[sdiy] Deadbugging a buffered mult :)

[Quincas Moreira]

Hey Tony, thanks :)

You are right about the design. This is just what I had working for years in my 4U system. i reduced the output resistor from 1k to 100r because i was getting a voltage drop, probably due to the 1m resistor in the input, lol. I'm getting a lot of excellent feedback from my EE friends though, so I might have to make a followup video showing possible improvements.

I deadbugged it for a few reasons: 
To make the video interesting - not a lot of people know about deadbugging, so this is a cool project to introduce the concept. 

A stripboard would have required some way to mount it to the panel. Deadbugging seemed easier and more compact.

i love the sound of the words "Deadbug Buffer" together :)

Again, thanks for your feedback!

All the best

Q



Sent from my iPad

> On Mar 21, 2017, at 10:33 PM, Tony K <weplar at gmail.com> wrote:
> 
> Hi Quincas, 
> 
> I got a hoot out of the sped up panel construction, reminding me of my sampled drum machine project build the same way, onto thick single- clad pc stock. Quick and cheap. I painted mine a cream colour however, not as sexy as the red you got there Sharpie graphics, I used an old Dymo labeler not the thermal one !
> 
> That's not going to be fun if that op-amp goes, as you say, but hey it got the job done. The engineers here are better equipped to comment on the design, but I am not sure the high value resistor is necessary as the input to the J-FET op-amp is low offset high-impedance, and on the output 1 K might be more common that 100 ohm. This is all off the top of my head, I would verify this say in Jung's IC Op- Amp Cookbook , or a good book, text. Of course it works as designed so the rest is all academic. 
> 
> Only pet peeve, is you call the power rails "energizing" pins, but it sounds charming , so it's a minor quibble.
> 
> Question: Why deadbug when proto boards are so handy? 
> 
> Nice video and soundtrack btw,
> 
> Tony K
> 
>> On Mar 21, 2017, at 7:28 AM, Quincas Moreira <quincas at gmail.com> wrote:
>> 
>> Hey beloveds, new video up on Synth DIY Guy! Fun times deadbugging and making a home made panel for a buffered mult. As always, please let me know if I said anything stupid :)
>> https://youtu.be/X4c9jcEzaBE
>> 
>> Cheers
>> 
>> Q
>> 
>> Sent from my iPad
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