Re: FeelElec New Arrival FY-6900 Signal Generator

[Labrat101]

 

know what you mean but a direct USB interface won't help, our brains have been evolved to absorb high data rate information via our senses of smell, sight and sound (pretty much in that order over the past 500 million years or so) so we use the intermediaries of display screens and loudspeakers (smell is a low bandwidth low priority channel in humans) to translate such data streams via USB and other serial interfaces. That's about as direct a link as we can create out of our technology.

That's Not quite true there are Thousands of people who have never evolved ..
They are called politicians and run the governments of major country's ..    
 And other No Good organisations.. no names but also have not evolved ..

 Thanks to say that most people in this forum are Human and are evolving for the better.

 Yea  Doc you have been eating too many carrots   ..
 I was reading this forum long before before i joined .. I read fairly fast and let my brain catch up later 

All the best . Have Fun Stay safe
  RNS

[g2]

First thanks to Labrat101, Bad_Driver and Johnny B Good for your really good answers.
I could possibly buy FY6900 and make "the three cheapest and highest priority (most essential) modifications that any" cash strapped hobbyist "should do to protect their modest investment." Quote from Johnny B Good.
When I read earlier Posts:
Reply # 302 had an interrupted sine ... lets do the sine repair in the help function .... turning device out and in (several times) did not help.
Reply # 305 I have the 6800 @ 60mhz also had a few problems ie the power supply went up in smoke after an hour.

I think it's okay for me to buy a device and make modifications, but after that I should be able to trust it and be happy with it.
A week ago I read about the RD JDS6600 and think it sounded OK.
But then I came to Johnny B Good comment: Shit, isn't it, compared to the FY6600 and FY6800 models?
(RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator  «Reply # 197).
The JDS6600 has far from as good data and feature as the Fy6900, but is it more stable, and you know what you get?
Are there any disadvantages to Siglent?
and are 2 channels useful?

Labrat101 comment:
and killed a lot of retirement boredom.
Yup .. retirement Fixing things is a great pass time and fun.
And been reading the News instead .. That really sucks ..
You're right, but I think it has nothing to do with retirement. It's a matter of keeping oneself engaged in something reasonably and still evolving. Electronics are good for that. I'm retired myself.
I think you write it yourself in Reply # 375.

[Labrat101]

I think it's okay for me to buy a device and make modifications, but after that I should be able to trust it and be happy with it.
A week ago I read about the RD JDS6600 and think it sounded OK.

First Thanks for the comments .. There is a "Say thanks" Button on the top of each post 

 As for the JDS6600  the only difference is the JDS which is the same exact animal as the FY . the markings on the case different colours.
 Also if you watched the YouTube demo's they all keep the frequents setting well below 1Mhz ..  ie 100Khz the sine square etc are fine.
 But why buy a unit that has a capability of much more 25Mhz  and demo it at low Hz  .. because it would show the yucky faults .
 The Spec sheet could have been written on toilet paper . it would be at least useful one time use  .
 The 6600 models are the first versions and the software has not been really updated. .
  I would stay clear of the 6600 they may well be very old stock .. The 6900 does have a better firmware .
 The Power supplies do have a lot of harmonic noise as well as being NON iso standard .. 
 Its sort of the luck of the draw how long the PSU will last . and the earth thing as well .
  If you do buy go for a newer model as there are a few changes ..
    but before you turn it on Take Dave's advice TAKE it a part .. check it well as the wiring etc does not get checked
 Don't worry about the guarantee  its not worth much ether .
  Be prepared to spend about a 100 hours modding it  ... and also read all the modes ..     

  JBG modes will give you Many happy hours of reading 

 May the force ''Not'' be with you .. 240vac to earth Ce      

BTW the sine repair does work on the 6800 I have used it
 There is also A Calibration function Not mentioned in the manual ..
 Hold the power on & Ch1 in and hold while powering up by switch on back..   System / More .. Osci 
 

RNs

[Fandorin]

Hello everybody,

My first post here.
I have plans to buy a signal generator and I was leaning toward FY-6900 60 MHz. But today I was browsing Aliexpress and saw models I haven't seen before: FY-6900 80M and FY-6900-100M: https://www.aliexpress.com/item/4000082390571.html
Are these new models? The specifications are suspiciously identical to the 60 MHz model and the only difference is sine wave max frequency. The prices are higher of course - 120 USD and 138 USD respectively.
Has anybody purchased any of these? I will appreciate your thoughts about these models.

