Ace Timer No. 1000 Timegrapher comparison #2
Here are more details of a side-by-side comparison between my brand new "Ace Timer No. 1000 Timegrapher" and the open-source "tg" timegrapher software by Marcello Mamino, aka "vacaboja" aka "contrate_wheel". Source code here.
- tg consistently reports +3 to +5 seconds/day higher than the Ace Timer. It agrees within 0.1ms on the beat, and about 5° on amplitude.
- On two watches tested overnight the Ace Timer was more accurate for seconds/day. I cannot independently confirm beat or amplitude.
- The microphone matters a lot. I ended up using a modified Logitech USB microphone.
- I compiled and ran tg as a native binary on my HP Envy laptop running Linux Mint 1.71. Windows binaries are supplied by the author. It has been reported to run on OS/X, too.
The sound source makes a big difference. In all honesty one of the best things about the Ace Timer is it includes an optimized microphone on a convenient rotating stand with built-in watch clamp. The biggest challenge I had with tg
was getting suitable audio input. Here's what I tried...
- Total failure. I tried to find the microphone on my laptop for laying the watch atop it, as others have demonstrated on this thread. No luck, after trying for a long time. If anyone knows where the mic is on an HP Envy 15-k016nr please let me know, heh.
- Total failure. I tried to use the microphone built-in to my Sennheiser Momentum headphone cable. Again, no luck.
- Partial success. I took a piezo mic for an acoustic guitar ($5 on ebay) and with the help of various adapters/cables connected it to the phonograph input of an old 5W amplifier. With more cables I routed the amp's output to the microphone input on my laptop. This worked very poorly until I resolved the 60Hz hum by connecting both the amplifier and the watch to the grounding plug on a 120V outlet. Without that grounding, the hum somehow caused "porpoising" of the signal line, throwing measurements off by minutes per day. Even after solving that problem I was not happy with the signal noisiness of that setup, as judged by the number of stray dots scattered about the tape.
- Success! I scrounged a 10 year old "Logitech 980186-0403 USB Desktop Microphone" from a box in the basement. It had a mic on the end of a long boom. With some precision hacking using a sharp screwdriver I managed to remove the boom from the stand and the microphone from the boom, leaving it dangling from an 8" wire. This I gently affixed to the watch with a rubber band. Those particular microphones are $35 used, but I expect any desktop USB microphone would work as well - Amazon sells one by "Tontec" for $7. Here's what mine looked like after the hack:
The tg Software
This is a repost of my prior instructions for building tg 0.2.3
on Linux Mint 17.1 (an Ubuntu 14.04 derivative). I post them here because order of installation turned out to be crucial, and I would like to save you the trial-and-error hassle.
[*]sudo apt-get install libgtk2.0-dev # install first of several various packages needed for compilation
[*]sudo apt-get install libjack-jackd2-dev # the order of installation is important
[*]sudo apt-get install portaudio19-dev # because libjack must be installed before portaudio
[*]sudo apt-get install libfftw3-dev
[*]sudo apt-get install git # if you don't have git, this is just for downloading the source, which you might prefer doing directly
[*]cd # go to home directory
[*]git clone [EMAIL="[email protected]:vacaboja/tg.git"][email protected]:vacaboja/tg.git[/EMAIL] # this downloads the source from [URL]https://github.com/vacaboja/tg[/URL]
[*]cd tg # change directory to location of source code
[*]make # build the program
[*]./tg # run it!
- Seiko SRP615. This watch used the fabulous Seiko 4R36A movement, hacking and hand-winding, until my boy and I wrecked it. The good news is that I got a replacement SII NH36A movement from StarTime Supply for under $50 delivered. Back in the day it had been running -15 seconds/day so I twiddled the knobs inside and managed to get it to a perfect 0s/d for two days. Alas, then my boy bashed a metal stool into my innocently passing arm hard enough to pop the crown into position 3 and pop off one of the spring bars. Fortunately the watch didn't fall because I had it on a Zulu strap. Even so, it reverted to being +60s/d and I couldn't get it any better than +60s/d or -60s/d, despite using a microscope to make adjustments. Eventually I pushed something too far and it broke. Hence the replacement movement. Now it's been runnning on the NH36A for four days, at about +5s/d, with no adjustment whatsoever. I'll probably wait a month before adjusting anything, anyway.
- Seiko SKX007. This watch has been running on its 7S26C for a couple months now, and it's never yet been opened. At about -1s/d, I'm reluctant to do so. But I do have a Dagaz thick domed crystal on the way, so I suppose I'll fiddle with it when installing that.
