Another Boss CE-1 query - Weird Cap

[nickbungus]

Hi Guys

It seems like every man and his dog are working on a CE-1 clone but I have a quick question.



On the above, C42 is polarised and rated at 47nF.  Not a polarised value that I've come across.   On the 2 schematics I have (the original Boss one and the TurretBoard.Org one), it reads the same.

This has lead me to one of three conslusions

• It is a mistake and the correct value is 470nF
• It is a mistake and it does not need to be polarised
• This is a magical capacitor and the beating heart of the CE-1 that needs to be exactly 47nF and polarised, hand crafted by elves from the horn of a unicorn.

Any ideas?

[Rob Strand]

Look here,
http://www.it11audio.com/wp-content/uploads/Boss-CE1-PCB.jpg

Then look at the top right quadrant of the PCB.  You will see two large electros near the centre of the PCB.  Then a SIL package IC just above it.   Now move to the right about 20mm.

In that region I can see some silicon diodes, large green cap (100n?), smaller green cap (33n>).
Then there's a0.47uF electro.  And just behind that looks like a 330k resistor (R68?).

Anyway to me it looks like the right part of the circuit.

So if you agree that the making is 0.47uF then the cap is marked with the incorrect value on the schematic.

[antonis]

Even IF it is 470nF, I can't see the reason of being electro..

It's a common practice on PCB design to mark a capacitor placement as if it was of electro type (polarized) when it's nominal value is close enough to polarized type use on future value modification..

[Rob Strand]

No doubt of the value:
http://cdn.tonegeek.com/wp-content/uploads/P1050405.jpg

[nickbungus]

Cheers Guys

Rob are you saying its definitely 470nF.  I'm not sure exactly where you are looking on the second image posted to confirm.

Thanks

[Rob Strand]

Rob are you saying its definitely 470nF.  I'm not sure exactly where you are looking on the second image posted to confirm.

OK, in that pic about the centre is an SIL package IC orientated top to bottom.  Under that is two large electros.  Along the right edge of the board you can see wire numbers 17, 18, 19.  Draw square around those three features and smack in the middle is an electrolytic cap (standard size).  Zoom in and you can see it is 0.47uF 50V and it is an electro.

[nickbungus]

Brilliant

I hadn't zoomed in enough and looked at the top



That is very conclusive

[thermionix]

every man and his dog are working on a CE-1 clone

Me and the cat are building a CE-2 clone.  Madbean Pork Barrel PCB.  Awaiting ICs from diy-tubes.com (not affiliated).  I'm not really a big chorus fan, but I was already placing an order, and their prices on MN3007 and MN3101 were too good to pass up.