I just got a Sofirn C8G from Amazon using the deal Sofirn is offering in the Dealer forum.
Great light that has been reviewed before. My “4000mAh” battery tested to 4800mAh(!) at 1a discharge. Good deal.
The only fault is the instructions. My old eyes, even with cheaters, have a hard time reading the tiny1.5pt font.
I found something not documented in the instructions.
On Ramping or Stepped settings, holding the side switch and turning on the end switch puts the light into Eco.
Supposedly 1lm. It looks brighter than that to me.
On the ramped setting, after getting to Eco,
Pressing and holding the side switch will ramp the light from Eco up to about the normal low mode brightness.
The light blinks to show it’s at the top of the ramp.
A second press and hold will ramp the brightness down passed Eco to very low brightness.
Call it a Sub-Firefly. It’s the lowest brightness I’ve seen so far in any of my lights. Way less than 1 lumen.
So essentially doing the Eco startup (with the light set to ramping) puts the light into an ultra low ramp setting.
Interestingly whatever level you turn this off with the end switch, translates to the equivalent setting in the normal ramp setting. This is regardless of where the light was set previous to jumping into the ultra low setting.
Normally the light (in normal ramp), turning off and on with the end switch, always gets back to the last used setting.
It has memory, just like expected.
Going into ultra low, if the brightness is changed, that will be reflected when going back to the normal ramp settings.
I need to measure the current in ultra low to see it the light will run, well darned near forever, in firefly levels.
All the Best,
Jeff
PS
O-Scope and Current measurements a few POSTS down.
Whoah, I never noticed that you could ramp after starting the light in Eco - good find!
This makes me wonder what they’re doing here for Eco mode…it’s almost like they just took the ramp and scaled it way down. But electronically, there’s definitely also something going on - at the high end of the compressed ramp, my light starts whining really loudly. This isn’t something I can hear at the low end of the normal ramp (which has a similar brightness), so they must actually be using the hardware differently to achieve this lower ramp.
I believe forum member Lux-Perpetua is involved with the manuals but I am not exactly sure about that, but it is very helpful to have the manuals on-line and another benefit for us from Sofirn.
I took a look at the C8G PWM.
In the normal ramp setting.
I see no PWM at all. Just a DC offset. Perfect.
In the undocumented Ultra Low Ramp setting.
As it ramps up to max, I see a DC offset with some ripple on top.
C8G Ultra Low Ramp Low
Getting brighter and the Waveform stays the same. C8G Ultra Low Ramp Near Top Going Up
After it hits max brightness, suddenly there is this odd waveform. C8G Ultra Low Ramp Max
As you can see the pulses are at 2.6KHz.
So this is well within the audible frequency range. And this is what you are most likely hearing.
I tried to hear something on mine, but I can’t detect it. But I have tinnitus and that maybe louder than the buzz you are hearing. Or my light is quieter.
The duty cycle (if you can call it that) is very short.
But the light is running a positive voltage for most of the time.
There is no obvious flicker to my eyes.
Ramping down from max, I see the same 2.6K wave.
Until it drops below a certain brightness.
Then for an short period, I get this. C8G Ultra Low Ramp Dropping From Max
A 35KHz sine wave looking PWM.
Still running a slight positive DC offset.
Lowering the brightness just a hair, and it jumps back to looking like the first plot. Pure DC.
If any others out there have this light and access to something to look at PWM, it would be interesting to know if yours lights do this.
No test gear, but I did check the function on my C8G and it is working as you detailed. In this mode, the output at the lowest setting (ramped down all the way) really is super-low and I also have no light that gets that low. You can look right at the LED and just tell it’s on during daylight.
That is a pretty cool camping (or dark room) feature to know about. One could perhaps leave it on overnight at the lowest setting hanging in the tent and be able to find it in complete darkness. Not sure how efficient it runs at the lowest setting, but it probably is outputting about the same light (maybe less?) than the side switch on my LT1 which I set at the lower level from the stock level (which is too bright for my dark bedroom where the lamp lives when not out camping).
Can you hear your light buzzing at the max setting in the low-ramp setting as Serlite did?
Just measured current at some settings.
Normal Ramp - Lowest Brightness - 0.89a
Eco Mode - 0.63a
Now it gets weird.
Ultra Low Ramp - getting brighter than the Eco setting, the light draws more to a max of about 0.84a
When it hits the max brightness, and the pulse PWM starts, the current drops to 0.60a.
I wonder if this is a real value, or a measuring error on my old Fluke meter due to the waveform.
Ramping down from this, the current drops to a min of about 0.55a. Because of the pulse PWM the same apparent brightness draws less than the Up Ramp DC waveform.
Then the current jumps back up due to the light switching back to a DC offset.
At the lowest brightness. I measured 0.56a. So no real savings over Eco. mode.
It would be too cool if that ultra low had some tiny current draw. So it could shine virtually forever.
I also checked the parasitic drain.
End switch on. Side switch off. 0.0009a Almost to the limit of my meter.
I like your idea of using the Sub-Firefly as a location function when camping. It’s so dim it shouldn’t bother anyone.
All the Best,
Jeff
rings… it has two fast frequency sweeps it goes through toward the top of the ramp- all in 1/2 a second.
The ramp takes right at 5 seconds from low-to-high. The frequency sweep starts at 4 1/2 seconds and it does keep ringing at around 1.5k Hz when it tops out- but its a bit less noisy at the top than at 4.5 seconds when you hear the “sweep” start.
The sweep starts at closer to 1k Hz, then quickly zips up to about 3k Hz then flips (super fast) back down to about 1-1.2k (ish). Frequencies also have some harmonics going too so some may hear those better than the fundamental pitch I am hearing.
I bought these apart from each other— one from an Amazon US deal (using a code), the other from Sofirn.com (China) from the Sofirn.com store (Barry and Lan). The Sofirn.com (newer) light has the logo and heat warning markings on it, the other (Amazon deal- first one I bought) is just black- no marks. So obviously these lights are from different runs.
Interesting how one rings and the other doesn’t. I had a KaiDomain C8.2 (drives an XHP 50) that rang similarly (and much loader) until it JUST died a few weeks ago.
Makes one wonder what the change was. My light is fresh out of the box.
I can see the PWM pulse in the hidden low ramp on the scope, but I can’t hear it.
I need to find someone younger to confirm this.
Although 2600Hz is in the range still left to me.
Well, we humans hear 2600hz better then the lower and upper freqs. I think it is 3500hz where a crying baby hits and wemon have been found to hear below the “threshold of sound” at those freqs. I also am winging it on the freq. ranges I put up. But I am a former studio owner and have done (too much) live sound professionally for about 40 yrs. So I’m always keen into anything making noise and have to say I’m NOT interested in hearing a whining driver during a hunt either.
Peg, sounds like (actually, no sounds), you have a winner!
Have you ever played with Room EQ Wizard?
It’s a free audio analysis package that runs on Windows, Mac, or Linux.
40 years ago I could have charged just to let other audio geeks watch it do tricks.
I used to look at PWM before I found better software and eventually a more modern O-Scope.
I did a POST about it a few years back:
I’m sure you’ve got a mike or two lying around.
It would be interesting to see if you could get a frequency plot from you light by holding a mike against it.
My (remaining studio) is in another town being used by younger guys lately So I’d have to drag out my DAW (Logic) and spend some time setting up the gear to run a sweep today. Not like the old days when I just went it, turned on and everything was in the right place Anyway, probably won’t happen but I’d not know what I was looking for anyway. Never got to the O-scope level like you!
Back when I developed pro loudspeakers with the guy at BassMaxx all hours of the night (weekend?) we used Praxis and I can tell you I’d heard THOUSANDS of full freq sweeps as that was how we “tweaked” the designs back then. It was always 95+ degrees (in Dallas at our warehouse), and we had a 100 ft diameter radius where we’d bury the box in the ground (in the center of the parking lot) then measure at every 15 degrees for polar plots. Lots of SWEAT back then— I don’t miss it!
Zappaman,
I used to play with audio a lot in my younger days. Never to the extent you clearly have done.
Bass Speakers? I’ll bet you have logged miles doing the Bass Crawl to find THE SPOT.
Once upon a time I had a 24” Hartley in a 36 cubic foot enclosure.
Back in the 70s, I could get the 16Hz(?) cannon shots off that Telarc disk.
I’m amazed how far the measuring has come since the old days. Plotting response with a sound meter and graph paper. What fun!
That Room Eq software can even model room response, and you can watch it change as the speaker and listening position is moved around.
And the darned thing can output a curve that can be used in various amps for room Eq.
Unreal.
I’ve used it with a cheap microphone to track down mechanical noises in equipment.
Beats sticking my head inside someplace it won’t fit.
Haha… I have indeed been a speaker freak as you obviously have. And Telarc (who basically invented the CD format) was about the ONLY way to get 16hz out of anything not on tape (oh ya, had the 10” reel-to-reel too, but way before the studio when tape got crazy again and we got down to ONE company making 1” and 2” tape around 1998 or so).
