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<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT face=Arial>Well,
it's a fairly big pain in the ass as it is just to grab the 60 or so unique
resistor values needed for the 12-stage Dome filter and the
18-stage Dome filter from the 60 different bags. Just stuffing those
PCBs takes about an hour, even though I have a box with the two sets of
resistors all organized in little baggies in the order in which they are stuffed
in the PCB. And that assumes that I'll have sets of 4+4+4 (102, 103, 104)
caps for the 12-stage filter and 4+4+4+6 (102, 103, 104, 105) caps for the
18-stage filter, all with more or less the same mantissa (to 0.2%). I have
a big inventory table of all my film caps with the four different values
separated into 46 different mantissa bins, from 968/9 all the way up to 1050/1,
so it is easy to assemble sets from my inventory for the two filters. My
inventory table is in the same Excel spreadsheet as my phase displacement
simulations, so if I have to mix mantissa values to make up a set, I can see
what effect this will have on the phase displacement error, and even figure out
the optimum way to arrange the caps within the filter so as to minimize the
error. For example, if I have to mix two adjacent mantissa values to make
up a set (for example, in my last 12-stage filter I mixed 974 and 976 caps), I
have found that it is far better to mix the values so that the average mantissa
is roughly equal between the two filter halves. For example, for the
974/976 mix, I used the following sets:</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT
face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT face=Arial>Filter
half A: 97400-97600-9740-9760-974-976(nF) Filter half B:
97400-97400-9740-9760-974-976</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT
face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT face=Arial>The
limiting factor there was that I only had one 976 104 cap and three 974 104
caps, but I had quite a few of both mantissas in the 103 and 102 values.
Putting them in that specific order gave a phase displacement error which was
scarcely different from the ideal (about 0.2 degrees off of 90 max). As
you can see, I'm fairly serious about building good Dome filters, with the
result that the Freak Shift is probably the best-sounding analog frequency
shifter that money can buy right now (plus, it's cheap!).</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT
face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT face=Arial>Anyway,
bottom line: if I had to customize the 60 resistor values for every Dome filter,
I'd kill myself.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT
face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=662423806-10042021><FONT
face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left>
<HR tabIndex=-1>
</DIV>
<DIV dir=ltr align=left><FONT size=2 face=Tahoma><B>From:</B> Synth-diy
[mailto:synth-diy-bounces@synth-diy.org] <B>On Behalf Of </B>Bernard Arthur
Hutchins, Jr via Synth-diy<BR><B>Sent:</B> Friday, April 09, 2021 6:26
PM<BR><B>To:</B> synth-diy@synth-diy.org<BR><B>Subject:</B> [sdiy] Hand
selecting capacitors<BR></FONT><BR></DIV>
<DIV></DIV>
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Non-UBC Email]</FONT></TD></TR></TBODY></TABLE>
<DIV
style="FONT-FAMILY: Arial, Helvetica, sans-serif; COLOR: rgb(0,0,0); FONT-SIZE: 10pt">
<P
style="LINE-HEIGHT: 107%; MARGIN: 0in 0in 8pt; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt">Oren
Leavitt<SPAN style="BACKGROUND: #fafafa"><SPAN> </SPAN>said F</SPAN><I>ri
Apr 9 17:17:01 CEST 2021<BR
style="mso-special-character: line-break"><BR></I></SPAN></P>
<P
style="MARGIN: 0in; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'">“Would
it be easier to take, say 4 1.03uF caps and nudge any frequency
<O:P> </O:P></SPAN></P>
<P
style="MARGIN: 0in; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'">determining
resistors up/down as needed?”<O:P> </O:P></SPAN></P>
<P
style="MARGIN: 0in; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P
style="TEXT-ALIGN: justify; MARGIN: 0in; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'">Indeed
– TRUE – see my frequently referenced, (even just in January):</SPAN><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; FONT-SIZE: 12pt"><O:P> </O:P></SPAN></P>
<P
style="MARGIN: 0in; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><O:P></O:P></SPAN></P>
<P
style="MARGIN: 0in; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt; tab-stops: 45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'">“Design
of Wideband Analog 90° Phase Differencing Networks Without a Large Spread of
Capacitor Values”; </SPAN><U><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: #d00000; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><A
href="http://electronotes.netfirms.com/EN168-90degreePDN.PDF">http://electronotes.netfirms.com/EN168-90degreePDN.PDF</A></SPAN></U><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; COLOR: black; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><O:P> </O:P></SPAN></P>
<P
style="LINE-HEIGHT: 107%; MARGIN: 0in 0in 8pt; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; FONT-SIZE: 12pt"><O:P></O:P></SPAN></P>
<P
style="LINE-HEIGHT: 107%; MARGIN: 0in 0in 8pt; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; FONT-SIZE: 12pt">Using this
state-variable approach (outside in), you can use a handful of 1% caps (ALL the
SAME value) and trim the poles with the resistors.<O:P> </O:P></SPAN></P>
<P
style="LINE-HEIGHT: 107%; MARGIN: 0in 0in 8pt; FONT-FAMILY: Calibri, sans-serif; FONT-SIZE: 11pt"
class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial',sans-serif; FONT-SIZE: 12pt">-<B>Bernie<O:P> </O:P></B></SPAN></P><BR></DIV></BODY></HTML>