MOTM

OK, I was supposed to see the 'March of the Penguins' movie but instead I sat at 
the bench for 2 hours and tweaked.

1) the resistors in the current kit are what are used in the Yamaha modules.

2) Yamaha was never a fan of high resonance

3) So, the following mods WILL increase the resonance (especially in LP mode)

R23 was 2K2, change to 1K2

4) the following mod will allow a +5V signal into RES IN to generate much more 
resonance

R15 was 120K, change to 47K (51K will also work if you have one handy)

I am going to make this s 'running change' for kits not shipped (Paul H. will 
swap them out).

If you bought a kit and want to make the change and do not have access to these 
resistors, send me a SASE (self-addressed stamped envelope) and I will send you 
these 2 parts taped to the back of a rare, collectible business card :)

Also: please note that toggling the HP/LP switch is just like switching the MODE 
in the WaveWarper: you are disconnecting multiple 'pins' from the circuit. You 
will get clicks, thumps and such. There is no way around it, and it's not 
'broken'. Rather, think of it as "circuit bending" :)

Lastly: the HP mode in this filter is VERY ODD, which according to Dave Wright 
and Robert Rich is a good thing.

OK, everyone back to soldering.

Paul S.

Nice mods.  Certainly opens up the range of the Q Peak trimmer so
you can adjust how 'gritty' you want the HP filter.  I'm running
mine at about 30%.

My module seemed to be sensitive to long power leads and being
outside  of the cabinet without the bracket.  Seems a bit more
behaved in the cabinet with the normal power cable so I'm thinking
of opening up the Q Peak trimmer a bit more.

Photo of the finished module at
http://modularsynthesis.com/modules/motm/MOTM-485.jpg

Dave

--- In motm@yahoogroups.com, "Paul Schreiber" <synth1@a...> wrote:

> 3) So, the following mods WILL increase the resonance (especially
> in LP mode)
> 
> R23 was 2K2, change to 1K2
> 
> 4) the following mod will allow a +5V signal into RES IN to
> generate much more resonance
> 
> R15 was 120K, change to 47K

I noticed something odd about Dave's assembly photo of the 485.  If the 
jacks are labelled like they are in the catalog photo:  Left side top to 
bottom:  IN1, IN2, RES; right side top to bottom:  1V/OCT, FM, OUT, then 
the jacks are not wired correctly.  The photo show IN2 as wired to the 
top, right jack, and a twisted pair to the middle left jack.  
Accidentally reversed?

-Richard Brewster

djbrow54 wrote:

>Nice mods.  Certainly opens up the range of the Q Peak trimmer so
>you can adjust how 'gritty' you want the HP filter.  I'm running
>mine at about 30%.
>
>My module seemed to be sensitive to long power leads and being
>outside  of the cabinet without the bracket.  Seems a bit more
>behaved in the cabinet with the normal power cable so I'm thinking
>of opening up the Q Peak trimmer a bit more.
>
>Photo of the finished module at
>http://modularsynthesis.com/modules/motm/MOTM-485.jpg
>
>Dave
>
>--- In motm@yahoogroups.com, "Paul Schreiber" <synth1@a...> wrote:
>  
>
>>3) So, the following mods WILL increase the resonance (especially
>>in LP mode)
>>
>>R23 was 2K2, change to 1K2
>>
>>4) the following mod will allow a +5V signal into RES IN to
>>generate much more resonance
>>
>>R15 was 120K, change to 47K
>>    
>>
>
>  
>

"The March of the Penguins" is quite excellent if you like nature stuff. 
Good soundtrack!

French production, shot on 16MM. Released by National Geographic Films.

-- 
Regards,
John Blacet

Blacet Research
http://www.blacet.com

The panel exchanged the IN2 and 1V/OCT jack positions from the photo
in the catalog.

Dave

--- In motm@yahoogroups.com, Richard Brewster <pugix@e...> wrote:
> I noticed something odd about Dave's assembly photo of the 485.  If 
the 
> jacks are labelled like they are in the catalog photo:  Left side 
top to 
> bottom:  IN1, IN2, RES; right side top to bottom:  1V/OCT, FM, OUT, 
then 
> the jacks are not wired correctly.