How is fan noise on a DS4000 compared to a DS2000 ? - Page 1
Forum section: electronics / testgear

author: alank2
author_rank: Super Contributor
timestamp: November 28, 2013, 04:31:01 am
content: How is fan noise on a DS4000 compared to a DS2000 ?

author: iceisfun
author_rank: Regular Contributor
timestamp: November 28, 2013, 05:47:55 am
content: My DS2000 is so quiet I can't hear it over the sound of other fans

author: Uup
author_rank: Regular Contributor
timestamp: November 28, 2013, 05:57:23 am
content: Quote from: alank2 on November 28, 2013, 04:31:01 amI think I know why you asked... the fan on my DS4k ismuchlouder than I would have liked.I was thinking of reducing the fan speed or even replacing the fan. What stopped me is that it also runs fairly hot; touch CH1 BNC after it has been running for a little while. You can check the internal temperature via the SelfTestInfo menu option. Mine is currently 44.8'C.

author: tautech
author_rank: Super Contributor
timestamp: November 28, 2013, 07:29:09 am
content: "Mine is currently 44.8'C."So you have to keep probes connected to keep it cool!

author: cosmos
author_rank: Regular Contributor
timestamp: November 28, 2013, 08:24:46 am
content: I tried swapping the fan in my ds4k for a low noise one.Original fan is this one:Delta AFB1212L, spec says it moves 1.782 m3/min (62.93 CFM) with max back pressure (for no flow) 3.93 mm-H2O 0.154 IN-H2OFan is given 11.9V (looks and sounds constant to me) at this voltage the AFB1212L should draw ~120mA and the noise should be about 32dBa (1900rpm).I tried to replace it with this one (unsuccessful but still useful info):Akasa Apache Black (just another computer store product)Spec says it moves 97.74 m3/h (57.53 CFM) with max back pressure (for no flow) 2.64 mm-H2O. At 12V it should do (1300rpm) with noise level 16dBa...Specs looked to be close enough for a try, and indeed it was very quiet (to the point you have to look at the display to know if it was running).Internal (found in self test menu) temperature increased from 38C to over 48C, and it was operating correctly.However, the air flow was very significantly reduced and the alu frame inside was now seriously hot to the touch while before it felt like close to room temperature...So I gave that up and put the original back in, to try another alternative at a later.The next candidate has arrived.Blade master 120 (Coolermaster, also just another computer store product)Spec says it moves (76.8 CFM) with max back pressure (for no flow) 3.90 mm-H2O. At 12V it should do (2000rpm) with noise level 32dBa while drawing up to 360mA.(testing on bench I measure 12V, ~175mA)Sound feels much better (note: it is not mounted in scope yet), basically like the AFBs airflow noise dialed back (guessing maybe 3dB) but most importantly the gnarling is gone.This could be on all day without me being bothered, with the original fan I would turn it off to be able to think while not taking readings.Will report back when I get it mounted.

author: cosmos
author_rank: Regular Contributor
timestamp: November 28, 2013, 05:00:39 pm
content: Blade master 120 installed, and this seems to work rather nicely.The gnarling sound I could not stand is gone.Noise from the airflow is about the same or maybe a bit lower.Airflow feels like it is about the same.Internal temperature is the same as before (to 0.5C).The temperature sensor I put on the alu frame reads slightly higher at 34.5C vs 31.5C with the original.DS4000 datasheet says it can operate to 50C ambient, my lab is nearly constant 25C so I think it will be safe.

author: commongrounder
author_rank: Frequent Contributor
timestamp: November 28, 2013, 06:01:05 pm
content: The fan on my DS4012 is MUCH too loud for my shop. Because I do exclusively audio equipment work, a quiet shop is imperative. I find I have to shut it down when I need to hear what is going on (or move to my fanless analog or handheld scope). The moment my warranty runs out I am replacing it with another. The first candidate is an Enermax UCTB12P Batwing fan. Has good air handling at 121m3/hr. and equivalent static pressure. We shall see.....

author: Co6aka
author_rank: Unknown
timestamp: November 28, 2013, 06:54:43 pm
content: Quote from: alank2 on November 28, 2013, 04:31:01 amWell, mine sounds something like this...

author: iDevice
author_rank: Regular Contributor
timestamp: November 28, 2013, 07:10:35 pm
content: Mine as well...

author: Hydrawerk
author_rank: Super Contributor
timestamp: November 28, 2013, 10:05:49 pm
content: I would not denounce Rigol for the loud fan. Even this Agilent generator that we have at school is quite loud.

