At just 57mA fan draw use a LM7809 or LM78L09.
Best to KISS. 
Yes! It was my first idea
But as I do "strange electronics" as some friends of mine tells me, I have made a schematic with 2x diode-bridge to have sufficient voltage drop, and a 45°C Thermal Switch to put the full power to Fan when Temperature is above 45°C inside.
I have just closed my Siglent to check what noise it does...cross finger...
Edit: I have made a photo to show that the green led is ON a very very very low value when the Siglent is powered down, and only visible at night. Also about 4.4W at the outlet shows on my UT230B wattmeter, and 26W full powered ON without any input signal.
@ceut
No worries, the face palm was simply a tongue in cheek poke at tautech who happens to be a dear friend of mine. Your post almost made it sound like he forced you into purchasing this particular scope which we all know he would never do.
Hi AdiGital!
Do I see it right that the Rubycon caps are gone in the power supply? When was your scope built? What kind of caps do you have?
When I measured the FPGA heatsink with the original cooling in a closed house, the FPGA temp was much higher than that (Don't remember right but around 50-60 degree Celsius) and the ADC also around 60.
Are you sure that you attached the probes right? I measured it with a BM789 with original probes, and didn't even stick it to the metal correctly.
Would be an interesting experiment to see whether the ADC would might be less noisier with a heatsink and much lower temp. Did you try to not to destroy the warranty sticker?
Sorry I didn't read your message before and have already removed the probes, put the fan on LM7809 and closed the scope - but if you want I'll re-open and verify - just let me know.
The FPGA Version from the system screen shows 2021-07-12, hardware version 01-05. I can also verify the probes with a thermal camera but I trust the measurements. I had all 4 probes showing exact (air) value before I put them inside. They were all firmly attached (by flat face of TO-92) with pretty strong thermal tape that's used for mounting heatsinks.
P.S.
Already silenced the SDM-3055 and SDG-1062X. The meter's fan is on 6V (LM7806). I didn't log the measurements but checked the temps with thermal camera. Not much heat inside but just in case I added small heatsinks to the warmest components (controller chip and +/-15V regulators on the analog board). The meter is now practically silent. The generator runs on ~8V as its switching power supply does get quite warm.
So I should learn to read...."above room temperature". So that means we are at around the same ballpark.
(If your text is not edited but it doesn't seems so.)
But still if you would happen to have time and motivation would be nice to know whether the caps were changed.
Isn't the fan on 10v normally? That stands in the SM for the scope.
Did you check if your temp. regulation might causing a cycling internal temp. change of the scope, throwing off the measurements as the fan rpm goes up and down?
Oh I am so fed up with that sticker...
Maybe there's some replacement fan that would do the job? A noctua or some other brand?
I have both a 1104x-e and a sdg1032x and they are really noisy and annoying.
That is what I am thinking of as well,(before after 3 years getting rid of some plastic on the exhaust side as a minimum) so now I checked the overhyped Noctua brand... they don't even provide the pressure-airflow chart of the fan, the bare minimum technical parameter. (Even the current cheap chinese has it in its doc.)
It seems to be the Dyson of the fans.
So I would rather try it with a Papst instead, usually they are very silent not just on the db scale but on the "annoyingness of the noise" scale as well. At least many years ago I did a lot of comparison of 80x80 fans, and nothing come close to them within the same airflow level. Also no commutation noise with them. (The roaring sound some slower turning fans have.)
[...]
But still if you would happen to have time and motivation would be nice to know whether the caps were changed.
[...]
As requested, the caps are identified along with the PSU version - see pics. After you mentioned ADCs I measured them with IR camera when disassembled. They showed about 50°C. So just in case I now added heatsinks to them as well.
Isn't the fan on 10v normally? That stands in the SM for the scope.
Double checked - the fan is definitely powered with 12V. I think it's the SDM3055 that's about 10.8V.
Did you check if your temp. regulation might causing a cycling internal temp. change of the scope, throwing off the measurements as the fan rpm goes up and down?
The fan isn't thermally regulated so there is no deviation. It's fixed speed.
I also included a shot of my mod. I know under-volting the fan isn't the best method but since the scope can work in 40°C environment, I assumed there is enough room to lower the air flow. It's been working for a couple of days and no issues noticed. As I mentioned earlier it's much quieter. Now having all 4 instruments on isn't a problem anymore.
Thank you for the pictures!
Nice little heatsink on the ADC. Did you check whether there is any difference in RMS (or rather standard deviation) noise level before and after the "heatsinking"?
How did you get them BTW?
It is quiet disappointing that the Rubycon caps are gone, and also begs the question wheter Dave might gets "prepared" examples sent to him for testing.