[Johnny B Good]

 Those higher frequency specifications for sine waves are realistically attainable with the 250MSa/s sample rate used by the DAC (Nyquist limit in this case being 125MHz). Presumably FeelTech have modified the AA filter to cut off just above 80 and 100MHz (probably just above 100MHz for both those models).

 If you're looking for a cheap AWG that can generate sine waves at frequencies beyond the 60MHz limit of the previous models, the price premium looks quite reasonable if you do have a need to generate sine waves in the 60 to 100 MHz range. I'm assuming that you're already well aware of the non-existent support from FeelTech and the various deficiencies these AWGs have compared to the more expensive mainstream brands.

JBG

[Fandorin]

Thanks for the reply.
I decided that the price for the 100 and 80 MHz models is too much for me and will get the 60 MHz. This should be enough for me.
Anyway, it will be interesting if someone buy one of these and post some test results in the forum.

[vutt]

I pulled the trigger on KKMoon FY6900 and it's on my way atm.

It looks like one of the most recommended upgrade is ground wire/resistor mod.
I have plenty of Schuko Power Cord donors laying around for nice wire, but what's the recommended wattage rating for resistor? I have bunch of 1/8 watts ones but they feel so tiny for handling potentially mains level current.
I'm fine with little shopping for proper one, resistors are cheap.

[Bad_Driver]

Keep it simple. I used a 5.6K 1/4 W resitsor from my shelf.
Take two 10k in parallel - than you are on the safe side.

[pizzigri]

OK, so I have a question however I cannot seem to find an answer using the search engine....
So, I made a whole host of mods to the FY6900, but essentially apart from the PSU upgrade, ground, fan etc etc all described in this thread, the most important one was upgrading the reference crystal - I replaced it with a VC-TCXO IQD LFTVXO009900BULK with a 0.9ppm accuracy, and indeed the DDS works like a charm, as there’s no more drift. However, I noticed that there’s an offset, that at 10 MHz is about +170 hz, is there any way to calibrate the FY6900 and remove it? It is vary stable and does not drift (too much).
However, I do not yet have a GPSDO, that’s next on my list, so I am relying on the fact that both my counter (a Fluke PM6666) and my DSO 1202x-e roughly agree on this offset.

Eta pictures

[Johnny B Good]

OK, so I have a question however I cannot seem to find an answer using the search engine....
So, I made a whole host of mods to the FY6900, but essentially apart from the PSU upgrade, ground, fan etc etc all described in this thread, the most important one was upgrading the reference crystal - I replaced it with a VC-TCXO IQD LFTVXO009900BULK with a 0.9ppm accuracy, and indeed the DDS works like a charm, as there’s no more drift. However, I noticed that there’s an offset, that at 10 MHz is about +170 hz, is there any way to calibrate the FY6900 and remove it? It is vary stable and does not drift (too much).
However, I do not yet have a GPSDO, that’s next on my list, so I am relying on the fact that both my counter (a Fluke PM6666) and my DSO 1202x-e roughly agree on this offset.

Eta pictures

 The short answer is "Yes, there is!" (or rather, there certainly is for the FY6600). However, if you use that hidden menu option, your 'magic'  (free of the 4ns jitter) frequencies at 50, 25, 12.5 MHz and so on, will no longer be jitter free. The best way to address this is to calibrate your VCTCXO to a reference traceable to an atomic standard - a GPSDO (or a RFS that's been recently calibrated within the past year or so against a traceable frequency standard (eg a GPSDO  ).

 I checked out that VCTCXO's datasheet which suggests there's every chance that your Fluke counter is overdue its next re-calibration (don't place too much trust in your DSO's frequency read out) since the tuning range is specified as being a minimum of +/-5ppm over a 2v tuning range centred on 1.85v (+/-50Hz for a 10MHz centre frequency). The actual tuning range could be as much as double that quoted minimum figure but more likely to be around the +/-7ppm mark.

 Assuming the EFC pin is at the 1.85V mark either by design or from a connection to an external trimpot across the 3.3v Vcc rail and ground, preset to its mid point for the time being until you can gain access to a trustworthy frequency reference by which to calibrate your VCTCXO as exactly as you can get it tuned to its specified 10MHz, it may already be within +/-1ppm of 10MHz to start with.

 IOW, there's every chance that it's closer to 10MHz than your DSO and frequency counter are implying. Wait until you have access to a GPSDO or RFS before attempting to recalibrate it, whether you use the software option or do it the right way with a trimpot wired to the EFC pin of that VCTCXO. 

