MOTM

For the first time this evening (so may have been going on prior to this
evening) I noticed what I think is "bleed-through" from my 320 into my
300's and 310's. When I (only) connect a patch cord from one of the
waveform outs on any 300 or 310 into the vca of my 110 (and set the gain
knob slightly above unity to listen), I can hear the 320 modulating the
osc. waveform, and changing the 320's rate knob also changes the waveform's
modulation rate correspondingly. It is not very prominent, but
definitely noticable. All of these modules are connected to the same 900
power supply. Any ideas? FWIW, I only built the 310's. Same thing
happens when I connect any waveform out to the Blacet mixer/vca, which is
on a different power supply.

Thanks, Jeff

How many modules are connected to your power supply.? Is this the stock
power supply, or have you upgraded the Power One unit to a higher
current unit?

John Loffink
jloffink@...

> -----Original Message-----
> From: Jeffrey Pontius [mailto:jpont@...]
> Sent: Sunday, February 09, 2003 7:47 PM
> To: motm@yahoogroups.com
> Subject: [motm] 320 bleed-through to 300's?
>
> For the first time this evening (so may have been going on prior to

this

> evening) I noticed what I think is "bleed-through" from my 320 into my
> 300's and 310's. When I (only) connect a patch cord from one of the
> waveform outs on any 300 or 310 into the vca of my 110 (and set the

gain

> knob slightly above unity to listen), I can hear the 320 modulating

the

> osc. waveform, and changing the 320's rate knob also changes the
> waveform's
> modulation rate correspondingly. It is not very prominent, but
> definitely noticable. All of these modules are connected to the same

900

> power supply. Any ideas? FWIW, I only built the 310's. Same thing
> happens when I connect any waveform out to the Blacet mixer/vca, which

is

> on a different power supply.
>
> Thanks, Jeff
>
>
>
>
> Your use of Yahoo! Groups is subject to

http://docs.yahoo.com/info/terms/

>

On Sun, 9 Feb 2003, John Loffink wrote:

> How many modules are connected to your power supply.? Is this the stock
> power supply, or have you upgraded the Power One unit to a higher
> current unit?
>

Stock 900, with some modules connected to the 900's power connectors and
some modules connected to a 960 distribution board. 16 modules:
820, (2) 310's, (3) 300's, (2) 800's, (1) 320, (1) 440, (1) 410, (1) 110,
(2) Hendry vc shifts, (1) Oakley 410 companion, 830.

It's been some time ago, but I remember computing mAmps used and thought
the sum was easily less than 80% of the 900's max.
Jeff

Your power load sounds okay, but I remember thinking I was okay with
around 20 modules when I started noticing definite power induced side
effects. You might try unplugging some of the unused modules from the
PS board, particularly some 300/310s and see if this helps.

I have two 320s, a 380 and a 390 all near my VCOs, and powered from the
same PS board. I could not duplicate this problem.

When you say the 320 modulates the 300 waveform, do you mean the timbre
changes rather than the frequency or amplitude?

John Loffink
jloffink@...

> On Sun, 9 Feb 2003, John Loffink wrote:
>
> > How many modules are connected to your power supply.? Is this the

stock

> > power supply, or have you upgraded the Power One unit to a higher
> > current unit?
> >
> Stock 900, with some modules connected to the 900's power connectors

and

> some modules connected to a 960 distribution board. 16 modules:
> 820, (2) 310's, (3) 300's, (2) 800's, (1) 320, (1) 440, (1) 410, (1)

110,

> (2) Hendry vc shifts, (1) Oakley 410 companion, 830.
>
> It's been some time ago, but I remember computing mAmps used and

thought

I think John's on the right track. Try as an experiment, unplugging
all modules from your power supply except for 1 320, 1 300, and 1
110. Then try the patch again.

Moe

> How many modules are connected to your power supply.? Is this the

stock

>
> When you say the 320 modulates the 300 waveform, do you mean the timbre
> changes rather than the frequency or amplitude?
>

Timbre, most noticable on pulse out. It's not obvious, but noticable if
I listen closely. The only reason I picked it up was I was checking if I
was getting audio out of my system (so vco -> vca only connection).

Thanks John and Dave. I'll try the "elimination method" when I get a
chance this week. Do you guys want to know what I find out (if
anything)?.

Jeff

Yes.

John Loffink
jloffink@...

> Thanks John and Dave. I'll try the "elimination method" when I get a
> chance this week. Do you guys want to know what I find out (if
> anything)?.

I would think that you're drawing too much current from your PSU. I
try not to run mine over 60% If you're using multiple supplies you
might also have a grounding issue. I've got a 5amp supply running
about 30 modules with zero crosstalk. Also, don't patch together
audio gear that's running off different legs of your house/studio AC
supply-that can be disastrous!!!

Good Luck,

Z.

Oh yeah, I forgot to mention that I saw the MOTM -600 sequencer in
action at the recent NAMM show. I was pretty set against buying this
module since I have 3 SQ10s, but after Paul gave me a demo and I saw
Robert Rich grooving with it I am convinced it's a winner!

My first questions would be:

Which modules are connected to the 960 PCB?

And, what kind of wire are you running over to the 960 PCB from the
900?

And, where did you attach that wire to the 900?

If you have used a normal MOTM power supply cable to daisy chain out
from the 900 to the 960 expander PCB, you are asking for this sort of
trouble IMO.

Larry


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A good point.

John Loffink
jloffink@...

> My first questions would be:
>
> Which modules are connected to the 960 PCB?
>
> And, what kind of wire are you running over to the 960 PCB from the
> 900?
>
> And, where did you attach that wire to the 900?
>
> If you have used a normal MOTM power supply cable to daisy chain out
> from the 900 to the 960 expander PCB, you are asking for this sort of
> trouble IMO.
>

On Monday 10 February 2003 05:16, Larry Hendry wrote:

On Sun, 9 Feb 2003, Larry Hendry wrote:

> Which modules are connected to the 960 PCB?
>

All 300's, 310's, 320 (and a few others) are connected to board on the 900
power supply. I'd have to inspect tonight.