Potientometer Replacement for MFB Microzweg

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: Kent, luketeaford, Joe.

Post Reply
ArneHauer
Learning to Wiggle
Posts: 6
Joined: Sat Aug 15, 2020 9:40 am

Potientometer Replacement for MFB Microzweg

Post by ArneHauer » Sun Nov 22, 2020 8:40 am

Hi All,
Attched pics are the failed Resonance Potientometer from a MFB Microzwerg MK I.
Printed on the underside is "B" and "10K". What does the "B" stand for? Anyone can identify what type this is to get a replacement? Was looking at Bourns PTV09 series, but they lack the additional two legs on top of the three connectors...

Thanks everyone and Kind Regards,

ArneImage
Attachments
IMG_20201122_141227.jpg
IMG_20201122_141314.jpg
IMG_20201122_141333.jpg
IMG_20201122_141351.jpg

User avatar
guest
Super Deluxe Wiggler
Posts: 5623
Joined: Mon Aug 19, 2013 11:49 am

Re: Potientometer Replacement for MFB Microzweg

Post by guest » Sun Nov 22, 2020 10:29 am

is there a switch on it as well? can you measure the resistance between the top pins and see what thats like as you turn the knob? 10kB is typically a linear taper pot of 10k. i dont think ive seen a pot with 5 tabs before, though, im curious what they do.
openmusiclabs.com

User avatar
guest
Super Deluxe Wiggler
Posts: 5623
Joined: Mon Aug 19, 2013 11:49 am

Re: Potientometer Replacement for MFB Microzweg

Post by guest » Sun Nov 22, 2020 10:43 am

ok, it looks something like this:
http://www.alphapotentiometers.net/html/9mm_pot_11.html

which is a dual taper pot, but at least one of the pins has to be doubled up, not sure which one, maybe both top and bottom are? again, not super common, but you can hack a regular dual taper in if need be.
openmusiclabs.com

User avatar
guest
Super Deluxe Wiggler
Posts: 5623
Joined: Mon Aug 19, 2013 11:49 am

Re: Potientometer Replacement for MFB Microzweg

Post by guest » Sun Nov 22, 2020 10:54 am

openmusiclabs.com

ArneHauer
Learning to Wiggle
Posts: 6
Joined: Sat Aug 15, 2020 9:40 am

Re: Potientometer Replacement for MFB Microzweg

Post by ArneHauer » Tue Nov 24, 2020 1:35 pm

Thanks everyone. Looks promising but also somewhat gets more confusing. Would "dual taper" for the alpha one be the same as the "dual unit" from Alps? Not sure how to get hold of the Alpha one. Seems to be OEM only. Thanks and BR, Arne

User avatar
guest
Super Deluxe Wiggler
Posts: 5623
Joined: Mon Aug 19, 2013 11:49 am

Re: Potientometer Replacement for MFB Microzweg

Post by guest » Tue Nov 24, 2020 2:58 pm

i would reccomend picking up some of the ones from mouser. there a dollar a piece, so you could get one of each, and then measure them to compare if they match or not. the only reason i cant give you an exact match is because they are not using the datasheet part numbering convention, so its unclear exactly what is what. but, its only 10$ to get them all, so seems like a small loss even if none of them work out.
openmusiclabs.com

User avatar
Altitude909
Super Deluxe Wiggler
Posts: 3631
Joined: Wed Aug 24, 2011 5:13 pm
Location: Meesheegan

Re: Potientometer Replacement for MFB Microzweg

Post by Altitude909 » Tue Nov 24, 2020 6:45 pm

Just FYI, "SH" Stands for Song Huei

User avatar
KSS
Super Deluxe Wiggler
Posts: 4852
Joined: Mon Jan 25, 2016 7:28 am

Re: Potientometer Replacement for MFB Microzweg

Post by KSS » Tue Nov 24, 2020 7:05 pm

Yes, and it's not in their catalog. A custom part.

The closest is a dual with threaded bushing and d shaft. That's the RK0952G-1
But yours is more like a dual version of their single R0903N. Even then your bushing is different.

I'd contact MFB.

ArneHauer
Learning to Wiggle
Posts: 6
Joined: Sat Aug 15, 2020 9:40 am

Re: Potientometer Replacement for MFB Microzweg

Post by ArneHauer » Wed Nov 25, 2020 12:02 pm

Tried contacting MFB twice, no response whatsoever. Always been a fan of their products but that's a bit of a let down. Well, then again the times are difficult...

User avatar
KSS
Super Deluxe Wiggler
Posts: 4852
Joined: Mon Jan 25, 2016 7:28 am

Re: Potientometer Replacement for MFB Microzweg

Post by KSS » Wed Nov 25, 2020 4:43 pm

That's unfortunate. But as you say, it might be influenced by the pandemic.

Did we ever get an answer about the two pins? Are they a switch? Or a tap? Or?

The first step to fixing this will be to *know* what we're trying to come up with.
----
Edit: You might try contacting one of their major distributors.
MFB might be more interested in keeping connected to them than an individual purchase.
Not saying that's true, just a thought for how to 'rise in the mix' when other issues might be raising the 'noise floor'.

User avatar
guest
Super Deluxe Wiggler
Posts: 5623
Joined: Mon Aug 19, 2013 11:49 am

Re: Potientometer Replacement for MFB Microzweg

Post by guest » Wed Nov 25, 2020 4:48 pm

i think its a dual pot, and one end (most likely the bottom) shares a tap between the two pots. there is a dual VCF on this synth with a single reso pot, so i think the signal just feeds back through the two seperate pathways. so a different value pot might also work in its place, or a different footprint pot with some wiring. but, if it is a dual pot with a shared bottom leg, one of those RK09K12C pots from mouser should do the trick. they have variants where the top of the pot is wired together, and the mouser product numbers dont match the datasheet, so its hard to say exactly whats what.
openmusiclabs.com

ArneHauer
Learning to Wiggle
Posts: 6
Joined: Sat Aug 15, 2020 9:40 am

Re: Potientometer Replacement for MFB Microzweg

Post by ArneHauer » Fri Jan 15, 2021 6:18 pm

Hi Everyone. Thanks for your help. How it turned out: Bough 2 versions of the vertical dual Alps RK09K12C, short one without collar and longer one with collar. We had to cut off a little bit from the longer one to fit the knob but technically it worked perfectly! Microzwerg is back in full working order.
Thanks again.
BR
Arne

User avatar
guest
Super Deluxe Wiggler
Posts: 5623
Joined: Mon Aug 19, 2013 11:49 am

Re: Potientometer Replacement for MFB Microzweg

Post by guest » Fri Jan 15, 2021 8:48 pm

awesome, glad its back to making music. and thanks for posting back, hopefully someone in the future benefits from that.
openmusiclabs.com

Post Reply

Return to “Music Tech DIY”