e-licktronic Forum

I am almost finished with building my two Navas (PCB v1.01). Unfortunately the wrong pot for VR28 in the master section is added to the kit! It has 7 pins instead of 6 (!) and is too wide to fit to the pad. What can we do Vincent?

The code in the parts list 'PTV112-4' suggests a Bourns part. See this datasheet.

http://www.mouser.com/ds/2/54/PTVPTT-56034.pdf

I would expect a Bourns part with a number PTV-11244??A-B?503 (dual-gang, no center detent). The missing numbers are shaft length in mm and taper curve id. See page 3 of the PDF I linked above.

The shaft length we can just measure with a caliper. (Don't have the parts nearby to do that myself right now.) So the only question is which variation of the 'B' curve from the Bourns datasheet. Not sure how much that actual number (which of the 5 B curves from the PDF) matters.

Hmm the part numbers on Mouser don't even have the 'sub curves'.

So then '50KB' 'PTV112-4' on the parts list would translate into PTV112-4420A-B503 (if the shaft length is indeed meant to be 20mm).

http://nl.mouser.com/ProductDetail/Bour ... KWdA%3d%3d

Must check the shaft length!

jvq wrote:The shaft length we can just measure with a caliper. (Don't have the parts nearby to do that myself right now.) So the only question is which variation of the 'B' curve from the Bourns datasheet. Not sure how much that actual number (which of the 5 B curves from the PDF) matters.

Maybe Vincent can chime in as well and enlighten us...

All the pots included in the kit (at least the ones I measured) stand 25mm tall from the board after mounting.

This stereo pot is from Bourns and has the right specs, BUT it is 20mm. I don't have my case yet but that may be a problem: too little of the shaft may poke through the case.

http://nl.mouser.com/ProductDetail/Bour ... KWdA%3d%3d

This one from Alps is similar spec (linear, 50K, 6 legs (haven't checked pinout)), but stands 30mm tall.

EDIT: fixed link: http://nl.mouser.com/ProductDetail/ALPS ... kOW6NFY%3d

My gut feeling would be to get the 30mm Alps pot and use a different knob on it if needed. If you have a pot that's too short you cannot mount any knob on it. If the shaft is too tall you can at least mount a tall knob on it.

But only if the pinout and pin spacing of that Alps matches what's on the PCB.

I see now the Alps has a center detent. Too many tabs open.

KlangGenerator wrote:I am almost finished with building my two Navas (PCB v1.01). Unfortunately the wrong pot for VR28 in the master section is added to the kit! It has 7 pins instead of 6 (!) and is too wide to fit to the pad. What can we do Vincent?

Our potentiometers manufacturer send us the wrong reference . Normally the master pot is a 11mm dual gang 50K linear 25mm D-shaft length.
The mouser Bourns PTV112-4420A-B503 is the one we use on our first prototype so it fit perfectly.
The only problem is that Mouser doesn't have the 25mm D-shaft length in stock but 20mm D-shaft is enough to put up the 21mm knob or the big knob from altitude.
With the HappyMum case, the shaft exceed 6.4mm (PCB holder are 11mm high) and with Erica synth case the shaft exceed 7.4mm as Erica synth case has 10mm PCB holder high.
[resize=800]https://c7.staticflickr.com/1/295/31878 ... ea50_o.jpg[/resize]
[resize=800]https://c2.staticflickr.com/1/532/31798 ... af43_o.jpg[/resize]

We contacted our potentiometers manufacturer to get the right potentiometers as soon as possible. Until we get them the Bourns PTV112-4420A-B503 was added to the Nava Mouser BOM.
We apologize for this inconvenient

Best regards,
e-licktronic

I just received master volume pots I ordered here in Germany. They fit and work perfectly and the shaft length is higher than of the suggested Bourns PTV112-4420A-B503, so it will fit better in happymums case. Just want to share the link where I bought them:

http://www.ltt-versand.de/Ersatzteile/P ... 31230.html

If you are in the same situation as me and already had all your parts together when realizing the missing pot in the kit, then this might be a good alternative to the Bourns pot from Mouser. Especially when you live in Europe or Germany like me and don't want to pay so much for shipping.

This is what it looks like:

KlangGenerator,

Nice found ! But the link you provide is for a A503 tape potentiometer, Nava need a B503.

Best regards,
e-licktronic