John

[pizzigri]

John, thank you.....
Do you think a small breakout board wired to the pads on the main pcb of the fy6900 with the TCXO and trimpot on it be feasible? If I keep the distance below a couple cm I can avoid using coax cabling. I’m thinking this could also allow for a jumper or switch to route the reference signal to a bnc for the GPSDO to control the DDS.... I imagine there should be a few decoupling caps.
What trimpot do you suggest?

I am shopping for a bg7tbl GPSDO, however I am a bit lost between the various sellers, any opinion on rf-experts on ebay?

[Labrat101]

I am shopping for a bg7tbl GPSDO, however I am a bit lost between the various sellers, any opinion on rf-experts on ebay?

I would recommend the Leo Bodnar GPSDO  it works great a little costly but has 2 outputs
and work out the box and accurate 10^-12

There is a good chance that your 69 has the same Fake cyclone chip as the 68 and in that
case putting a better tcxo with a faster rise time the cyclone internal correction will fail
 and will produce a ghosting over the waves .
It will give better accuracy if you can live with a badly formed waves . Arb will show over shoot on things like the ramp , Staircase is some thing special more like an escalator .
 
I spent many months trying to solve these problem and have done ever upgrade plus a few of my own . Also the mother board its self has a really bad track error layout problems which means cutting and reconfiguring the tracking solve a few errors but it has too many .
 JBG has the 66 model that has a slightly different layout and is properly better in the Mods

 Have Fun
 

[pizzigri]

Demoralizing .....
However I did not see the ghosting, can you give me a setting to check on the DSO, where it is obvious?
As for the LB unit I looked it up, they have two, one that is quite affordable at 99£ and the 150£ one....
Thank you for your insight I really appreciate it!

[Labrat101]

Demoralizing .....
However I did not see the ghosting, can you give me a setting to check on the DSO, where it is obvious?
As for the LB unit I looked it up, they have two, one that is quite affordable at 99£ and the 150£ one....
Thank you for your insight I really appreciate it!

Try 11Mhz square wave . Do you get a shadow on both sides of the wave . depending on
your scope speed . the wave will shake as is . appear to wobble from left to right .
on a digital scope it will look like what I call a jelly wobble .
on an analogue it will show a distortion on the rise and fall .

Sorry if I have upset you .

[Labrat101]

Update while its set for 11Mhz set the display to DOTs  & persistence to 1 sec
it will enable you to see the ghost overlay .. its not jitter because its a complete wave
duplication about 15 deg offset

If you have a clean square wave . congratulation yours is working well .
 don't tell any one because you may have the only good one  that slipped by.

[pizzigri]

Ok, so now that I see it i realize that I did notice it in the past.
There’s ghosting at basically every MHz step above 1 MHz. But, wasn’t that there before? I did this upgrading the TXCO?

[Labrat101]

Ok, so now that I see it i realize that I did notice it in the past.
There’s ghosting at basically every MHz step above 1 MHz. But, wasn’t that there before? I did this upgrading the TXCO?

The 69 had added what they called Magic jitter or something like it.
 which by using software they tried to fix what the internal clock phase circuit that is hardwired into the cyclone developed by its original manufacture Intel .
Which very cleverly counts the xtal pulse and compares it to the last if there is an error it ignores bad pulses it then carries on . So it removes jitter . So any drift of frequency is corrected.  From what I understood from the documentation from the Intel doc's .
its PLL 's &  DAC array  . Also the cyclone was designed to have an internal clock speeds upto
100Mhz .  I checked my cyclone in my 68 and those pins are not operational nor are the ref points operational which are hardwired and not software controlled .
 I worked in Intel for nearly 10yrs and I know that no substandard chip ever left the FAB without being destroyed .

 Actually your square wave is not that bad  .
  I have got a 4ns on both sides but I put an OCXO in and has a very fast rise.
 This is when I realized that there was a bigger problem that I should have guessed right at the begin .
 As I mentioned it an early post . How can any one produce a item like this for around
 $80 and the cyclone cost on its own nearly $35 - 40 . maybe buy a million and get 30% off.
 The DAC s are also properly  not original that's why they scratched the numbers off .
 The PCB has cross talk as well . .
 The error  can also be seen in the FFT  If your scope has a good range

 So if you do upgrades be careful not to change the voltages etc that there software is monitoring  also the High Z resistors are 82ohm. aprox .
  I did not change mine as I gave up trying to make  a round peg fit into a square ..
 
    OK 20KG hammer would solve the Peg problem 

   Sorry No Bad feelings .
 