author: AndersAnd
author_rank: Frequent Contributor
timestamp: November 29, 2013, 12:46:06 pm
content: For reference:RIGOL DS2000 mod - silent fanhttps://www.eevblog.com/forum/testgear/rigol-ds2000-mod-silent-fan/Rigol 1052e Fan Replacementhttps://www.eevblog.com/forum/projects/rigol-1052e-fan-replacement/

author: cosmos
author_rank: Regular Contributor
timestamp: November 29, 2013, 01:12:28 pm
content: I am playing with external power for the Blade master 120.At full speed (12V) I get internal temp (Self test info) 12C over ambient, and alu frame (measured just over the Frontend FPGAs) shows 8C over ambient.Dropping to 8V I now measure internal 18C over ambient and alu frame is 12C over ambient.Noise.@ 12V is liveable but you notice it is there.@ 8V I can notice it if the fan stops but otherwise I have to think about it to notice it is on.Thinking about making or buying a temperature controller to put in between fan and original fan connector (suggestions of designs are most welcome).Min speed/voltage (8V) up to internal temperature of 42C then rising to max speed at 62C.12V @ 62C should then be same as the original 12V and 50C ambient (assuming the fan moves same amount of air).

author: alank2
author_rank: Super Contributor
timestamp: November 29, 2013, 01:34:48 pm
content: Quote from: Co6aka on November 28, 2013, 06:54:43 pmThat does paint a picture of the noise all right...

author: cosmos
author_rank: Regular Contributor
timestamp: January 09, 2014, 09:42:20 pm
content: Here is what I did in the end to get my ds4k to be nice and quiet.Fan is changed to a "Blade master 120", any 120mm 4 pin fan with similar flow and backpressure as the original delta should be ok for the below setup.MSP430G2230IDR uC in SO8,AP1117E33G LDO,2N7002 sot23 mosfet,two connectors, 2x power in and fan: MOLEX - 47053-1000 - HEADER, 4POS, 1ROW, 2.54MM.a few capacitors and resistors.(total comp cost in the 2USD range from Farnell)programming the MSP trough this board:TEXAS INSTRUMENTS - MSP-EXP430G2 - MSP430G2XX, LAUNCHPAD, DEV KIT. (cost about 12USD)MSP drives the Nch mosfet gate.Gate is driven trough a 1nF capacitor, with diode and 100k resistor in parallel to the gate to GND (10k pull-up on the drain).This makes it a bit more fail safe by making the fan run at 100% if PWM stops high, no need to fry a 500Mhz scope due to a uC crash.Code is based on a TI demo: measuring temperature and blinking two LEDs with duty-cycle corresponding to diff vs temp at init.MSP runs on internal RC osc using factory calibration data to get (within 1%?) of 1MHz.MSP timer set to cycle time of 25kHz (typ. PWM freq of 4 pin fans)The mosfet gate driven as PWM output from timer.MSP uses internal ADC and converts the internal temp sensor... since it sleeps most of the time it has negligible dissipation and should measure close to ambient temp.Temperature sensor is not very accurate (large offset) unless it is trimmed, I trimmed this unit by changing a define in the code and reloading flash until it got the temp right.MSP only runs when triggered by the (timer) interrupt, when pending work is done it sleeps with only the timer osc active.Once every second the code hijacks the timer and uses it to send a 9600baud char (=> 1ms gap in fan PWM signal) on a free output (interrupt driven bitbanging) This is nice for checking the temp it thinks it sees.Fan control algorithm uses 4 main parameters, min speed (50%), min temp(35C), max speed(100%), max temp (55C), and makes a straight line between these points.Fan should not go below 50% with this setting (that it actually goes to 46% may be attributed to rounding errors... PWM resolution is about 2.5%)Note that even with fan at full speed the internal sensor will read 10C or more over ambient outside the scope.When starting the fan runs at 100% the first 2 seconds, then drops to 46%With room temp of 25C it stabilizes at ~66% fan speed (eq to ~8V voltage) and a measured temp around 40C, DS4k internal sensor reads around ~42.5C after a few minutes.Delta temp over room is now about 18C.If the internal temp increases the delta will drop towards 12C at full speed, internal temp should stay below 62C at 50C room temp.I used the ds4k to monitor its own fan control ... decoding the serial char. and the PWM duty-cycle ... including graphing the fans tacho frequency. (with 10 sec. trig hold-off to slow graph down to ~10sec per sample)(sry no plots... forgot to do plots and now the scope is closed again)

author: dr.diesel
author_rank: Super Contributor
timestamp: January 09, 2014, 09:47:15 pm
content: Here is a test on a MSO4000, with a decibel meter.

