Signal generator choice

[malagas_on_fire]

"....with a leakage current of close to 1mA at 90V AC...."

Opppsss:

https://sdgelectronics.co.uk/feeltech-fy3200s/

This is not acceptable by me. I could mod easly if it was a used unit, but a brand new unit must comply with our electrical standards.  Also the time and effort maybe would be a better isolated product. 

At least this model i can use one of my USB power cords which has proper isolation and it's more like what i've used in the past

https://ebay.us/IEFesp

[malagas_on_fire]

Well i've found a way to bypass the problem. Use the brand new isolation transformer 12VA  

[Mr. Scram]

The FY6800 is supposed to have that issue fixed.

[JS]

The FY6800 is supposed to have that issue fixed.

Yes, it's grounded! That the issue with SMPS, and if you want it tl be floating you still need capacitive coupling to ground, other models from feel tech doesn't have ground connections at all. For other models you could ground it from a BNC, as you won't use every BNC at  any time but I don't know how well it would work and even then is not ideal.

JS

[malagas_on_fire]

Hi

i ask for cancel the order and bought this cheapo one that is powered by USB. it has the basic stuff to revived the old memories, it can be used with a good USB power brick,   or a power bank , and good usb cable:

https://ebay.us/VDZTD0

Later i'll step up this option has well the scope.

[Mr. Scram]

Hi

i ask for cancel the order and bought this cheapo one that is powered by USB. it has the basic stuff to revived the old memories, it can be used with a good USB power brick,   or a power bank , and good usb cable:

https://ebay.us/VDZTD0

Later i'll step up this option has well the scope.

You'll need to test whether USB ground connects to BNC ground and take appropriate action if it does. You can be in for a nasty surprise otherwise.

[JS]

  Hi, while we are at it, I'll be seeing an analog generator on Sunday, I'm acctually going to look for a power supply, but as I'm at it the seller offers the generator as well and I'm after one too. The main drawback is it's 2MHz only, but it has quite a lot of features not present in the most basics generators. Sweep generator, AM, and more interestingly, in the back, VCF in, CFV out, TTL output and modulation input. I leave a few pictures from google and the link to the paused publication as I go to see it. The unit is a Leader LFG-1300S
https://articulo.mercadolibre.com.ar/MLA-738623741-generador-funcionessweeper-lfg-1300s-leader-japon-mlab-_JM

  The price is about $140, it's likely U$ goes up tomorrow as we are going through rough times so the price might drop, and I can probably get a nicer deal as I get the two units. (A power supply, old school, also branded Leader, LPS-152 tracking ±25V 1A and 6V 5A) Both units are very well documented and maintenance doesn't seem so hard, in case something happens, pretty trustable units, recapping it might not be a bad idea. There are quite a few of this Leader things on fleabay, the price for the PS agrees about there with international prices, which is a great thing here. The price for the sig gen doesn't, is a bit higher but looks in really good shape. I'd be getting a 6800 for that money, which sounds tempting for the features, but the reliability of this seems much higher and I could probably sell it for about the same later, if it comes to that. I haven't seen much about it online, no good reviews or testing, some repairs but nothing too trending to one failure mode, dirty switches mostly.

  What do you say? Should I go for it? Note that I don't have any gen, using my phone for that so far, 2MHz is a great upgrade. The possibility of selling it again is also there so I'm not too worried if it's all working fine, and I'm going to test it before bringing it home, which is great!0

JS

[ferdieCX]

Hi JS,

I bought a second hand Leader LFG-1300 eight years ago, and I am very satisfied with it.

[JS]

Hi JS,

I bought a second hand Leader LFG-1300 eight years ago, and I am very satisfied with it.

Thanks! I'll see how it goes.

Even if it has some limitations, like lack of slow enough sweep for the lower frequencies, as it can be controlled externally I could put something together to generate the slower sweeps. If I do any of those tweaks I'll be sure to post them here.

JS

[malagas_on_fire]

Hi

i ask for cancel the order and bought this cheapo one that is powered by USB. it has the basic stuff to revived the old memories, it can be used with a good USB power brick,   or a power bank , and good usb cable:

https://ebay.us/VDZTD0

Later i'll step up this option has well the scope.

You'll need to test whether USB ground connects to BNC ground and take appropriate action if it does. You can be in for a nasty surprise otherwise.

I'll let you know when i got it. It is supposed to be in the next week.

By he way here is the english manual , that i couldn't find in the feeltech webpage :

https://www.insidegadgets.com/wp-content/uploads/2015/06/FY21xxS-User_s-Manual_V2_2.pdf

Some of my USB wall chargers present 80Vac volts between earth and GND of USB port in open, but when loaded it vanishes.

[JS]

Hi

i ask for cancel the order and bought this cheapo one that is powered by USB. it has the basic stuff to revived the old memories, it can be used with a good USB power brick,   or a power bank , and good usb cable:

https://ebay.us/VDZTD0

Later i'll step up this option has well the scope.

