Mutron Flanger dissection.

[armdnrdy]

Let's not test this version so we can keep the smoke in our 3007s.

The MN3007's pin connections aren't correct for positive voltage.

I'll redraw it in eagle with the 3007 retrofit when I get a moment.

I'm working on a ADA STD-1 redraw right now.....it's a monster!

[Ronan]

Sorry Dino and Larry, I know nothing about the BBD chips so can't help with a schematic (without doing possibly days of research and regurgitating the work that has already been done on this forum). The conversions have been done before, here's a couple:

http://www.diystompboxes.com/smfforum/index.php?topic=72329.0

http://www.diystompboxes.com/smfforum/index.php?topic=78270.0

If a schematic is decided on, I can have a go at a pcb layout. I agree with GL, just do a layout for MN3007, not SAD1024. Will need some pointers on how to lay clock traces, minimize noise, or whatever issues come up with flanger layouts.

I also think the LED/LDR tubes are unnecessary, and the 2nd LDR is not needed. Better off just doing it the Morley way, one LED, one LDR and a shutter - it works fine and will make for an easier build.

On a technical note, the ground symbol of a schematic pretty well must be 0V, since there should not be any DC offset on a ground or output signal. The IC power supply pins must go to + and - supplies (as specified in their datasheets) and ground is 0V. This is the convention, not the rule however, so just my 2c. In this circuit, the virtual ground is created with an IC, and this is an acceptable way of doing this, just as Vref in many 9V pedals is created with an IC in exactly the same way. But note how Vref does not use a ground symbol, it is usually labelled Vref or similar, to distinguish it from ground (0V). In these circuits, a capacitor is then used to take out the DC component from the output signals.

[digi2t]

The MN3007's pin connections aren't correct for positive voltage.

Crap!... I just looked at the datasheet.

Better off just doing it the Morley way, one LED, one LDR and a shutter - it works fine and will make for an easier build.

I'm not quite sure how the second LDR works in concert with the LED. I know that section and trimmer is for setting up the pedal range, but it seems awfully elaborate. Can someone dumb it down for me? Will we need something similar/simpler for adjusting the range otherwise?

[Fender3D]

OK, I hacked in the MN3007 chip. Does this look right? (You're not the only one who's desperate Larry. )

It looks ok!

You may sub the 100k trimmer on BBD output with a 100k or 47k resistor and connect a 20k trimmer from Q4 emitter to -7.5V (down arrow), wiper to C19 and you're done!

[Govmnt_Lacky]

Better off just doing it the Morley way, one LED, one LDR and a shutter - it works fine and will make for an easier build.

There are some Morley pedals that have 2 LED/LDRs and 2 cut outs on the treadle piece.

I am pretty sure the Bad Horsie Wah has 2 LED/LDRs.

Can you confirm that Dino? Ill have a look at my Alligator pedal as well.

[armdnrdy]

It looks ok!

Federico,

I think you missed the point where Dino stated that there is no negative voltage in this build. The supply is +15 / power ground with a virtual signal ground being created by Z11B.

Dino has the 3007's gnd pin going to ground and the VCC pin going to +15 volts. It should be the other way around

[digi2t]

Better off just doing it the Morley way, one LED, one LDR and a shutter - it works fine and will make for an easier build.

There are some Morley pedals that have 2 LED/LDRs and 2 cut outs on the treadle piece.

I am pretty sure the Bad Horsie Wah has 2 LED/LDRs.

Can you confirm that Dino? Ill have a look at my Alligator pedal as well.

I haven't opened it up yet, but the Bad Horsie schematic shows 2 led's and 2 ldr's.

Would be nice to try and stick to the original design, just for posterity. I can understand that replacing the SAD is pretty much required, considering cost, but I don't think an extra led/ldr would hurt the pocket book. Besides, the op amp is already there.

What say you all?

[Fender3D]

Federico,

I think you missed the point where Dino stated that there is no negative voltage in this build. The supply is +15 / power ground with a virtual signal ground being created by Z11B.

Dino has the 3007's gnd pin going to ground and the VCC pin going to +15 volts. It should be the other way around

...

Oh ok, we built up a confusing thread...

Let's put it this way...
3007's pin 1 is @+ 15V and pin 5 @0V, then it's ok...

BTW the 20k trimmer I was talking above, then goes from Q4 emitter to 0V (down arrow), wiper to C19

[Govmnt_Lacky]

I haven't opened it up yet, but the Bad Horsie schematic shows 2 led's and 2 ldr's.

Would be nice to try and stick to the original design, just for posterity. I can understand that replacing the SAD is pretty much required, considering cost, but I don't think an extra led/ldr would hurt the pocket book. Besides, the op amp is already there.

What say you all?

I would just like to say that the baseline stuff is there already for a 2 LED/2 LDR setup with the Morley shells. There is also a template to follow (somewhat) for those who will attempt a drop-in PCB.

Finally... there is A LOT of space inside those Morley shells. There is PLENTY of open space to work with for the PCB layout PLUS... there is plenty of room to add the potentiometer controls on either side of the foot pedal 

[armdnrdy]

...

Oh ok, we built up a confusing thread...

Let's put it this way...
3007's pin 1 is @+ 15V and pin 5 @0V, then it's ok...

