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It seems that the change 1 suggested by takfuji should be also done on the -12V (or -12.5V judging by the resistor ratio?) rail, it is basically identical with the positive side (other than the charge pump series capacitor in between).
I noticed some additional points to improve, like one opamp missing a positive supply cap and a shared opamp having (likely) much less supply cap than suggested in datasheet for the marketed crosstalk figures, but their effects are still only at maybe/theory level, I haven't had time to test/measure those yet. -
Hi everyone,
Could some kind person please look at the 5V smps PSU sent with their JDS6600 and tell me the output current rating printed on the label. It's not actually given in the manual.
I've got all my 5V "wall-wart" supplies totally mixed up, and want to label the correct one.
Thanks!
H-P -
Here's a photo of the thing.
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Many thanks BUGI
I have both updated my manual, and also saved your photo.
H-P -
The one thing that REALLY bugs me is the button labelled, "AMPL" that changes the voltage value displayed (e.g. the 5V appearing after bootup). This is because the value is actually the peak-to-peak voltage of the sinewave shown on the screen - not its AMPLitude! So in fact the output is really v(t)=2.5sin(wt) volts into a high impedance. This confused me quite a bit initially! If there is room on the screen, a little "ptp" added after the V symbol would help a lot.
Also, my unit rather annoyingly gives out 5.24Vptp into hiZ when set to 5.000V @ MHz frequencies = a +4.8% error! This makes a nonsense of having voltage resolution settable to 1mV! This 5.24Vptp value was confirmed correct by re-calibrating a new HP54645D, a TDS210 and a Rigol DS1102E just before measurement. In addition I also checked each scope's DC calibration using an AD584JH precision voltage reference! (Terminating at the scope input with 50\$\Omega\$ just halves this value as expected). I'd love to know how to correct it - hopefully it's only a pot adjustment, when I get brave enough to open the box! Anyone know how?
But otherwise, at the price, the JDS6600 is a pretty good piece of equipment for non-professionals. Yes, it has some deficiencies, but to compare it to $$$k truly professional equipment, as others have tried, is not fair to the designers.
H-P -
Afaik, the most common "symbol" for peak to peak voltage is "Vpp" (without the t between p's). The amplitude vs Vpp is one of the quirks I have planned to print on a sticker to be on top of the unit.
tjones99 noticed the amplitude/voltage error earlier, but there hasn't be any hints how to adjust it so far. -
Hello
Hi friend
I want to buy one 60MHz function generator
but what's the difference between Feleltech, Kuman, JDS, Koolrtron 60MHz function generators?!!
for example I found the below device:
https://www.amazon.com/gp/product/B07596133Q/ref=ask_ql_qh_dp_hza
I don't know what I should do!
actually I should tune my medical board (Step response and Frequency response) and I need such a device
Best Regards
thank you for your message and your question
about Kuman, JDS, Koolrtron, they are from same designer . our engineer and Minghe engineer design the JDS6600. other Kuman and Koolrtron should use the brand. JDS6600 is newest version.
about the link, it is also new . it is a hand-held, JDS6600 is desktop. data and function are same
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RD Tech - I have, regrettably, already ordered a 30Mhz "koolertron" off Amazon before finding this forum. There are a few posts with some issues like phase changes when running 2 channels, and the unit powering off by itself after a while.
Is there anyway to determine how old the HW or firmware or SW is in mine - to determine if its worth returning the unit in order to buy one from 'aliexpress' that has more recent updates?
Already found out that mine shut itself off after a while the first time I powered it on and so I'm letting it run again to see if it does that on a regular basis.
That is going to be a problem if I can't let it run continuously - is that a bug that has been fixed in a newer version? If so can mine be updated or do I have to return it and buy a newer issued unit?
Thanks for the help and all your info provided to the forum on your product!
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I saw a YouTube vid of JDS6600 teardown, and it was said that the unit has a problem where it will spontaneously shut down after 10-20 minutes of operation.
Is this still a problem with these units? Or did the YouTuber get a bad unit?
I am very hesitant to purchase this unit, based on what I have read on the first page of this thread (sorry, I haven't had time to read the whole thread yet, but will keep on reading) in spite of its low cost and good quality (if questionable), so maybe I will go with a vintage HP or Agilent on Ebay...
I don't need laboratory specs, but I want something that isn't going to annoy and frustrate me to the point that I put it on a shelf somewhere to collect dust while I buy that vintage Ebay item after all... or perhaps just save a bit more $$ and get a Siglent or Rigol model. -
Hi Guys
You can get the JDS6600 in a different physical form as the JDS2900. Here is a link to Aliexpress, which is having a sale on Nov.11 (both are on sale for the same price):
https://www.aliexpress.com/item/JUNTEK-JDS2900-60M-60MHZ-Signal-Generator-Digital-Control-Dual-channel-DDS-Function-Signal-Generator-frequency-meter/32867045945.html?spm=2114.10010108.100009.4.e23747ae4Z9x43&gps-id=pcDetailLeftTopSell&scm=1007.13482.95643.0&scm_id=1007.13482.95643.0&scm-url=1007.13482.95643.0&pvid=c5308da1-6feb-41d0-85e1-2c87c5a3e620
If you look at the different views of this package, there is a lot of ventilation at each end, so maybe the turning-off problem was just thermal?