I mounted the watch into the Ace Timer's microphone stand as usual. Then, using a rubber binder through the spring bars I clamped the USB microphone to its back. I adjusted the input level on my computer until the tg software reliably reported four green bars. The Ace Timer's input levels were left at their default. I adjusted the lift-angle appropriately: 53° for the NH36A and 52° (*) for the 7S26C. After moving the watch into position, I waited a full minute for the movement to settle down before recording the readings. The Ace Timer had its test period set to the default 12 seconds. Test period is not user-configurable for tg
, and after a brief search I couldn't find anything in the code to even tell me what it is.
(*) Since testing this I have learned that the correct lift angle for the Seiko 7S26 movement (aka SII NH26) is actually 53°, per the NH25/26 Technical Guide.
I tested each watch in the dial-down position simultaneously with the Ace Timer and tg
. I then used Time.is
to record the watches' equations of time and left them overnight in that position. Sixteen hours later I checked them again. The Ace Timer was less accurate with the SRP615, but more accurate with the SKX007. I attribute this to the fact that the SRP615 movement is only a few days old, and probably needs breaking in. Specifically:
- Seiko SRP615. Ace Timer reported +0 s/d, 282° amplitude, 0.1ms beat error. tg reported +5 s/d, 0.2ms beat error, 270° amplitude. Actual measured time delta after 16 hours was +3 seconds change.
- Seiko SKX007. Ace Timer reported +1 s/d, 254° amplitude, 0.0ms beat error. tg reported +5 s/d, 0.1ms beat error, 251° amplitude. Actual measured time delta after 16 hours was 0 seconds change.
Along the way I took a few photos showing simultaneous measurements. I also took a video. Here they are...
Here is the video. When I started the video the SRP615 had been running stably for well over a minute in the crown-right position. I adjusted it to dial-down and filmed while it was re-stabilizing. Open it in youtube and go full-screen to realize the high-def.
I'd like to explicitly note that tg
consistently gives a reading of +4s/d higher than the Ace Timer. It may vary from +3 to +5, but after stabilization it always settles in around that same difference. That's a clue to something though I'm not sure what.
program is pretty spectacular considering the price. 100% free. You may hassle with installation, and you will hassle with microphones, but your total outlay won't exceed $20. This compares pretty favorably to basically everything else out there. Heck, I paid over $30 for the "tick-o-print" Android app and never did manage to get a good reading off of it, presumably from microphone problems, but I digress. My point is: I was able to get timings from tg
for free that were within a few seconds of the $170 Ace Timer No. 1000 timegrapher.
Sure, if you have the funds, the Ace Timer is the better tool. This is principally because it has a dedicated microphone that supplies a few key features.
- Easy mounting. Just slide back the bracket, set down the watch and release
- Easy positioning. It rotates easily for pitch/yaw/roll. You can test in all the standard positions and anything in between.
- Noise filtering. The Ace Timer is very forgiving of external noises. Normal conversation, typing and household noises are not picked up and do not disturb the measurements. Contrast to tg which relies on a normal microphone and requires a very quiet room to work properly.
Apart from the microphone the Ace Timer also feels more reliable. This is a subjective assessment so please bear with me. I say this because it varies less from moment to moment in it's readouts. Given the same conditions, a good meter measures the same metrics every time. The Ace Timer shows more of this stability than the tg
software. That may be an artifact of the "test period", which is an open question. Or it may be something to do with external noise. Or it may be an issue with irregular CPU cycle allocation. It's hard to say. But when using the Ace Timer it just feels more stable. Yes, that's a subjective assessment. I've yet to read any review contrasting the $170 hobbyist Ace Timer No. 1000 with something more professional and expensive. Nor do I have any way to confirm which tool's beat error or amplitude is more correct. So what I'm saying is, take that assessment with a grain of salt.
If you lack the funds, or just want to experiment before investing hundreds, then tg
is a fabulous! tool. And at the end of the day I would use it precisely the same way I intend to use the Ace Timer. Namely, adjust the beat until it averages 0.0ms in different positions without sacrificing amplitude, then adjust the timing until it averages 0s/d in different positions. That done, wear the watch normally for a few days and make note of the timing error per day. Then I would find the position where tg
reported the same timing as observed in actual use, and from there adjust again to zero. I expect the end-result of that process would be equivalent whether I were using tg
or the Ace Timer. Which in a way is kind of disappointing as I just laid out $170 for this guy. But I suppose I do at least have a more convenient tool vis-a-vis positioning and noise-resistance, so I'm going to hang onto that.