You'll need to test whether USB ground connects to BNC ground and take appropriate action if it does. You can be in for a nasty surprise otherwise.

I'll let you know when i got it. It is supposed to be in the next week.

By he way here is the english manual , that i couldn't find in the feeltech webpage :

https://www.insidegadgets.com/wp-content/uploads/2015/06/FY21xxS-User_s-Manual_V2_2.pdf

Some of my USB wall chargers present 80Vac volts between earth and GND of USB port in open, but when loaded it vanishes.

That's why usually current is measured, which makes more sense to represent the leakage from mains to isolated ground. The question that was asked to you was about the BNC and USB in the generator.

JS

[malagas_on_fire]

Hi i found another DDS that is powered by external 5V power brick and has more features than the one i've ordered.

https://ebay.us/qc8KzX

[Microcheap]

Hi i found another DDS that is powered by external 5V power brick and has more features than the one i've ordered.

https://ebay.us/qc8KzX

There is a newer version of this MHS5200A function generator with some improvements, the details are discussed in this thread https://www.eevblog.com/forum/testgear/mhs-5200a-function-generator-teardown-review-reverse-engineering/msg724647/#msg724647 or https://youtu.be/TQXd7u4kPvs

[JS]

Hi JS,

I bought a second hand Leader LFG-1300 eight years ago, and I am very satisfied with it.

  I got it, the ranges go far beyond specs to the low side, so the sweep can be very slow. Even then, the seep generator is hard to know what's putting out, the lower freq is the fixed but the higher you never really know what it is, so I'm not sure, I should play a bit more with it. I did a calibration yesterday, many tweaks were required but the freq is bang on now.

I also got the Leader power supply, pretty nice gear! I will make a review when I make time for it, I didn't found any when I was looking to buy them.

JS

[malagas_on_fire]

Here are the Fy2100 signal generator tested with my cheapo scope.

It camed with power brick, BNC cable and USB A to B


Square wave becomes undershoot due to bandwith limit of scope, so stopped to 1Mhz. Also triangle wave has some curvature in that frequency
(Edit Forgot to put image on the square wave and switch from DC to AC in some pictures )
At 100Hz i can't see in my scope any distortion because of it's low resolution.

I've tried in the Khz range up to 200 by adjusting the ADJ knob and it seems fine.

The only thing i see is atennuation on the signal ( around 100mV or more of 1Vpp ) when the frequency is increased to the maximum 2Mhz

It has a simple interface, lightweight and has no leakage from mains.(Edit)... when powered by a USB power bank but using power brick it revealed 96V and around 60 uA of leakage.

[LogicalDave]

I have several signal generators including the SDG1025, DG1022, and several high-end RF signal generators (IFR 2025).  When only considering signal generation, the DG1022 is very slightly better than the SDG1025 due to the ability to synchronize and offset channels, but overall I prefer the SDG1025 for two reasons:

• The frequency counter feature - this is surprisingly useful
• The ability to easily replace (via hack) the internal crystal oscillator with a high-precision (0.1ppm) TCXO

The two downsides of the SDG1025 are:

• The airflow arrangement makes it a little noisy; the fan itself is quiet, but the airflow through the vents is loud enough to be annoying in a quiet room: it makes a steady rushing sound like a white-noise generator.
• The frequency counter feature (which is great) is buried under several menu layers; it should really be a top-level menu choice. @Siglent, if you ever release another firmware update for this model, please consider this.

Perhaps @tautech or @Siglent know whether newer models fix the airflow noise and still support the TCXO hack? I know you can always connect an external standard (and I usually do), but a high quality internal standard is often very useful and in the case of the SDG1025, and many users may not have a separate GPSDO or similar standard.

[tautech]

I have several signal generators including the SDG1025, DG1022, and several high-end RF signal generators (IFR 2025).  When only considering signal generation, the DG1022 is very slightly better than the SDG1025 due to the ability to synchronize and offset channels, but overall I prefer the SDG1025 for two reasons:

• The frequency counter feature - this is surprisingly useful
• The ability to easily replace (via hack) the internal crystal oscillator with a high-precision (0.1ppm) TCXO

The two downsides of the SDG1025 are:

• The airflow arrangement makes it a little noisy; the fan itself is quiet, but the airflow through the vents is loud enough to be annoying in a quiet room: it makes a steady rushing sound like a white-noise generator.
• The frequency counter feature (which is great) is buried under several menu layers; it should really be a top-level menu choice. @Siglent, if you ever release another firmware update for this model, please consider this.

Perhaps @tautech or @Siglent know whether newer models fix the airflow noise and still support the TCXO hack? I know you can always connect an external standard (and I usually do), but a high quality internal standard is often very useful and in the case of the SDG1025, and many users may not have a separate GPSDO or similar standard.

SDG1000 series are an old design superseded by the much improved SDG1000X models so apart from any newly discovered bug I see little further development done on them, sorry.
I had the fanless SDG1010 for a few years but replaced it with SDG1032X that you can sync channels however the Counter is still buried in a menu.