Hey folks, so given that I'm sure these FNIRSI devices have popped up on people's radars I thought I would share my experience with the DSO-TC4, a combination signal generator, oscilloscope, transistor tester.
I purchased this device primarily for the SigGen and Oscope abilities. There are a couple cheaper devices available from them that have only this functionality, but I figured it would be useful to have a device on the bench that can also fulfill testing duties. It's hard to find many SigGen Oscopes at this price point.
The device looks a lot more high end than many of the cheaper devices available on Amazon/eBay/AliX etc. I would say a lot more of the dev budget went to the optics of the device than the firmware but I'll get to that later.
I've actually been quite happy with the SigGen and Oscope functionality. It has a single channel for signal generating and it has a single channel for the oscilloscope. The SigGen can span the entire audio spectrum and quite a bit more. However, there is a quirk, if you wish to run the Oscope and SigGen at the same time, the SigGen is locked to 1khz. Not an issue for my pedal testing, but for HF work, not so great. Another problem is the SigGen output voltage has no units attached. It turns out the output is specified in V Peak to Peak, but it doesn't tell you that anywhere (not even in the manual) and there is no option to specify a different unit, like RMS for instance.
The Oscilloscope is easy enough to use and again performed really well in the audio range, it has a fairly high max voltage of 400v in the 10x mode. I found it calibrated itself nicely on all signal I tried it with.
I don't rely on the device for anything critical, but it has been really helpful for calibrating my recording setup when I'm doing NAM captures. If all you care about is the SigGen Oscope functionality, I think personally the cheaper 1ch option, or the 2ch options might be a better choice than the DSO-TC4 and that's because of the device tester.
The device tester isn't the best. It did fine on the basics, resistors, caps, inductors, diodes. But the transistor testing, at least for Germaniums was not very useful. These are the parameters it can detect:
Amplification factor“hfe”；
Base-Emitter voltage“ Ube”, Ic/Ie, Collector-
Emitter reverse leakage current“Iceo”, Ices,
Forward voltage drop of protection diode“ Uf"
This is the reading on a 3AX31C... oof.
To be fair, I am expecting to receive some better functioning devices to test in the near future and I will report back, but this wasn't great. It did correctly identify PNP vs NPN at least. Further, when I floated the emitter, it did detect a diode with the type of forward voltage I would expect for a Ge. Maybe the devices were just too garbo for the tester, we shall see.
It seemed to do fine on a BS170, and I don't currently have any TH JFETs to test, hooking up an SMD to this using the provided clips was a nightmare so I gave up. The LCR-P1 does have that handy SMD adaptor, but reports on that aren't so great, so unless I hear about a firmware upgrade, I won't be investing in one of those.
TlDr then, I'm not unhappy with my purchase. The SigGen Oscope aspect has opened up some interesting data analysis avenues for me and I'm happy with it on that aspect alone. The device testing is a mixed bag, it's handy on the basics, but there are question marks around older Ge transistors.
I purchased this device primarily for the SigGen and Oscope abilities. There are a couple cheaper devices available from them that have only this functionality, but I figured it would be useful to have a device on the bench that can also fulfill testing duties. It's hard to find many SigGen Oscopes at this price point.
The device looks a lot more high end than many of the cheaper devices available on Amazon/eBay/AliX etc. I would say a lot more of the dev budget went to the optics of the device than the firmware but I'll get to that later.
I've actually been quite happy with the SigGen and Oscope functionality. It has a single channel for signal generating and it has a single channel for the oscilloscope. The SigGen can span the entire audio spectrum and quite a bit more. However, there is a quirk, if you wish to run the Oscope and SigGen at the same time, the SigGen is locked to 1khz. Not an issue for my pedal testing, but for HF work, not so great. Another problem is the SigGen output voltage has no units attached. It turns out the output is specified in V Peak to Peak, but it doesn't tell you that anywhere (not even in the manual) and there is no option to specify a different unit, like RMS for instance.
The Oscilloscope is easy enough to use and again performed really well in the audio range, it has a fairly high max voltage of 400v in the 10x mode. I found it calibrated itself nicely on all signal I tried it with.
I don't rely on the device for anything critical, but it has been really helpful for calibrating my recording setup when I'm doing NAM captures. If all you care about is the SigGen Oscope functionality, I think personally the cheaper 1ch option, or the 2ch options might be a better choice than the DSO-TC4 and that's because of the device tester.
The device tester isn't the best. It did fine on the basics, resistors, caps, inductors, diodes. But the transistor testing, at least for Germaniums was not very useful. These are the parameters it can detect:
Amplification factor“hfe”；
Base-Emitter voltage“ Ube”, Ic/Ie, Collector-
Emitter reverse leakage current“Iceo”, Ices,
Forward voltage drop of protection diode“ Uf"
This is the reading on a 3AX31C... oof.
To be fair, I am expecting to receive some better functioning devices to test in the near future and I will report back, but this wasn't great. It did correctly identify PNP vs NPN at least. Further, when I floated the emitter, it did detect a diode with the type of forward voltage I would expect for a Ge. Maybe the devices were just too garbo for the tester, we shall see.
It seemed to do fine on a BS170, and I don't currently have any TH JFETs to test, hooking up an SMD to this using the provided clips was a nightmare so I gave up. The LCR-P1 does have that handy SMD adaptor, but reports on that aren't so great, so unless I hear about a firmware upgrade, I won't be investing in one of those.
TlDr then, I'm not unhappy with my purchase. The SigGen Oscope aspect has opened up some interesting data analysis avenues for me and I'm happy with it on that aspect alone. The device testing is a mixed bag, it's handy on the basics, but there are question marks around older Ge transistors.
