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