# Princeton Tec Apex Seoul SSC P4 mod with beamshots



## luminari (Feb 27, 2007)

So I decided to open up my Princeton Tec Apex and give it a nice upgrade. This is a u-bin P4 bare emitter bought from a CPF group buy.

I don't plan on writing a detailed mod thread as there are better writers on CPF who have already done so for the Apex, but I would say the mod is not too difficult: you need to unscrew the housing (make sure you don't lose that o-ring) and pull the old emitter out.

The results were quite bright, though the optics in the Apex continue to disappoint with their ringy spill beams. I may replace it with a reflector at some point. The hotspot was huge, though, so I guess that reduces the problem a bit.

I have some DealExtreme HASTO 3W headlamps in the mail that I plan on modding and giving as gifts, but the PT Apex's good electronics, reliable construction and, most importantly, excellent heatsink (external heatsinks are great, Petzl and Black Diamond!) has made me want to kick it up a notch.

The heatsink indeed got a workout as it got warm to the touch when running on high. I guess that means the thermal compound on the heatsink is doing its job.

Apex stock high





Apex stock low




Apex with SSC P4 high





Apex with SSC low





I'm hoping to test this on two 14500 lithium ions due to the great weight savings, but their combined 8.4 volt peak voltage gave me pause. Does anyone know the Apex's maximum rated input voltage? I know it can run on lithium primary AA's, but four of those still fall short of 8.4 volts.


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## jar3ds (Feb 28, 2007)

you can run two lithium-ions in the apex... i can't remember the exact max voltage but i'm sure it works just fine....

i'm interested in modding the apex 5mm LEDs to red LEDs... but i'm not sure which red leds would be the best... what do you think would be the best red LED's to mod the apex with?

Thanks and thanks for sharing!


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## ktronik (Feb 28, 2007)

jar3ds said:


> you can run two lithium-ions in the apex... i can't remember the exact max voltage but i'm sure it works just fine....
> 
> i'm interested in modding the apex 5mm LEDs to red LEDs... but i'm not sure which red leds would be the best... what do you think would be the best red LED's to mod the apex with?
> 
> Thanks and thanks for sharing!



I had the same idea... I found a 20,000 MCD red 5mm LED...Vf 50ma...

http://www.jaycar.com.au/products_uploaded/ZD-1790.pdf

I guess it depends on the current output to the 5mm LEDs in the apex...

I also found a 5mm LED that could take 1A... but no use in the apex...

you know I was also thinking of putting 2 RED leds on the flat bits on the sides of the EOS...

keep up the great work guys... :candle: 

Ktronik


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## mdocod (Feb 28, 2007)

You could rewire the battery box to run a 2P2S configuration of 4 14500s. 

basically, it would be a 7.4V 1500mah pack...
11.1 watt hours or so....

not bad compared to NIMH which would be 4.8V @~2500mah 12 watt/hours...

the lack of self discharge would probably mean that by the time you use the cell, you'd have more power available in the li-ions..


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## luminari (Feb 28, 2007)

Hmm, I don't know much about the red 5mm LED world, but that got me thinking... the Apex's 5mm LEDs are heavily driven. Does anyone know at what level?

Is it possible to swap them out for high-flux LEDs like the SSC P4 or the Cree? I know they won't be driven very hard, but imagine the spill and color quality! That would be awesome! I guess the question is if they would even light up at that low drive/voltage level.


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## ktronik (Feb 28, 2007)

luminari said:


> Hmm, I don't know much about the red 5mm LED world, but that got me thinking... the Apex's 5mm LEDs are heavily driven. Does anyone know at what level?
> 
> Is it possible to swap them out for high-flux LEDs like the SSC P4 or the Cree? I know they won't be driven very hard, but imagine the spill and color quality! That would be awesome! I guess the question is if they would even light up at that low drive/voltage level.




In theory, the white 5mm LED will be driven @ around 3.2v-3.6v so the voltage would be the same... & yes it would be more efficient to run a lightly driven led than a heavily driven one.... in fact most modern leds are most efficient @ 100ma... so good idea... I know cree has a half watt led that is real small...

ktronik


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## TMorita (Mar 3, 2007)

I just did a PT Apex SSC mod today.

The best reflector for the mod is the McR-20 Seoul. You need to remove a few tenths of a mm off the rim, and afterwards it fills most of the clear plastic bezel and looks almost stock.

Toshi


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## jar3ds (Mar 4, 2007)

TMorita said:


> I just did a PT Apex SSC mod today.
> 
> The best reflector for the mod is the McR-20 Seoul. You need to remove a few tenths of a mm off the rim, and afterwards it fills most of the clear plastic bezel and looks almost stock.
> 
> Toshi



excellent! I have a question though... where did you take the mm off of? you say rim... but does that mean the base (where the LED is) of the reflector or the top (big end)?



ktronik said:


> I had the same idea... I found a 20,000 MCD red 5mm LED...Vf 50ma...
> 
> http://www.jaycar.com.au/products_uploaded/ZD-1790.pdf
> 
> ...



ktronik, how do the LEDs you mention compare in terms of output? Would they be similar to the nichia 2x white leds only in red? As far as total output? How would their beam profiles line up? Thanks!


