Epic Polar Boost v1.0
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9
Modifications
Charge pump
If you want to leave out the charge pump then do not solder
C8
,
C9
,
C10
,
D2
,
D3
and
IC1
. You must
solder a jumper between pad 1 and 2 on
SW1
like this:
You could also change
D1
back to a 1N4148 like the original.
D1
has no tonal function so it would be
for optics/purism only.
Tone section
This is the interesting part and yes we are going to get a bit techy
. Let’s start by a simple explanation
of the original tone part in the boost.
First of some EQ definitions:
Bass
60 Hz - 250 Hz
Low Mids
250 Hz
–
500 Hz
Mids
500 Hz
–
2kHz
High Mids
2 kHz
–
4 kHz
Treble
4 kHz
–
6 kHz
R5
(1k),
R6
(15k) and
C5
(3n3) form a fixed
high cut/low pass RC filter
with a cut off frequency of:
𝑓
𝑐
=
1
2𝜋𝑅𝐶
=
1
2𝜋 ∙ 16000 ∙ 3.3 𝑒
−9
≈ 3𝑘𝐻𝑧
Note:
R5
and
R6
are in series so
R = R5+R6
= 1k + 15k= 16k
So the original effect cuts off the top high mids and treble part of the signal.
