Merlin's Glassblower TH Custom, assembly help needed

[Matness]

Hello forum,

I am hoping someone can help a beginner with assembling a pedal.

I purchased the kit from Musikding, it is made by TH Custom and designed by Merlin Blencowe.

Populating the circuit board was easy, but the instruction sheet stops there - it does not explain how to wire up the battery, DC jack, potentiometer, switch, input and output jacks, etc.

The circuit board is marked (see photos) but I'm not sure how to interpret those markings.

Could someone point me in the right direction?  Maybe someone has a photo of the completed device?

Also, the enclosure that came with this kit does not include standoffs or holes for mounting the PCB to the chassis, so it seems it will float freely... What should I do about that?  Insulate it with foam?

Thanks in advance!

See attached photos

[jimilee]

https://www.madbeanpedals.com/tutorials/downloads/StandardWiring_MBP.pdf


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[Matness]

Thanks for the link jimilee!  That will at least get me started!

Another question:  The DC jack has three tabs, but only two contacts, right?  So two of the tabs are internally connected?

Thanks again!

[jimilee]

A switching DC jack has 3.


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[Matness]

Well, I have the potentiometer wired in now, thats at least some progress.

A switching DC jack has 3.

Took me a moment to understand, but now I get it:  When the power supply is plugged into the jack it disables the battery.  Now I just need figure out which is which... Should be able to determine that easily enough with a multimeter.

I know this shouldn't be complicated, but I'm still uncertain of how to wire up the rest.

The main board has:
1 "in"
1 "out"
3 "GND"s (ground)
2 "+9V"s

The switch board has:
"JI" = ____ in?
"JO" = ____ out?
"BI" = ____ in?
"BO" = ____ out?
Two "+9V"s
Three "GND" (ground)

Do I understand correctly that I only need to hook up one GND on each board?

[jimilee]

Well, I have the potentiometer wired in now, thats at least some progress.

A switching DC jack has 3.

Took me a moment to understand, but now I get it:  When the power supply is plugged into the jack it disables the battery.  Now I just need figure out which is which... Should be able to determine that easily enough with a multimeter.

I know this shouldn't be complicated, but I'm still uncertain of how to wire up the rest.

The main board has:
1 "in"
1 "out"
3 "GND"s (ground)
2 "+9V"s

The switch board has:
"JI" = ____ in?
"JO" = ____ out?
"BI" = ____ in?
"BO" = ____ out?
Two "+9V"s
Three "GND" (ground)

On the switching jack, the ground is the l shaped lug. Immediately to the right is the DC power supply, to the right of that is the battery. That one isn’t necessary if you don’t plan on using a battery.

JI=jack in 
JO= jack out.
BI=board in
BO=board out

Extra +9vs and grounds are just helpful sometimes. You don’t necessarily have to use them.


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[Matness]

On the switching jack, the ground is the l shaped lug. Immediately to the right is the DC power supply, to the right of that is the battery. That one isn’t necessary if you don’t plan on using a battery.

Thanks for that tip, I would prefer to skip the battery.

Just to make sure I understand correctly I've uploaded another photo.
You're saying that the upper lug / middle lug is the one for the DC power supply, and that I can completely ignore the lug furthest from the L-shaped one (far right in the photo)?

JI=jack in 
JO= jack out.
BI=board in
BO=board out

Excellent! Now its beginning to make sense!
I'll likely have a few more questions yet though, since this board looks too fragile to tolerate much desoldering/resoldering I want to try to get it right the first time.

I think I have the two PCBs wired together now.
Assuming that:
"BI" on the switch board = in FROM main board (wired to 'OUT' on main board)
and
"BO" on the switch board = out TO main board (wired to 'IN' on main board)

Extra +9vs and grounds are just helpful sometimes. You don’t necessarily have to use them.

So in theory it shouldn't matter which GND or 9V+ point I choose on each board?
Duplicate connection points on the same board are redundant and purely for convenience?
Do I need to connect GND and 9V+ to both boards?  Or only one?

Your advice on this is hugely appreciated!  Thanks a lot!!!

[Matness]

So I made some guesses and seem to have guessed wrong...

I connected the ground wire DC jack ---> Output jack sleeve ---> Switch board GND ---> Main board GND.
I connected 9V+ to main board and to LED side of switch board.

Wired everything else up according to the link jimilee provided at the beginning of this thread, which all seemed to make sense...  The only thing I didn't do was make any connections between switch poles, being under the impression that the switch PCB was already making those connections...  I'll remove the board tomorrow and follow the traces to see whether this is the case or not.

Plugged in DC power and hit the switch... LED did not light up.
Plugged guitar and amp in - with pedal off(?) audio passes through unaltered...

With pedal on(?) there is no audio, and a quiet high pitched whine which which disappears when I turn the potentiometer yet won't return at any position? I unplugged it immediately rather than risk damage.

I also notice that the switch PCB seems to have an empty space for a resistor right before the LED...
Unfortunately the instructions that came with this kit don't mention or show photos of the switch PCB at all...  Its as if a page was missing - they go straight from populating the PCB to "You now have a boost pedal"!
https://diy.thcustom.com/?wpdmdl=3881   (link to instructions)

So I'm a bit lost and will wait for advice here before proceeding.

Looks like I won't complete this project tonight, but I look forward to trying again tomorrow if I haven't fried any components...

[jimilee]

Can we have some clear close up pics of where you’re at? There’s a lot of information the re.


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[Matness]

Can we have some clear close up pics of where you’re at? There’s a lot of information the re.

See attached photos.
First photo is most useful - I drew a wiring diagram, since the real-world wires aren't so easy to follow visually.
Forum won't let me put them all in one post, so additional photos will follow in 2nd post.

[Matness]

Additional photos (see previous post also)

[Matness]

I'm going to wait for expert advice before doing anything, but my guesses:

- The switch board may need another 9V+ connection?
- The LED is missing a resistor of unknown value
- I may have also made a beginner mistake which will be obvious to Jimmilee

Did you check out the link I gave to the instruction sheet? 
Am I mistaken in thinking that the instructions are incomplete?

The switch PCB is double-sided, I can't follow all of the traces now that the switch is soldered but I assume that all necessary switch connections are being made by the PCB.

[jimilee]

The instructions look complete, some people don’t put wiring instructions I. The build docs, some do.

The I put jack is a a little blurry, so here is how it’s supposed to go.On the input jack, the ground is the inner most lug, the out lug is the outermost or the bottom of the stack. The CLR is anything from 2k to. 10k with 4.7k being the most common. The DC jack looks right.


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[Matness]

the out lug is the outermost or the bottom of the stack.

One jack is mono, one is stereo.   The stereo is the input, and the mono is the output, right?

The stereo jack is kind of strange, the bottom of the stack connects to ring, the middle of the stack connects to tip.  The top of the stack is shield as expected.   I connected the output to the tip.   

I'm thinking the jacks must be wired correctly, because with the switch off(?) audio does pass through.

Does the switch board need another DC connection?
I ran a 9VDC wire to the LED hookup on that board, but maybe I need to run one elsewhere on the same board?
Or maybe adding the resistor will complete the circuit?  I also ran a 9VDC wire to the main board.

I'll install a resistor for the LED and see what difference that makes.

Thanks for all your advice!

[jimilee]

Absolutely, I’m happy to help. Thanks for the input clarification on the input jack. The switch board doesn’t need any more 9vDC connections.. As a matter of fact, if you put your DMM on the continuity setting, you’ll find they’re already connected.

If you still have no sound, check all your components to make sure they’re all in the right place and your polarities are all correct.


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