PIMETA Volume Pot Mounting

[digitaldave]

I've got the Blue Velvet volume pot for my PIMETA, which I will be mounting in a Hammond case. If I mount the pot on the board using the holes provided, will this make putting the whole thing in the case difficult? Or should I just mount the pot on the front panel and run wires to the board?

Thanks

.

 

[__redruM]

It's much simpler to board mount it, and you won't save enough space to make it worth running wires. If space is a concern, order the panasonic pot, and save the Alps for your PPA. If you want a portable pimeta, you really need to use the Panasonic pot (IMO).

 

[StevieDvd]

I think mounting on the pcb is better but there must be a trick to get the case hole lined up.

If you can get the pcb ready for the case then surely you could slide the pcb and pot so that the inside of the case front gets marked, indicating the centre of the drilling point.

Something like bluetak inside, a felt-tip dabbed on the pot, or maybe a better suggestion from those who've done it more times than me.

Steve

 

[Nisbeth]

Depends. Which hammond case do plan on using? If you want the K-type, you will not be able to fit the jack on the front panel if the pot is mounted on the PCB. If you have another case size where there is enough space for the jack, I would definitely mount the pot on board. Then you just have to drill a single 8mm hole in the front panel to fix the whole thing in place

/U.

 

[digitaldave]

I'm not going for a portable, so I'll stick with the pot I have.

The case is a Hammond K. However, I've had a look, and I reckon it'll fit... watch this space

.

 

[digitaldave]

Quote:

Originally Posted by Nisbeth Depends. Which hammond case do plan on using? If you want the K-type, you will not be able to fit the jack on the front panel if the pot is mounted on the PCB. If you have another case size where there is enough space for the jack, I would definitely mount the pot on board. Then you just have to drill a single 8mm hole in the front panel to fix the whole thing in place /U.

Apologies, it seems you were right

. The large caps get in the way of the output socket, and there's no way round it on a Hammond K apart from mounting the pot off the board. So I've gone that route.

I'm getting there slowly

.

Now, to figure out how to fix the PCB inside the case...

 

[Nisbeth]

FWIW, I mount my board using the screw holes in the back and a shaft coupler/extender (see picture. The screws are visible as well) and mount the pot on board. If you're mounting the pot off-board I would just enlarge one of the mounting holes for the EVJ-pot (which will not be needed) to fit a screw as well.

/U.


EDIT: If you don't want visible screws, instead you can screw the board onto a piece of aluminum that fits in the mounting slots in the case

 

[bg4533]

Nisbeth,
Where did you get that extender?

 

[Nisbeth]

I got it from Reichelt in Germany (here )

We have discussed these a while back, but I don't think anyone came up with a US source for this or an equivalent part

/U.

 

[Magsy]

Quote:

Originally Posted by Nisbeth FWIW, I mount my board using the screw holes in the back and a shaft coupler/extender (see picture. The screws are visible as well) and mount the pot on board. If you're mounting the pot off-board I would just enlarge one of the mounting holes for the EVJ-pot (which will not be needed) to fit a screw as well. /U. EDIT: If you don't want visible screws, instead you can screw the board onto a piece of aluminum that fits in the mounting slots in the case

I have mine in that case, I had some fun with the jack... I ended up with the jack and knob a bit too close together. I didn't use the big neutrik though, I had a smaller one but the caps were still a pita

I have the alps on the pcb and the jack upside down between the pot and caps - just

 

[MisterX]

Just don't populate the front two C2 caps and everything will fit in that case with out messing around with shaft extenders and the like.

 

[tangent]

Quote:

Just don't populate the front two C2 caps and everything will fit in that case with out messing around with shaft extenders and the like

Bingo, one gold star for MisterX.

This is a new feature in PIMETA v1.1: you can populate just the rear pair, and it'll work. With PIMETA v1.0, you had to populate "1 and 3" or "2 and 4".

 

[digitaldave]

Quote:

Originally Posted by tangent Bingo, one gold star for MisterX. This is a new feature in PIMETA v1.1: you can populate just the rear pair, and it'll work. With PIMETA v1.0, you had to populate "1 and 3" or "2 and 4".

It's almost like it was designed so that you could leave out the caps to accomodate the output socket

.

So, what will be the effect on the sound if I leave them out? I'm interested from a theoretical point of view, as I'm 99% sure I'll be remote mounting like Nisbeth.

 

[Syzygies]

Quote:

Originally Posted by daveabrey So, what will be the effect on the sound if I leave them out? I'm interested from a theoretical point of view, as I'm 99% sure I'll be remote mounting like Nisbeth.

The Panasonic FM EEUFM1E222L is 12.5x30mm, 2200uF, 25V, $1.34 at Digi-Key, and fits. No one needs that much capacitance or better caps. The four cap positions are for boutique caps or those of us with severe height restrictions, e.g. I'm going with four 470uF 10x16's.

What I'd love to know, is this: With those front cap slots vacant, they're crying out for Zener diodes to protect the caps in the event of a virtual ground collapse, so the caps don't have to be rated for over twice the voltage they'll ever see in normal use. Would this adversely affect the sound?

 

[tangent]

Quote:

they're crying out for Zener diodes to protect the caps in the event of a virtual ground collapse, so the caps don't have to be rated for over twice the voltage they'll ever see in normal use

That's one way to go, but I'm not certain it would work. If you yank hard enough on a zener, can't you break it? And hard yanking is the sort of thing you expect when the virtual ground has collapsed.

What I recommend in the docs is to simply pick caps with a voltage tolerance higher than the power supply's total voltage. Then it doesn't matter if the vground collapses.

Quote:

Would this adversely affect the sound?

It shouldn't. Zeners are only noisy when conducting, and they wouldn't be, in normal operation.