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Cgs synth

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Re: Cynare filter problem

2008-09-18 by Kendall James

not to beat a dead horse, but i am currently building the cynare, and
the datasheet i have seems to contradict this advice. i'm not really
in the mood to screw it up. ;)



http://www.onsemi.com/pub_link/Collateral/P2N2222A-D.PDF



am i missing something? did i get the wrong transistor? or is it just reversed from most of the 2n2222s?

Kendall


--- On Mon, 9/15/08, Scott Deyo <contact@...> wrote:
From: Scott Deyo <contact@...>
Subject: Re: [cgs_synth] Re: Cynare filter problem
To: cgs_synth@yahoogroups.com
Date: Monday, September 15, 2008, 8:04 PM











There you go. The round part of the transistor goes towards the BP HP

LP holes.



Scott Deyo

The Bridechamber

contact@bridechambe r.com

http://www.bridecha mber.com

Jealous Edison Record Kompany

http://www.jealouse dison.com



On Sep 15, 2008, at 7:49 PM, Dave wrote:



> I am wondering whether I put the transistors in the right way. I am

> using TO92 style trans that are black plastic with one flat side.

> Right now I have all the 2N2222 and the 2N2907 trans facing the same

> way with the flat part facing up towards the BP HP and LP holes. Is

> this correct?

>

> Thanks,

> Dave

>

> --- In cgs_synth@yahoogrou ps.com, Scott Deyo <contact@... > wrote:

> >

> > The CV pot is wired the way you say, but terminal 3 is also wired to

> > ground. (i.e., it's wired as an 'attenuator' or voltage divider --

> good

> > to remember, they're common).

> >

> > The wiring diagram looks good for freq and res.

> >

> > Everything has the right orientation -- transistors, diode,

> > electrolytics, TL071? The TL071 isn't a TL072? Did you install on

> the

> > links on the board? (I've missed one a few times before.)

> > For me, it's usually something painfully obvious once I see it, but

> for

> > some reason I just can't see it though I've looked at it ten times.

> > Especially on a single-sided board, make sure all your soldering is

> OK.

> > One weak connection can wreak havoc.

> >

> >

> > Scott Deyo

> > The Bridechamber

> > contact@...

> > http://www.bridecha mber.com

> > Jealous Edison Record Kompany

> > http://www.jealouse dison.com

> >

> >

> > On Sep 15, 2008, at 1:17 AM, Dave wrote:

> >

> > > Hi Scott,

> > >

> > > Thanks for the confirmation about the switch wiring :) I'm gonna

> > > rewire the Decay an Damper pots too. I've tried various switch

> > > setting from all off to individual on to all on and they all

> react the

> > > same to the resonance pot.

> > >

> > > Is it possible that the wiring diagram is wrong for the res or

> freq

> > > pots? The freq pot wiring seems a little strange compared to the

> rest

> > > with the 3 leg of the pot wired to the ferrite bead.

> > >

> > > While I'm at it how do I wire the VCF CV pot? Do I wire from EX to

> > > the middle lug of the pot and then from terminal 1 on the pot to

> the

> > > jack?

> > >

> > > Thanks,

> > > Dave

> > >

> > > --- In cgs_synth@yahoogrou ps.com, Scott Deyo <contact@> wrote:

> > > >

> > > > I think Decay and Damper are backwards on the CGS diagram.

> > > >

> > > > It just occured to me that my panel's envelope pot is labeled

> wrong!

> > > > Instead of 0 to 10, it should read -5 to +5. It should be at 0

> in

> > > the

> > > > middle, negative envelope to left, positive to right. Ugh!

> > > > : (

> > > >

> > > > It sounds like you have the switches wired up correctly. Try

> > > testing it

> > > > with just lowpass on at first, and checking the resonance again.

> > > >

> > > > Cheers,

> > > > Scott Deyo

> > > > The Bridechamber

> > > > contact@

> > > > http://www.bridecha mber.com

> > > > Jealous Edison Record Kompany

> > > > http://www.jealouse dison.com

> > > >

> > > >

> > > > On Sep 14, 2008, at 11:11 PM, Dave wrote:

> > > >

> > > > > Hi all,

> > > > >

> > > > > I just finished building a cynare :) But am having problems

> with

> > > > > the filter section. I am building a kit supplied by

> bridechamber

> > > > > which has three separate SPDT switches for the filter types. I

> > > have

> > > > > added the 6 pots for the osc and also added the impact gen

> mod to

> > > it

> > > > > too (I subbed in a 100k pot for the 25k for now until I can

> get

> > > the

> > > > > 25k pot). These mods seem to work correctly. I also changed

> the R

> > > > > gain resistor to 1.5k instead of the 10k.

> > > > >

> > > > > I followed the CGS wiring diagram exactly assuming that the

> pot

> > > > > shafts are facing away from me and CW is 3 (I am not sure

> about

> > > this).

> > > > > One strange thing I noticed with this is that the Decay and

> Damper

> > > > > pots seem wired backwards so that as I turn it from 0 to 10

> the

> > > decay

> > > > > shortens for both, I would think it should lengthen the decay

> as

> > > you

> > > > > turn the pot towards 10. The tone or balance between noise and

> > > > > shimmer operates correctly.

> > > > >

> > > > > The problem with the filter is that the filter sweep is

> minimal

> > > > > in effect, the envelope affects the impact sound strangely,

> when

> > > in

> > > > > the middle (5) there is little to no impact sound and when at

> > > either 0

> > > > > or 10 the impact is back (sweeping the impact pot mod changes

> the

> > > > > character of the impact sound). The resonance pot is also

> acting

> > > very

> > > > > strange. I have wired the three switches as best I

> > > > > knew how which is took the LP, BP, and HP and wired them to

> the

> > > bottom

> > > > > lugs of three switches then I wired some bus wire across the

> three

> > > > > middle lugs of the switches and attached the common wire to

> that.

> > > I

> > > > > don't know if that is correct but it makes sense to me. When I

> > > switch

> > > > > between the filter types I can hear changes in tone that

> > > corresponds

> > > > > to the filter type.

> > > > >

> > > > > Did I wire the three switches correctly, if not how should I

> do

> > > this?

> > > > >

> > > > > The main malfunction seems to come from the resonance pot. It

> does

> > > > > not increase the resonance and when I turn it all sound going

> > > through

> > > > > the filter is silenced for about 1-2 seconds and then comes

> back

> > > again

> > > > > with no change regardless of whether it is at 0 or 10.

> > > > >

> > > > > I'm new to the DIY so I don't want to mess with things too

> much

> > > > > while trouble shooting, so I've gone over the board looking

> for

> > > shorts

> > > > > and poor connections but have not found anything yet, should

> I try

> > > > > changing some of the wires around on the res pot or maybe the

> freq

> > > > > pot? I'm confused as to why the decay and damper seem to

> operate

> > > > > backwards from convention and am wondering if I got these

> wired

> > > > > backwards maybe I wired the res or freq pots backwards but

> I've

> > > > > checked over and over again and they match up to kens

> diagram...

> > > > >

> > > > > Sorry for the long post :) Any help would be greatly

> appreciated,

> > > > >

> > > > > Thanks,

> > > > > Dave

> > > > >

> > > > >

> > > > >

> > > >

> > > > [Non-text portions of this message have been removed]

> > > >

> > >

> > >

> > >

> >

> > [Non-text portions of this message have been removed]

> >

>

>

>



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