Thank you for the pictures!
Nice little heatsink on the ADC. Did you check whether there is any difference in RMS (or rather standard deviation) noise level before and after the "heatsinking"?
How did you get them BTW?
It is quiet disappointing that the Rubycon caps are gone, and also begs the question wheter Dave might gets "prepared" examples sent to him for testing.
I didn't do any other analysis than the temperature plots. In my opinion, the mod should not affect any dynamic parameters in the slightest. The only result is that I raised the "environment" temperature the scope operates in. The highest temperature increase is the FPGA heatsink which raised by 5°C and the other components even less than that. My room temperature is in the range of 22-26°C. So after the mod it's like it was working in 27-31°C without it. Way below 40°C max stated by Siglent. Also, since I used a linear regulator there is no additional noise introduced (like switching from buck converter).
The blue heatsinks are for stepper motor drivers. I bought them a while ago when building 3D printer. I believe these are the ones I used:
https://www.amazon.co.uk/Easycargo-Heatsink-conductive-adhesive-9mmx9mmx12mm/dp/B07G12KXH6/ref=sr_1_7?crid=1KGHHTW5RY9XA&keywords=stepper+motor+driver+heatsink&qid=1648118712&sprefix=stepper+motor+driver+heatsink%2Caps%2C69&sr=8-7
I was thinking about a possible much cooler ADC actually performing a bit better, but not a lot is told in its tech doc about this topic.. But in your case the difference is not much anyway, as for the cooling fins you also have a slightly higher inside temp.
I also included a shot of my mod. I know under-volting the fan isn't the best method but since the scope can work in 40°C environment, I assumed there is enough room to lower the air flow. It's been working for a couple of days and no issues noticed. As I mentioned earlier it's much quieter. Now having all 4 instruments on isn't a problem anymore.
Hello,
Thank you for sharing your mods !
I have ordered this one:
https://fr.aliexpress.com/item/32954848967.html and select "10pcs Type A".
As I have 2 bigs 12cm Noctua Fan in my computer since some years (on the CPU heatsink, in push-pull configuration) , works very well and I don't hear them at all, I also ordered the Noctua NF-A6Fx25 FLX to try it.
I'm going to tinker with my sds1104 and sdm3065, when 1 or both are on, next to my PC, it's too loud. And I don't like turning off the DMM since it has no memory of my settings.
I live in a fairly cold place, so I'll be fine turning it down a little, or trying some old PC case fans I have.
I'm going to tinker with my sds1104 and sdm3065......And I don't like turning off the DMM since it has no memory of my settings.
Oh yes it does !
Goto:
Utility (Shift + Dual) > Store/Recall > Power On = Last. < Last used settings saved for next boot.
[...]
Oh yes it does !
Goto:
Utility (Shift + Dual) > Store/Recall > Power On = Last. < Last used settings saved for next boot.
Any chance I've missed "Power On Line" setting, that powers on the meter after power loss/line on? I use it with SDS1104. All gear is connected to remote power plug. It's the only device that doesn't "Wake up" is the SDM.
As I have 2 bigs 12cm Noctua Fan in my computer since some years (on the CPU heatsink, in push-pull configuration) , works very well and I don't hear them at all, I also ordered the Noctua NF-A6Fx25 FLX to try it.
Did you try a Noctua fan, and was it effective?
Just a rhetorical reply here.
In my lab I usually have at least 3 computers, a power supply, a function generator, and a benchtop DMM and sometimes multiples of each of those along with a DC load and some other equipment on with the scope(s) (I have 3 workstations) so I have never really noticed how noisy my SDS1104X-E is. So I just compared it with the other two scopes in there and it is the quietest of the lot.
It makes about the same noise as the little Lenovo X230 I have at my soldering station when its fan is on. From my perspective, it's pretty quiet.
As I have 2 bigs 12cm Noctua Fan in my computer since some years (on the CPU heatsink, in push-pull configuration) , works very well and I don't hear them at all, I also ordered the Noctua NF-A6Fx25 FLX to try it.
Did you try a Noctua fan, and was it effective?
Our customer did with a Noctua with very similar spec to OEM without gaining any significant difference.
Investigating further for him I cut the metal fan grille from mine and this too didn't gain a significant difference.
IMO the only way to address this is to undervolt or change the fan to one of a different spec, however then throw the datasheet accuracy spec out the window.
Just a rhetorical reply here.
In my lab I usually have at least 3 computers, a power supply, a function generator, and a benchtop DMM and sometimes multiples of each of those along with a DC load and some other equipment on with the scope(s) (I have 3 workstations) so I have never really noticed how noisy my SDS1104X-E is. So I just compared it with the other two scopes in there and it is the quietest of the lot.
