Mutron Flanger dissection.

[armdnrdy]

Update:

It turns out that I was taking measurements from a different point than where the voltages Dino supplied were taken from.

I am able to achieve 2.3V & 11.4V compared to Dino's 2.29V & 11.60V measurements.

The pedal sweep has an "issue" at the very end where the voltage changes in a fairly linear fashion until it reaches around 9 volts to the end. The last 1/2" of toe down pedal movement doesn't increase the voltage. Looking at the shutter, I believe this can be fixed by slightly extending the slot in the shutter, reducing the width of the slot to the end. (slim V shape)

Anyway,

I'll move ahead and start work on routing the board. When the LDR assortment arrives, I'll revisit the testing for the best, absolute, LED/LDR combo for this circuit and pedal.

@ Govmnt_Lacky,

Yeah, the GL5539 or the GL5537-2 look pretty good. I'll definitely find the right one out of the bunch. (I ordered 10 of each flavor)

[digi2t]

The pedal sweep has an "issue" at the very end where the voltage changes in a fairly linear fashion until it reaches around 9 volts to the end. The last 1/2" of toe down pedal movement doesn't increase the voltage. Looking at the shutter, I believe this can be fixed by slightly extending the slot in the shutter, reducing the width of the slot to the end. (slim V shape)

Yup, V shape is what I figured. The fat T shape of the Morley card is probably creating your problem.

Can you try the Waitrony LDR`s again? I`ve got quite a few of them, and if they work, it would be a bonus. If you wish I can mail you a couple of G15177`s as well to try. I have a feeling that they`ll do the job.

Nice to see that the voltages are attainable. I think we`re on our way now. Great work Larry.

[armdnrdy]

Hey Dino,

I tried the Waitronys again last night just to be sure. I wasn't able to obtain the low voltage point with the trimmer, moving the LDR, or changing to different brightness LEDs. I think that they are too low resistance at light on. We could change the circuit, add trimmers and such, but my thought was to find an easily available LDR that works best.

I was thinking to fab a replica shutter out of something (aluminum, plastic) and get the extended V slot working right before I go hacking on the Morely shutter. When it's good to go, I'll make a template for the modification.

If you want to send a couple of G15177s, I'll try them out. Maybe they're the "magic" component!
I'll PM my address. 

[Govmnt_Lacky]

Dino/Larry

Certain LDRs respond differently to the wavelengths of LEDs. Maybe a color change is in order? 

[digi2t]

Dino/Larry

Certain LDRs respond differently to the wavelengths of LEDs. Maybe a color change is in order? 

Damn... he's right. (forehead slap!)

[armdnrdy]

I've been trying green as well!

3mm and 5mm LEDs for different spreads of light.

[Govmnt_Lacky]

Maybe different brightness levels 

I know that my Lovetone flanger was very particular about the LED type on the daughter board. It had to be a water clear HIGH BRIGHTNESS type. Not super bright, not ultra bright, it had to be HIGH brightness. I tried different types of brightness and the only one that worked was HIGH brightness.

Food for thought 

[armdnrdy]

Hey GL,

I've been experimenting with different brightness LEDs as well. Besides the end of the sweep issue noted earlier, I think I'm pretty close. The end of the sweep thing should be fixed by extending the slot just a bit.

What happens is, the slot on the shutter runs into the "dark" area to the LED before the pedal is all the way toe down. I've watched  the shutter/slot location and the meter's readings. I'm sure that's all that needs to be done.

I'm having other issues that need immediate attention before I can start routing the board.

The Morley enclosures board standoffs are approx. 5mm from enclosure. (looking at the enclosure upside down with the bottom cover removed) The board has to be at that level because of the pedal shutter arrangement.

I wanted to use the existing IN/OUT jack holes as well as the power jack hole.
I also planned to use board mounted pots like the original build but......with the board at that low level, pots don't fit between the enclosure and the board.

I thought to make the shutter board separate.so that I can keep it at the existing level. There are only three connections to that board, +V, GND, and the control (pedal) voltage out to a footswitch.

I was thinking to flip board mounted jacks upside down in the enclosure (from their current orientation) and mount all of the components facing inside the enclosure, with the trace side showing when the bottom cover is removed.

I apologize, I know my description doesn't sound very clear! You have to see it. Post a picture?

