Mutron Flanger dissection.

[armdnrdy]

Just when I thought I was finished with the R&D of the LED LDR board......

When I performed the original testing for the design of the LED/LRD board, I purchase an assortment pack of different color/size diffused LEDs from Fry's Electronics. (I usually use water clear in my builds)

I purchased 5mm yellow diffused LEDs from Tayda so that we may have a universal "go to" LED for this build.

When I received the parts order from Tayda, I tested the LEDs and found that they were much brighter than the LEDs I had been using.

Back to the drawing board.....or should I say....the LED board!

About a month ago, I built a resistance substitution box which has two modes, (ohms and K ohms) twenty-four selectable resistors in series with potentiometers, capable of 10Ω to 1.25MΩ. This "box" really proved to be a valuable piece of test equipment in getting this circuit dialed in.



I ended up pulling R68 (330Ω 1/2 watt) and replacing it with a couple of header pins. I attached the resistance box and dialed it in to the resistance needed to reach the proper output voltages of this circuit.

I decided to add a 10K trimmer in series with R68 to make the resistance adjustable to compensate for different brand LEDs. The LED I went with is a 3mm, yellow, diffused.

I made the appropriate changes to the board and reposted it on the previous page.

[alanp]

It's been interesting, following this. (Especially since I don't really know what a Mutron Flanger *looks* like.) I gather it won't be true to the original, but a second version that uses an Expression jack, rather than a mechanical optical wah arrangement, could be something to look at, perhaps?

[armdnrdy]

If you think about it...the pedal is an expression pedal of sorts.

You could build a straight flanger with a CV input to be controlled by an expression pedal but......that feature is already built in.

About the only other function that would be worthwhile controlling with a pedal is the Rate control. There's a bit of a problem with getting that one off of the ground....the rate control is a 25KC pot. It might be kind of a trick emulating a reverse audio pot with an expression pedal.

I've done a bit of exploring in the world of designing a switchable, multi taper, multi value, voltage divider, one size fits all expression pedal.

Let's put it this way.....I haven't reached my destination......I'm still exploring!  

Alan,
If you want to see what a Mutron Flanger looks like and sounds like, go to the first page of this thread. It's all Dino's fault! 

[armdnrdy]

We've got board! 

[Govmnt_Lacky]

SWEET!!! 

[armdnrdy]

I placed the Input/output jacks and the power jack on the board to check alignment with the enclosure......looks good!

I think my next step is to make a drilling template that fits snuggly inside the enclosure. The template can be printed out on a bit heavier paper stock to alleviate misalignment.
I'd like to check all board/enclosure alignment before I populate the board.....although I'm pretty confident that there are no issues. (I spent a little time on this!)

We are getting even closer!  

Dino,
Front lighted view:

[digi2t]

Oh heck yeah! Much better. The lighting on the other shot was VERY deceiving.

Looks great.

[armdnrdy]

If you follow the letter "E" in the word Flanger, you'll see a hole to access a trimmer from the trace side. Right above that hole there is another hole that has been widened horizontally. That hole is for a test point that gets soldered to the trace side. There are four test points on the board.

There is very little clearance from the trace side of the board to the bottom cover of the enclosure.....so I devised a method to make this work.

Take a medium diameter component lead cutting, (example: 1N4001 lead) wrap it around a small jewelers screw driver shaft, (or something similar in diameter) squeeze the tag ends together with some pliers to form an eyelet.
Place needle nose pliers about 2mm below eyelet and bend the eyelet over to form a right angle.

This can now be soldered to the trace side with no clearance issues. The eyelet provides a good place for an alligator clip or an oscilloscope test hook.

This will be outlined in the build document. 

[digi2t]

How about these?



http://www.newark.com/keystone/5000/test-point-pcb-color-coded/dp/07J9695?in_merch=Popular Test Connectors&in_merch=Popular PCB Test Points&MER=PPSO_N_P_PCBTestPoints_None

[armdnrdy]

These were my first thought but I checked the PDF and they stand too high. There's not enough clearance.

I think these would actually work:
http://www.mouser.com/ProductDetail/Keystone-Electronics/5021/?qs=fP5bVVCrK/eNcXCJeuA88Q==

But the way that I outlined making test points with resistor lead cuttings, it doesn't make sense to buy them. There's only four! Now if there were fifty!  

Update:
I found that if you wrap a standard resistor lead (not the thin Tayda type) around a large (1 3/4" to 2") paperclip this makes the height only about 2.8mm which works for the bottom plate clearance.

The paperclip I used has a 1.33mm diameter.

[armdnrdy]

Dear diary,

Making some progress!

Yesterday I worked out a drilling template that fits inside of the enclosure rather than the top. This allows for definitive borders for the template resulting in a much better alignment.

After I checked the template to the onboard components and was satisfied with the results, I started populating the board.

[digi2t]

Yea, though I walk through the valley of the shadow of Mutron, I will fear no flanger: for thou art with me; thy iron and thy solder they comfort me.

Amen.

[armdnrdy]

You know....

I would occasionally dive in to a folder full of Mutron Flanger information over the last several years.
I would come away thinking.......there's just too many missing pieces to this puzzle! It's just not doable!

Now that we've filled in the blanks, and I'm working on the actual build, it's a bit surreal at times!
Every now and again the thought crosses my mind......we're building a Mutron FXXXXXG Flanger!   

Then a warm fuzzy feeling comes over me and I feel a sense of peaceful contentment. 

[Govmnt_Lacky]

Then a warm fuzzy feeling comes over me and I feel a sense of peaceful contentment. 

Crossed fingers that your feeling of contentment carries over throughout the buildup AND testing process! 

[armdnrdy]

Crossed fingers that your feeling of contentment carries over throughout the buildup AND testing process! 

I've heard that a feeling of contentment comes over you right before you die as well!  Can you say crash and burn?

I'm feeling pretty good about this so far....I've checked the board two, three, and four times for bugs.





And I've made sure that all of the dimensions are as close as I can get them!
With all this attention to detail......what can possibly go wrong?

[digi2t]

 

[armdnrdy]

The main board is populated except for the input/output jacks, the pots, and the power jack.

Next step is to drill the enclosure, fit the board with unsoldered pots into the enclosure, tighten up the pot nuts, then solder the pots in place to ensure the correct height. The same goes for the main board mounted rate LED.

When I'm through, I'll post a picture with the results. So far so good! 

[Govmnt_Lacky]

Billy D approves!!!!

Can't wait! 

[digi2t]

I'll throw a smattering of glitz as well...

[armdnrdy]

Billy Dee and Orson encouraged me to move this project forward!

I printed the drilling template on a heavier "card" type stock thinking that it would be better for alignment with the enclosure.
I had file folders on hand that I trimmed down to letter sized stock (8.5 X 11) for printing.

Here's the template inside of the enclosure with the initial pilot holes drilled:



After I drilled the enclosure, I fitted the board mounted pots, set the PCB in the enclosure, and soldered the pots in place at the correct "installed" height.

Here's a shot of the main board component side:



Here's a shot with the main board installed, all buttoned up with everything aligned. (I threw some knobs on to give the effect an effect!)



Tomorrow I'll work on the LED/LDR board and beyond.