ok great! I will when I have a spare moment think of a couple of different resistors over the pulse width circuit which limits the throw of the knob like I other designs for people who would rather the lack of the drift right at the extremes. coolio! glad its like mine, hardly a noticeable thing, especially when in a bank of oscillators. and right at the extreme. all good! glad its coming together!@
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I looked at the schematic for some inspiration on how to program my peak meter in my mixer to also be a tuner on the cue bus. A question about the schematic: Isnât the 3340 ramp output 0-10 V and the maximum on the analog input pin on the Arduino 5V?
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Hi Sam
Are these the right ones?
https://www.taydaelectronics.com/review/product/list/id/3048/category/98/
They are sold out at Rapid, I assume u bought them al 
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yep they look right!
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3340 ramp out is 0-8 V with a ±12 V supply (2ĂVcc/3). The waveforms in the datasheet are for ±15 V supplies.
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Ah, OK. But still more than 5V to the Arduino.
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The AVR chips have clamping diodes on all inputs, which keep the voltages between â0.5 V to Vcc + 0.5 V, so as long as you donât fry the diodes, the chip will survive higher input voltages (thereâs an Atmel appnote that shows how to detect zero crossings in 240 V AC with two 1M resistors and nothing else).
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Ok, thank you didnât know that.
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Went looking at the schematics, and it looks like ramp out is connected via a 1k resistor, which seems a bit low â iirc the appnote recommended keeping the current through the diodes below 1 mA. Iâd try maybe a 4.7k instead.
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10k/47k - WTF DOES THIS MEAN??? -_-
Just got to this resistor in the build⊠anyone have an answer?
I read above a little bit but idk wtfâŠ
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The different resistor values are recommendations for the two different versions of the 3340 chip. Try both and decide which works for you.
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From Samâs web page:
âYouâll notice as per the Datasheet the AS3340 and the CEM3340 require different pull down resistors for the square output. ILL LET YOU INTO A LITTLE SECRET. it doesnât make a difference. infact in all the ones i have build i just split the difference and put a 20k in place of the 47/10k, and for all intended purposes its fine, its your life donât be scared by naysayers and pedanticâs on the internet.â
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The 10k/47k resistor is a pulldown for the pulse output (pin 4), which is an NPN open emitter, i.e. a transistor with the collector connected to +V and the emitter connected directly to the output. The transistor pulls the signal up when on, and leaves it floating when off (which is why you want the pulldown).
The AS3340 data sheet suggests 51k, but the pin can source at least 2.8 mA so in theory you can go as low as ~3k without breaking things, but the pulse peak voltage will suffer. 20k is a pretty good choice if you want max signal, or you can go a bit higher.
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Can confirm. I tried several values last time with fuck all difference. As Fred pointed out, itâs less about breaking things, and more about comparable signal output. In my exp however, even the two suggested values seemed to be putting the level of the pulse either higher or lower than the saw, but never as low output as the tri. It totally makes sense that the tri would be lower, but i mean, if one waveform is going to be way lower than them all, i just figure w/e works.
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Yeah, pulse is +Vcc minus voltage drop over the output transistor (which depends on current, but is nominally +Vccâ1.5V), while triangle output is fixed at +Vcc/3 (so 4 V with a 12 V supply) and any non-trivial load will affect the tuning (so you really want a buffer on that one). Ramp/sawtooth is +VccĂ2/3 (8 V), with more internal buffering.
(there may be an argument for turning triangle or ramp into PWM outside the chip to make things more stable, cf the AS3340-HYB variant discussed here, but havenât experimented with that);
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Question about the Rotary Switch Wiring and placement of the shunt.
The 1 (no hole) 2 (1st hole) 3 (2nd hole) 4 (3rd hole) 5 (4th hole) - so would the shunt go in spot 4 (3rd hole) or spot 5 (4th hole)
And for the Wiring -
I am getting a little confused because I was just watching the build Video and the silk screen on the board shows -
GND (1st pin) 1V (2nd pin) 2V (3rd pin) 3V (4th pin) 4V (5th pin) Arrow/Central (Center Pin)
I put the wires in before watching the video thinking that GND should be a black wire, lol.
So, is this the correct way to wire this -
Thanks all.
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well shit
so i figured the wiring outâŠ
went to pop her on for the first time and fried the TL074âŠ
and likely the arduino.
Pulled the ICâs and tested what like I should have in the first place and well⊠a bunch of my pins are spitting out 24v⊠and I am absolutely perplexed.
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Did you accidentally plug the power into the âlinkâ port? (same connector, wrong port) That would feed +12V into GND and â12V into ramp out (which is connected to a TL074 output).
EDIT: Oh, didnât see the video. Yeah, looks like you powered the wrong thing No idea what happens on the power pins if you run voltage backwards through a TL074, but with a little luck you only fried that one (U1).
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holy fuck. LMAO yes. I did.
I believe i fried the arduino, but not positive - the TL074 was shot lol.
It is getting proper voltages but when i powered it up, the arduino light was red and the front leds and the tuner screen turned on then turned off.
So not really sure, gonna try another arduino i think (and TL074 lol)
*** update:
Video update :
Now hereâs the issue
Blinky blinky scramble screen everything go bye bye. Lol
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