If I make a main board that stands off much higher than the original....I think that I need PC mount, right angle, long pin pots. Mouser, Smallbear, Mammoth, and a few others sell them.

One problem. I can't seem to find a data sheet for the long pin type. The model # for a 10KB is RV16AF-42-15R1-B10K

[digi2t]

I wanted to use the existing IN/OUT jack holes as well as the power jack hole.

On my Talking Pedal retrofit, I simply cut the Morley board, and retained the upper part.

[armdnrdy]

That looks like a great idea....for the talking pedal. 

Look at the talking pedal next to your flanger. There are a "few" more controls and a "whole dang bunch" (spoken with an American western slang accent) more components.

Because of the angled foot pedal, I'm also entertaining the thought of putting two controls on one side and two on the other.
The four controls plus the rate LED above an LED and a footswitch leading up to the input jack can get kind of cramped.
We'll see....nothing set in stone. Definitely open to suggestions.

[Govmnt_Lacky]

What about pots that mount through the PCB and to the enclosure a-la the old RAT pedals? 

[armdnrdy]

What about pots that mount through the PCB and to the enclosure a-la the old RAT pedals?  

I took measurements for that kind of arrangement as well, the threaded bushing isn't long enough to make it through the 5mm (board to enclosure) and the approx. 2mm enclosure thickness. The threads end at approx. 6.5mm from the front of the pot.

I thought about not making the board as wide (side to side in the enclosure) but I kind of need room behind the controls to route traces as on the original board.

[Govmnt_Lacky]

@Larry

Always trying to find the brighter side... 

Dont they have options on most pots to have longer bushing lengths? How much bushing do you think you would need in order to make the through-PCB idea work?

[armdnrdy]

Dont they have options on most pots to have longer bushing lengths? How much bushing do you think you would need in order to make the through-PCB idea work?

Standard Alpha pot threaded bushing length is approx. 6.5mm. To make the "rat" style through hole mounting work, we would need about 10mm.

Last night a forum member posted measurements for the right angle, long pin pot RV16AF-42-15R1-B10K. This morning Steve from Small Bear confirmed with a sheet from Alpha.

My idea of flipping the pots and making two boards will work perfectly with these pots. (almost as if these pots were custom made for this build)
I scoured suppliers sights and can't seem to find anything readily available to make this build work with the board at the standard Morley height.

Here's a shot of a jack "flipped" and a piece of circuit board for reference. All of the components will be facing down into the enclosure at this view. Also...there are no clearance issues with the bottom cover.

[armdnrdy]

A little bit of progress to report.

I have the board dimensioned, parts placed, and have started routing. (Eagle)

I fabricated a test shutter out of a piece of .89mm (original is .79mm) electrical flash guard/insulation material. It's some sort of fiber composite, fairly easy to cut and drill.

The original is on the right:




I received an order from Mammoth today which included the long pin pots (RV16AF-42-15R1-B10K) and a right angle 25KC pot for the rate pot. (It seems nobody stocks a 25KC in the long pin model)
I was planning to switch out the wafer from the 25KC pot to a long pin model.......I must have been suffering from a brain cloud!
The wafer is attached to the pins! I'm not sure what I was thinking....anyway....I fabricated a pot with the proper dimensions using a small piece of perf board and header pins. Problem solved:

[Govmnt_Lacky]

Wow Larry!

You are like a dog with a bone on this one! 

Great looking work. Folks are gonna owe you and Dino a huge debt of gratitude after this. Well... At least I know I will 

Cheers and thanks for all the hard work.

[digi2t]

Larry.... 

The vero extension on the pot... sheer brilliance. This is why I come here. I'm going to bed less stoopid... AGAIN!

Excellent.

[armdnrdy]

I'm finished with the preliminary routing of the main board. I'll be putting the final touches on it over the next few days. (fresh eyes)

We're getting close to building the prototype!




Here's the enclosure layout:



The power input can accept 18VDC or 12VAC. No jumpers needed.

[digi2t]

I am... slackjawed.

Wow. I want one.

I don`t see the slot for the shutter card though, or will that be added later.

[wavley]

I'm not sure how much I actually need one of these considering the love I have for my Morley PFL, but DANG!!!!!!!!!!!

I WANT ONE