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DIY Stompboxes => Building your own stompbox => Topic started by: Quarterflip on December 05, 2015, 09:43:33 AM

Title: MS-20 Vero layout
Post by: Quarterflip on December 05, 2015, 09:43:33 AM
Hey, just finished doing a layout for a MS-20 filter that I've put into a wah enclosure. Something tells me I've done the layout wrong as all I get is a massive volume cut and no cool whistly lp filter like I was hoping.

Heres the schematic I used:

(http://img.scoop.it/UB2Vdkzi-EKeKIoUfgCWCzl72eJkfbmt4t8yenImKBVvK0kTmF0xjctABnaLJIm9)

And here's my layout:

(http://i.imgur.com/rU5JK8c.png)

Is the problem with the LM13700? I was pretty sure the pinout was the same as the LM13600.
Title: Re: MS-20 Vero layout
Post by: slacker on December 05, 2015, 10:25:22 AM
Your layout looks ok, except it doesn't show any cut traces under the LM13700, have you actually cut them? Are D1 and D2 connected together off the board, they don't connect to the 9 Volt row?
Title: Re: MS-20 Vero layout
Post by: Quarterflip on December 05, 2015, 10:37:23 AM
Yep they're all cut under the IC, just couldn't figure out how to show that in DIYLC. The two LED's aren't on the 9v either. I'm starting to think this may be a problem with my pots.
Title: Re: MS-20 Vero layout
Post by: ElectricDruid on December 05, 2015, 12:18:02 PM
Is the problem with the LM13700? I was pretty sure the pinout was the same as the LM13600.

The pinout is the same, but are you sure that circuit works with the 13700? The only difference between the 13600 and the 13700 is in the buffers and the way they are biased. I often leave the darlingtons unused anyway, so it doesn't make any odds. But in this schematic, the buffers are used, so...
Dunno, it's just a thought.

HTH,
Tom
Title: Re: MS-20 Vero layout
Post by: ElectricDruid on December 05, 2015, 12:19:25 PM
Oh, and you haven't shown the cut at the midpoint of D1-D2 either. That needs to be there.
Title: Re: MS-20 Vero layout
Post by: digi2t on December 05, 2015, 08:48:10 PM
Yep they're all cut under the IC, just couldn't figure out how to show that in DIYLC.

Double click on the part, and in the pop up, move the "Alpha" slider to the left. This will increase the transparency of the part.
Title: Re: MS-20 Vero layout
Post by: Quarterflip on December 05, 2015, 10:26:14 PM
So I added the cuts under the IC and LED's

(http://i.imgur.com/mPH0rJl.png)

Would the darlington's bias make that big of a difference?
Title: Re: MS-20 Vero layout
Post by: ElectricDruid on December 06, 2015, 05:58:09 AM
Would the darlington's bias make that big of a difference?

I don't know, but it might. There's another thread about it here:

http://www.diystompboxes.com/smfforum/index.php?topic=85279.0 (http://www.diystompboxes.com/smfforum/index.php?topic=85279.0)

Some of these comments imply that people built working filters with the 13700, so I'd guess it works. A simple wiring error is still more likely.

HTH,
Tom
Title: Re: MS-20 Vero layout
Post by: duck_arse on December 06, 2015, 09:45:05 AM
shift the cut under the leds left 1. shift the bottom led right 1. anchor both ends of both leds to the board.
Title: Re: MS-20 Vero layout
Post by: chemosis on February 07, 2018, 10:26:11 AM
did anyone get this to work????
Title: Re: MS-20 Vero layout
Post by: reddesert on February 07, 2018, 03:55:10 PM
You might be interested in comparing this circuit to the schematic and (more complex) vero layout for an MS-20 filter using two LM13700, in the forum section of the tagboardeffects.blogspot.com blog. See http://guitar-fx-layouts.42897.x6.nabble.com/Korg-MS20-LP-HP-Filter-tp31433.html (http://guitar-fx-layouts.42897.x6.nabble.com/Korg-MS20-LP-HP-Filter-tp31433.html)  Note that is intended to run off +/- 15V.
Title: Re: MS-20 Vero layout
Post by: FUZZZZzzzz on May 17, 2019, 06:43:26 AM
I know this is an old thread, but I've succesfully build this with the layout above. Just make sure that the led junction does not connect to the 9v ic pin. I've used the 13700 chip and two 5mm red leds. Ive made a version before with 5mm yellow leds but that drastically changes the sound and resonance. Heres a video impression.

Title: Re: MS-20 Vero layout
Post by: javierperez.21 on August 10, 2020, 11:06:26 AM
Hey, this might be a dumb question, but I´m a beginner. What does Vr mean?
Thanks!
Title: Re: MS-20 Vero layout
Post by: 11-90-an on August 10, 2020, 11:14:21 AM
Welcome to the forum.... :icon_wink:

Vr normally means “Reference voltage” which normally is about 1/2 the power supply... :icon_wink:

Don’t think the question is dumb, we all were there before... :icon_wink: