# CEM3340 or AS3340? **URL:** \ **Category:** KOSMO MODULES\ **Created:** [March 15, 2022, 12:45pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774 "2022-03-15T12:45:28Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![unexpectedbowtie](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/unexpectedbowtie/32/10648_2.png) [@unexpectedbowtie](https://lookmumnocomputer.discourse.group/u/unexpectedbowtie)\ **Post date:** [March 15, 2022, 12:45pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/1 "2022-03-15T12:45:29Z")
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? ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [March 15, 2022, 1:17pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/2 "2022-03-15T13:17:45Z")
There’s a significant difference in price. 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… ---
**Author:** ![unexpectedbowtie](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/unexpectedbowtie/32/10648_2.png) [@unexpectedbowtie](https://lookmumnocomputer.discourse.group/u/unexpectedbowtie)\ **Post date:** [March 15, 2022, 1:28pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/3 "2022-03-15T13:28:50Z")
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! ---
**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\ **Post date:** [March 15, 2022, 2:52pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/4 "2022-03-15T14:52:14Z")
Hmm. Says they’ve lowered the price on the CEM. It’s £8.99 at Thonk versus $14.99 at SynthCube, decidedly cheaper at Thonk. Still, it’s £6.60 for the AS3340A (not the AS3340, which I don’t even see listed). ---
**Author:** ![unexpectedbowtie](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/unexpectedbowtie/32/10648_2.png) [@unexpectedbowtie](https://lookmumnocomputer.discourse.group/u/unexpectedbowtie)\ **Post date:** [March 15, 2022, 3:21pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/5 "2022-03-15T15:21:57Z")
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. I might just get one to try them both out 😃 ---
**Author:** ![eric](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@eric](https://lookmumnocomputer.discourse.group/u/eric)\ **Post date:** [March 15, 2022, 6:20pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/6 "2022-03-15T18:20:35Z")
Anyway, you’ll be building another VCO soon, and then another, and… None of the AS nor CEM will be sitting idle for a long time 🙂 ---
**Author:** ![devicex](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/devicex/32/28_2.png) [@devicex](https://lookmumnocomputer.discourse.group/u/devicex)\ **Post date:** [March 15, 2022, 11:46pm UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/7 "2022-03-15T23:46:22Z")
I have used the AS3340 with no problems . like eric said you will build another so you might as well get both its a sickness … ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [March 16, 2022, 9:18am UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/8 "2022-03-16T09:18:09Z")
I made my 1 VCO with a CEM3340 and all the following ones with AS3340 and I never noticed a difference. btw AS3340 5.25 euro on Electric Duid ---
**Author:** ![unexpectedbowtie](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/unexpectedbowtie/32/10648_2.png) [@unexpectedbowtie](https://lookmumnocomputer.discourse.group/u/unexpectedbowtie)\ **Post date:** [March 16, 2022, 9:36am UTC](https://lookmumnocomputer.discourse.group/t/cem3340-or-as3340/4774/9 "2022-03-16T09:36:18Z")
Haha. I like your thinking. > [@Dud](#): > > btw AS3340 5.25 euro on Electric Duid Nice! I’m in the UK though and since BrexShit everything is 1000x more expensive from the EU. Sigh.