Hiya. I picked up a 1222 Tuner VCO recently, and couldn’t get the CEM3340 in stock, so I picked up an AS3340 clone. Sod’s law dictates of course that Thonk just got the CEM3340 back in stock, for a reasonable price. Sooo now I am wondering whether it’s worth picking up the CEM3340, or if they are so similar in practice that it’d be silly to do so.
Has anybody futzed about with both and noticed any significant differences etc that I should be aware of? Should I just buy one and play about with it?
I bought a CEM3340 but the first thing I did with it was to plug it in backwards and the second thing I did with it was to throw it away. Then I bought and have been using (and not plugging in backwards) AS3340 and AS3340A and they’ve been fine.
The manufacturers recommend different values for the pulse wave pulldown resistor, though the effect of that seems to be small from the tests I’ve done, and Sam says he’s used both values with both chips with no problems. Other than that they’re supposed to behave the same.
The AS3340A is supposed to be better than the AS3340:
AS3340A/AS3345A … have much more output frequency stability against VCC and VEE . … AS3340A/AS3345A benefits from improved symmetry of rising and falling edge of triangle signal (approx… 50%).
I haven’t really noticed a difference but haven’t spent that much time comparing. I chose an AS3340A for the VCO I’ve been working on. Then again, I only have one AS3340 and I’m not sure where it’s gotten to…
Believe it or not, the CEM3340 at Thonk is about the same price as the AS3340, which is why I am toying with the idea of picking up another one. It’s only a tenner shipped!
I got my AS3340 at Soundtronics in the UK for just under £5, though with postage it was closer to £9 I think. Thonk - for the chip and UK postage is £11.
