VFE Pinball - VERIFIED

[chance]

I have made this layout based on the project document you will find on Madbeans site: http://www.madbeanpedals.com/projects/_folders/VFE/pdf/VFE_Pinball.pdf
It works perfectly as designed therefore it is VERIFIED.
The 330uF filter cap could be as small as 100uF, I just put 330uF because there is space for one. 22uF pairs can be used instead of 10uF bipolar caps if you don't have them. The custom C10k/C100k dual-gang pots could be an issue of you don't have access to them, you can make your own by splicing them together/changing the wafers around.

[MOPO]

Hello,

Thank you for the layout,

For C10k / C100k dual-gang pots I do not know how to do so I think I choose a 10K C + 100K C and they will be independent.
Unless someone is a better solution?

[GrooveChampion]

Dissasseble a C10K pot and put it instead of the rear wafer if a C100K dual gang, you cant make an egg without breaking a few omlettes.

[chance]

Just like Groovechampion said, you will have break a few eggs, and then put them back together, sort of... Myself, I took a C100K dual-gang pot and removed the front wafer/shaft assembly from the housing, I then replaced this with the wafer/shaft assembly previously removed from the housing of a C10k single-gang pot. Some needle nose pliers and maybe a small flathead screwdriver may be needed to open the tabs and disassemble the pots. From there you will just have to work out how to unclip/swap the wafers around and clamp it back together.

[GrooveChampion]

I had issues with certain pots where the shaft and the wiper were one piece that you couldnt disassemble without breaking, that was a pain.

[MOPO]

Thank you I will try it on if I break the eggs :)

[GrooveChampion]

A few dozen eggs.

[chance]

The pots from tayda work well. The wiper at the rear of the dual-gang pots unclips and becomes the single-gang version

[brazdj]

Awesome! I actually have a vero in progress. Pretty much all done myself. I get some clipping however oy...

Could you please measure your op-amp voltages and post them here? On madbeans site, he gets ~ 3.5 volts on the op amp pins downstream of the Vb->2M2->op-amp non-inverting pin.

I have been getting ~ 1.7 volts.

Thanks in advance.

[brazdj]

Oh! Another thing.

The schematic shows a 10K to ground just upstream of the final "1k->output". This should be 100K to ground. You can see this on the PCB layout, and the Standout project (pretty Similar) shows the 100K on both the PCB and Schematic. This shouldn't make too much of a difference, but it does change the intended output filter frequency response.

I am talking about the 10K in your vero layout located in column 20, rows D-E.

[brazdj]

Okay.. I tested my vero again and with guitar signal level it works like a charm. I tend to use an mp3 (iphone) to test my builds due to space constraints in my 1 bedroom apartment replete with a collapsible-DIY-bench-on-dining-room-table setup. I believe my line level distortion is due to the rather large discrepancy between my inverting and non-inverting pin voltages, but whatever it works wonderfully with guitar...I guess my volume pot will stay near zero with all that op amp gain.

On another note, I used dual A10K and A100K alpha pots from Tayda (smallbear has em too). I just swapped the back plates out. In order to get the intended resistance sweep, I used pins 2 and 3. So I still get a reverse log sweep, but my knobs spin opposite of the VFE design. This doesn't matter to me.

I plan to verify a standout vero soon, after which I will post that vero layout along with my now verified Pinball vero layout.

[chance]

No worries buddy, I'm glad you got it working! I did look over the schematic for that 100k resistor but yeah it says 10k so I won't change the layout. I guess if it's marked 100k elsewhere then we can always experiment but I think we've established that the current layout is verified. Thanks again!

[chance]

I have just posted a layout for VFE Standout and I previously posted a layout for the VFE Dragon some months ago if you are interested.

[MOPO]

Hello,
There is a small error the link in 4 B is not connected to anything, the 15 nf should not it go in 3 B instead of 3 C?

[chance]

Hi MOPO. I'm having trouble identifying your issues because your references don't appear on my layout. But I can tell you that in relation to the DPDT ON/ON/ON switch, 2 of those poles are not connected to anything as per the schematic. I looked at both 15nF capacitors and they are connected to the things they are meant to be, I can't see any errors. If someone else can then please let me know. It's a simple schematic and the good news is that we can see at least 2 successful builds have been completed including mine.

[MOPO]

Hello,
I just noticed that the link in B4 is not related to anything, I will test it on breadboard. I am very bad at
English I use a translator so I may not be very clear :)

But I think I just understood, the capacitor 15 nf is probably connected to B3 but as it is large it looks like it is linked to C4

Thank you :)
@ +

[MOPO]

Your layout is probably fair but the components are not the right dimmension, for example filter 1 n 'is by reading related to nothing and it is really confusing, but nothing serious because we can look at the basic shemas

[chance]

It shows in the layout that FILTER 1 is the open end of a 150nF non polarised box type capacitor as per the schematic, maybe it's just hard to see. Maybe the confusion lies in how the DPDT ON/ON/ON switch works, this article may help https://www.seymourduncan.com/blog/the-tone-garage/guitar-wiring-explored-switches-part-3 

[chance]

I think it would make it easier to read if you could see the capacitor legs through it's body to show exactly where they go but I can't fix that one. I personally measured the capacitors by hand to ensure they are proper scale size but that's not critical at all.

[MOPO]

Now that I understand there are no worries I wait for the potentiometers to realize it. And thank you again for the layout.