually lit up the letters almost perfectly IMO.

However for PF use on the High Speed, I tested lots and the CT 2 LED WW Frosted won by a landslide.

I have run it about a month now, and it is quite tight under the cap against the white base plastic. I don't think it will bounce out. I wondered if I got a thin yellow tinted paper I might be able to get the reflection tinted even closer to the incandescent. Since the 4 SMD LEDS are so short, that gives a lot of space to expand and then reflect while still illuminating the center and edge of the cap.

I tried the $1.69 (2x as much) CT 4 side LED + 1 center ones and they were far from the same effect. I think this will only work well with opaque caps. For plain translucents, perhaps a light white spray paint underneath would do a nice job as the paper would be too visible.

Below is the net result of 4 SMD Warm White Ablaze with paper under the cap centers:
final_popbumpers.jpg