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 09, 2014, 10:32:37 pm
content: Quote from: cosmos on January 09, 2014, 09:42:20 pmThat's a slick, and nicely engineered solution. I'll make note of it, in case I wind up with a 4000 at some point. I doubt I could stand to use one otherwise. Thanks!

author: Circlotron
author_rank: Super Contributor
timestamp: January 10, 2014, 04:54:16 am
content: Quote from: ilcibernetico on November 21, 2013, 08:55:49 amThose sharp metal edges that the air has to flow through can make a fair bit of noise too. I have cut them off on computer power supplies for a reasonable improvement. Seeing it is inside the scope case you could do this without it being visible from the outside.

author: MarkL
author_rank: Unknown
timestamp: January 10, 2014, 12:19:35 pm
content: Quote from: Circlotron on January 10, 2014, 04:54:16 amI would think twice about cutting away pieces of metal chassis. The chassis is part of the shielding system and you might end up adversely affecting the EMC characteristics of the instrument.

author: Circlotron
author_rank: Super Contributor
timestamp: January 10, 2014, 01:10:34 pm
content: That's true. if it were an issue you could use a wire fan guard. It's circular cross section is relatively quiet as regards airflow. ->http://www.automationnews.info/wp-content/uploads/2013/01/SC80-W2.jpg

author: rsivan
author_rank: Contributor
timestamp: January 14, 2014, 12:29:38 am
content: Quote from: cosmos on January 09, 2014, 09:42:20 pmHave you try to put fan reverse?I ordered a noctua nf-s12a which have high air volume but low pressure and replacing as you done my also do same noise low but temp go higher I try to mount fan reverse pushing air inside and result was fantastic running fan at 900rpm onlytemp from system go from 31-34 to under 30 and noise is very very low I make pictures with my flir i7 of what happening insideanyway pushing air from back seem better I will post more soon

author: alank2
author_rank: Super Contributor
timestamp: October 03, 2014, 07:58:02 pm
content: You guys are saying the noise is so awful, but that meter video doesn't look so bad. My testing on the ds2000/ds1000z came to like 54 using a radio shack sound level meter. Does anyone have both a ds2000 and ds4000 to offer a comparison?

author: dimbmw
author_rank: Regular Contributor
timestamp: February 03, 2017, 08:14:22 pm
content: The noise from my DS4024 is just destroying my nervous system.It is unbelievable that they could not design this thing better.The instrument is pretty new, so I am a little hesitant to hack into it, but man, the noise is really killing me.Sometimes when I work at night, it seems to be especially loud and I just can't stand it.Honestly fot the noise alone I would not buy it again.So what is the best and most silent fan replacement option as of today? I am getting closer to taking a decision...Thanks!

author: commongrounder
author_rank: Frequent Contributor
timestamp: February 06, 2017, 08:05:02 pm
content: dimbmwI am in the same situation. I use my DS4000 scope for audio work and the fan is so noisy I have to turn the scope on and off more often than I really should, so I can hear what is going on. I did try replacing the stock fan with a low-noise Enermax batwing bladed fan. I found the air-flow was too low, however, and the internal temps climbed to uncomfortable levels. I noticed that the power supply for the fan is a DC/DC converter (the entire scope derives voltages from a single 5VDC source). The output of the fan converter is 7VDC. I assume this is to slow down the stock fan and keep it from sounding like a shrieking wind tunnel. Unfortunately, this slows the low-noise fan down too much. For now, I have gone back to the stock fan, because I need to use the scope every day for my work. I do need to figure out the circuit changes needed on the fan power board to have it convert up to 12 volts. I think the low-noise fan would then move enough air and still be quieter than the stock fan. It may be simple as a chip change and possibly a few outboard parts. If I could ever get some free time.

author: DaJMasta
author_rank: Super Contributor
timestamp: February 06, 2017, 08:51:11 pm
content: I swapped my DS4024's fan a couple months back with a pricey, very low noise fan rated for slightly more airflow, the Noiseblocker b12-3http://www.blacknoise.com/site/en/products/noiseblocker-it-fans/nb-eloop-series/120x120x25mm.php?lang=ENThe fan was very quiet when just hooked up to a power supply, but is considerably louder in the chassis - though the sound is still much less than the stock fan and is much lower in pitch. The fan also came with an anti-vibration mount that fit in with the install just fine. It's also worth noting that the pin pitch for the fan power connector is less than a standard .1" header, so I needed to make a cable to convert the three pin fan connector (one unused in the installation) to what the board could take.I think the main fan noise issue in the unit is that there's too much obstruction of the airflow. Yes, you could dremel it out or something, but it's also part of the emi shielding for the chassis and the fan is right over the ADCs... so it's probably not the best idea. The sharp edges on the grid of square punched holes that the fan exhausts through create a lot of turbulence, and there's no spacer between the fan and the vent (there may be space for a millimeter or two of standoff which could further improve sound level), but the normal fan doesn't sit far from the heatsinks on the board, so I don't think going with a 38mm thick fan is viable... you may not have much space to play with beyond the standard 25mm thick fan.Anyways, swapping the fan can improve the sound levels, but if you're going to maintain the amount of airflow, you can only get so much sound reduction without more significant chassis modifications.