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## ktronik (Mar 4, 2007)

jar3ds said:


> excellent! I have a question though... where did you take the mm off of? you say rim... but does that mean the base (where the LED is) of the reflector or the top (big end)?
> 
> 
> 
> ktronik, how do the LEDs you mention compare in terms of output? Would they be similar to the nichia 2x white leds only in red? As far as total output? How would their beam profiles line up? Thanks!



for some reason red is always brighter in the same type of led...ex for a lux3 the red puts out more lumens than the same lux3 in white... beam profiles should be the same... but someone smarter should chime in and give you a better answer...

I guess red is easier to make than white...red-orange is brighter again...

ktronik


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## HEY HEY ITS HENDO (Mar 4, 2007)

....... for some reason red has a lower forward voltage, the ones in your link are only 2.1v so they may go 
and the lux 111 red/orange output spec is at 1400ma
http://www.lumileds.com/pdfs/DS45.PDF


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## jar3ds (Mar 5, 2007)

HEY HEY ITS HENDO said:


> ....... for some reason red has a lower forward voltage, the ones in your link are only 2.1v so they may go
> and the lux 111 red/orange output spec is at 1400ma
> http://www.lumileds.com/pdfs/DS45.PDF


 sigh.... still looking for the best red 5mm leds to put into an apex


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## peekay331 (Mar 6, 2007)

would anyone be interested in adding a seoul ssc p4 to my apex for me? i'd pay you a little for your trouble.


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## jjyoung (Mar 6, 2007)

Just put a seoul p4 in my apex and it was quite easy. What reflector is everyone using? The stock one is good but I want a tighter beam and longer spot. Has anyone tried a IMS 20 mm? Also, I want to switch the white 5mm led's to red ones. Anyone try this yet?


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## cave dave (May 6, 2007)

Just put a SSC P4 in today. The results are great. I tried a few reflectors I had lying around and liked the IMS17 the best. I had to trim the IMS legs and the little alignment pins next to the LED, then dab a bit of glue to hold it in place. The IMS20 is too tall and requires removing some material and I never can do that without screwing up the reflector.

you can see the spill angles line up.





The new P4 in place:


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## LED_Thrift (May 7, 2007)

CaveDave - how is the beam w the reflector? I would consider this mod if I could get a floodier beam.

How good do I have to be at soldering for this mod? I've replaced Lux stars w Cree stars, but this looks like the leads on the LED have to be soldered - I don't know if I can be that precise.


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## cave dave (May 7, 2007)

The IMS beam is pretty floody. The hotspot is about the same as the original optic but the spill is so much brighter and even. I added some writewright to smooth it out a bit more (actually it was left over from the optic). I think its just about perfect for caving and hiking now. It has a real smooth transition from spot to spill and lights up a wide area evenly. For a real floody beam you could use the P4 textured reflector that PhotonFantastic sells. I tried it but it was too floody.
The only problem with this mod is the 5mm LEDs are now obsolete. All blue and artifacty, the main beam is so good they are useless. I would like to have a couple more lower levels though on the main beam. I think low is putting out almost 50 lumen's.


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## HEY HEY ITS HENDO (May 7, 2007)

cave dave said:


> The only problem with this mod is the 5mm LEDs are now obsolete. All blue and artifacty


Hi dave, nice work and thanks for the pics .........
re. the (obsolete) 5mm LEDs,
..... would it be feasible to run them at the same time as well as the p4, and thus, would you still, consider them as "obsolete"?, 
if, it is possible to run them at the same time, then you could maybe consider them as a bonus instead of .......


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## gandbag (May 21, 2007)

ktronik said:


> for some reason red is always brighter in the same type of led...
> ktronik



red and orange are the longest wavelengths ( lowest frequencies) of visible light, and have the lowest energy requirements to produce, as defined by _E = hf_, where _E_ is the energy of the photon in electron volts, _h_ is Planck's constant and _f_ is the frequency of the photon.

I am not commenting on the internal efficiency of the LED, just noting that the wavelengths you mentioned are the cheapest to produce, photon for photon.


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## Changchung (Feb 1, 2008)

jar3ds said:


> sigh.... still looking for the best red 5mm leds to put into an apex



Hi, I find some time ago the brightest red Led like I never saw

I buy from here;

http://www.hyledchina.com/led-lamps/led-5mm.html

5034R1C-BUA-D AlGaInP Red 620-635 Water Clear 1.9 2.5 10000 15000 15º

Trust me, is realy bright...

If you want I can record a video for you...


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## grnamin (Feb 1, 2008)

Trimmed down McR20 reflector:


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