[sdiy] There is no fun analogue chips anymore!

[nvawter at media.mit.edu]

Just wanted to say thanks for these PDFs.

And skimming them actually made me think...  sometimes people have  
inclinations to tune things by ear and maybe this is part of the  
reason...  perhaps they aren't tuning things so arbitrarily, but  
tuning them toward the technical ideals that they can't reach with  
non-ideal parts...   fascinating.


Quoting Paul Schreiber <synth1 at airmail.net>:

> Required reading:
>
> http://www.electrical-integrity.com/Paper_download_files/EPEP03_cap_models_poster.pdf
>
> http://www.electrical-integrity.com/Paper_download_files/DC11_13-TH2Paper_Novak.pdf
>
> or as I like to call it "What they leave off the data sheets".
>
> Paul S.
> /former TDK capacitor FAE
> //Shhhh...it's a secret.....sigh......
>
>
>
>
> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl  
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Dan Snazelle
> Sent: Friday, June 29, 2012 8:08 AM
> To: Barry Klein
> Cc: sdiy diy
> Subject: Re: [sdiy] There is no fun analogue chips anymore!
>
> On Jun 28, 2012, at 4:19 PM, Barry Klein <Barry.L.Klein at wdc.com> wrote:
>
>> Many designers don't realize that effective capacitance drops often  
>> 50% with DC across multilayer type ceramics - and this varies  
>> between manufacturers and voltage ratings.
>> I hadn't come across any that got worse over time though.  Any  
>> background on this - a particular vendor?
>>
>> Barry
>>
>>
>
>
> Woa! This sounds like a potential nightmare.
>
> So does this mean that I should not use ML caps in parts of my  
> circuits where Dc exists? Can you explain this more?
>
> Are plain old (cheap brown disc) ceramics at risk also?
>
>
> Thanks
>
>
>
>> -----Original Message-----
>> From: synth-diy-bounces at dropmix.xs4all.nl
>> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Gordon JC
>> Pearce
>> Sent: Thursday, June 28, 2012 12:26 PM
>> To: sdiy diy
>> Subject: Re: [sdiy] There is no fun analogue chips anymore!
>>
>> On 28/06/12 20:16, Pete Hartman wrote:
>>> So I have displayed my ignorance publicly again :-)
>>>
>>> Thanks for the pointers.  Glad to see it's not as complicated as I
>>> had thought from some long past exposure to things like "flowing
>>> solder with a toaster oven".
>>>
>>> Pete
>>
>> http://www.gjcp.net/~gordonjcp/capacitor.jpg
>>
>> That was taken with a cheapy USB microscope.  It's an 0.1?F ceramic  
>> capacitor in a Kenwood HT, part of the mic preamp, and like all  
>> little ceramic caps prone to going leaky if there's a DC voltage  
>> across them - like, uh, the preamp bias voltage.  The replacement  
>> in the picture was hand-soldered, cleaned up with some flux  
>> cleaner, and you'd hardly tell it had been touched.  I used a  
>> fairly pointy soldering iron tip and some tweezers that I'd  
>> reshaped a little to be better at picking up tiny grain-of-sugar  
>> components.  I didn't use the USB microscope because it is too  
>> "laggy" to update.
>>
>> Now, I don't need glasses, but I'm 38 and I can tell my eyesight isn't
>> as sharp as it was ten years ago ;-)
>>
>> It's not that hard...
>>
>> --
>> Gordonjcp MM0YEQ
>>
>>
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