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Vintage Synth Repair

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Re: [vintagesynthrepair] Re: CS80 Shelving filters

2008-10-12 by Max Fazio

r_j_d_2.phila, thx for your reply
HPF+LPF ?
Are you talking about the master filters? Yes I know there are HPF+LPF: I would like to know another thing: on every poly CS, just before the speakers' jack output, there is a network that gets the voltage from the expression pedal, but it isn't the EXP-WAH circuit, as it is placed earlier in the sound path; this is the place where the action of the pedal is converted to be sent as control voltage to EXP-WAH; this network works around two photoresistors (Vactrol) ; ok , now if you look at the picture I posted on the "files" section of the group you'll see that the sound (fat orange arrow) is passed to what seems another filter; as I'm not such an expert about reading schematics someone told me this is a LPF: now I'd like to know if this filter is an EQ filter able to low shelf the sound or is it instead a common LPF...
Thx for reply!
M
----- Original Message -----
Sent: Sunday, October 12, 2008 5:35 AM
Subject: [vintagesynthrepair] Re: CS80 Shelving filters

there is a hi pass and low pass filter in series on the cs80-is that
what you are asking?

--- In vintagesynthrepair@yahoogroups.com, "maxferfranc"
.> wrote:
>
> Hi all
> As declared inthe files section there is a new image of the outputs
> from the Yamaha CS80 (same on other CS poly synths); leave the Vactrol
> for a moment: just would like to know if these are lowpass shelving
> filters, as they are used by the pedal to control the volume,or instead
> they are common lowpass filter: could anybody tell me if are they two
> pole filters?
> Thx for any help!
> Max
>

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