Zvex - Box of Metal  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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DimebuGG
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Post by DimebuGG »

It's okay... :thumbsup
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mysticwhiskey
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Post by mysticwhiskey »

Cheers - thanks again for the layout, it's great as I was looking for a PCB-mounted 16mm pot layout. 8)

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Wlat
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Post by Wlat »

Hi! This is my first post here, so be gentl ;-)

I am intruiged by the noise gate on the Mox of Betal, so I took some effort to draw the schema based on the sketch, the layout/silkscreen overlay and the gutshots. I couldn't find the correct symbol for the VTL, but I think the idea is clear.
I'm confused about the use of both a VTL(5C9) and a FET (J175?). If I read the layout correctly, the VTL seems to be connecting the signal path to the positive supply voltage. The FET is only switched by the footswitch, but connects the gate to the signal path. Looks to me like this can't work...
It would appear more logical to connect the VTL not to the source of the FET but to the gate, controlling the switching function of the FET. Also, connect the footswitch to the drain and source, thus bypassing the FET and ingoring the gate function.

Anyone has any thoughts about this?

greetings,
Wlat
the Netherlands
Attachments
MoB Noise Gate schematic
MoB Noise Gate schematic

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Wlat
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Post by Wlat »

I just found out that the pinout of the J175 in the silkscreen overlay seems to be incorrect:
J175 pinout
J175 pinout
J175-pinout.jpg (12.9 KiB) Viewed 3306 times
The gate and drain are swapped, and so all schematics made up from this have this error.
So, when I redraw my schematic of the noise gate with this swap adjusted it gives me the following:
J175 gate and drain corrected
J175 gate and drain corrected
BoM Noise Gate v0.1 error.png (6.49 KiB) Viewed 3306 times
However, this doesn't appear to be right either. The FET gate connected to the Treble pot wiper???
My best guess is the following:
Noise gate... my best guess
Noise gate... my best guess
For good measure I've also drawn the complete schema:
Mox of Betal redrawn
Mox of Betal redrawn
And the footswitches:
Footswitch logic
Footswitch logic
I would very much appreciate any comments...

regards,
Wlat

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rasta_maleek
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Post by rasta_maleek »

have anyone the layout of this?

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Wlat
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Post by Wlat »

I'm working on a layout...

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Post by rasta_maleek »

Wlat wrote:I'm working on a layout...
did you finish tath layout Walt?
thanks for the working progress

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Post by ballfire »

amazing...

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Post by sinner »

askwho69 wrote:does the noise gate works? :D
No idea matey, but it looks like there is no any

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rasta_maleek
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Post by rasta_maleek »

any news about the bom with gate?
great proyect!

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Post by rasta_maleek »

Up for GAS :applause:


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Post by JebemMajke »

So i really need zener or can i replace it with some other diode?
Great work with the schematic.

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Post by rasta_maleek »

JebemMajke wrote:So i really need zener or can i replace it with some other diode?
Great work with the schematic.
I think that if you don't use the 9,1v Zener, you must use two 1N4148 like older SHO, Zener is limiting the voltage too.

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Post by JebemMajke »

In series? With both 1n4148's negative on where negative part of Zener would go?

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Wlat
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Post by Wlat »

Hi!
It's been a while since I started working on the noise gate. Somehow life got in the way...
Anyway, I'm at it again and started to use Eagle now for a pcb. I took Madbean's excellent layout as a basis (hope that's allright?) but I'm still having a bit of trouble getting the noise gate parts neatly without to much "spaghetti".
Here's my layout so far [unverified]:
First draft PCB
First draft PCB
Does anyone have a tip for getting a better layout?

Thanks,
Wlat

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wgtp
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Post by wgtp »

Joe Davisson, whose Obsidian mosfet distortions preceded Zvex' designs by several years, has reported that P-channel BS250 mosfets are quieter than the N-channel BS170's, due to construction. You would have to flip the power around, but it might be worth it with all the gain and mosfets. :twisted:

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wgtp
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Post by wgtp »

Joe Davisson, whose Obsidian mosfet distortions preceded Zvex' designs by several years, has reported that P-channel BS250 mosfets are quieter than the N-channel BS170's, due to construction. You would have to flip the power around, but it might be worth it with all the gain and mosfets. :twisted:

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served
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Post by served »

Hi,

Do you have a schematic with the original Gate control around?

I already built the BOM but now I feel like there is too much noise in this pedal. Is there a way to add a Gate function to the pedal?
How complicated is it? Does any one have a glue how Zvex made it?

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Wlat
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Post by Wlat »

served wrote:Hi,

Do you have a schematic with the original Gate control around?

I already built the BOM but now I feel like there is too much noise in this pedal. Is there a way to add a Gate function to the pedal?
How complicated is it? Does any one have a glue how Zvex made it?
View my posts of feb 2011 and feb 2012 (both page 8). Alas, not verified yet. I'm having trouble finding time to complete this project...

Greetings,
Wlat

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