hi max,

sorry, i usually just check the group messages at the
site and don't check this email address that often. i
guess i should.

the drawing looks like it should work. i'm not sure
which caps i used, i think they say 104 on them. and
actually, i used smaller ones for the bass and snare
(maybe 682) because they tuned way lower than i
needed; i think maybe they have a lower sample rate.
the schematic i posted the link to is not what i
worked from, just an example of the 555 oscillator in
general. thats why my component values are different.
it's also a matter of personal taste; if it doesn't go
low enough for you, use a bigger capacitor. the
ride/crash oscillator needs a bigger resistor than 1k.
i think i used 2.7k, but that's not even quite big
enough. i get a little bit of strange noise at the
clockwise end of the pot.

another note, the 555 scales in a linear fashion,
which sounds exponential to our ears, so as you turn
the pot, it sounds like it changes less at the low end
than the high end. reverse-logarithmic pots exist, and
would counteract this behavior, though i wouldn't know
where to get them. another idea is to use regular
logarithmic pots wired backwards, so that clockwise
tunes the sounds down. if you don't care which way is
up and which way is down this is an easy way to get a
more even response. i might do this or i might just
live with it the way it is. it's no big deal. it just
means you have more room to play in the lower ranges
than the higher.

oh yeah, no you don't need to ground the pots to
anything.

greg

--- ms < max_schroeder@... > wrote:

> hi greg,
>
> i noticed that most of my questions were already
> asked in the group, so i
> know now..;-)
>
> but to be sure i�m doing everything correct i�ve
> attached a pattern drawing
> with my design for a board, and it would be very
> nice if you could check if
> it�s correct like this, if it is, i�ll put it up to
> the groups file section.
>
> And one stupid newbie question - do i have to ground
> the pots i mount in
>
>
> Thanks for your help,
>
> regards,
>
> max
>
> ----- Original Message -----
> From: "ms" < max_schroeder@... >
> To: "gregory zifcak" < foleymachine@... >
> Sent: Thursday, February 26, 2004 9:35 PM
> Subject: Re: [benders] 707 pitch mod (OT)
>
>
> > hi greg,
> >
> > thank you so much for your help so far.
> >
> > i got some other questions in the meantime..;-)
> >
> > according to the oscillators you wrote you think
> you used a 0.1 uF
> > capacitor, but the circuit drawing says it�s a
> 0,01 uF - so i�m confused
> > now...;-)
> >
> > now another couple of total newbie questions:
> >
> > where do you get the +5 power for the oscillators
> from
> >
> > why are there two seperated ground points on the
> oscillator
> > is one for the power, and the other one for
> grounding on the board
> > or just both grounded on the board my knowledge
> in electronics is really
> > poor..:-(
> > I�m asking because i want to build a single board
> with all oscs to save
> > space, and therefore put all ground points
> together on the board and then
> a
> > single wire to the main board ground.
> >
> > I�m also planning a detailed documentation of the
> modification with
> photos,
> > pattern drawings and written explanation, and
> since i haven�t started yet
> > (have to wait 2 weeks for the ne555 ics) i want to
> be sure i�ll be doing
> > everything right....;-)
> >
> > Of course i�ll load the documentation up to the
> tr-707 group
> files-section.
> >
> >
> > best greets from vienna and thanks again,
> >
> > max
>

> ATTACHMENT part 2 image/gif name=patterndrawing.gif

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