Comparing cheap signal generators

[MarkMLl]

I know that there are multiple threads discussing these, but has there ever been a consensus regarding the relative merits of the JDS6600 (Juntek, frequently rebadged) and the FeelElec FY69000?

They seem to be very similar... perhaps a common ancestor? but the Juntek is explicitly supplied with an interface CD and uses a wall wart which implies better isolation, while the FeelElec isn't shown as having a CD but has extra modulation inputs on the back and is explicitly described as having AM modulation.

I've got a couple of things coming up which will involve audio repair and sweeping a signal over a tank circuit. And I enjoy having hardware that I can hook onto a PC if necessary.

MarkMLl

[robot.golem]

I got FeelElec FY6800 60 MHz and generally liked it.  However, it stopped working after a few months: Channel 1 is completely out, and channel 2 has positive DC bias and unregulated amplitude.  I contacted FeelElec about getting the warranty service (they promise 1-year warranty), but in return they send me a series of emails amounting to what I would call a run-around.  Still waiting for them for instructions on how to obtain the warranty service.

Anyone has repair manual/schematics for the instrument?  -- This could be a very long shot for me, but this is the only option before trashing a fairly expensive device.

Also thinking of writing to the Communist Party leaders in these guys' province and city, how their company gives China a bad name in commerce.  Maybe that will catch their attention.

[SpecialK]

I have a Juntek JDS2800 and it's gnerally decent.  However, I've generally outgrown it.  At the time I bought it the Juntek PSG9080 and Uni-T UTG-962 weren't on the market.  I stongly would suggest you checking Youtube reviews on those two.

[MarkMLl]

@robot.golem Noting of course that there are multiple revisions, my notes say

PCB is "Rev.15". All chip identifiers obliterated, TTL outputs via 330R, TTL inputs unidentified.
Don't know whether TTL Rx monitors the CH341 signal or can be used to drive the Big Chip.

Photo of a Rev.10 PCB at

would suggest that the Rx signals are distinct.

I presume that the (Lattice?) FPGA implements a simple CPU for command parsing, although it
would be simple enough for this to have been handed off to the STM32 on the back of the display board.

...so I think it's probably fairly important to get the right board version, and there's still the possibility of gross incompatibilities in the FPGA.

@SpecialK I ended up getting a JDS6600 since I needed something in a bit of a rush and somebody was quoting a good price (subject to international delivery time, and the seller looking as though they had a one-off that they didn't know anything about). So far it's doing what I needed.

I must say that I'm rather taken by the additive encoding used to construct arbitrary waveforms. At some point I'll redo the software for Linux (which will probably also run on Windows, but that's of little interest to me) and will consider enhancing that with a full set of APL-style array operations... not that I'd expect anybody else to notice or to recognise them :-)

MarkMLl