Products > Test Equipment
FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
danco:
Where did you buy in BG with free shipping, my suplyer of choice (TME) doesn't seem to stock it?
soundtec:
Heres a comparison between the chips I have in my 6600 and the ths 3491, shows very much improved linearity and bandwidth ,I might order the 3491's for my 6800 ,upto 420ma of current x2 ,did you replace the power supply too Bdivi? looks like these new chips could signifgantly reduce harmonics by up to 10 db,the specs quote harmonics for the 3491@50mhz and the 3091@10mhz so if they were measured on a like for like basis you would expect very much improved performance from the 3491 .Which component package is the most appropriate for the upgrade?
Have you done any comparisons before and after the op amp upgrade Bdivi ,to confirm the much reduced distortion of the waveform ?
DaveR:
Hi soundtec - I think you forgot to post the comparison you mentioned.
By coincidence, I've just received a 6800 which I ordered a week ago, just before C82 blew on the 6600. It's got a KKMoon logo on the front instead of FE, but it's still a Feeltech instrument - just 20% cheaper! I was just about to use the £20 saving to buy a D75J oscillator for it, and replace the THS3002 with 3095s as in the FY6600, but then I thought I may as well try the 3491s instead to see what happens. They'll be a big improvement over the 3002, I know, but now I'll be able to do a comparison against the 3095s as well, where the difference might not be so visible.
The under-load voltages from the SMPS are 4.958, +11.792 and -11.953, so pretty good except for the +ve rail being a bit low. I'll see how it gets on before I consider any mods to the PS this time.
The D75J is an essential though - I did a frequency stabilty test starting them both from cold, and the FY6800 took over 50 minutes to settle down, compared with just 10 minutes (probably less) for the FY6600. The total deviation was 41ppm for the FY6800 and just 1.5ppm for the FY6600, so it was a no-contest.
Amusingly, the FY6800 came with a non-UK mains lead and an adapter plug - which has a plastic earth pin!! I suppose the seller would claim he just sells them, and doesn't have to know anything about them?!
Dave
soundtec:
http://www.ti.com/product/ths3491#
Thats the link to the comparison chart with the 3095 , I forgot to post it
Thats a night and day difference with the DJ75J too ,I might get a pair of them in .
I swapped out the diodes in the switcher I use on my 6800 ,with low forward drop diodes on the outputs of the rails +/- ,I instantly got a much better voltage balance across the rails ,the difference now is only a few tens of millivolts ,and I also gained a couple of hundred millivolts bringing my rails to 11.9 volts , might be a simple worthwhile mod for others too .,
In the case of the ths 3491 I fairly sure the heatsink will need attention ,even with the 3095 with both channels flat out into 50 ohms ,quite a bit of heat is generated ,with 3491 its almost double the current and the heat.
It is a bit funny that the cost of the upgrades ,2x3491 and DJ75J arent too far off the cost of the unit itself maybe the 15mhz model at least ,still very much worth the effort for me though . My guess is the upgraded 66 or 68 measures up well against even machines at multiples of price ,you'd probably need to get a sig gen with variable clocking to get much better performance and they usually cost 1000$'s.
Mr. Scram:
Is this thread about the FY6800 now too? Maybe it's a good idea to change the title to represent this. :)
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