Beginner - Help narrow down a signal generator  - Page 1
Forum section: electronics / testgear

author: Tomer
author_rank: Regular Contributor
timestamp: December 29, 2017, 11:05:19 am
content: Hello everyone, and thanks for reading.I am setting up a small/home lab for learning and developing pro audio gear such as guitar pedals, compressors and preamps.I am looking for a signal generator (I belive that 2 channels will be needed for stereo applications but i am not sure?).My area of working is very limited 0Hz to about 20-25 Khz.Also, i don't think that i need anything special or over complicated.After researching, i have few models in mind and i am seeking help to find the better one for me.1) Hantek HDG2002B (http://www.hantek.com/en/ProductDetail_149.html)On paper, it seems to have everything. and more than i need, big screen, and "scope" like design.When i am searching online i mostly find bad reviews on Hantek, and i am afraid that the UI is complicated and annoying to use.2) GW-insteak AFG-2005 (http://www.gwinstek.com/en-global/products/Signal_Sources/Arbitrary_Function_Generators/AFG-2100_AFG-2000) the specs here are far lower than the Hantek, i really love the display and the simplicity of the screen. also its made in Taiwan and overall seems like a more well made quality box.It will be great to hear your inputs about those choices, and maybe get some more recommendations for (up to 300$) signal generators.Thank youTom

author: cncjerry
author_rank: Unknown
timestamp: December 29, 2017, 08:05:30 pm
content: save money and use a PC audio card unless you need higher voltages and varying loads.

author: Tomer
author_rank: Regular Contributor
timestamp: December 29, 2017, 10:48:24 pm
content: Hi, thank you for the replayI am trying to avoid working in a computer, my budget compromise will be to use the DAW as spectrum analyzer.Is there any review on the Hantek signal generators i can't find any ?ThanksTom

author: TurboTom
author_rank: Super Contributor
timestamp: December 29, 2017, 11:39:34 pm
content: Tomer -in general, the reputation of the Hantek instruments isn't too good but I have to say, I'm using a HDG2002B (modified) since about two years quite frequently and despite a few "quirks", it's doing what it's supposed to. Hantek is still regularly providing firmware updates and once in a while an annoyance in the U/I gets eliminated. At 210 Euros shipped (AliExpress), there isn't anything with equivalent performance available for less or even moderately more money.You've got to be aware though that you cannot compare this device with a recent Siglent or Rigol AWG but also these aren't without their shortcomings. You should also be prepared to do at least one modification: Since the HDG's signal ground is isolated from mains earth, and the switching power supply Hantek used in the device, cannot be considered the world's safest, I'ld wire a substantial 20V suppressor between the signal ground (PCB frame) and earth. This should do it's job in case of an "oops" situation and at the same time it will still prevent ground loops. Be sure to scan through this thread if you're interested in one of these devices:https://www.eevblog.com/forum/testgear/hantek-hdg2002b-awg-5mhz-or-100mhz-let's-see!/To sum it up, I think the HDG2002B is a useful device for a hobby user who's not afraid of some modifications and who's primary concern is initial investment.All the best and good luck,Thomas

author: rhb
author_rank: Super Contributor
timestamp: December 30, 2017, 12:19:18 am
content: How sophisticated do you want to get? If you want super low THD, then search on "Max Wien, Mr. Hewlett and a Rainy Afternoon" by Jim Williams and read it. There's a thread in the forum about measuring THD using a sound card.If you want an audio AWG and are willing to use some *nix system, I'll write and send you a program which will generate a WAV file from a CSV file which you can either play on your PC or record to CD. I wrote most of the code several years ago for another project. It's a pretty trivial change.

author: Tomer
author_rank: Regular Contributor
timestamp: December 30, 2017, 04:02:58 pm
content: TurboTom:Thank you so much for sharing your personal experience with the device and guide me to the correct thread. i will dig in there!If possible i would like to ask a specific question about this device.* Can you change the output impedance or at list change it to Hi-Z?Thanks againTomrhb:Thank you for offering me your program, if i will choose to use a pc, i will PM about that.I will search for that book, sounds really interesting.I wan't to keep it as simple as possible (Also looking on analog signal generators with only few push buttons and a dial).Currently i am doing a guess about my needs, maybe the Hantek will be overkill for my needs or maybe I will have to change again.Thank youTom

author: rhb
author_rank: Super Contributor
timestamp: December 30, 2017, 06:12:25 pm
content: The book is great, but there are scans of that chapter online.

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 30, 2017, 06:44:38 pm
content: I own the bigger brother of the AFG-2005, the AFG-2125, and I'm very happy with it. It's built very nicely and the performance is good. The only drawback I've found so far is that the square wave shits the bed above 10 MHz. Of course, it's a single channel AWG, so it depends on your needs whether that's enough.I consider it to be one of the better purchases I made the past year. It continues to surprise me how much I use it.

author: Tomer
author_rank: Regular Contributor
timestamp: December 31, 2017, 06:15:55 pm
content: Thank you for your input about the AFG-2125, I really like to look of that unit.I think that overall i will try to get a second hand unit and if not i will try to get the cheapest option with 2 channels.Thank youTom

author: nctnico
author_rank: Super Contributor
timestamp: December 31, 2017, 06:26:48 pm
content: IMHO the generators from Feeltech are also a good starting point.

author: rhb
author_rank: Super Contributor
timestamp: December 31, 2017, 10:25:26 pm
content: Quote from: nctnico on December 31, 2017, 06:26:48 pmQuote from: nctnico on December 31, 2017, 06:26:48 pmProvided you don't mind fixing it :-(Their signal quality is great, but the UI FW issue makes them a poor choice if you want to get something done. Hopefully this will get fixed soon either by FeelTech or members of the forum hacking it. But Id' suggest avoiding them until the UI FW issue is resolved.It would be really interesting to know what the JDS/Koolertonics version is like. They look better, but don't have the back panel connections.