Anyway…
I once built a house in Austin TX and the city guys a few blocks down had just installed a larger water tower. They had a 7’ long piece of water main pipe left over (32” wide cast iron cement/poly lined)— it weighed about 700 lbs. I paid them $30 bucks to drop it in the front of this house the week it was being finished. I took the hinges off the front door to get it in the house using two (steroid laden) movers to move it into the living room on TWO piano dollies, and tilt it up on the carpet in the corner. It instantly sealed at the bottom where the flange was 3” thick… then the “cut” end was open at the top and left open and up a few feet from the ceiling.
I then bought McCauley’s 6174 (the second neodymium 18” woofer ever made after Bob Diamond built the first for Aura about 1995). I mounted that woofer onto a custom cut 2 1/4” thick baffle (three plys of 3/4” glued and screwed baltic birch). I powered it with a BGW 750C amp that weighted about 90 lbs (behind the living room wall in the garage in the amp rack). I ran NHT 3.3 modified (of course) towers. I listened to pipe organ music some back then (true 16hz fundamental notes coming from a Telarc recording made in St Peter’s Cathedral NYC if I recall). Three months later I had the builder out to “fix” the ceiling above the sub
I had some parties and the whole block was REALLY cool about the noise (and thankfully the neighbors were usually AT the party). I called this massive black pipe “industrial art” and mounted a 4’ long steel cut lizard on it for aesthetics— It was definitely a “bachelor pad” in the day when Austin was SUPER COOL! The studio happened about 7 years later in Stevie Ray’s last house he lived in in Travis Heights- man we had some fun back then! But we are having it here in other ways today in Kansas. And I STILL listen daily to the compound loaded sub-woofer I designed and built in 1991. I replaced woofers (several times) and added a plate amp on this dorm fridge sized sub- and I have never heard anything better to date.
Anyway, I get it… it’s (like these lights) and an addiction for sure!!!
Too Cool,
Saint-Seans Sym. In C was my go to vinyl for low bass.
Nothing beats a 32 or 64 foot stop.
On the Telarc 1812 record, you could see the cannon shots in the groves with naked eyeballs.
I’ve heard both live and, well, amazing. Especially the Organ Sym. Ya’ can’t help but make the “air baton” when things get cooking.
A trick some organists used was to step on two peddles at a time. The fundamentals would beat against each other. 8Hz, 10Hz? Made the whole place shudder.
You brought back a lot of good memories.
I had an Ampex 1” tube deck for a short time. Got it cheap, then somebody made me an offer I couldn’t refuse.
I’ve still got an AKAI tape deck with the 10in. reels.
It has Dolby (A or B) whichever was the pro version. I don’t remember anymore.
Had the best S/N ratio for recording I’ve ever seen.
You could have the Dolby NR off and the tape hiss screaming out of the monitors.
Hit the Dolby button, and silence. I never caught it breathing.
Unfortunately one channel is intermittent. And nobody works on such things anymore.
I still have NHTs in my small home theater system. Still sounding good after all these years.
I’d love to hear your rig sometime. Even with my crappy hearing.
I started ringing in my left ear with Lyme about 10 yrs back… thousands of tick bites by then and bound to happen as I’m always hunting or fishing in more remote locations than most. I also lost about 4db at 8k in that ear.
I remembered Julian Hirsch back in the early 90s who wrote in Audio Magazine that his hearing at 80 yrs old was obviously not as good as it was back in the day. But he ALSO stated in the same article that his cognitive ability to listen with the current ears was WELL beyond where he was at 30 yrs old. He mentioned how he was sure his brain was “creating content” what he wasn’t physically hearing. Even with new music, he felt his brain delevoped this ability after a live of almost daily listening.
I NOW understand what he wrote then, as I have spent MANY hundreds of hours SPECIFICALLY studying my hearing on the technical level. Don’t watch TV, but DO listen to a lot of Pandora (something that I can no live without) and I too have a Iifetime of listening that my brain thankfully uses to my benefit. I REALLY do perceive 8k in my left ear and stereo imaging has never been more dimensional as it has the last decade. I am very greatful for this anomaly!!!
As far as the tinnitus, I discovered a protocol from Stephen Bhuner using Venpocetin, magnesium, zinc and vitamin E (along with a few other Lyme herbs) and I have all but eliminated the ring 90% of the time. Of course the Lyme was my core cause of the ringing, so but these herbs are specifically used for the ringing and so I’ve suggested them to anyone with tinnitus. Several who tried them found some success, one buddy found real good results like me.
Anyway, I won’t ramble anymore for today, cause I’d guess you and I could talk for days
So I’d have to drag out my DAW (Logic) and spend some time setting up the gear to run a sweep today. Not like the old days when I just went it, turned on and everything was in the right place 
Anyway, probably won’t happen but I’d not know what I was looking for anyway. Never got to the O-scope level like you!