The rated sine wave 20-20kHz THD is 0.8% but maybe it is actually lower? One would hope.
I looked at OWON's AWGs and the AG1022 is rated at 0.2% and is about twice the price of the JDS. The AG has more memory.
OWON has their XDS-series which is rated at 0.05% sine THD 20-20kHz. I have not seen a price for this one, but stylistically it matches their XDS scopse.
All of the above are 14-bit -
Guys, so i bit the bullet on this one and just posted a command line program for mac to control these devices. I primarily wanted it for uploading arbitrary waveforms but it will also be handy for defining different configurations.
https://github.com/kpishere/mhs52xxA
Protocol is defined there too. -
hi there.
Just a tip that the software works perfect in Debian and Ubuntu using WINE emulation. Install as if were for windows.
You will need to create a symlink to the serial port under $HOME/.wine/dosdevices dir
On the command line:
Example if it is detected as USB0 ( dmesg)Code: [Select]ln -s /dev/ttyUSB0 com1
Also follow arduino instructions to add your user to the serial portCode: [Select]
sudo usermod -aG dialout <username>
Logout and login and should be good to go.
Ohh another thing that has appened to a JDS2900 which is a similar model to this in terms of SW ( metal case) , the inputs stopped working and it needed to perform a hard reset. To do turn power off, press and keep "right" key, power up unit and change language.
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Hi, I'm new to the forum, but I've studied many threads on here over the years, I just never before had reason to post.
I have one if these jds6600's, the 25mHz model. I bought it a bit over a year ago and have used it a lot with no real issues. I primarily repair analog electronics. Mostly car audio amplifiers and I use the function generator as a source while testing. Today when I turned on my function generator I found ~60Vac referenced to earth on the outputs of the generator. I thought something had went South in the little switchmode wall wart, and I swapped it with another one, but the issue persists. It can't drive any real current, but I really need to deal with it. I'd rather not have to buy another function generator for this. Do any of you have any suggestions on what to do to solve this.
Thank you all in advance!
Sincerely,
Jason -
That is normal for devices using a SMPSU. You can read much about it e.g. in the FeelTech 6600 thread. You may replace the SMPSU by a linear one to get rid of this ghost voltage or you need to use an isolation transformer.
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Thank you, that is what I was thinking, I just thought it was odd that after 1 year and 3 months that this issue suddenly showed up. I would have expected to see it before, my test setup was exactly the same as I always setup. I noticed it while hooking the scope up to the amps outputs. The signal gen was attached, the amp had 12 supply hooked up, but the remote trigger was not powered yet, so it was effectively powered off. I hooked up the scope and found 60 Hz AC on the amp output. I removed the 12v supply (it's a linear transformer supply) and the AC was still there. That's when I started looking in earnest and tracked it down to the function generator. I tried to test the amp anyway and I get the function generator test wave riding on a 60Hz carrier. There is literally no way I would have missed this while testing in the past. That's why I was thinking it might be more serious than just the wall wart.
Thank you for taking the time to answer. I appreciate it.
Sincerely,
Jason -
Well, apparently there was something more going on with this one than the ghost voltage. The attached image is what I got after powering it up this am. Is there a way to hard reset this thing, or is it just scrap?
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Well, apparently there was something more going on with this one than the ghost voltage. The attached image is what I got after powering it up this am. Is there a way to hard reset this thing, or is it just scrap?
Check if the last paragraph with the hard reset key works:
https://www.eevblog.com/forum/testgear/anybody-know-anything-about-this-signal-generator/msg2028949/#msg2028949 -
Thank you! I'll give it a shot.
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Hello i have the jds6600 60mhz model,when i open tha case i have see that the ic is erased!someone knows what ic is??
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Hello i have the jds6600 60mhz model,when i open tha case i have see that the ic is erased!someone knows what ic is??
Bro... can you be a bit more specific? There are 14 ICs visible in that picture that have at least 8 pins. -
all the ICs in the box is erased!very bad this!Good meter but this is problem..
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Here is a pic of an earlier model, maybe same IC's.
https://www.eevblog.com/forum/testgear/anybody-know-anything-about-this-signal-generator/
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Interesting, quite big changes between those versions. Mine is somewhere between and the changes compared to the 1.0 were minor, I had to really look for them.
Especially, on that v1.5, more heatsinks/components under heatsink... and can you spot any adjustable components (v1.0 has 2 per channel)? -
@ jdev99
Shit, isn't it, compared to the FY6600 and FY6800 models?