  There is another panel not shown in Photo of the 10mhz board Ref Frequency,
 which uses the bottom 2 BNC connectors
 Note is hard to see the name on the Cyclone .  it sort of rubs off

[pizzigri]

What hard feelings? Nahhh at least I know now to simply stop... I got nowhere near your level of tinkering inside my 6900, basically PSU mods, ground improvement, additional 7V PS to power a 12V fan, placed Raspberry Pi heatsinks on everything my thermal camera said it needed, improved heatsink for the opamps and the TXCO replacement. I got second thoughts on making an adjustment board for the TXCO....

 Maybe I will improve the PAD on the output like masterx81 did on his copy of the thing - I'm having difficulties getting the resistors to do it.

 So if you do upgrades be careful not to change the voltages etc that there software is monitoring  also the High Z resistors are 82ohm. aprox .
  I did not change mine as I gave up trying to make  a round peg fit into a square ..

Uh that means I am not supposed to change the 82-85ohm pad to 50? Your suggestion is not clear
My scope is a Siglent SDS1202x-e.

Next step, learn as much as possible until I got enough dough to move on to a real DDS, even a "cheap" one like the Siglent SDG2042X, and maybe keep the 6900 as a backup. The specs remain impressive all the same, I have to move to the 2000x series to have basically as much stuff as it, for ten times the money. But, yeah, its a pile of crap.
Thank you for your kind help.

[Labrat101]

What hard feelings? Nahhh at least I know now to simply stop... I got nowhere near your level of tinkering inside my 6900, basically PSU mods, ground improvement, additional 7V PS to power a 12V fan, placed Raspberry Pi heatsinks on everything my thermal camera said it needed, improved heatsink for the opamps and the TXCO replacement. I got second thoughts on making an adjustment board for the TXCO....

 Maybe I will improve the PAD on the output like masterx81 did on his copy of the thing - I'm having difficulties getting the resistors to do it.

 So if you do upgrades be careful not to change the voltages etc that there software is monitoring  also the High Z resistors are 82ohm. aprox .
  I did not change mine as I gave up trying to make  a round peg fit into a square ..

Uh that means I am not supposed to change the 82-85ohm pad to 50? Your suggestion is not clear
My scope is a Siglent SDS1202x-e. 

Next step, learn as much as possible until I got enough dough to move on to a real DDS, even a "cheap" one like the Siglent SDG2042X, and maybe keep the 6900 as a backup. The specs remain impressive all the same, I have to move to the 2000x series to have basically as much stuff as it, for ten times the money. But, yeah, its a pile of crap.
Thank you for your kind help.

Siglent SDS1202x-e.   

Hi I would leave the Pad alone as it won't help much . also I found that they choose those values were to try and correct the capacity of
the low grade relays. . On my photo you will see i put a 10pf cap on the opamp output after the filter .
This is to correct the contact capacity of the relay . which makes the square wave much sharper . but it does not cure the jitter/ghost .

The Only reason I bought this in the first place was that I could not Believe that the Specs could be that good for $80 .
 So I took the Gamble .. Naa next time I will but my money on the  at least I will know it will always be in last place.
 My FY68 failed after only 2hrs of operating the SMPS gave off Magic smoke and very nice toasty .
This is what started the whole long STORY     .. They would not except a return and gave me 30% refund and said get
someone to fix it.    . .
 So I came to the conclusion that FY roughly transliterated into English =  F_uckY_ou .

 I had added a 20Mhz CTS OCXO  2PPB with a PLL @ x2.5 to give 50Mhz and a divide by 2 from the PLL ref pin to give me also
 10Mhz out reference and was adjust with the Leo Bodnar to a 10.000,000,001 Mhz .  .
I now only use this !!68 for reference frequency .

I ordered a UTG962 from Uni-T direct a month ago and was sent via DHL who in there wisdom put the wrong Address code.
 what happened to Copy&Paste . Ok they have now resent it via Fedex and If the Gods are with me should arrive in the next few days.
 
 As for me this project is dead and the only further upgrades will be carried out with the delicate swing of a 20KG hammer.
 Of course I will remove my OCXO first ..
 

 Just out of interest can you take a close up Photo of your main PCB  I would like to see IF they made any changes to the panel layout.