BTW the 20k trimmer I was talking above, then goes from Q4 emitter to 0V (down arrow), wiper to C19

My mistake...sort of.... the MN3007 symbol pin numbers and pin names for GND and VCC are switched.

[armdnrdy]

Here's my "quick" take on the 3007 retrofit. MN3007 pin names corrected.

[wavley]

I haven't opened it up yet, but the Bad Horsie schematic shows 2 led's and 2 ldr's.

Would be nice to try and stick to the original design, just for posterity. I can understand that replacing the SAD is pretty much required, considering cost, but I don't think an extra led/ldr would hurt the pocket book. Besides, the op amp is already there.

What say you all?

I would just like to say that the baseline stuff is there already for a 2 LED/2 LDR setup with the Morley shells. There is also a template to follow (somewhat) for those who will attempt a drop-in PCB.

Finally... there is A LOT of space inside those Morley shells. There is PLENTY of open space to work with for the PCB layout PLUS... there is plenty of room to add the potentiometer controls on either side of the foot pedal 

The Morley Pro Flanger has two LDRs and one bulb.

[Fender3D]

Here's my "quick" take on the 3007 retrofit. MN3007 pin names corrected.

Ok.
I'd add a 100k resistor from bias trim's wiper to pin 3 otherways you might attenuate signal a bit too much, or feed too much current...
Again I'd buffer MN's output with a transistors, better have more signal than less... (it may always be regulated later)

[armdnrdy]

Here's my "quick" take on the 3007 retrofit. MN3007 pin names corrected.

Ok.
I'd add a 100k resistor from bias trim's wiper to pin 3 otherways you might attenuate signal a bit too much, or feed too much current...
Again I'd buffer MN's output with a transistors, better have more signal than less... (it may always be regulated later)

Hey Federico,

Schematic updated with 100K and buffer.

Yeah....I missed the 100K.
Without dragging up the data sheets....the SAD has a higher output than the MN yes? no?

I'll redraw this in Eagle later today.

[digi2t]

I would just like to inject a quick, but very sincere, "Thank you" to all lending their brain power to this.

There. Everyone, carry on please. 

[Fender3D]

Larry,

SAD has a positive gain, while MN is more towards 0dB/-2dB, usually. So, yes SAD has a higher output than MN

BTW gain depends on output load resistor(s).

[Ronan]

Looks like the power for the MN3007 is 7.5V instead of 15V in the above schematic, because "ground" is actually sitting at +7.5V. There's an emitter resistor missing on the buffer after the MN3007.

[Gus]

Here is the drawing of the LDR's - LED arrangement too. For some reason, I accidentally deleted it from Photobucket.

Look at the LED setup and the schematic what photo cell goes to Z10a and Z10b?

Note when more light hits PC1 it resistance drops moving pin 2 the inverting input of Z10A more positive this reduces the drive to Q5 so this looks like a feedback loop to control the output of the LED. C51 is part of the damping of the servo network so I would guess PC1 is the one next to the led.  Adjusting R78 looks to adjust the brightness.

Yes it is a +- supply like some of us posted about

I would check C50s connections again the 470uf in the power supply

Looking at the schematic what makes this a little different?
The start and stop caused by adjusting DC levels
The foot control supplies a changing DC voltage to the 4046

one can build a different +- 7.5VDC supply

[Ronan]

Note when more light hits PC1 it resistance drops moving pin 2 the inverting input of Z10A more positive this reduces the drive to Q5 so this looks like a feedback loop to control the output of the LED. C51 is part of the damping of the servo network so I would guess PC1 is the one next to the led.  Adjusting R78 looks to adjust the brightness.

I agree with that. Also, in a Morley enclosure the tubes are not needed, (its dark in there) and the 2nd LDR (PC1) is a bit overkill these days, but its proly best to reproduce the original circuit and people who don't want to go to the trouble of putting PC1 in the tube with the LED can replace it with a fixed resistor on the pcb. Just thinking out loud. I was thinking an easier build in a Morley shell could use no tubes and function very well.

I would check C50s connections again the 470uf in the power supply.

The original ARP schematic has C50 in the correct position, but there was confusion over the regulator pinouts. Well spotted.

one can build a different +- 7.5VDC supply.

All it needs is 15VDC regulated, or 18VDC unregulated, or around 14VAC, these options could be incorporated into the pcb. If the original circuit is to be kept reasonably intact I think the virtual ground system should also be kept intact, which it can be with the above options. There's many ways to do it, but I'd rather see it kept fairly original vs charge pumps etc

[Govmnt_Lacky]

Looks like the power for the MN3007 is 7.5V instead of 15V in the above schematic, because "ground" is actually sitting at +7.5V. There's an emitter resistor missing on the buffer after the MN3007.

I thought we settled this. Doesn't the circuit run off of +15VDC and 0VDC?

There's many ways to do it, but I'd rather see it kept fairly original vs charge pumps etc

The only problem is that the proposed Morley wah enclosures do not have enough internal OR external room for a power transformer 

I am thinking that this is either going to have to be built with a charge pump circuit OR it will need to be directly fed with REGULATED 15VDC-18VDC depending on the build.

Also, with respects to biasing and incorporating the MN3007.... can we use some of the A/DA mod to leverage?