I've just read the whole of this thread (didn't take very long) to try and track down a video, which I've not been able to relocate again, that showed the artefacts you'd expect to see on the 20vp-p sine and triangle waveforms from the use of an R2R network made up from 1 or even 0.1% tolerance smd resistors.
As bad as the FY6600 might have seemed (unjustly in view of its very low price point compared to even a Siglent function generator), this JDS6600 is just a "Poor Man's" version of the FY6600 it's aping. For anyone still looking for something a lot better for similar money who is still unable to justify spending some 5 to 7 hundred dollars/euros/pounds, the FY6800 is the obvious contender.
Feeltech responded to the criticism of the half mains live touch voltage issue that afflicts the unmodified FY6600 by replacing the IEC C8 figure of eight mains socket with an IEC C13/14 earthed mains socket on their improved version, the FY6800. Unfortunately, they did the absolute minimum they possibly could to link the Protective Earth pin to the ground rail by simply snipping one of the two ground returns at the main board end of the ribbon cable that links to the PSU board simply because that left them with a flylead just long enough to divert to the earth pin of the mains connector.
Unfortunately, this compromised the connection between the PSU and the main board ground rails and worse, introduced a new problem that had never existed before with the FY6600, the issue of ground loop induced interference from galvanic and thermocouple induced dc offsets in the mains earth wiring and the more usual mains hum and random noise induction so familiar a problem to vintage audio enthusiasts.
For anyone working at millivolt levels, this cure was worse than the disease. Luckily, the solution to this problem, without compromising the half live mains touch voltage fix, is simply to wire a 1 or 10 K resistor in series with the wire connected to the mains socket earth pin (the PSU is still the original class II double insulated PSU it's always been so no electrical safety issues involved in this case). Using a 10K resistor attenuates the 90 odd volts on a 220/240v supply to a mere half volt (50mV using a 1K resistor) and attenuates unwanted earth loop effects by some 60 to 80dB (40 to 60dB in the case of a 1K resistor).
At least, in the case of the FY6800, Feeltech have already done the hard work for you by fitting an earthed mains socket, all you have to do, compared to owners of the FY6600 doing their own conversions from the C8 mains inlet socket to a C6 clover leaf or C13/14 socket, is add a 1 or 2.2 or 10K resistor in series with the earthing wire, preferably a replacement wire soldered onto a convenient ground point on the main board so you can rejoin that borrowed ground return to the ribbon cable plug to uncompromise the ground return circuit. Easy peasy!
Thereafter, it's just a question of which of the many improvements that have been described in the 74 page long FY6600 thread that you'd like to apply to your recently acquired FY6800 (which is essentially just an enhanced version of the FY6600). However, do make sure there are no pre-existing faults before you embark on any such warranty voiding modifications.
You can make up an external mains extension lead incorporating this resistor in the earth circuit by way of a temporary external modification and use a small desk fan to mitigate the high internal temperatures due to ventilation slots unsympathetic to the requirements of passive cooling (an effect actually made worse when it's propped up on its kick stand). If nothing else, adding a small 12v cooling fan driven off the 5v rail will have a dramatic effect on the internal temperatures for virtually no additional noise.
I know it might seem a bit off topic to be "selling" the FY6800 like this but, quite frankly, the DJS6600 is such a pile of excrement, I suspect, given the dearth of posts in this thread, that most of its contributors may have already sold or even given away their JDS6600s in favour of something a little better, perhaps even an FY6600, or more recently, an FY6800 (if not a Siglent or better). I was just posting to set the record straight and offer any cash strapped hold outs a better and more cost effective alternative to consider.
HTH & HAND
JBG
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hi to all
iam loocking for a dds like this but have a question
its possible to adjust frequency on real time via knob like analog generators or need to set every time new frequency ?
thanks -
hi to all
iam loocking for a dds like this but have a question
its possible to adjust frequency on real time via knob like analog generators or need to set every time new frequency ?
thanks
They tune in real time. However, you need to pick which digit you want to base your incremental steps on, 1Hz or 10Hz and so on. If you have 10MHz dialled in and you want to go up and down in 1Hz steps, you'll have to select the 1Hz digit before rotating the tuning knob. if you keep rotating it clockwise the units digit will roll back to zero and generate a carry into the tens digit just like you see on a vehicle's trip odometer, except you can go down as well as up in frequency in whatever step size you care to select (tens of MHz right down to microHertz).
If you want to dial in a spot frequency such as 2182KHz, it's probably easier to select the MHz step, wind it backwards to zero all the digits then dial it to 2MHz, drop to the 100KHz digit and dial in 200KHz so you're tuned to 2.2MHz, then select the 1KHz digit and wind it back down to till you get your target frequency of 2182KHz showing on the frequency read out.
You could simply step to each digit and set them individually but this usually takes longer to input the frequency than a bit of clever manipulation to reach your target as per the example above.
HTH & HAND
JBG