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Gate Sequencer hiccups

Gate Sequencer hiccups

2007-06-21 by Andrew

Well I took the "Experiment with it!" suggestion, but probably
shouldn't have since I don't know what I'm doing all that much :)

My Gate Sequencer was running fine. I had replaced the 4017 with the
proper chip (I originally had the HCF version in there) and that had
stopped all the little quirks. The outputs all worked, the CLOCK,
RESET and END signals were OK, and the Rotary LENGTH selector worked
fine. (I have not wired the LOOP/HOLD switch up yet, so it always
loops)

Then I thought I'd hook up momentary buttons on the CLOCK and RESET
inputs. Using the Sequential Switch schematic as a guide, I did this:

http://www.ph.k12.in.us/~drew/gate-seq-2.GIF

Now it *always* goes 8 steps, and it *skips* the step # that is after
the rotary-selected length value. So if the LENGTH is set at 5, it
goes:
1 2 3 4 6 7 8

So I cut out both my "mods", but now it *still* does the step-
skipping thing; no change. I thought maybe I had damaged a chip, so
I replaced the two chips on the main board, to no avail.

Any suggestions?

thanks!
Drew (who is backing off on the "experiments" for awhile)

Re: Gate Sequencer hiccups

2007-06-21 by sasami@hotkey.net.au

What you did should in no way have caused what you are seeing. Are you still
using an LM358? If so, try a TL072 instead.

Ken
Show quoted textHide quoted text
>Well I took the "Experiment with it!" suggestion, but probably
>shouldn't have since I don't know what I'm doing all that much :)
>
>My Gate Sequencer was running fine. I had replaced the 4017 with the
>proper chip (I originally had the HCF version in there) and that had
>stopped all the little quirks. The outputs all worked, the CLOCK,
>RESET and END signals were OK, and the Rotary LENGTH selector worked
>fine. (I have not wired the LOOP/HOLD switch up yet, so it always
>loops)
>
>Then I thought I'd hook up momentary buttons on the CLOCK and RESET
>inputs. Using the Sequential Switch schematic as a guide, I did this:
>
>http://www.ph.k12.in.us/~drew/gate-seq-2.GIF
>
>Now it *always* goes 8 steps, and it *skips* the step # that is after
>the rotary-selected length value. So if the LENGTH is set at 5, it
>goes:
>1 2 3 4 6 7 8
>
>So I cut out both my "mods", but now it *still* does the step-
>skipping thing; no change. I thought maybe I had damaged a chip, so
>I replaced the two chips on the main board, to no avail.
>
>Any suggestions?
>
>thanks!
>Drew (who is backing off on the "experiments" for awhile)
>
>
>
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

Re: Gate Sequencer hiccups

2007-06-21 by Jason Proctor

suggest LT1013 instead as it's a unipolar supply?

i remember bad things (tm) happening with me + TL072 + unipolar supply
Show quoted textHide quoted text
>What you did should in no way have caused what you are seeing. Are you still
>using an LM358? If so, try a TL072 instead.
>
>Ken

Re: Gate Sequencer hiccups

2007-06-21 by bill bigrig

Howdy,

I thimk the way it's wired is throwing in an extra
pulse when ou push the button. I can only see half the
schematic in the attachment. on the 4017, you have to
wire the reset AND the 0 output to the step you want
to stop at. I would try eliminating the signal to the
clock. It is stepping the counter past your set point
and completing it's full count. Also make sure the
reset button is spdt with the button takinr ir high
and the release takes it back to ground.
Rig

Show quoted textHide quoted text

--- sasami@... wrote:

> What you did should in no way have caused what you
> are seeing. Are you still
> using an LM358? If so, try a TL072 instead.
>
> Ken
>
> >Well I took the "Experiment with it!" suggestion,
> but probably
> >shouldn't have since I don't know what I'm doing
> all that much :)
> >
> >My Gate Sequencer was running fine. I had replaced
> the 4017 with the
> >proper chip (I originally had the HCF version in
> there) and that had
> >stopped all the little quirks. The outputs all
> worked, the CLOCK,
> >RESET and END signals were OK, and the Rotary
> LENGTH selector worked
> >fine. (I have not wired the LOOP/HOLD switch up
> yet, so it always
> >loops)
> >
> >Then I thought I'd hook up momentary buttons on the
> CLOCK and RESET
> >inputs. Using the Sequential Switch schematic as a
> guide, I did this:
> >
> >http://www.ph.k12.in.us/~drew/gate-seq-2.GIF
> >
> >Now it *always* goes 8 steps, and it *skips* the
> step # that is after
> >the rotary-selected length value. So if the LENGTH
> is set at 5, it
> >goes:
> >1 2 3 4 6 7 8
> >
> >So I cut out both my "mods", but now it *still*
> does the step-
> >skipping thing; no change. I thought maybe I had
> damaged a chip, so
> >I replaced the two chips on the main board, to no
> avail.
> >
> >Any suggestions?
> >
> >thanks!
> >Drew (who is backing off on the "experiments" for
> awhile)
> >
> >
> >
> >
> >
> >The CGS Modular Synth home page:
> http://www.cgs.synth.net/
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
>
_______________________________________________________________________
> Ken Stone sasami@...
> Modular Synth PCBs for sale
> <http://www.cgs.synth.net/>
> Australian Miniature Horses & Ponies
> <http://www.blaze.net.au/~sasami/>
>
>



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Re: Gate Sequencer hiccups

2007-06-22 by Mark

On 6/21/07, Jason Proctor put forth:
>suggest LT1013 instead as it's a unipolar supply?

The LT1013 is listed as an improved LM358.

>i remember bad things (tm) happening with me + TL072 + unipolar supply

I don't think it's you :) Afaik, there is no way to run a TL072 single-sided.

> >What you did should in no way have caused what you are seeing. Are you still
> >using an LM358? If so, try a TL072 instead.

Re: Gate Sequencer hiccups

2007-06-22 by Jason Proctor

>On 6/21/07, Jason Proctor put forth:
>>suggest LT1013 instead as it's a unipolar supply?
>
>The LT1013 is listed as an improved LM358.

yes indeed. Ken is suggesting replacing the LM358 as he's had bad
experiences with them.

Re: Gate Sequencer hiccups

2007-06-22 by Richard Brewster

Really? Ken, should we replace all LM358 with LT1013?

Richard Brewster
http://www.pugix.com

Jason Proctor wrote:
Show quoted textHide quoted text
>> The LT1013 is listed as an improved LM358.
>>
>
> yes indeed. Ken is suggesting replacing the LM358 as he's had bad
> experiences with them.
>

Re: Gate Sequencer hiccups

2007-06-23 by Jason Proctor

as i understand it, if an LM358 is working in place then that's fine.
i have a bunch in service with no problems.

but apparently Ken has had bad batches of 358s and with that in mind
usually advises replacing them with TL072s in bipolar applications
and MC34072s or LT1013s in unipolar applications.

(correct me if i'm wrong here Ken)

LT1013 is the MOTM opamp of choice for rail-safe CV processing, which
is a stellar recommendation in and of itself.
Show quoted textHide quoted text
>Really? Ken, should we replace all LM358 with LT1013?

Re: Gate Sequencer hiccups

2007-06-23 by sasami@hotkey.net.au

>Really? Ken, should we replace all LM358 with LT1013?

If you have troubles, yes. If it works, leave it alone. I've mentioned on a
few pages that the LM358 varies too much between batches to be reliable. My
original protos were made with what appears to have been an exceptional
batch. These days I use TL072 on a split supply instead. I should update the
gate sequencer to match.
NOTE: this only applies to the clock input chip. You can leave the output
buffers as LM358.

Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

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