David,

before we continue: does this problem occur only with the combination of
A-155 with A-154 Or does it occur even with a standalone A-155. If the
A-155's have been modified earlier (for standalone mode) this modification
has to be cancelled (i.e. undo). Please refer to page 16 of the A-154 manual
and the attached document.

Best regards
Dieter Doepfer
Doepfer Musikelektronik GmbH
Email address: hardware@...
Web Site: www.doepfer.com

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto: Doepfer_a100@yahoogroups.com ]Im Auftrag von deastman2
> Gesendet: Donnerstag, 6. April 2006 09:54
> An: Doepfer_a100@yahoogroups.com
> Betreff: 1 A-154/dual A-155 combination false triggering
> problem
>
>
> I have an A-154 configured to control two A-155's. I've noticed that
> for Trigger Rows 1&2 for both A-155's, some steps seem to generate
> one or more extra, erroneous trigger pulses. I looked at the output
> on a scope, and I see the following:
>
> Steps 1 and 5 show the main trigger pulse, followed by three very low-
> level pulses at the spots where steps 2, 3, and 5 would be.
>
> Steps 3 and 7 show the main trigger pulse, followed by one very low-
> level pulse at the spot where steps 4 and 8 would be.
>
> Steps 2, 4, 6, and 8 function normally.
>
> These extra pulses are strong enough to at least partially trigger an
> envelope generator controlling a VCA with an osc feeding into it.
> For example, with all steps/rows on both sequencers in the 'off'
> position, except for row 1/step 1 on one seq, I get an envelope
> trigger at step one, followed by a lower-level trigger at step 2 (and
> in theory, it probably triggers again steps 3 and 5, if the envelope
> was set properly). These extra pulses stay in sync when I adjust the
> clock rate.
>
> I had this same problem when I first got the sequencers back in
> January, except at that time, row 3 also had the same problem. With
> only one A-155 connected to the A-154, there is no problem. Either A-
> 155 will function properly with the A-154, but once they are chained
> together, the problem appears. I sent the A-154 back to Analogue
> Haven for replacement, and the new one they sent me worked fine for a
> couple of months, until yesterday when this malfunction resurfaced.
>
> Other relevant information: The connecting cables were replaced as
> well. The sequencers are all powered by a single new PSU2. Aside
> from the A-100, there is nothing else in close proximity which could
> be causing interference.
>
> I'm hoping there is a simple answer other than shipping back more
> modules...
>
> Thanks,
> David
>
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>
> Yahoo! Groups Links
>
>
>

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