BTW you mentioned  Raspberry Pi  what were you using this for?
  About the TCXO adjustment use JBG advise there

  RNS

[Bad_Driver]

Hi Friends,

there is a new kid on the block:

https://www.eevblog.com/forum/testgear/juntek-psg9080-programmable-signal-generator-(80-mhz-300-msas-14-bit)/

Seems to be better than the Feeltec crap. Watch DefProms YT-tear down. Can be a chance for a new generation of enthusiastic hobbyist to spend weeks
in improvements 

I like Labrat's idea with the big 20 kg hammer. I noticed that I after having finished the OCXO and PSU update of my 69 and buying the Siglent SDG 2122 (2042 before improvement) never touched the FY 

So I think I will it rebuild into the state of origin. The PSU I used for improvement and the OCXOs demands is industrial grade and I think it will have a bright future with another project. The FY PSU can spend the rest of it's life in the plastic box.

cu B.D.

[Labrat101]

Hi  All I finery  got my long awaited UTG962 ..

 So I had to run some quick test plugged it in all fired up .. in cheesiness    armed with the Samsung phone translator
put it into English no big deal . 2mins .
  The first thing I did was set the limit from high Z to 50 ohms . and set the sine to 60Mhz .. OK not bad at all . not perfect but
 liveable .
Next the big test the SQUARE wave 1mhz  . 5Mhz  ok what's going on the display I noticed shows a trapezium and as
 I increase the Mhz it gets more and trapezium 
 The GOOD news there is NO jitter or wobble or shacking .
So I tried the pulse . very nice has the same the Rise & Fall time can be set . But the minimum setting is 15ns .
 But the manual and the spec say it can go to 20Mhz Square . I sent them a message to quire this .
 Other than that the controls and the setting are really good and also a lot of presetting that are very nice .
over all it has some amazing features  . There are lots of menus  and it also has a sinc out .
The Screen is really nice and clear to read .
over all its far better than the FY68 with a lot of fine tuning available  .
The overall frequency accuracy is from a regulate TCXO  so the 10mhz is a little off maybe 2sec a day  (30ppm) (not for time nuts)
The over all foot print is very small 180 x 95 x 70  . I could drop it inside my Old Tektronix TDS 340 and take a week to find it.
 
The only down side is the slow Rise & Fall time being 15ns .

I will do some more test on it .. and I am not going to buy any more stuff for awhile ..

 Update I just checked the sinc out pulse and that is clean upto 20Mhz square @ 4ns  perfect square there is a hidden power
 it just need a small mode some where .. but as its still under warrantee I am Not opening it .

 
 PS.. Really Need a scope with 200Mhz+ bandwidth to see 20Mhz Square 

[Bad_Driver]

As explained I used a free hour to rebuilt the FY6900 into it's state of delivery before all my PSU improvements.

I kept only the wiring with the drain resistor and the fan.

Unfortunately I forgot that I killed the weak 10 MHz XO during desoldering since I don't own a SMD station.
So I was faced with the problem to find a new XO.

As mentioned above I used for my improvements a 3.3 V OCXO (Vectron) with the new PSU.
It takes during warm up about 1 A later 0.3 A.

I gave the origin PSU of the FY69 a chance and I was surprised!!
It has enough reserves to feed the additional 1 A  from the 5V line into my simple 3.3 V LDO-OCXO solution.

At the end I have a FY6900 with the original PSU, a fan, a earth-drain resistor-ground wiring and a 3.3 V OCXO that is feed from this PSU.
Now the FY can R.I.P. on the shelf.

btw: Is there a new firmware for the FY on the market?

[Ernest1]

Oh wow, poor FeelTech lol.

Are these that bad? I mean the price seems reasonable or is there something better at a lower or same price?

[Labrat101]

Oh wow, poor FeelTech lol.

Are these that bad? I mean the price seems reasonable or is there something better at a lower or same price?

Do you want the short answer . YES .. Total waste of money More Bugs than you have in the Garden.
If you want a Good AWG at  almost the same price that just works out the box.

 Go for the UNI-T UTG962  .  I have bought 1 and it just functions great .
 The link for the OEM supplier .
 https://www.aliexpress.com/item/4000373256414.html?spm=a2g0s.9042311.0.0.49434c4dAwQI7Y

 The Manual Downloadable  from  www.uni-trend.com
    
           Be happy Don't go for a non functional AWG   ..
 

[precaud]

Are these that bad? I mean the price seems reasonable or is there something better at a lower or same price?

There's a lot of hyperbole flying around about how bad the FY6900 is. Sometimes I wonder if these folks actually use test equipment for anything, or whether they just test and opine on it. It takes very little effort to make this a very usable FG. Mine is replacing my HP 8116A while it gets cleaned, recapped, and a quieter fan in my spare time. I like the HP's user interface better. Very fast and easy. But the little FY is doing OK otherwise.