Breadboarding a Eurorack Sample and Hold

In this video I am going to go over a sample and hold circuit, and how to build it on a bread board.
For those of you have haven't seen it in the lofi module here is the first video
• LoFi Eurorack Module P...
recklessexperimentationaudio.com

[@jimmy_jamesjams_a_lot4171]

THANKS! You’ve brought my mind to one of those “Eureka” moments, this one over understanding Sample and Hold! I know I’ve watched other videos but I was actually paying close attention to yours. Really cool how you’ve actually shown your prototyping, and even shared a really cool method for mounting your breadboard to a panel. I often like to just mount a pot or switch to panels that don’t do anything at all, but tell people that it’s the ultimate mod if they ask. Thanks for explaining Sample and Hold, great job!!

[@cnfuzz]

love your breadboard projects , thank you

[@danobrien3292]

Fascinating and enlightening. Thank you for the plain-speak demonstration. I plan to build one of these circuits for my Buchla which is +/-15V. Would that have an impact on the resistors or caps sizing? I may build a +/- 12V on my breadboard so I can use my eurorack power to test it. Don't want to damage the Buchla. Then upsize the components. What size Ecaps are those that you use to purify the power source to the breadboard?as needed

[@Recklessexperimentationaudio]

I think it would be an identical circuit on a +/- 15 volt supply. I generally use 10uf 25V caps for power filtering (+ or - power rail to ground), and 50V ceramic caps for everything else. The op-amps are good to 36V total supply voltage. Resistor values shouldn't need to change either.

[@danobrien3292]

Thank you so much@@Recklessexperimentationaudio . Makes perfect sense. Your schematic show you using a pair of 104s for power filtering (only needed on breadboard, not needed on a pcb?) and a 103 for your input to gnd reference. but what was the other capacitor you used to slow down the input to the 3904? A 20? C36.

[@Recklessexperimentationaudio]

@@danobrien3292 104 or 100nf cap are recommended to be placed as close to the chips as possible for best noise reduction. All the chips should get one on each power rail. The 20pf cap is to provide a pulse of current to the 3904 to capture the voltage sample. higher value longer sampling time, I found 20pf worked for me.

[@federico8918]

Awesome video! Is it good for feeding it white noise to generate random voltage? Thanks for sharing!

[@MJLouer]

How can i eliminate the high pitch bleed??

[@user-mp1tk3fq6r]

Amaizing and also simple circuit! Would really love to build one. But could you please answer a dumb question, what is c36 caps value?

[@danobrien3292]

Your circuit worked great on a breadboard, but on perfboard noise frequencies are too high, clean when I run the noise through a LP filter. Should I consider changing the values of my component’s? I’m getting 50pF on trigger and 9nF on the 5 pin to ground. Or do I add a LP gate, (resistor/cap)

[@Recklessexperimentationaudio]

Might want to try cleaning the flux off the perf board. Sometimes, on high impedance circuits, the flux residue can become slightly conductive. This can cause voltage leakage to different parts of the circuit. Fortunately the fix is easy.

[@danobrien3292]

Interesting, your schematic show a TL082, but your video indicates that you opted for the TL072; is that because of what you had on hand? I think I will try both to see which performs better, if there is any difference at all.

[@Recklessexperimentationaudio]

I accidentally typed an 8 instead of a 7. That being said, for this application, I think the two chips would work the same.

[@danobrien3292]

Actually the TL082 works a little better for my eurorack V/oct modulation purposes. Thank you this circuit performs better than one that uses TL074 and JFET.

[@cnfuzz]

can you post a simple logic gate circuit