Products > Test Equipment
FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
svetlov:
Hello ! Comrades :) - but there is a photo of the insides of the generator model 6900
it’s mostly interesting to see the main board of the generator - and in particular its output part
Thanks friends
DaveR:
--- Quote from: Johnny B Good on August 08, 2019, 03:29:03 am ---As for both yours and DaveR's view that there's no need to fit a cooling fan if either a more efficient smpsu is fitted or else an R type transformer is used for an analogue PSU replacement, I feel I must point out that you're overlooking the fact that both the FY6600 and Fy6800 models were already running uncomfortably hot before any additional heat sources were introduced into the box.
The 25W rated smpsu might be cooler running from its point of view but the fact remains that its efficiency at a relatively low loading may be no better than the crappy original and quite likely adding a little more heat into the box. R type transformers in an analogue PSU aren't the problem, it's the waste heat from the analogue regulators that poses the real threat. R transformers are a good way to go but I'm not so sure about the analogue aspect unless it's being used to eliminate the high frequency ripple of a switching psu with consideration to the penalty of additional waste heat this introduces.
--- End quote ---
I have to admit being rather puzzled by your statements about "running uncomfortably hot" initially, Johnny, as neither my 6600 nor my 6800 has ever run anywhere near a temperature I'd describe as hot. "Moderately warm" is how I'd describe it, but perhaps it's a subjective assessment? The biggest source of heat, by far, after I did the PS mods in the 6600 was from the 7805 regulator, which got to around 75C and created a local hot spot on the top of the case, but I cured this by swapping it for an OKI 78SR regulator, which runs as cool as the rest of the PS. Any heat inside the case now comes from the Cyclone chip and the 3095 op amps, but even then I need to run them very hard for a couple of hours (something I've only done once, as a test) to get them to an elevated temperature. (In real world usage I rarely use more than about 1Vp-p output, so everything stays very much cooler.) In the same test the D75J TCXO had no problem in coping, with only a 0.1Hz drift at 10MHz after the first 10 minutes of warm up, and no drift after the next 15 minutes - pretty much in line with what you'd expect from an OCXO, depending on the level of sub-Hz accuracy you want.
I still haven't bothered to modify the 6800's PS or op amps even though I've had all the parts to do it since I bought the generator about a year ago - the D75J is the only change I've made, as the awful drift caused by the original XO just had to go. The distortion produced by the original op amps is minimal at the levels I use, so I can live with them, and they run cooler than the the 3095 upgrades so heat produced in the case is even less than that in the 6600. Looking back, the 6600 mods were done more for the challenge than out of necessity, but the 6800 works well enough as it now stands, so I'll probably wait until they do become a necessity before I do anything else to it.
Finally, it's nice to see you back Arthur, and thanks for the update on your mods!
Regards,
Dave
DaveR:
--- Quote from: svetlov on August 08, 2019, 12:09:32 pm ---Hello ! Comrades :) - but there is a photo of the insides of the generator model 6900
it’s mostly interesting to see the main board of the generator - and in particular its output part
Thanks friends
--- End quote ---
Is there a link to the photo, Svetlov?
maxwell3e10:
I just got one of these generators. One of the limitations I found (it may have already been discussed here before), is that the number of time points is 8192 even for a sine wave. As a result the "14 bit" resolution is not really realized. There are very visible steps in the sine waveform every 1/8192 of the period and the voltage steps correspond to about 11 bits of vertical resolution. To do it properly the number of time steps should be 2*Pi*(#vertical steps).
I am not sure anything can be done about it, just something to be aware of. Other function generators typically use more time steps.
rhb:
FYI I just sent service@feelelec.com an email asking that they replace the front panels for the 4 people I was able to identify who are forum members with borked V 3.0 units. I was able to furnish shipping information for 3 of them. I never heard from @canyon.
As before I held out my carrot of a detailed comparison against a Keysight 33622A using my HP 8560A spectrum analyzer. I attached some screen shots at under 5 V output levels which are close enough that I don't think you can tell them apart.
So we shall see if there has been a change in attitude or if it is just more BS.
Reg
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