M-121 Highpass modification REPOST !

Repair or Modifications of the Roland System 100M
ryk
Posts: 117
Joined: Wed Sep 26, 2007 2:14 pm
Location: London
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M-121 Highpass modification REPOST !

Postby ryk » Mon Feb 24, 2014 8:27 pm

Hello

Seeing as the original post has dissappeared . . .
I thought I should post the mod details again.

Also I am working on a switchable 24db multimode mod
so you can switch between LP,HP, or BP, which is a bit more fun !

Trying to upload some sound samples but this site doesnt seem to allow.

-ryk
Attachments
m121_highpass_mod_v2_board.jpg
m121_highpass_mod_v2_board.jpg (380.12 KiB) Viewed 7655 times
M121_highpass_mod_v2_amended.jpg
M121_highpass_mod_v2_amended.jpg (338.41 KiB) Viewed 7655 times

polyconnect
Posts: 37
Joined: Mon Mar 16, 2009 10:55 am

Re: M-121 Highpass modification REPOST !

Postby polyconnect » Thu Mar 06, 2014 10:38 am

Thanks for that ! ;)

DAS SYSTEM
Posts: 10
Joined: Sun Dec 08, 2013 9:37 pm

Re: M-121 Highpass modification REPOST !

Postby DAS SYSTEM » Thu Jul 03, 2014 8:16 pm

very nice - will try that for sure.

but work this mod on BOTH filters,
or is it possible to split it by having only
one of the DUAL VCFs modded?

A:

ryk
Posts: 117
Joined: Wed Sep 26, 2007 2:14 pm
Location: London
Contact:

Re: M-121 Highpass modification REPOST !

Postby ryk » Thu Jul 03, 2014 9:15 pm

Hello

The mod as drawn only effects one filter, the LHS one.

You can do both, just check the schematic
and find the relevant components.

-ryk

polyconnect
Posts: 37
Joined: Mon Mar 16, 2009 10:55 am

Re: M-121 Highpass modification REPOST !

Postby polyconnect » Mon Oct 20, 2014 6:31 pm

any new for the switchable 24db multimode mod ? :D

ryk
Posts: 117
Joined: Wed Sep 26, 2007 2:14 pm
Location: London
Contact:

Re: M-121 Highpass modification REPOST !

Postby ryk » Sun Oct 26, 2014 9:56 pm

Hello

Sorry not yet . . .
But thanks for the remind, I will try and get around to it.

Basically it is an analogue multiplexor switch ADG333ABNZ
that connects the four cells of the VCF in different
permutations to create the different LP/HP/BP modes.

Cheers
-ryk

yusynth
Posts: 10
Joined: Sat Aug 02, 2014 4:24 pm

Re: M-121 Highpass modification REPOST !

Postby yusynth » Fri Oct 31, 2014 3:23 pm

I am currently designing one but with 4052s

ryk
Posts: 117
Joined: Wed Sep 26, 2007 2:14 pm
Location: London
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Re: M-121 Highpass modification REPOST !

Postby ryk » Mon Nov 03, 2014 8:20 pm

Hello

Cool Yves !

Here's some progress of the board
for the mod.
Attachments
image.jpg
image.jpg (70.68 KiB) Viewed 6511 times

polyconnect
Posts: 37
Joined: Mon Mar 16, 2009 10:55 am

Re: M-121 Highpass modification REPOST !

Postby polyconnect » Fri Nov 07, 2014 5:56 am

Looks nice.

Do you already know how you're going to implement that on the front panel ?

ryk
Posts: 117
Joined: Wed Sep 26, 2007 2:14 pm
Location: London
Contact:

Re: M-121 Highpass modification REPOST !

Postby ryk » Fri Nov 07, 2014 9:48 am

polyconnect wrote:Looks nice.

Do you already know how you're going to implement that on the front panel ?


Hello

Yes, just reuse the fixed HPF switch.
Involves a bit of track cutting on the
pcb but seems ok.

Board populated and tested, seems works
well.

Pics and sounds coming soon.

-ryk

ryk
Posts: 117
Joined: Wed Sep 26, 2007 2:14 pm
Location: London
Contact:

Re: M-121 Highpass modification REPOST !

Postby ryk » Thu Nov 20, 2014 9:09 pm

Board wired up !
Attachments
image.jpg
image.jpg (253.79 KiB) Viewed 6356 times
image.jpg
image.jpg (270.72 KiB) Viewed 6356 times


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