author: sycho123321
author_rank: Regular Contributor
timestamp: December 31, 2017, 10:35:23 pm
content: Quote from: rhb on December 31, 2017, 10:25:26 pmI have the jds version and imo it is quite good. I really like it's front panel compared to the feel tech. Since it has an external power supply it is also very easy to use a power supply with a transformer rather than a switch mode.

author: rhb
author_rank: Super Contributor
timestamp: January 01, 2018, 12:31:46 am
content: How long have you had it? What's the FW version.? I might buy one to use while I await the resolution of the FeelTech saga.Do you have access to a spectrum analyzer? If so, would you please post a few screenshots at different frequencies? It would be particularly helpful for others if you used the same frequencies and spans as the ones in this:https://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg1364674/#msg1364674I would expect that they are very similar, but you never know.

author: sycho123321
author_rank: Regular Contributor
timestamp: January 01, 2018, 12:35:25 am
content: Quote from: rhb on January 01, 2018, 12:31:46 amUnfortunately I don't have access to a spectrum analyser :/Edit: I've had it for about 2 months

author: tautech
author_rank: Super Contributor
timestamp: January 01, 2018, 07:08:03 am
content: Quote from: rhb on December 31, 2017, 10:25:26 pmIIRC nctnico has a SDG1000 model that he's had for some years.Seems weird that for the price they can be bought now he's not suggesting one.The OP indicates he'll go to $300 for a decent unit and with the SDG1025 (25 MHz 2ch) on special now for $319 it's not much over his budget.These AWG's have been around for a few years now, the firmware is reasonably mature and they don't give problems.Here's the 3 yr old thread on them and the 800 single channel series:https://www.eevblog.com/forum/testgear/the-sdg1000-and-sdg800-thread/

author: nctnico
author_rank: Super Contributor
timestamp: January 01, 2018, 07:51:13 pm
content: Quote from: tautech on January 01, 2018, 07:08:03 amDon't claim you are getting old because your memory still works well.Let me explain my reasoning. I have a Siglent SDG1010 and a Feeltech FY3200S (added grounded inlet and wire from 0V to ground). The Feeltech has 2 identical outputs capable of doing 20Vpp where the SDG1010 can only do 20Vpp on one output and the other is limited to only 6Vpp. That has bitten me several times already and is one of the reasons I bought the FY3200S. While the SDG1010 can do more fancy things the FY3200S is easier to operate and there is not much lost if it breaks. Every now and then I use it to drive a small relay to switch something on/off over a long period of time.All in all both generators have their strong and weak points but the Feeltech FY3200S being cheap and doing what it is supposed to do IMHO it is a good function generator to start with. Even if you buy a more advanced generator later on the cheap Feeltech will still be handy to have around. You can't loose any money.

author: AmadeusMozart
author_rank: Newbie
timestamp: January 05, 2018, 03:32:38 am
content: From my HAM radio days I still have a distinct anti-digital hangover. Yes you can set frequencies exactly etc. however the noisefloor of digital is more often than not below what can be achieved with far cheaper analog gear. In audio a low noisefloor / high dynamic range is desirable and in digital that will be expensive to achieve.For audio you'll want to measure distortion, noisefloor and instability. For instability a square wave generator is required and almost anything will do. For distortion you'll want a good sinus generator and you can use a test CD in a decent CD player and the noise floor is well below most digital function generators that have an affordable price. You can also buy an old fashioned signal generator based on the Wien Bridge oscillator. You can buy a kit and you may well find that it outperforms more expensive digital function generators. EG. this one is available on ePrayhttps://www.ebay.com.au/itm/Audio-Frequency-AF-signal-generator-oscillator-KIT-for-assembly/172711809322?hash=item28366d112a:g:E6EAAOSwaEhZMw19. Or tou can buy direct:https://www.rv3yf.store/product-page/audio-frequency-oscillator-assembled-unit.You may also consider getting a Distortion Factor Meter. I recently bought one for approx USD 80.00 equivalent and it can measure a noisefloor of at least -95dB which is good enough for me when I play around with tube amplifiers. It was working but after inspection I replaced two electrolytic capacitors in the power supply that had started to leak. I did look at digital stuff and would have had to spend substantially more. The older analog stuff is normally good enough for home use, I am having a lot of fun with an old latop and a cheap Owon oscilloscope together with the DFM (which has also a mV meter built in going up to 500kHz). Frankly I do not know how I managed without the DFM, it has been an eye opener.AM

author: Studio1@29
author_rank: Contributor
timestamp: January 05, 2018, 12:02:43 pm
content: Hello TomI have just purchased a FeelTech FY3200S Dual Channel Arbitrary Function Signal Generator for just such a purpose as you are looking for. My current 'on-the-Bench' is a Denon AVR-1912E2/EA. The FeelTecch 3200S came with a micro CD with a pretty useless User Manual - but, since I had numerous questions about its operation I contacted their Technicians by e-mail <feeltech@126.com> about an hour ago and already have a reply from Lijun Ge, a technician there. He, in his reply, also appended a pdf of 20 pages which is most instructive, all in English and comprehensive. I bought mine through e-Bay and it cost £46.99 incl delivery.Michael UK

author: Calambres
author_rank: Frequent Contributor
timestamp: January 06, 2018, 06:50:26 pm
content: I've also got a FY3200S. Can you make that pdf available to us?