It makes about the same noise as the little Lenovo X230 I have at my soldering station when its fan is on. From my perspective, it's pretty quiet.
Is there something seriously wrong with your notebook? I wouldn't call the SDS1104X-E noisy by test equipment standards, but those standards are pretty low. I have an X220 beside the scope right now, and the scope completely swamps the notebook.
Most of the electronics work I do these days is fairly low power, and pretty much silent. When everything I worked on was high power and really loud I wouldn't have noticed a scope like this at all.
As I have 2 bigs 12cm Noctua Fan in my computer since some years (on the CPU heatsink, in push-pull configuration) , works very well and I don't hear them at all, I also ordered the Noctua NF-A6Fx25 FLX to try it.
Did you try a Noctua fan, and was it effective?
Our customer did with a Noctua with very similar spec to OEM without gaining any significant difference.
Investigating further for him I cut the metal fan grille from mine and this too didn't gain a significant difference.
IMO the only way to address this is to undervolt or change the fan to one of a different spec, however then throw the datasheet accuracy spec out the window.
That's very useful input. Thanks. It sounds like you just have to live with this. Its not horrible, but it is annoying.
As I have 2 bigs 12cm Noctua Fan in my computer since some years (on the CPU heatsink, in push-pull configuration) , works very well and I don't hear them at all, I also ordered the Noctua NF-A6Fx25 FLX to try it.
Did you try a Noctua fan, and was it effective?
Our customer did with a Noctua with very similar spec to OEM without gaining any significant difference.
Investigating further for him I cut the metal fan grille from mine and this too didn't gain a significant difference.
IMO the only way to address this is to undervolt or change the fan to one of a different spec, however then throw the datasheet accuracy spec out the window.
That's very useful input. Thanks. It sounds like you just have to live with this. Its not horrible, but it is annoying.
The same form factor 2ch SDS1202X-E has a much quieter fan but also less than half the HW inside also and that is where they would be great to be but I think the 4ch X-E would run too hot.
The FPGA generates most of the heat as I checked on this recently when doing a warranty repair but the fan is some distance from it so maybe directed ducting and a quieter fan can do the job adequately but we mustn't overlook cooling the PSU also. The mainboard is fixed to the internal metal chassis in numerous places so that too will be adding to the overall heat dissipation picture.
To do a proper job IMO exhaust heat and FPGA temp need be monitored while progressively slowing the fan in 30 minute steps to find where temps start lifting and the corresponding fan RPM. However results must be related back to ambient and of course only be valid at those temps but for those working in climate controlled workspaces it could be done successfully.
Is there something seriously wrong with your notebook?
No. It's quiet when the fan is off, but when the fan kicks in it's noticeable. Maybe a tad quieter than the SDS1104X-E, but not a ton. If they are both on together they just seem to blend into each other. My UNI-T scope makes the Siglent veritably noiseless. Let's not even talk about my Tek 475 let alone the KORAD KA3305P power supply which re usually on too! I honestly don't know what it would be like to actually do work in lab where the sound of the Siglent scope would be the slightest concern. I guess the point I'm trying to get across is, if your doing any work, you will have stuff turned on. There will be noise.
Even sitting in my office right now the sound of the PC and the NAS would drown out the Siglent scope.
Is there something seriously wrong with your notebook? I wouldn't call the SDS1104X-E noisy by test equipment standards, but those standards are pretty low. I have an X220 beside the scope right now, and the scope completely swamps the notebook.
It's something in between a hair dryer and a vacuum cleaner. I regularly use SDS5000s and they are *much* more silent than the 1104x-e.
Today, I tinkered with an old 1 GHz Agilent scope at the university. It's as deep as a CRT scope despite being digital, weighs a ton, and needs a lot of cooling. In terms of sheer sound pressure, maybe it's even a bit over the 1104x-e, but since the pitch is much lower (big fan), one finds it to be more bearable (but it worn me off after a while nonetheless).
The 1104x-e exhibits both high sound pressure and high pitch.
Pity, because it's a good scope. However, consider that the fan always run at maximum rpms, and is made to cool the scope under stress with 40C.
From my experience with small fans, if you run them at 9V rather than 12V, the difference in airflow and static pressure won't be dramatic, but the difference in acoustical noise could be substantial.
My UNI-T scope makes the Siglent veritably noiseless. Let's not even talk about my Tek 475 let alone the KORAD KA3305P power supply which re usually on too! I honestly don't know what it would be like to actually do work in lab where the sound of the Siglent scope would be the slightest concern.
Now I'm really thinking that maybe I got a defective 1104x-e specimen.
