<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hz - per - volt synths don’t need tempcos, do they?<div class=""><br class=""></div><div class="">I have no experience with the MS-20 but I do have a Korg 700 from a few years earlier. It never needs re-tuning.</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 9 May 2017, at 11:53 AM, matt holland <<a href="mailto:matt@mattholland.org" class="">matt@mattholland.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">ebers moll equation: Ic = Is*e^(Vbe/Vt -1)<div class=""><br class=""></div><div class="">a single transistor itself is an exponential converter. the second transistor in the common two transistor expo converter compensates for the complicated temperature dependance hidden in the Is term (Is goes away to the extent that the two transistors are identical). the tempco resistor compensates for the less severe effect of the temperature dependance hidden in the Vt term. gory details of the equation terms can be found in your nearest device physics textbook.</div><div class=""><br class=""></div><div class=""><br class=""></div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Mon, May 8, 2017 at 5:36 PM, Tony K <span dir="ltr" class=""><<a href="mailto:weplar@gmail.com" target="_blank" class="">weplar@gmail.com</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello, those so-called special Rx's are 0.1% or precision resistors , the ones with the circle around the resistor symbol.<br class="">
<br class="">
When we recorded I always had to tweak the Master Tune as time went on. I never bothered adding one either. In mono synths it's not critical , the exponential pair handles the biggest part of the temp drift - forget the equation offhand.<br class="">
<br class="">
Just referring to my notes , it's been a while.<br class="">
<span class="HOEnZb"><font color="#888888" class=""><br class="">
TK<br class="">
</font></span><div class="HOEnZb"><div class="h5"><br class="">
> On May 8, 2017, at 7:48 PM, Declare Update <<a href="mailto:declareupdate@gmail.com" class="">declareupdate@gmail.com</a>> wrote:<br class="">
><br class="">
> wait a second... no tempcos in the MS-20? what's with all the special resistor symbols in the schematic? and how does that super common and known-to-be-temp-dependent expo converter not need compensation?<br class="">
><br class="">
> Chris<br class="">
><br class="">
>> On May 7, 2017, at 4:14 PM, Michael E Caloroso <<a href="mailto:mec.forumreader@gmail.com" class="">mec.forumreader@gmail.com</a>> wrote:<br class="">
>><br class="">
>> That's the one...<br class="">
>><br class="">
>> MC<br class="">
>><br class="">
>>> Anyway, I think Michael E C was referring to this posting of his:<br class="">
>>> <a href="http://search.retrosynth.com/ah/search/lookit.cgi?-v9901.2166" rel="noreferrer" target="_blank" class="">http://search.retrosynth.com/<wbr class="">ah/search/lookit.cgi?-v9901.<wbr class="">2166</a><br class="">
>><br class="">
>><br class="">
>>>> On 5/7/17, Michael Zacherl <<a href="mailto:sdiy-mz01@blauwurf.info" class="">sdiy-mz01@blauwurf.info</a>> wrote:<br class="">
>>>><br class="">
>>>>> On 7.May 2017, at 19:48 , Michael Zacherl <<a href="mailto:sdiy-mz01@blauwurf.info" class="">sdiy-mz01@blauwurf.info</a>> wrote:<br class="">
>>>>><br class="">
>>>>> On 7.May 2017, at 19:04 , Quincas Moreira <<a href="mailto:quincas@gmail.com" class="">quincas@gmail.com</a>> wrote:<br class="">
>>>>><br class="">
>>>>> Michael, thanks for saving me frustration, I will refer to your<br class="">
>>>>> instructions.<br class="">
>>>><br class="">
>>>> uhm .. I didn’t do anything -<br class="">
>>><br class="">
>>><br class="">
>>> whoops *blushes* … the other Michael.<br class="">
>>><br class="">
>>> Anyway, I think Michael E C was referring to this posting of his:<br class="">
>>> <a href="http://search.retrosynth.com/ah/search/lookit.cgi?-v9901.2166" rel="noreferrer" target="_blank" class="">http://search.retrosynth.com/<wbr class="">ah/search/lookit.cgi?-v9901.<wbr class="">2166</a><br class="">
>>><br class="">
>>> sorry, Michael E C, Michael.<br class="">
>>><br class="">
>>><br class="">
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